If possible, please watch at least half the video before commenting about individual carbs, inline 6 single carb and carbed Audi i5. It's all in the video. After making the video I discovered, thanks to commenter "user-ox7lg4tp9s" that the carbed Audi i5 actually has a special intake synchronizing device or similar inside it that makes it work. I haven't yet dug much deeper but info is hard to find. I might try getting my hands on the physical manifold if possible and interesting.
YES, Audi 100 C3- 1.9 WH engine code, also Audi Coupe B2-1,9 WN engine codes, both carb, one is Keihin, one is zenith carb, that might make it easier finding the inlet manifold.
The "device" inside the manifold for a carbureted engine is probably just rational runner routing... but it would be interesting to see, and I'm certainly not buying an obscure old Audi and pulling the carb off to look. 🙂
As an owner of a Volvo 2.5 fivezylinder powered car i enjoy every trip on the Autobahn. The stock exhaust kills most of the sound but you can feel it. Gettig above 4000rpm gives me a smile. Audi RSs are more rude. The Volvo is kinda gentleman in this case..😂So sad that there will be no more fivers on the road in the future.
2:38 This was the solution to straight eights in the 50s that had problems with cylinders 1 and 8 getting so little fuel they barely even fired on a single carb. They just put two carbs on a common manifold, one between cyls 2 and 3, one between 6 and 7. This solved the fuel distribution problems and the engines ran like clockwork.
They got twin carbs because that was the cheapest way to get a bit more power output to keep up with the competition. the reason why straight-8's were phased out in favour of V8's was not any problem with unequal cylinder charge. it was because a V8 is shorter - less issues with crank tortional resonance and wind-up, less weight, and less friction. And no need for a great long ugly bonnet. Pre-war a long bonnet was a marketing advantage as men perceived it as a statement of power, but post war, women buyers considered it ugly and unwieldy. 8 cylinders inline or 16 in V is the limit as far as crankshaft tortional resonance and windup is concerned - that's why you never see longer engines in large industrial engines - except that Caterpillar do make a V20 gas engine (the 3520) - but its power output is limited to the same as their diesel v16 in the same range, so that the long crank is not over-stressed.
It was a lot of information I didn't even know I wanted. As a mechanic since the 80's with various 5 cyl cars, I never thought that there was a reason why there was always injection on the 5 cyl. Thanks for an interesting video.
@@jamesbosworth4191 That must be a special model. They usually had multi port manifold injection. The 67hp model had, unlike the other models, precombustion chamber injection.
@@gsp911 It was the regular production model. Only thing "special" about it was the 5 cylinder engine, but for most it's production run, it was fuel injected.
I had a series of Audi 5 cylinders over the years, and they were all great. The major advantage in my opinion was that they had 6 main bearings, which made them pretty much indestructable. I ran all of my old Audis for several hundred thousand miles each without an engine failure. Of course you need to change the oil, and they would eat power steering pumps every 70K or so, but they were great cars.
I don't know if it was because Audi 5 cylinders with Solex carbs were in my first two cars, but I have never driven anything that sounded as good. By modern standards they were a bit slow, my diesel Jeep has more than twice the power and over three times the torque, but if I could have my Audi 100 Avant GL5S today I would.
I know it's a v6 not a 5, but this also makes the dodge v6 magnums crazy strong. They are V8s with a shortened block. So they have 1 main bearing per cylinder. Whereas the v8 has the same 6 for 8 cylinders. Eventually I am going to build and boost the piss out of one to prove my theory.
I owned 2 '80s VWs with the Audi 5 cyclinder 1.9L, the first was carburettor, both did 200k miles with no major mechanical issues (first needed a new head gasket when I bought it at around 100k), both were great, reliable engines, just a couple of new water pumps. If I could still get hold of one I would be very tempted.
The counter argument to the firing order issue is the same as the runner length issue found in all carburated engines, and was solved. With a mixture of runner pathing and runner diameter adjustment, you can terminate all the runners right under the carb such that the amount of fluid resistance is equal across all runners. This has been the stock design of v8 intakes.
Yes, but a v8 is not an inline 5. You have two opposed banks which changes things. As far as I know the intake manifold of the actual carbed inline 5 has something more complex to compensate and make the engine run acceptably, unfortunately it's impossible for me to find verifiable info on this and I never got one in my hands.
@@d4a but the two banks don't help, and actually make the problem worse because cylinders on opposite banks must be routed to the same carb barrel to work properly. Look at dual plane V8 intake manifolds(where are many illustrations online) to see how (with a normal cross-plane crank) the end cylinders from one bank are combined with the middle cylinders from the other bank to form a four-cylinder group which fires at even intervals. Runners pass over and under each other to achieve this. To understand the dual-plane V8 manifolds for four-barrel carbs, it helps to realize that a 4-barrel is functionally two separate carbs in a shared housing, with each side being a progressive 2-barrel. That's one 2-barrel carb for each group of four cylinders... and those four cylinders are not all in the same bank. The runner from any cylinder can arrive at the plenum with the same path length as the runner for every other cylinder, and in any position relative to the others that is desired.
@@brianb-p6586 Just adding that it's the vacuum signal of a 4 cylinder engine that the V8 carburetor is "seeing". I'm guessing that on the 5 cylinder and "log" manifold the center cylinder would run rich.
Yes, @@peterdarr383 in the V8 4-bbl case the induction system works as two 4-cylinders. The fix to carb issues with a "log" manifold on an inline-5 is to not use a "log" manifold... just as they are not used for properly designed 4's or 6's.
@@d4a mistake/missed the 3-carb/mechanically-injected options the outside use the jag-style-twin-casting-carb and the central/middle odd-child use a single-barrel as your 1st drawings had with a equaliser-pipe for all 5 cylinder's to balance air intake-manifolds ( exhaust manufacturing/manifold is probably okay with being casted-5L-cyl as 1-peace, but L6 in my experience/pro-mechanic 👨🔧🇺🇸 markets cracking in the middle and requires 2 or more parts/castings ) being casting as 1-peace not-3, not covered the mechanical-injection as there's lots of different ways to do it/design on a mopar slant-6 1970 220CI~ or jeep-2006-LWB i still wouldn't use a central 4 barrel ( i own a 2g-charger + 1960-75 hemi-heavily-moded + EFI plus 7-speed-manual-transmission-ect for reference ) as it really wants ( IGT/6-carbs or ) 3-carbs ( and exhaust-L6 side 2X separately-casting 3cylindered murged the 3's-manifold down to one back/final-tailpipe vs my v8 hemi needing duels-tailpipes's but bank is 4-1 collator or 2 into 1 then down to 4-1/main-pipe ) or PFI/EFI the later of the 2 is my general preferences nowadays as im not into carbs anymore really but the video was something different/entertaining to me
Love this video, thanks! I wondered if at any point there was going to be suggestion than an equal-length intake manifold might cure the carb-fed inline 5 issues, but obviously it's pointless when fuel injection does it much better. We've got a Volvo inline 5 in a Ford S-Max and the first thing I noticed about it was how smooth it is and how it will pull cleanly almost from tickover, almost in any gear! Really underrated power delivery.
During WWII there were predictions that Chevy was working on an inline five. It seems to me that the cross section of the runners on a cast manifold could vary enough to even out the flow, although getting the velocity to be equal throughout the RPM range could be tricky. In any case, a snake farm of welded tubing would absolutely work.
The carbureted Audi 5-cylinder actually had a long production life. After making its debut in the C2, the carb 5 continued to be available until 1988's C3 facelift. It was also used in the same 1.9 and 2.1-litre displacements in the B2 VW Passat, with the 2226 cc injected engine eventually also becoming available as that Passat's performance offering. The 1.9 in the Passat was pretty impressive in its day,.and gave up to 85 kW with the Pierburg twin-choke carb.
The carbed engine continued its life only in markets that had little or no emissions control legislation at the time, such as certain countries in Africa, some parts of South-Eastern Europe etc.
A single carburetor for every cilinder works very well and no peak torque at all, you could fix that with changing the bore/stroke ration. My Yamaha XJ650J (4 cilinders) runs very well and from 2500-3000rpm (slightly above idle) pulls away nicely, could go to 9500 if I want to. Maximum torque is at 7200 but you have more than enough between 2500-7000 (I mostly stay below 6000) but the torque rises gradually between tose RPM,s no peak at all! Yes, the coniguration will be bulky, but that should be a bigger problem with motorcycles. I have to remove a lot to remove the carbs an fitting them in place afterwards is a hell of a job. But in the "carburetor" days most car engines were mounted longitudaly with a lot of space left and right of the engine, even the spare wheel was mostly mounted in the engine bay. Yes, 5 inline with carbs is probably not an economical or logical configuration (the history of ICE's is filled with uneconomical and/or unlogic configurations), but it could work. Definitely if you give it a YICS (after the carburetors intakes are linked to eachother before they go to the cilinders, improving emissions) like my '82 Yamaha which I run almost daily these days, if it had "peak torque" it would be a hell of a ride every day to my work (+/75km's a day). The Honda CBX had an inline 6 with 6 carbs.
I was going to say the same. My 1981 Kawa has one carb per cylinder. A bit of a pain but effectively it´s like 4 single cylinder engines connected at the crankshaft. Other than practicality, you could add a fifth cylinder. Honda had a six in line with six carbs. Imagine synching them…
I drive a Honda GL1500 Valkyrie. 6 carbs 6 cyl boxer. Except for gear 4 and 5, the power unfolds smooth. 5th has a clear spike at around 3k rpm (6,5k max).
A long runner between the carb and block will bring the torque back down from the stars a bit especially with a nice smoothe bend. Like a c shaped intake runner from the side of the block up over the top with side drafts over the valve cover. Surely your hood won't mind the extra ventilation!😂
I agree, I also feel like he went over and dismissed this solution too fast. Like basically boiled it down to it not being the most cost effective when that wasn't the point he made in the title. Like a inline 5 is already a niche solution.
I had a VW Passat (B2) with the 1.9 L I5 from 1981 in Germany. That engine had a carburetor and 115 PS. It was a blast running on the Autobahn and listening to the sound of the engine. The car was pretty fast for the time (and you were still able to drive fast). BTW, the 5 cylinder Diesel engine from Mercedes is also a child of Ferdinand Piéch. He worked for Mercedes as a consultant after his time at Porsche and before going to Audi.
@@thegenrlI think he's making valid points. It's not that the issues could not be solved, just that the solutions are too expensive for mass production.
@@getwellgetfitgetlaid3514 solved by making runners equal length. Lots of inline sixes have similar challenge. The reason why 5s were very rare wasn’t carburetion - it was roughness. And lack of need. The advent of transverse fwd larger cars couldn’t fit an I-6.
@gordtulk Which in turn reqires more space and more expensive intake manifold. One of the main benefits of V-engine over inline is the short intake manifold.
I used to have a 1990 Audi 80 Quattro with an inline 5. I got it really cheap because it wouldn't start when it got below 45 degrees F. If anyone has that issue check the fuse box, there were 4 fuses positioned in a manner that made it look like they were spares. The one missing was labeled timing. That car was a beast in the snow.
@@clemenszink9909 It was my favorite car, until I hit a deer and immediately after a weird wind gust blew a portable basketball hoop onto the windshield. Like fate didn't want me to have her.
@@clemenszink9909 I think Audi had its biggest market in Europe back then, I remember the 5-cyl 80 and 100 quattros very well. You could even get a base equipped simple Audi with quattro. I had a friend who putted a V8 in his 80 quattro, the Audi V8 bolts right in. Of course there was some work to make it run, but it was a really fun and quick car.
I used to drive a slant six engine and and thankful you brought it up. It was so funny to see such a large engine with a tiny simple little carburetor.
It's easy to carburete that engine, just change the volume of the runners on the inner ones to reduce the engine side vacuum. Bernouli's formulas are thankfully easy to simulate, especially these days. It can also be tuned by using a shorter or longer tubing whip coming off of a nipple odd of the runner. There were plenty of 5cyl engines in the radial aircraft world and this was how they balanced them. Multiple cylinders pulling from one carb is no big deal as long as its consistent and repeating every 4 cycles.
or just accept that runner length doesnt have to be the same. look at V8 dual plane intakes, or straight 6 intakes. their runners werent the same length. i figured this would be his reason when i clicked on the video, and sure enough, it was.
furthermore, the cross plane v8's also fire adjacent cylinders on the same bank, and have MORE overlap between intake strokes. they seem to do just fine.
VW/Audi had two carburetted inline 5-cyl engines. The 1.9 was made 1980-82 while the 2.1 was made 1978-82. The former were available outside the US on VW Passat/Santana and Audi 80 variants while the latter was available, also outside the US, on the Audi 100 5S variants.
@user-wv1pj6wh4h Yeah, Driving 3 Answers embedded at 6:54 that VW Audi made a Keihin 2bbl carb 1921cm³ in line five from 1981-1983, so it's all klickbate. And that's okay...I clicked!
Excellent presentation. My first Audi was a GT5S with a carbureted 2 litre engine. I did have problems with the carb but they weren’t related to the issues discussed here. I think balancing shafts went a long way to compensating for the roughness. The I5 is a fantastic engine. I had many other fuel injected 5 cylinder Audis since. Beautiful noise!
Very tough engine too. Well maintained they lasted forever. And were tuned to outrageous power levels in the S1 versions of the Quattro. I still drive Audis but I so miss my Ur Quattros.
@@alwoolhouse6255those 70s/80s Audis were fantastically over-engineered mechanically. There is a video on RUclips of a chap who uprated his B2 80 Quattro from its standard 136hp to over 600bhp using the standard running gear.
Amazing, i didn't know that firing order played such a huge part in why some engines can or can't by carburated. I adore the Inline 5 a lot. i got introduced to it by the Audi Quattro(especially the Group B varient]. i love the v10 like sound. a true automotive symphony
They can be carbureted check out Alan milliard hand makes modified motorcycles he has built at least two Kawasaki motorcycles that has turned from triples into five cylinders and both are carbureted
@@malcolmwhite6588one has to speak in generalities in the tagline to get views, sure it’s possible, he even says that Audi made one, but it just runs poorly.
On the automotive side you really should look into the Ram Chargers of the 60's. They were Engineers from Chrysler who raced on weekends and brought that tech to the Masses. They did some interesting stuff with intake pulses and plenums and runners. It's how Chrysler ended up with the Cross Ram on the 413/426 Wedge engines back in the mid 60's.
Have driven 5 cylinder Audis a few times, I really like these engines for their sound, smoothness and relatively good fuel economy (better than most V6 engines anyway). Always been a bit surprised they are not more common as the counter argument to 4 & 6 Cylinders doing the job sufficiently is that you could replace both 4 & 6 cylinder engines with a 5 cylinder (maybe with performance turbo option) for some car models.
It's a Renault engine,early versions had the Renault name cast on firewall of the Mitsubishi FWD platform....which Volvo engineers/ marketing folks, consumers would claim it was Swedish engineered....a complete lie. Engine wave pattern exhaust is annoying,even the Honda 5 pot makes the same annoying exhaust notes.
Or you could say that it is an unnecessary intermediate step without the advantages of either side. Fuel economy OR power. It is an inherently unbalanced system. 6 inline are naturally perfectly balanced. 4 inline or V6 can be perfectly balanced with easy compensation. 5 bangers can not. They need two sets of mass compensators for the same smoothness. You can make enough power for any daily driver car with a 4 cylinder engine. If you want more and you can't squeeze it out a 4 banger: Go a significant step and 6 are your friends! When using I6 you even can recover some added complexity by not needing any mass compensators at all.
@@initialyeet3951V6s aren't boring per se, I daily an inline 5 (09 VW Jetta Wagon) and there's a reason why there are few manufacturers who decided to build inline 5s. they often say "power of a 6 with fuel economy of a 4" but it's mostly the opposite, I have the fuel economy of a V6/inline 6 (I average between 10-11L/100 km) and the power of an inline four (170 hp for 2.5L, and the early models had 150 hp for 2.5L). they sound great and last long, but they're not efficient engines.
This was actually pretty informative! I didn't even realize that gasoline inline 5's were never mass-manufactured before 1976. Also, that SOUND is exactly the reason why I want an older Volvo wagon with a 2.5L B5 engine swap. 🥰
Yet another fantastic video 👍😎 I was the glad owner of an Mercedes 250 from 1985, with an 5 cylinder D engine. A piece of art. Have been driving this car up to 686000 km from 150000 km that it had on the dashboard, when I bought it as used. Not a single problem with that car in this time. The engine was running exactly like the day I bought it.
Amazing car! Have you seen the iconic direct sales letter Mercedes used to sell it? Well worth the time to look that up, it is used ias an example in product marketing education.
Ever hear of a "plenum"? Chrysler 426 Hemi with two four barrel carbs had one. All intake runners feed into the common plenum at the same length (most injected engines have this now). Another variation of this was the "Cross Boss" intake system on the Boss 302. This plenum had a removable top that you could swap out for other carb configurations, 2 four barrels, 1 four barrel, 4 two barrels and even fords rare inline four barrel Autolite. One of the advantages of having a plenum is that intake runner length can be designed to be equal and can also be tuned to the desired length for maximum volumetric efficiency. One of the drawbacks to this design is the tendency for the fuel to "puddle" in the plenum and mess up the fuel to air ratio. Injection does not have this problem because no fuel is in the plenum, just air. Costs are the deciding factor here for the design choices here. It's a lot cheaper to just use an injector with a dry plenum. I guess the moral of the story is "Never say Can't". Especially to an engineer
Fantastic video🎉 Small correction: As far as I know, Audi didn't mean to use the 5 in transversal lay out initially. They just couldn't use an inline 6 in its cars longitudinally, so they went to the 5. Ferdinand Piech is the father of this beauties.
I was wondering about that as I seem to remember all those late 70s and early 80s Audi Quattro, Audi Coupe and Audi 100 were longitudinal. The first transverse Audi 5 cylinder car, must have been a couple of decades later.
but today, I suspect they do everything thinking in the possibility of sharing it with VW cars and such. So I think they think how to fit it in both longidinal and transvesal ones.
Thinking about it, all Audi's were longitudinal engines, and they made their fame with the 5 cyl in performance aplications. I think the modern tranversal configuration was just for nostalgia of the 5's era, and not techinical terms. The TSI's 4cyl would pretty much do this job in the RS's.
Audi introduced the Inline 5 with carburator in Europe in 1978 in the Audi 100 B2 (Type 43). It was the offered as the highest engine option for the Volkswagen Passat B2 (Type 32B) from 1980 till 1983 before it was succeded by the version with fuel injection with the same power output (in 1982 for the Audi with ID "WB", in 1983 for the Passat with "WN") but with different displacement (1921ccm to 2144ccm in the Audi). So the I5 with carburator was pushing the same power output as the later fuel injection versions (85kW/115HP) and the reason for having it was simply cost. The mechanical fuel pump though was directly placed above the spark plugs between cyl 4 and 5 and in case of any leakages... the enigine was notorios for engine burns.
The Audi fuel injected versions in the US had similar power output to the carb versions due to emission regulations, but in Europe the fuel injected versions were 130/136hp.
Few things to add. Audi made a lot of i5 engines with carbs on c2 and c3 platforms in europe. And the power is 85kw on some models. The same as kjets. Other thing - one fot the most popular vag engine produced i think for more than 30yrs is i5 diesel. From audi c3/c4 and mostly vw t4-t5 use the same diesel i5 base. So it has its own big market
Slight correction, Audi mounted the I5 longitudinally, not transversally, but space was the reason - Audi has whole engine in front of the front axle due to concept of their 4wd system.
Small correction,audi did that not because of four wheel drive ...but because it traditionally had that arengment of engine and transmission for front wheel drive ..
6:44 To be fair it's not a multiport fuel injection , it's just a nozzle in each port spraying continuously and fed by a common fuel distributor,it's a complete mechanical system. The injectors do not regulate the injected fuel here ,while mechanical injectors does,and solenoid injectors does regulate. On the 5 cylinders engines with this K jetronic one of the nozzles has a diferent size compared to the others.
I owned a 1990 Mercedes 190D 2.5 5cyl diesel for nearly 15 years, and it was the best diesel engine in a car I have owned to date. Bullet proof design and racking up nearly 240,000 miles in it, leaving my ownership with just over 300,000 miles on the clock and still going strong! Mechanical injection system with no electronics and no turbo also helps a lot with reliability and long life! I have heard taxi drivers getting well over 500k out of these engines.
I agree, I had a straight six with a carburetor. I don’t see a significant difference where the compression stroke occurs, either in 1,2 cylinders or 1,5. Nothing prevents us from solving the issue of filling in the same way as a manifold for a 6-line engine, with the only difference being that instead of the fifth we will connect the pipe to the second cylinder and so on.
Just for clarification, first 5 cyl. diesel was mounted first time in W115, not W123 as seen at the end of your movie. It was OM617 engine, first version was signature OM617910, 3005ccm displacement and 79hp of power. W123 was produced from November 1975. Writing that because it may be a little misleading ;). I had that one in my W115, it was my first car.
45 years ago, I drove cab in an upscale city. The fleet had lots of big Cadillacs and Lincolns, and one lowly Mercedes, 5 cylinder diesel. I loved it and it was speed daemon. Pulling on to freeway, if you weren't careful, in seconds you were 20-30% over the limit, it was so smooth and powerful. Fine car and a great engine.
I have a 2013 Golf with the last of the 2.5l I5 engines from VW. When driven carefully, the mileage is as good as a Pontiac Wave. It makes a very distinctive rumble while we park it. But the fun part is the glorious sound that engine makes when you put your foot into it on the highway. I'm going to miss it when we go electric.
I had both the Audi 100 5S 2,2L and the Passat GL5 1,9L. Both carburetted, and the carb versions were actually pretty common in Europe. As far as I can remember Audi solved the intake issue with a double plane intake manifold. The carb 5 engines were thirsty though..
If it runs with fuel injection, it can run with a carburetor. Since a carb is a draw-through device, as long as there is negative pressure in the intake (intake stroke) it will pull fuel through with the air. It may not be optimal, but it WILL work.
The old heads who actually use science to do carb stuff put stuff like deflectors inside the intake manifolds to get equal flow and distribution. Kind of cringing at some points in this video.
I agree! But that's not quite how carburettors work. It's the air *flow* that causes fuel to be drawn in, not directly pressure or suction. I seriously doubt that the proliferation of fuel injection had anything to do with the production of straight 5s. Probably nobody thought there was a good reason to build one. Nobody builds a straight 7 either.
I would have thought adding some baffles to the intake so the 3rd cylinder didn’t have such a direct shot from the carb would have solved the fuel balance issue.
I think the only real problem with individual carburetors was cost, packaging, a niche use case and not much else. I get that individual carbs are mostly associated with high revving engines, but almost nothing about them makes them inherently unsuitable for low rpm torque. Runner length and runner diameter are the two parameters with which you can tune the power band of individual carburetors, just like with any other type of intake setup. There's lots of motorcycles with individual carburetors that were made for low rpm operation, like Japanese cruiser bikes like the Honda shadow. That bike made peak torque at 3000 rpm and peak power at 5500, which is exactly what you'd expect from a car from the carb era. In fact, those engines make 90% of peak torque at 2000 rpm and pull strong basically from idle. I don't know if you've ever ridden a Honda shadow, but I highly recommend it. It's only of the smoothest and most relaxed 2 cylinder engines you'll ever experience. Tuning 5 individual carbs is hardly the most difficult thing a mechanic has to do to a carburetor engine to maintain it. But I understand no manufacturer would develop an intake setup that's not really applicable to or needed for any other engine in their lineup just to be able to use an i5 over an i4 or i6. Fuel consumption also isn't proportional to the amount of carbs you use in any way. Don't know where you got that from. 5 individual carbs consume no more fuel at the same AFR than a single or dual carb set up would, because nothing makes them inherently less efficient at providing an engine with air and fuel. The R&D cost doesn't really make sense and I think that's about all there was to it back then. From a business standpoint I completely get why only 5 manufacturers have even bothered with i5's even now with EFI being completely trivial and mundane. In a modern car with a displacement of at most 2 liters there's really no reason to consider them. As you said modern engine mounting technology and just general advancements in engine design mean that a 2.0 i4 can somewhat trivially be made to be smooth enough for the driver to barely notice that it's even running other than by the sound. Add a turbo and VVT and making 250 horsepower with a torque band starting from 2000 rpm or even lower is easily accomplished by all engine manufacturers today. This performance level easily covers every european economy car and then some. For the premium segment the i6 makes MUCH more sense as there is enough budget to package the i6 in the design of the car. So great video overall, but I do think some of your arguments against carb i5's were just a tiny little bit far fetched.
If a mechanic can balance a 4 cylinder they can balance a 5 cylinder. There was a time when any half decent motorcycle mechanic could balance the carbs on a multi cylinder bike. Mercury sync gauges and a little bit of effort, job done. @@ngauruhoezodiac3143
Yeah, there was no need for an inline 5. We did (and do to this day) the one carb per cylinder on many engines. The best example is the old vw beetle with its flat4. There we have 1,2 and 4-carb setups. The problem really is that carbs are (were) costly so on most consumer cars (except for sports cars) you'll find single-carb setups. However, it is not a problem to make an inline 5 with two carbs where one is for cylinders 1-3-5 and the second one for cylinders 2-4 (or any other configuration). But why make it? For the average consumer, there are inline 4s, for sports cars inline 6, flat 6, v8 ...
Correct, he is only considering the sequential in line five. A different crank, like a straight six minus a cylinder, would take a single carb fine, but with increased vibration
They actually can be run off a carbie, I know because I used to have a 5 cylinder carbie running off nos. Just need an intake that has equal length and a perfect centered split point in the intake piping to each intake port. All it takes is a mig welder.
Hello, the first inline five was the introduced in 1974, the OM617 in the famous Mercedes /8, engineered by Ferdinand Piech who also did the Audi Quaddro. Almost all 5 cylinder engines were coming from him, as he worked for Porsche,, Audi an VW. Land Rover also has a 5 cylinder diesel engine, the Td5.
For a while Rover was trying to develop 5- and 6-cylinder versions of the 4-cylinder engine in the P6. The 5 had one carburetor feeding 2 cylinders and one feeding 3. Rover managing director William Martin-Hurst stumbled onto the Buick 3.5-liter aluminum V8. It was only slightly heavier than the existing 4 but much more powerful, so the proposed 5 and 6 were abandoned. It’s not clear that the issues you discuss couldn’t have been dealt with. Having said that, fuel injection is a good thing regardless of the number of cylinders.
I was just about to write a similar comment so good minds think alike... Although Rover did initially have fueling issues it was generally considered that this would be overcome as progress was being made, until the V8 was found. Well before 1975 date as per this video!
the carb intake could just be a dual plane. the first and fifth cylinders would be fed by the carb on their own plane and cylinders 2,3,4 can all be in the other plane. this gets rid of adjacent cylinders drawing on the intake at the same time. this intake would still be the same height as a single plane intake shown, but it basically has a divider in the plenum blocking the first and fifth cylinders from interacting with the others. maybe im wrong about this but it seems like it would work
I have a first gen Volvo v70 with 2.4 5cyl engine, it has only 140hp, so it isn't fast by any means, but god damm, the sound of the engine with high rpms put a smile on my face every time. Great video as always, you are making the best videos about cars on yt.
@@solomonjenkins9505 depends on the market it's sold at, usa got other engine options than europe or asia. there was a 144hp 2.0 20V in the 850 wich never got to europe, ecept italy and some other countrys around the globe like iceland for tax reasons. same on 2.0 T-5. thailand, if i remember correctly got a unique natural aspirated 2.3l 20v with 170hp. the 144hp 2.5l 10v was popular in europe and it can just be destroyed if one tries to. yes not fast but a dependable companion.
@@solomonjenkins9505 reliability, I guess. Volvo buyers weren't bothered by a small amount of HP, but they surely wanted an engine that could last. Less power > less stress > less breakdowns.
Two questions: @2:20 Wouldn´t you overcome the problem, if you would differentiate the inner diameters of the manifolds according to their positions? The differential flow and stream resistance would find an equilibrium point. @5:40 Couldn´t you change the firing order in the "inline 5" like e.g. 1,4,2,5,3 so that not two adjacent cylinders would fire ?
Great explanation. While fuel distribution in the manifold my be a contender, it's that firing order having more effect than manifold runner length in the case of a I5. Radial 5 cyl aircraft engines worked well with a single carb, placed at the bottom of the engine between #3 & #4 The carburetor typically place low, between the #3 & #4 cylinders resulted in unequal fuel mixture paths. With a 1-3-5-2-4 firing order, every other cylinder fired in the sequence. Just from personal observation, Packard, Buick, and Pontiac had I8 engines until 1954. And maybe some others that I don't know of. Thanks.drivingforanswers, your content always hits a bullseye every time.
Well, here's the unasked question then... why wouldn't you be able to redesign the firing order of the i5? I'm sure something like 1-3-5-2-4 would fix the breathing issue on the carb at the expense of engine vibration, but if you have a balancing shaft anyway?
As someone who had never worked or seen an i5 engine in real life, I always thought the firing order would be 1 4 2 5 3, thinking that would keep the best of balance and keeping fires away from adjacent cylindres. My logic is, 4 is almost on the opposite side of 1, but that couple would be countered by 2 and 5, then 3 is in the middle of the engine so it wouldn't do that much of a rocking effect. Maybe I'm not an engineer for a good reason. xD
It's a shame the I5 never really made it mainstream in more cars/trucks, it's such a cool sounding engine. That moment when you think you hear a Viper but it's a Chevy colorado, lol
The I5’s used by Audi in the 2.5 (both iron and aluminum blocks, and same for the NA 07K engines) don’t have balance shafts. You should do a video on how they get it to run so smooth and well without balance shafts.
@@CarelessGamer15 I have stiffer drive train mounts in my TT RS for performance benefits, which transmits the vibrations from the engine a bit more than stock. Ironically, I notice the engine most when sitting still idling. Once driving, especially over 3k RPM, it’s very smooth.
The main crank is weighted and balanced, Volvos don't have balance shafts either. Go to Speedkar99 he has great videos of both Audi/VW and Volvo i5 engine teardowns.
@@JustinBoneGotta love that poly bushing life. "I'm not revving because I want to race you, I'm just trying to make my change stop buzzing in the cup holder."
It'd be a more complicated to make, but you could cross over the intake runners for cylinders 2 and 4, then at the carburettor, the 1-2-4-5-3 order becomes 1-4-2-5-3. The runner for the middle cylinder is still a lot shorter than the others, but it wouldn't be much worse than some of the straight-six intakes shown.
6:50 "not smooth and powerful as fuel injected engines" this can be said about any carb engines, they are always not powerful and smooth as EFI and you said yourself carb I5 indeed existed, i dont know why you put this is in the title audi carb I5 doesnt even use some special carb or special intake, although IT COULD use something like equal intake runner
It's just a clickbate title, and it seems many people typed angry/snobby comments without watching and finding out that he did mention audis carbed 5, so I'd say the title was successful, lol.
best engine of all time. so so SO unique. owner of a 90s italian 20valve vvti 5 cylinder turbo here running 400bhp through its front wheels via 6 speed manual.
Great video, d4a! In a reverse-case to your video, the Chrevolet inline 6 of the 50s-80s cannot be used with multi-point fuel injection, it must be carbureted or throttle-body injected. This is because of the siamese intake ports that are shared between cyls 1-2, 3-4, 5-6. With MPFI, charge robbing occurs for cylinders 1 and 6 by their adjacent cylinders due to the firing order. Cylinders 3 and 4 are fine.
I desagree, the chev inline 6 can be converted to use a muit-point fuel injection without any major problem. Its very common here in Brasil on a variaty of configuration, from 1 to 3 carbs and multi-point injection.
Wow such a great video again! Im honestly astonished at the sheer amount of videos that explain concepts about engines that no one has talked about! Thank you for always producing such original content! I hope you know that it is not going unseen, great work and story telling
I had a Volvo 540 with a 5 speed manual and an in-line 5. A bit surprised at first, but solid family car with great mileage. We got rear ended by a pickup truck and only the bumper and rear trunk had to be replaced. Unusual engine but it worked flawlessly.
Exactly, so fuel injection CANNOT correct for bad airflow. Carbs (and throttle body injection) mix fuel air at intake so "correct" mixture (which DOES flow through manifold) will get to each cylinder - just at different volumes. Manifold with these problems using port or direct injection WILL give incorrect AFR to cylinders not getting enough, or to much air. So whole argument of this video is BS.@@threynolds2
@@threynolds2 Not necessarily right, and in fact, mostly wrong. Excluding Direct Injection cases, the majority of multi-port fuel injection has the injectors positioned at the intake manifold, not the engine head.
Minor nit to pick: Volkswagen also made a few I5s over the years, including the EA855 (in use until 2014 in the US market). You mentioned the OM617 by everything but name there at the end, I see. One of the most well-regarded engines of all time.
My sister had a carburettor 5 cylinder VW for several years. It turned out to be very reliable, but the engine nots was a bit odd. It seems one way VW/Audi addressed the fuel distribution issue was to have a heated hemispherical plate with lots of spikes to vaporise the fuel far more than the vacuum effect of the venturi. Unsurprisingly it was known as the "Hedgehog". This helped more fuel to reach #1 & #5 cylinders thus aiding getting the correct fuel/air mix to all cylinders. A downside was the hot gasses in the manifold hurt the maximum power that could be reached. This didn't bother my sister in the slightest, it was smooth, had plenty of torque, and returned good fuel economy, very desirable qualities in a family car which was its main purpose. Of course development of fuel injection and ever tighter emission standards meant it had a limited lifespan. However Audi were good at ironing out design flaws, they worked very hard at making their very nose heavy inline engined fwd cars have acceptable handling.
I have first gen V70 with NA i5. I love the car because of it. The engine has very pleasant character and even as a NA has enough power and torq in lower RPM + those longer gears making it very comfy car on freeways. Its not a rocket, just a very comfy family "van". And the combination of i5 with the image of boxy looking Volvo is something that gets me every single day. Btw, nice video,as always.
Audi had multiple inline 5s with single carburetor, not sure how they dealt with the problem, but I am sure the engines worked fine. Check WN, WH engines with Keihin carb.
The whole carburetor discussion is bunk. V8 and V12 have the same issues. Fuel injection doesn't solve these issues as you still have to balance airflow. But engineering of the fluid dynamics can't be done with hand-waving in a RUclips.
I used to have a inline 5 stick shift truck. This video is spot on. The inline 5 is that tiny little space between fuel efficiency of a 4 cylinder, and power of a six-cylinder. Especially with modern turbo 4 cylinders, there is basically no space for an inline 5.
We owned a 2.5L I5 half-a-lambo-Gallardo engine powered VW Jetta for several years, which was pretty reliable, save for the crappy swashplate AC compressor I replaced. I always thought it sounded better than a V6 when you got on it hard, and while weird, it beat the 4 cylinder option. I always figured the reason we didn't see more was the lack of need, given existing I4, V6, and I6 engines. I had no idea it originated from the overlapped power stroke and sequential firing order. Cool and interesting watch my dude, as always.
Your explanation is phenomenally good. I was going to comment that a straight 6 has a similar intake runner problem to a 5, then you explained about the firing order. You are brilliant!
The original mini dealt with port sharing / charge robbing which I'd expect would be worse because it involved 2 of 4 cylinders rather than 1 of 5. Additionally as the A series is a siamese port there's the ability to rob charge from the port and the manifold not just the manifold as with the 5 cylinder. I think the answer later in the video is more accurate, between straight 4s, straight 6s and v6s all the bases were covered and it just wasn't worth the hassle.
@@d4a so why can't the engine be designed to fire 1-3-5-2-4 so that no adjacent cylinders are firing one right after the other on a carburetorated inline 5 engine .
@@craigalston2208 MAYBE it would make power distribution too much asymmetric along the revolution. MAYBE the weight distribution of pistons would be a problem. But I also want a better answer.
As someone, who drove a Volvo C70 T5 and a V70 TDI from 2011 to 2022, I got goosebumps at 9:59. As much as I enjoy my current car (a '09 Skoda Octavia RS 2.0 TSI), I really miss the sound of an I5 engine.
It would solve most of the issues, but just like performance exhaust manifold, they are expensive, hard to manufacture and overall too complex for mass production
Excellent video as always! Follow up question: what about V10 engines? Don’t they have one carb for each 5 cylinder bank, and therefore suffer from the same issues?
i still own a 1992 2.5 inline 5 T3 vw bus, that was built by VW in South Africa for the SA Market. there is a lot of the carburetor versions here in SA, a lot of people has dropped of the fuel injection system as here is not a lot of mechanics that can still work on the Boshtronic injection systems here. and to be very honest. the guys that go to the carb setup here loves them.
The five cillinder sound is so great... I think another reason for its relative rareness is due to the fact that most countries outside Europe have little specialized people to work on engines such as these, so models for these engines must only be aiming either for european markets or for niche consumers in other markets. In Brazil we had Audi A3s with 5 cillinders, as well as VW Jetta's with the 2.5 that was really fun to drive, and those faced a hard life when service was needed. But obviously the main thing was the Fiat Marea, which was a mass produced car with 5 cillinder engines (including a variation with a turbocompressor) in a very hot weather and, despite all adverse conditions with weather and all the fuel injection issues we had with poor gasoline quality, they worked very well until service was needed. It was then, when mechanics had to change timing belts, to fix the engine after a gasket was damaged or to try and salvage it from Fiat's team huge mistake (they basically said to consumers to only change oil every 20 thousand kilometers, in the 90s, on a weather much hotter than what they designed the engines to run). Most engines never recovered from the first time they were opened here, since trying to sync a different engine was basically witchcraft for mechanical workers at the time. They already went through hell years before, trying to learn how to swap the timing chain on the first 16v DOHC engine of the Fiat Tempra. Fiat was innovating, but it didn't went so well... today, very few of those remain, and those that keep up smooth are almost impossible to spot. But the sound... it is impossible to not be happy when you hear it.
Well, it has been done in custom setups, with equal length runner intakes, but it's not exactly something practical for mass production in the same way equal length runner exhaust manifolds aren't practical for it.
Actually, yes, they can be carbureted; One carburetor per cylinder. The other option is to create a manifold with equal length runner tubes; Just like headers in an exhaust system. So, how do I know? 🙂
I had one in my GMC Canyon, Chevy also had one in the Colorado. I never had any problems with it. A radial engine is sort of like an inline engine with all cylinders on the same place on the crankshaft. That arrangement has equal spaed intakes. They were usually in 5, 7, and 9 cylinder rows..
4 stroke radial engines can only be an odd number of cylinders. Each time a cylinder fires, the next cylinder is on the exhaust stroke. So in 2 revolutions, each cylinder gets to fire. A 2 stroke wouldn't have that problem, and there is at least one example of of a 2 stroke radial with 2 banks of 4 cylinders.
I was told by a racing mechanic of the fifties to seventies who was trained by manufacturers of Weber and SU that while the Weber was able to be adjusted very finely it varied according to height and humidity so in sports car racing across country say Mille Miglia the variable needle in jet had advantage over multiple fixed jets of Weber. As regards the six cylinder this engine took much time to develop originally as it had vibration periods which required a damper on the front of the crank to make them run smoothly. The five cylinder I think was first used with a four cylinder firing and the fifth cylinder as a supercharger to the other four which was a novelty but I cannot now recall who did it - a Continental manufacturer I think. I must admit the two fives I owned were remarkably good engines, both injected as you say one was the Volvo which had prodigious power and the other a VW diesel which would ‘climb the side of a house’ as the saying goes. The power overlap was very good. It was a pity that it was never able to match up to the emission laws and I sold it 18 months ago with sadness.
If possible, please watch at least half the video before commenting about individual carbs, inline 6 single carb and carbed Audi i5. It's all in the video. After making the video I discovered, thanks to commenter "user-ox7lg4tp9s" that the carbed Audi i5 actually has a special intake synchronizing device or similar inside it that makes it work. I haven't yet dug much deeper but info is hard to find. I might try getting my hands on the physical manifold if possible and interesting.
Tottaly unrelated but can you stuck an vaccum to an exhaust to imprve scavenging? For small displacement, and totally real here 😢
YES, Audi 100 C3- 1.9 WH engine code, also Audi Coupe B2-1,9 WN engine codes, both carb, one is Keihin, one is zenith carb, that might make it easier finding the inlet manifold.
The "device" inside the manifold for a carbureted engine is probably just rational runner routing... but it would be interesting to see, and I'm certainly not buying an obscure old Audi and pulling the carb off to look. 🙂
Was just about to correct when i saw this message .being an owner of a audi 500se 2.3 10 valve carburated engine
😀 Thank You, Very Special, Quite Charming Middle Child!! 😃
As an owner of a Volvo 2.5 fivezylinder powered car i enjoy every trip on the Autobahn. The stock exhaust kills most of the sound but you can feel it. Gettig above 4000rpm gives me a smile. Audi RSs are more rude. The Volvo is kinda gentleman in this case..😂So sad that there will be no more fivers on the road in the future.
I had a Volvo S40 T5 2.5l 5 Zylinder Turbo. I still remember it very fondly... I loved that car.
Why would you have a stock exhaust, though?
uhhh, one of my dream is a Volvo C30 T5, it's just so unique
@@negativeindustrial Approved/legal exhausts are expensive in Germany...
@@MrNordsturm
Ah, got it. I always forget because as long as you have a converter it’s legal here in Texas. After 25yo nothing at all is required.
2:38 This was the solution to straight eights in the 50s that had problems with cylinders 1 and 8 getting so little fuel they barely even fired on a single carb. They just put two carbs on a common manifold, one between cyls 2 and 3, one between 6 and 7. This solved the fuel distribution problems and the engines ran like clockwork.
50s? are you sure? most I8s disappeared before WW2
wow
@@igortchelzoff3736Buick straight 8 until 1953
@@igortchelzoff3736Maybe it was only the solution that arrived in the 1950s. The solution to a 30 year old problem 😅
They got twin carbs because that was the cheapest way to get a bit more power output to keep up with the competition. the reason why straight-8's were phased out in favour of V8's was not any problem with unequal cylinder charge. it was because a V8 is shorter - less issues with crank tortional resonance and wind-up, less weight, and less friction. And no need for a great long ugly bonnet. Pre-war a long bonnet was a marketing advantage as men perceived it as a statement of power, but post war, women buyers considered it ugly and unwieldy.
8 cylinders inline or 16 in V is the limit as far as crankshaft tortional resonance and windup is concerned - that's why you never see longer engines in large industrial engines - except that Caterpillar do make a V20 gas engine (the 3520) - but its power output is limited to the same as their diesel v16 in the same range, so that the long crank is not over-stressed.
Awesome D4A content as per usual! I got a 3.5 Colorado I5 I’m modifying, such cool motors and cool sounding 😎
Thank you for your support, I highly appreciate it.
How is this not top comment
It was a lot of information I didn't even know I wanted.
As a mechanic since the 80's with various 5 cyl cars, I never thought that there was a reason why there was always injection on the 5 cyl.
Thanks for an interesting video.
They are not all injected. That is a big lie. The early Audi 5000 did indeed use a carb.
@@jamesbosworth4191 Which Audis have a carburetor and 5 cyl?
Never heard about that.
@@gsp911 The early 5000 had a carburetor.
@@jamesbosworth4191 That must be a special model.
They usually had multi port manifold injection.
The 67hp model had, unlike the other models, precombustion chamber injection.
@@gsp911 It was the regular production model. Only thing "special" about it was the 5 cylinder engine, but for most it's production run, it was fuel injected.
I’m a retired mechanical engineer and I really enjoy this channel immensely. Excellent content and fantastic explanation. Love it ❤
Yeah, this guy expains things so well without ueing jargon or advanced tech language.
@@partymanau Pity half of it is bs...like this vid, in which he himself admits that inline 5s CAN be carbed...lol, your standards must be pretty low
@@TheChzoronzonyou must be fun at parties
@@jkk916 I don't think you know when to apply that sentence properly... but ey, if that makes you feel smart, go ahead buddy ;)
@@TheChzoronzonAll I see from your end is criticism. Where are the videos where you explain how things work, and that is beyond reproach?
I had a series of Audi 5 cylinders over the years, and they were all great. The major advantage in my opinion was that they had 6 main bearings, which made them pretty much indestructable. I ran all of my old Audis for several hundred thousand miles each without an engine failure. Of course you need to change the oil, and they would eat power steering pumps every 70K or so, but they were great cars.
I love the 5 cylinders. They are getting hard to find these days but you can do some epic turbo builds, and they sound so good
I don't know if it was because Audi 5 cylinders with Solex carbs were in my first two cars, but I have never driven anything that sounded as good. By modern standards they were a bit slow, my diesel Jeep has more than twice the power and over three times the torque, but if I could have my Audi 100 Avant GL5S today I would.
I loved the Audi 80, 5000 Turbos of the 1980’s but the turbos and water pumps would keep failing. They were all great to drive but not to own.
I know it's a v6 not a 5, but this also makes the dodge v6 magnums crazy strong. They are V8s with a shortened block. So they have 1 main bearing per cylinder. Whereas the v8 has the same 6 for 8 cylinders. Eventually I am going to build and boost the piss out of one to prove my theory.
I owned 2 '80s VWs with the Audi 5 cyclinder 1.9L, the first was carburettor, both did 200k miles with no major mechanical issues (first needed a new head gasket when I bought it at around 100k), both were great, reliable engines, just a couple of new water pumps. If I could still get hold of one I would be very tempted.
The counter argument to the firing order issue is the same as the runner length issue found in all carburated engines, and was solved. With a mixture of runner pathing and runner diameter adjustment, you can terminate all the runners right under the carb such that the amount of fluid resistance is equal across all runners. This has been the stock design of v8 intakes.
Yes, but a v8 is not an inline 5. You have two opposed banks which changes things. As far as I know the intake manifold of the actual carbed inline 5 has something more complex to compensate and make the engine run acceptably, unfortunately it's impossible for me to find verifiable info on this and I never got one in my hands.
@@d4a but the two banks don't help, and actually make the problem worse because cylinders on opposite banks must be routed to the same carb barrel to work properly. Look at dual plane V8 intake manifolds(where are many illustrations online) to see how (with a normal cross-plane crank) the end cylinders from one bank are combined with the middle cylinders from the other bank to form a four-cylinder group which fires at even intervals. Runners pass over and under each other to achieve this.
To understand the dual-plane V8 manifolds for four-barrel carbs, it helps to realize that a 4-barrel is functionally two separate carbs in a shared housing, with each side being a progressive 2-barrel. That's one 2-barrel carb for each group of four cylinders... and those four cylinders are not all in the same bank.
The runner from any cylinder can arrive at the plenum with the same path length as the runner for every other cylinder, and in any position relative to the others that is desired.
@@brianb-p6586 Just adding that it's the vacuum signal of a 4 cylinder engine that the V8 carburetor is "seeing".
I'm guessing that on the 5 cylinder and "log" manifold the center cylinder would run rich.
Yes, @@peterdarr383 in the V8 4-bbl case the induction system works as two 4-cylinders.
The fix to carb issues with a "log" manifold on an inline-5 is to not use a "log" manifold... just as they are not used for properly designed 4's or 6's.
@@d4a mistake/missed the 3-carb/mechanically-injected options the outside use the jag-style-twin-casting-carb and the central/middle odd-child use a single-barrel as your 1st drawings had with a equaliser-pipe for all 5 cylinder's to balance air intake-manifolds ( exhaust manufacturing/manifold is probably okay with being casted-5L-cyl as 1-peace, but L6 in my experience/pro-mechanic 👨🔧🇺🇸 markets cracking in the middle and requires 2 or more parts/castings ) being casting as 1-peace not-3, not covered the mechanical-injection as there's lots of different ways to do it/design
on a mopar slant-6 1970 220CI~ or jeep-2006-LWB i still wouldn't use a central 4 barrel ( i own a 2g-charger + 1960-75 hemi-heavily-moded + EFI plus 7-speed-manual-transmission-ect for reference ) as it really wants ( IGT/6-carbs or ) 3-carbs ( and exhaust-L6 side 2X separately-casting 3cylindered murged the 3's-manifold down to one back/final-tailpipe vs my v8 hemi needing duels-tailpipes's but bank is 4-1 collator or 2 into 1 then down to 4-1/main-pipe ) or PFI/EFI the later of the 2 is my general preferences nowadays as im not into carbs anymore really but the video was something different/entertaining to me
Love this video, thanks! I wondered if at any point there was going to be suggestion than an equal-length intake manifold might cure the carb-fed inline 5 issues, but obviously it's pointless when fuel injection does it much better. We've got a Volvo inline 5 in a Ford S-Max and the first thing I noticed about it was how smooth it is and how it will pull cleanly almost from tickover, almost in any gear! Really underrated power delivery.
During WWII there were predictions that Chevy was working on an inline five.
It seems to me that the cross section of the runners on a cast manifold could vary enough to even out the flow, although getting the velocity to be equal throughout the RPM range could be tricky.
In any case, a snake farm of welded tubing would absolutely work.
That was my thought. Similar shape to a equal length exhaust manifold
The carbureted Audi 5-cylinder actually had a long production life. After making its debut in the C2, the carb 5 continued to be available until 1988's C3 facelift. It was also used in the same 1.9 and 2.1-litre displacements in the B2 VW Passat, with the 2226 cc injected engine eventually also becoming available as that Passat's performance offering. The 1.9 in the Passat was pretty impressive in its day,.and gave up to 85 kW with the Pierburg twin-choke carb.
Exactly
Correct, I did my apprenticeship at VW, we had a Passat 5 cylinder with a carb as out test vehicle tolerance on, carb was a Pierburg 2B5
The carbed engine continued its life only in markets that had little or no emissions control legislation at the time, such as certain countries in Africa, some parts of South-Eastern Europe etc.
Yep, but that didn`t mean it couldn`t be carbed @@d4a
Yes. My dad had a 1980s B2 VW Passat with a carbureted 1.9 litre I5 in the UK. It was a good car.
A single carburetor for every cilinder works very well and no peak torque at all, you could fix that with changing the bore/stroke ration. My Yamaha XJ650J (4 cilinders) runs very well and from 2500-3000rpm (slightly above idle) pulls away nicely, could go to 9500 if I want to. Maximum torque is at 7200 but you have more than enough between 2500-7000 (I mostly stay below 6000) but the torque rises gradually between tose RPM,s no peak at all! Yes, the coniguration will be bulky, but that should be a bigger problem with motorcycles. I have to remove a lot to remove the carbs an fitting them in place afterwards is a hell of a job. But in the "carburetor" days most car engines were mounted longitudaly with a lot of space left and right of the engine, even the spare wheel was mostly mounted in the engine bay. Yes, 5 inline with carbs is probably not an economical or logical configuration (the history of ICE's is filled with uneconomical and/or unlogic configurations), but it could work. Definitely if you give it a YICS (after the carburetors intakes are linked to eachother before they go to the cilinders, improving emissions) like my '82 Yamaha which I run almost daily these days, if it had "peak torque" it would be a hell of a ride every day to my work (+/75km's a day). The Honda CBX had an inline 6 with 6 carbs.
I was going to say the same. My 1981 Kawa has one carb per cylinder. A bit of a pain but effectively it´s like 4 single cylinder engines connected at the crankshaft. Other than practicality, you could add a fifth cylinder. Honda had a six in line with six carbs. Imagine synching them…
I drive a Honda GL1500 Valkyrie. 6 carbs 6 cyl boxer. Except for gear 4 and 5, the power unfolds smooth. 5th has a clear spike at around 3k rpm (6,5k max).
A long runner between the carb and block will bring the torque back down from the stars a bit especially with a nice smoothe bend. Like a c shaped intake runner from the side of the block up over the top with side drafts over the valve cover. Surely your hood won't mind the extra ventilation!😂
I agree, I also feel like he went over and dismissed this solution too fast. Like basically boiled it down to it not being the most cost effective when that wasn't the point he made in the title. Like a inline 5 is already a niche solution.
I had a VW Passat (B2) with the 1.9 L I5 from 1981 in Germany. That engine had a carburetor and 115 PS. It was a blast running on the Autobahn and listening to the sound of the engine. The car was pretty fast for the time (and you were still able to drive fast). BTW, the 5 cylinder Diesel engine from Mercedes is also a child of Ferdinand Piéch. He worked for Mercedes as a consultant after his time at Porsche and before going to Audi.
exactly, the guy is putting out misinformation on technical information as well as the history.
@@thegenrlI think he's making valid points. It's not that the issues could not be solved, just that the solutions are too expensive for mass production.
@@getwellgetfitgetlaid3514 solved by making runners equal length. Lots of inline sixes have similar challenge.
The reason why 5s were very rare wasn’t carburetion - it was roughness. And lack of need. The advent of transverse fwd larger cars couldn’t fit an I-6.
@gordtulk Which in turn reqires more space and more expensive intake manifold. One of the main benefits of V-engine over inline is the short intake manifold.
I used to have a 1990 Audi 80 Quattro with an inline 5. I got it really cheap because it wouldn't start when it got below 45 degrees F. If anyone has that issue check the fuse box, there were 4 fuses positioned in a manner that made it look like they were spares. The one missing was labeled timing. That car was a beast in the snow.
jesus christ i like the 80. but nearly none available with the 5cyl
@@clemenszink9909 It was my favorite car, until I hit a deer and immediately after a weird wind gust blew a portable basketball hoop onto the windshield. Like fate didn't want me to have her.
@@wesKEVQJ thats sad to hear. i really like the shape of the coupe!
@@clemenszink9909 I think Audi had its biggest market in Europe back then, I remember the 5-cyl 80 and 100 quattros very well. You could even get a base equipped simple Audi with quattro. I had a friend who putted a V8 in his 80 quattro, the Audi V8 bolts right in. Of course there was some work to make it run, but it was a really fun and quick car.
I used to drive a slant six engine and and thankful you brought it up. It was so funny to see such a large engine with a tiny simple little carburetor.
Fantastic video. The best internal combustion channel on the internet imo.
It's easy to carburete that engine, just change the volume of the runners on the inner ones to reduce the engine side vacuum. Bernouli's formulas are thankfully easy to simulate, especially these days. It can also be tuned by using a shorter or longer tubing whip coming off of a nipple odd of the runner. There were plenty of 5cyl engines in the radial aircraft world and this was how they balanced them. Multiple cylinders pulling from one carb is no big deal as long as its consistent and repeating every 4 cycles.
Yea or put five carbs on it😂😂
I agree.
possibly ; exhaust pressure - dependant intake adjust
or just accept that runner length doesnt have to be the same. look at V8 dual plane intakes, or straight 6 intakes. their runners werent the same length. i figured this would be his reason when i clicked on the video, and sure enough, it was.
furthermore, the cross plane v8's also fire adjacent cylinders on the same bank, and have MORE overlap between intake strokes. they seem to do just fine.
VW/Audi had two carburetted inline 5-cyl engines. The 1.9 was made 1980-82 while the 2.1 was made 1978-82. The former were available outside the US on VW Passat/Santana and Audi 80 variants while the latter was available, also outside the US, on the Audi 100 5S variants.
Yes, you are right. Here in my country the 5 cyl VW Passat and Santana and also some Audi 80 ran with a so sophisticated Pierburg carb.
And Audi used the Honda Kehin carb to do it. Not impressed...
@user-wv1pj6wh4h Yeah, Driving 3 Answers embedded at 6:54 that VW Audi made a Keihin 2bbl carb 1921cm³ in line five from 1981-1983, so it's all klickbate. And that's okay...I clicked!
@@deanstevenson6527 And VW used the Pierburg 2B5
I've got a Jetta with the 2.5l I5, has 213k miles on it now. Great motor and it's very smooth, especially at idle. It loves to rev too.
Does it have 1 or 2 carburetors?
Wow. I was only going to watch part of this, but I had to finish. Fascinating! Great use of the graphics. Thank you.
Thanks
Thank you, much appreciated
Excellent presentation. My first Audi was a GT5S with a carbureted 2 litre engine. I did have problems with the carb but they weren’t related to the issues discussed here. I think balancing shafts went a long way to compensating for the roughness. The I5 is a fantastic engine. I had many other fuel injected 5 cylinder Audis since. Beautiful noise!
Diesel I5s were pretty reliable too.
Very tough engine too. Well maintained they lasted forever. And were tuned to outrageous power levels in the S1 versions of the Quattro. I still drive Audis but I so miss my Ur Quattros.
@@alwoolhouse6255those 70s/80s Audis were fantastically over-engineered mechanically. There is a video on RUclips of a chap who uprated his B2 80 Quattro from its standard 136hp to over 600bhp using the standard running gear.
Amazing, i didn't know that firing order played such a huge part in why some engines can or can't by carburated. I adore the Inline 5 a lot. i got introduced to it by the Audi Quattro(especially the Group B varient]. i love the v10 like sound. a true automotive symphony
They can be carbureted check out Alan milliard hand makes modified motorcycles he has built at least two Kawasaki motorcycles that has turned from triples into five cylinders and both are carbureted
@@malcolmwhite6588 he uses one carb/cylinder, right? And that solves the issue.
@@malcolmwhite6588one has to speak in generalities in the tagline to get views, sure it’s possible, he even says that Audi made one, but it just runs poorly.
On the automotive side you really should look into the Ram Chargers of the 60's. They were Engineers from Chrysler who raced on weekends and brought that tech to the Masses. They did some interesting stuff with intake pulses and plenums and runners. It's how Chrysler ended up with the Cross Ram on the 413/426 Wedge engines back in the mid 60's.
Great video, thank you for taking the time to post it
My dad had Audi 100CD diesel and the car sounded like a sowing machine, beautiful sound and smooth driving, drove 1200km on 1 tank of gas.
Have driven 5 cylinder Audis a few times, I really like these engines for their sound, smoothness and relatively good fuel economy (better than most V6 engines anyway). Always been a bit surprised they are not more common as the counter argument to 4 & 6 Cylinders doing the job sufficiently is that you could replace both 4 & 6 cylinder engines with a 5 cylinder (maybe with performance turbo option) for some car models.
Yeah, it’s a shame we’re now stuck with boring I4s and V6s with very very few 5cyl left.
It's a Renault engine,early versions had the Renault name cast on firewall of the Mitsubishi FWD platform....which Volvo engineers/ marketing folks, consumers would claim it was Swedish engineered....a complete lie. Engine wave pattern exhaust is annoying,even the Honda 5 pot makes the same annoying exhaust notes.
Or you could say that it is an unnecessary intermediate step without the advantages of either side. Fuel economy OR power. It is an inherently unbalanced system. 6 inline are naturally perfectly balanced. 4 inline or V6 can be perfectly balanced with easy compensation. 5 bangers can not. They need two sets of mass compensators for the same smoothness.
You can make enough power for any daily driver car with a 4 cylinder engine. If you want more and you can't squeeze it out a 4 banger: Go a significant step and 6 are your friends! When using I6 you even can recover some added complexity by not needing any mass compensators at all.
@@initialyeet3951V6s aren't boring per se, I daily an inline 5 (09 VW Jetta Wagon) and there's a reason why there are few manufacturers who decided to build inline 5s. they often say "power of a 6 with fuel economy of a 4" but it's mostly the opposite, I have the fuel economy of a V6/inline 6 (I average between 10-11L/100 km) and the power of an inline four (170 hp for 2.5L, and the early models had 150 hp for 2.5L). they sound great and last long, but they're not efficient engines.
This was actually pretty informative! I didn't even realize that gasoline inline 5's were never mass-manufactured before 1976. Also, that SOUND is exactly the reason why I want an older Volvo wagon with a 2.5L B5 engine swap. 🥰
I like the graph where the I5 fits. It’s a small niche and explains why it’s wasn’t mass produced.
Yet another fantastic video 👍😎
I was the glad owner of an Mercedes 250 from 1985, with an 5 cylinder D engine. A piece of art. Have been driving this car up to 686000 km from 150000 km that it had on the dashboard, when I bought it as used. Not a single problem with that car in this time. The engine was running exactly like the day I bought it.
Amazing car!
Have you seen the iconic direct sales letter Mercedes used to sell it?
Well worth the time to look that up, it is used ias an example in product marketing education.
You must have really kept up on the maintenance. Timing chain replacement, injectors serviced, etc.
I used to own an Acura Vigor so I'm "in the know" about these engines. Probably not many know about the Acura Vigor, but I do.
Ever hear of a "plenum"? Chrysler 426 Hemi with two four barrel carbs had one. All intake runners feed into the common plenum at the same length (most injected engines have this now). Another variation of this was the "Cross Boss" intake system on the Boss 302. This plenum had a removable top that you could swap out for other carb configurations, 2 four barrels, 1 four barrel, 4 two barrels and even fords rare inline four barrel Autolite. One of the advantages of having a plenum is that intake runner length can be designed to be equal and can also be tuned to the desired length for maximum volumetric efficiency. One of the drawbacks to this design is the tendency for the fuel to "puddle" in the plenum and mess up the fuel to air ratio. Injection does not have this problem because no fuel is in the plenum, just air. Costs are the deciding factor here for the design choices here. It's a lot cheaper to just use an injector with a dry plenum. I guess the moral of the story is "Never say Can't". Especially to an engineer
Fantastic video🎉
Small correction: As far as I know, Audi didn't mean to use the 5 in transversal lay out initially. They just couldn't use an inline 6 in its cars longitudinally, so they went to the 5.
Ferdinand Piech is the father of this beauties.
I was wondering about that as I seem to remember all those late 70s and early 80s Audi Quattro, Audi Coupe and Audi 100 were longitudinal. The first transverse Audi 5 cylinder car, must have been a couple of decades later.
but today, I suspect they do everything thinking in the possibility of sharing it with VW cars and such. So I think they think how to fit it in both longidinal and transvesal ones.
Thinking about it, all Audi's were longitudinal engines, and they made their fame with the 5 cyl in performance aplications. I think the modern tranversal configuration was just for nostalgia of the 5's era, and not techinical terms. The TSI's 4cyl would pretty much do this job in the RS's.
@@alexjenner1108 My first car was a 198x Audi 80 Quattro 5cyl. I loved that car.
@@alexjenner1108and Audi 200
I owned a 115 hp 5 cylinder VW Passat with a two barrel carburator. Great engine.
My dad had a 1985 Passat 5 cylinder. I think it was a Pierburg twin barrel carb that it used.
Audi introduced the Inline 5 with carburator in Europe in 1978 in the Audi 100 B2 (Type 43). It was the offered as the highest engine option for the Volkswagen Passat B2 (Type 32B) from 1980 till 1983 before it was succeded by the version with fuel injection with the same power output (in 1982 for the Audi with ID "WB", in 1983 for the Passat with "WN") but with different displacement (1921ccm to 2144ccm in the Audi). So the I5 with carburator was pushing the same power output as the later fuel injection versions (85kW/115HP) and the reason for having it was simply cost. The mechanical fuel pump though was directly placed above the spark plugs between cyl 4 and 5 and in case of any leakages... the enigine was notorios for engine burns.
The Audi fuel injected versions in the US had similar power output to the carb versions due to emission regulations, but in Europe the fuel injected versions were 130/136hp.
I've got a v10 audi, it kinda sounds like two inline 5:s together. Love it
Few things to add. Audi made a lot of i5 engines with carbs on c2 and c3 platforms in europe. And the power is 85kw on some models. The same as kjets.
Other thing - one fot the most popular vag engine produced i think for more than 30yrs is i5 diesel. From audi c3/c4 and mostly vw t4-t5 use the same diesel i5 base. So it has its own big market
Slight correction, Audi mounted the I5 longitudinally, not transversally, but space was the reason - Audi has whole engine in front of the front axle due to concept of their 4wd system.
Small correction,audi did that not because of four wheel drive ...but because it traditionally had that arengment of engine and transmission for front wheel drive ..
@@vasopel true that, 4wd came after the I5.
@@Papinak2 ;-)
…and awful handling.
@@808bigisland - If you don't know how to drive.
The 5 cylinder VW Jetta has a beautiful exhaust note when she's running down the highway. The cold air intake system just compliments the music.
Stock 07k engines roar..... on a cold day not bothered by heat soak, the intake sound wakes up the neighbors.
6:44 To be fair it's not a multiport fuel injection , it's just a nozzle in each port spraying continuously and fed by a common fuel distributor,it's a complete mechanical system.
The injectors do not regulate the injected fuel here ,while mechanical injectors does,and solenoid injectors does regulate.
On the 5 cylinders engines with this K jetronic one of the nozzles has a diferent size compared to the others.
I owned a 1990 Mercedes 190D 2.5 5cyl diesel for nearly 15 years, and it was the best diesel engine in a car I have owned to date. Bullet proof design and racking up nearly 240,000 miles in it, leaving my ownership with just over 300,000 miles on the clock and still going strong! Mechanical injection system with no electronics and no turbo also helps a lot with reliability and long life! I have heard taxi drivers getting well over 500k out of these engines.
Individual intake tubes of equal length should solve a lot of these issues.
Same concept as long used with exhaust header tubes.
Was thinking the same thing.
Could the fire order be changed in inline 5?
Yes, but I think the aim is always to reduce the length of the intake headers, to improve power at high rpm
@@davidrikelv9529 of course, but it will be even more shaky
I agree, I had a straight six with a carburetor. I don’t see a significant difference where the compression stroke occurs, either in 1,2 cylinders or 1,5. Nothing prevents us from solving the issue of filling in the same way as a manifold for a 6-line engine, with the only difference being that instead of the fifth we will connect the pipe to the second cylinder and so on.
Just for clarification, first 5 cyl. diesel was mounted first time in W115, not W123 as seen at the end of your movie. It was OM617 engine, first version was signature OM617910, 3005ccm displacement and 79hp of power. W123 was produced from November 1975. Writing that because it may be a little misleading ;). I had that one in my W115, it was my first car.
It was fuel injected.
@@jamesgeorge4874 Yes, it was diesel.
Lancia built an inline 5 diesel in 1938, for a military truck.
The Mercedes engines are legendary, though.
240D 3.0❤my first car too
@@petrhencl8822240 should have been a 2.4l 4 cylinder.
45 years ago, I drove cab in an upscale city. The fleet had lots of big Cadillacs and Lincolns, and one lowly Mercedes, 5 cylinder diesel. I loved it and it was speed daemon. Pulling on to freeway, if you weren't careful, in seconds you were 20-30% over the limit, it was so smooth and powerful. Fine car and a great engine.
Diesels are fuel injected and very torquey
I have a 2013 Golf with the last of the 2.5l I5 engines from VW. When driven carefully, the mileage is as good as a Pontiac Wave. It makes a very distinctive rumble while we park it. But the fun part is the glorious sound that engine makes when you put your foot into it on the highway. I'm going to miss it when we go electric.
I had both the Audi 100 5S 2,2L and the Passat GL5 1,9L. Both carburetted, and the carb versions were actually pretty common in Europe. As far as I can remember Audi solved the intake issue with a double plane intake manifold. The carb 5 engines were thirsty though..
If it runs with fuel injection, it can run with a carburetor. Since a carb is a draw-through device, as long as there is negative pressure in the intake (intake stroke) it will pull fuel through with the air. It may not be optimal, but it WILL work.
The old heads who actually use science to do carb stuff put stuff like deflectors inside the intake manifolds to get equal flow and distribution. Kind of cringing at some points in this video.
I agree! But that's not quite how carburettors work. It's the air *flow* that causes fuel to be drawn in, not directly pressure or suction.
I seriously doubt that the proliferation of fuel injection had anything to do with the production of straight 5s. Probably nobody thought there was a good reason to build one. Nobody builds a straight 7 either.
I would have thought adding some baffles to the intake so the 3rd cylinder didn’t have such a direct shot from the carb would have solved the fuel balance issue.
I think the only real problem with individual carburetors was cost, packaging, a niche use case and not much else. I get that individual carbs are mostly associated with high revving engines, but almost nothing about them makes them inherently unsuitable for low rpm torque. Runner length and runner diameter are the two parameters with which you can tune the power band of individual carburetors, just like with any other type of intake setup. There's lots of motorcycles with individual carburetors that were made for low rpm operation, like Japanese cruiser bikes like the Honda shadow. That bike made peak torque at 3000 rpm and peak power at 5500, which is exactly what you'd expect from a car from the carb era. In fact, those engines make 90% of peak torque at 2000 rpm and pull strong basically from idle. I don't know if you've ever ridden a Honda shadow, but I highly recommend it. It's only of the smoothest and most relaxed 2 cylinder engines you'll ever experience. Tuning 5 individual carbs is hardly the most difficult thing a mechanic has to do to a carburetor engine to maintain it. But I understand no manufacturer would develop an intake setup that's not really applicable to or needed for any other engine in their lineup just to be able to use an i5 over an i4 or i6. Fuel consumption also isn't proportional to the amount of carbs you use in any way. Don't know where you got that from. 5 individual carbs consume no more fuel at the same AFR than a single or dual carb set up would, because nothing makes them inherently less efficient at providing an engine with air and fuel. The R&D cost doesn't really make sense and I think that's about all there was to it back then.
From a business standpoint I completely get why only 5 manufacturers have even bothered with i5's even now with EFI being completely trivial and mundane. In a modern car with a displacement of at most 2 liters there's really no reason to consider them. As you said modern engine mounting technology and just general advancements in engine design mean that a 2.0 i4 can somewhat trivially be made to be smooth enough for the driver to barely notice that it's even running other than by the sound. Add a turbo and VVT and making 250 horsepower with a torque band starting from 2000 rpm or even lower is easily accomplished by all engine manufacturers today. This performance level easily covers every european economy car and then some. For the premium segment the i6 makes MUCH more sense as there is enough budget to package the i6 in the design of the car.
So great video overall, but I do think some of your arguments against carb i5's were just a tiny little bit far fetched.
It is also very tricky to adjust each carburettor individually.
If a mechanic can balance a 4 cylinder they can balance a 5 cylinder. There was a time when any half decent motorcycle mechanic could balance the carbs on a multi cylinder bike. Mercury sync gauges and a little bit of effort, job done. @@ngauruhoezodiac3143
Yeah, there was no need for an inline 5. We did (and do to this day) the one carb per cylinder on many engines. The best example is the old vw beetle with its flat4. There we have 1,2 and 4-carb setups. The problem really is that carbs are (were) costly so on most consumer cars (except for sports cars) you'll find single-carb setups. However, it is not a problem to make an inline 5 with two carbs where one is for cylinders 1-3-5 and the second one for cylinders 2-4 (or any other configuration). But why make it? For the average consumer, there are inline 4s, for sports cars inline 6, flat 6, v8 ...
Correct, he is only considering the sequential in line five. A different crank, like a straight six minus a cylinder, would take a single carb fine, but with increased vibration
Jaguar V12 had six double barrel carbs. Alfa twincam 2 double barrel.. adjusting. Easy, just have a few tubes of mercury.
They actually can be run off a carbie, I know because I used to have a 5 cylinder carbie running off nos. Just need an intake that has equal length and a perfect centered split point in the intake piping to each intake port. All it takes is a mig welder.
So fuel injection is like low carb diet except it’s a no carb diet. I learned something today.
Hello, the first inline five was the introduced in 1974, the OM617 in the famous Mercedes /8, engineered by Ferdinand Piech who also did the Audi Quaddro. Almost all 5 cylinder engines were coming from him, as he worked for Porsche,, Audi an VW.
Land Rover also has a 5 cylinder diesel engine, the Td5.
I’ve worked on many 5 cylinder carbureted marine engines. They had 3 carbs.
Hello
It was gasoline or diesel engine ?
Two stroke gasoline. Force 150 outboard.
@@felixstevenin6589 Diesels don't have carbs :)
For a while Rover was trying to develop 5- and 6-cylinder versions of the 4-cylinder engine in the P6. The 5 had one carburetor feeding 2 cylinders and one feeding 3.
Rover managing director William Martin-Hurst stumbled onto the Buick 3.5-liter aluminum V8. It was only slightly heavier than the existing 4 but much more powerful, so the proposed 5 and 6 were abandoned. It’s not clear that the issues you discuss couldn’t have been dealt with.
Having said that, fuel injection is a good thing regardless of the number of cylinders.
I was just about to write a similar comment so good minds think alike... Although Rover did initially have fueling issues it was generally considered that this would be overcome as progress was being made, until the V8 was found. Well before 1975 date as per this video!
Rover built a inline 5 in 1963, it had 3 carburettors, 2 big and 1 small. The project was scrapped due to the purchase of the Buick 215
decent chunk of useless knowledge :D
the carb intake could just be a dual plane. the first and fifth cylinders would be fed by the carb on their own plane and cylinders 2,3,4 can all be in the other plane. this gets rid of adjacent cylinders drawing on the intake at the same time. this intake would still be the same height as a single plane intake shown, but it basically has a divider in the plenum blocking the first and fifth cylinders from interacting with the others.
maybe im wrong about this but it seems like it would work
i like that you stepped back and looked at it from multiple perspectives and angles
the rs3 is such a cool car, audi's rs division has evolved so much in the last decade
I have a first gen Volvo v70 with 2.4 5cyl engine, it has only 140hp, so it isn't fast by any means, but god damm, the sound of the engine with high rpms put a smile on my face every time.
Great video as always, you are making the best videos about cars on yt.
not sure why my 94 850 has 170 hp and your newer vehicle has 140 0.o
@@solomonjenkins9505 depends on the market it's sold at, usa got other engine options than europe or asia. there was a 144hp 2.0 20V in the 850 wich never got to europe, ecept italy and some other countrys around the globe like iceland for tax reasons. same on 2.0 T-5. thailand, if i remember correctly got a unique natural aspirated 2.3l 20v with 170hp. the 144hp 2.5l 10v was popular in europe and it can just be destroyed if one tries to. yes not fast but a dependable companion.
@@solomonjenkins9505They were deliberately tuned down by Volvo.
@@SBT300 for what purpose?
@@solomonjenkins9505 reliability, I guess. Volvo buyers weren't bothered by a small amount of HP, but they surely wanted an engine that could last. Less power > less stress > less breakdowns.
Two questions:
@2:20 Wouldn´t you overcome the problem, if you would differentiate the inner diameters of the manifolds according to their positions? The differential flow and stream resistance would find an equilibrium point.
@5:40 Couldn´t you change the firing order in the "inline 5" like e.g. 1,4,2,5,3 so that not two adjacent cylinders would fire ?
First part - you would mess up the flow that way, as it's limited by the diameter.
Second part - definitely yes.
Great explanation. While fuel distribution in the manifold my be a contender, it's that firing order having more effect than manifold runner length in the case of a I5. Radial 5 cyl aircraft engines worked well with a single carb, placed at the bottom of the engine between #3 & #4 The carburetor typically place low, between the #3 & #4 cylinders resulted in unequal fuel mixture paths. With a 1-3-5-2-4 firing order, every other cylinder fired in the sequence. Just from personal observation, Packard, Buick, and Pontiac had I8 engines until 1954. And maybe some others that I don't know of. Thanks.drivingforanswers, your content always hits a bullseye every time.
Had my 20v Fiat Coupe Turbo for 20yrs...the engine's power delivery and the sound is intoxicating.
Well, here's the unasked question then... why wouldn't you be able to redesign the firing order of the i5? I'm sure something like 1-3-5-2-4 would fix the breathing issue on the carb at the expense of engine vibration, but if you have a balancing shaft anyway?
As someone who had never worked or seen an i5 engine in real life, I always thought the firing order would be 1 4 2 5 3, thinking that would keep the best of balance and keeping fires away from adjacent cylindres. My logic is, 4 is almost on the opposite side of 1, but that couple would be countered by 2 and 5, then 3 is in the middle of the engine so it wouldn't do that much of a rocking effect.
Maybe I'm not an engineer for a good reason. xD
@@rata536 Exactly! It's like when tightening lug nuts; you skip every other lug until they're all snug.
It's a shame the I5 never really made it mainstream in more cars/trucks, it's such a cool sounding engine. That moment when you think you hear a Viper but it's a Chevy colorado, lol
So it's not just me who thought it sounded like a V-10 lol
I think it was maintream because so many volvos had it. Maybe they are not so common outside europe.
The I5’s used by Audi in the 2.5 (both iron and aluminum blocks, and same for the NA 07K engines) don’t have balance shafts. You should do a video on how they get it to run so smooth and well without balance shafts.
Sometimes I forget the car is running 🤣
@@CarelessGamer15 I have stiffer drive train mounts in my TT RS for performance benefits, which transmits the vibrations from the engine a bit more than stock. Ironically, I notice the engine most when sitting still idling. Once driving, especially over 3k RPM, it’s very smooth.
The main crank is weighted and balanced, Volvos don't have balance shafts either. Go to Speedkar99 he has great videos of both Audi/VW and Volvo i5 engine teardowns.
@@JustinBoneGotta love that poly bushing life. "I'm not revving because I want to race you, I'm just trying to make my change stop buzzing in the cup holder."
I am pretty sure the Volvo white block I5 engines do not have balance shaft(s) either.
Best video I have ever seen. No bullshit music, interesting information and whispering.
My 1993 VW Eurovan camper has a 2.5l inline 5. Great engine well over 200k miles and running strong.
It'd be a more complicated to make, but you could cross over the intake runners for cylinders 2 and 4, then at the carburettor, the 1-2-4-5-3 order becomes 1-4-2-5-3. The runner for the middle cylinder is still a lot shorter than the others, but it wouldn't be much worse than some of the straight-six intakes shown.
Would not work. The crankshaft would be unstable
1-3-5-2-4?
@@NikolaTesla-nb5nm he specified that change *the intake runners* (snake them around the third) but do not change the firing order.
The VW 2.5 TDI is one of the most reliable engines out there. And it sounds good :P
6:50 "not smooth and powerful as fuel injected engines"
this can be said about any carb engines, they are always not powerful and smooth as EFI
and you said yourself carb I5 indeed existed, i dont know why you put this is in the title
audi carb I5 doesnt even use some special carb or special intake, although IT COULD use something like equal intake runner
It's just a clickbate title, and it seems many people typed angry/snobby comments without watching and finding out that he did mention audis carbed 5, so I'd say the title was successful, lol.
best engine of all time.
so so SO unique.
owner of a 90s italian 20valve vvti 5 cylinder turbo here running 400bhp through its front wheels via 6 speed manual.
I had an Audi 100 5s. That was a carburated inline 5. It was a great running engine.
I did also have 100 5S 1980 model.
why are we whispering
Right?😂 It feels like his mom is constantly checking on him so he whispers so that she can't hear him
I love it
Y r U all yelling
Kids are sleeping
Hes just in that Z E N zone
Audi made a 5E and a carbureted 5S
Great video, d4a! In a reverse-case to your video, the Chrevolet inline 6 of the 50s-80s cannot be used with multi-point fuel injection, it must be carbureted or throttle-body injected. This is because of the siamese intake ports that are shared between cyls 1-2, 3-4, 5-6. With MPFI, charge robbing occurs for cylinders 1 and 6 by their adjacent cylinders due to the firing order. Cylinders 3 and 4 are fine.
I desagree, the chev inline 6 can be converted to use a muit-point fuel injection without any major problem. Its very common here in Brasil on a variaty of configuration, from 1 to 3 carbs and multi-point injection.
Maybe in a batch-fired MPFI system. With sequential injection I don't think it would be a problem.
Wow such a great video again! Im honestly astonished at the sheer amount of videos that explain concepts about engines that no one has talked about! Thank you for always producing such original content! I hope you know that it is not going unseen, great work and story telling
I had a Volvo 540 with a 5 speed manual and an in-line 5. A bit surprised at first, but solid family car with great mileage. We got rear ended by a pickup truck and only the bumper and rear trunk had to be replaced. Unusual engine but it worked flawlessly.
Straight 5 is an absolute power house when you compare it to a 4 or 6 cylinder it's just makes sense
The irony is that along with EFI, we now have the ability to make a computer designed carb manifold for anything with near-perfect mixing and flow.
And an EFI manifold that works properly.
We can also make the most powerful, most efficient steam locomotives to grace the rails, but our technology has 'unfortunately' superseded such needs.
@@jonathanrees3765 fuel doesn't travel through the manifold. Fuel is injected at the intake port of the head, not the intake opening of the manifold.
Exactly, so fuel injection CANNOT correct for bad airflow. Carbs (and throttle body injection) mix fuel air at intake so "correct" mixture (which DOES flow through manifold) will get to each cylinder - just at different volumes. Manifold with these problems using port or direct injection WILL give incorrect AFR to cylinders not getting enough, or to much air. So whole argument of this video is BS.@@threynolds2
@@threynolds2 Not necessarily right, and in fact, mostly wrong. Excluding Direct Injection cases, the majority of multi-port fuel injection has the injectors positioned at the intake manifold, not the engine head.
What did you Make The animations in?
Fusion 360 + paint net + premiere pro
Minor nit to pick: Volkswagen also made a few I5s over the years, including the EA855 (in use until 2014 in the US market).
You mentioned the OM617 by everything but name there at the end, I see. One of the most well-regarded engines of all time.
617 is fuel injected, doesn't quite fit with his premise about carbs.
My sister had a carburettor 5 cylinder VW for several years. It turned out to be very reliable, but the engine nots was a bit odd. It seems one way VW/Audi addressed the fuel distribution issue was to have a heated hemispherical plate with lots of spikes to vaporise the fuel far more than the vacuum effect of the venturi. Unsurprisingly it was known as the "Hedgehog". This helped more fuel to reach #1 & #5 cylinders thus aiding getting the correct fuel/air mix to all cylinders. A downside was the hot gasses in the manifold hurt the maximum power that could be reached. This didn't bother my sister in the slightest, it was smooth, had plenty of torque, and returned good fuel economy, very desirable qualities in a family car which was its main purpose. Of course development of fuel injection and ever tighter emission standards meant it had a limited lifespan. However Audi were good at ironing out design flaws, they worked very hard at making their very nose heavy inline engined fwd cars have acceptable handling.
I have first gen V70 with NA i5. I love the car because of it. The engine has very pleasant character and even as a NA has enough power and torq in lower RPM + those longer gears making it very comfy car on freeways. Its not a rocket, just a very comfy family "van".
And the combination of i5 with the image of boxy looking Volvo is something that gets me every single day.
Btw, nice video,as always.
Audi had multiple inline 5s with single carburetor, not sure how they dealt with the problem, but I am sure the engines worked fine. Check WN, WH engines with Keihin carb.
Exactly.. Audi 80/100 and CoupeGT 5S!
Aaah... to watch the video before commenting
@d4a individual carburetor? For the 5 banger?
Very well done, well organized, laid out and presented. A great overview of the drawbacks without getting bogged down in the minutiae. Bravo.
The whole carburetor discussion is bunk. V8 and V12 have the same issues. Fuel injection doesn't solve these issues as you still have to balance airflow. But engineering of the fluid dynamics can't be done with hand-waving in a RUclips.
I used to have a inline 5 stick shift truck. This video is spot on. The inline 5 is that tiny little space between fuel efficiency of a 4 cylinder, and power of a six-cylinder. Especially with modern turbo 4 cylinders, there is basically no space for an inline 5.
We owned a 2.5L I5 half-a-lambo-Gallardo engine powered VW Jetta for several years, which was pretty reliable, save for the crappy swashplate AC compressor I replaced. I always thought it sounded better than a V6 when you got on it hard, and while weird, it beat the 4 cylinder option. I always figured the reason we didn't see more was the lack of need, given existing I4, V6, and I6 engines. I had no idea it originated from the overlapped power stroke and sequential firing order. Cool and interesting watch my dude, as always.
Your explanation is phenomenally good. I was going to comment that a straight 6 has a similar intake runner problem to a 5, then you explained about the firing order. You are brilliant!
The original mini dealt with port sharing / charge robbing which I'd expect would be worse because it involved 2 of 4 cylinders rather than 1 of 5. Additionally as the A series is a siamese port there's the ability to rob charge from the port and the manifold not just the manifold as with the 5 cylinder. I think the answer later in the video is more accurate, between straight 4s, straight 6s and v6s all the bases were covered and it just wasn't worth the hassle.
My dream engine/chassis combo would be an naturally aspirated, 2.5 liter, inline 5 with around 220 HP in an MX-5 or S2000 chassis.
That exact thing is the blue vehicle towards the end of the vid. Has ITBs too.
@@d4a I thought it was a Fiat coupe
@@d4a so why can't the engine be designed to fire 1-3-5-2-4 so that no adjacent cylinders are firing one right after the other on a carburetorated inline 5 engine .
@@craigalston2208 MAYBE it would make power distribution too much asymmetric along the revolution. MAYBE the weight distribution of pistons would be a problem.
But I also want a better answer.
The Mercedes OM617 is one of my favorite diesel engines and a childhood favorite at that! Well done.
As someone, who drove a Volvo C70 T5 and a V70 TDI from 2011 to 2022, I got goosebumps at 9:59. As much as I enjoy my current car (a '09 Skoda Octavia RS 2.0 TSI), I really miss the sound of an I5 engine.
Would a possibility be having identical intake manifold lengths? Like a performance exhaust manifold?
My thoughts exactly.
It would solve most of the issues, but just like performance exhaust manifold, they are expensive, hard to manufacture and overall too complex for mass production
Only watched until 2:45 and wonder why not just lengthen the shorter runner
Excellent video as always!
Follow up question: what about V10 engines? Don’t they have one carb for each 5 cylinder bank, and therefore suffer from the same issues?
I guess the firing order is different, but i dont know
They could have at minimum each carb feeding opposing banks. As in having runners going under and over each other just as carb V8 manifolds usually do
i still own a 1992 2.5 inline 5 T3 vw bus, that was built by VW in South Africa for the SA Market. there is a lot of the carburetor versions here in SA, a lot of people has dropped of the fuel injection system as here is not a lot of mechanics that can still work on the Boshtronic injection systems here. and to be very honest. the guys that go to the carb setup here loves them.
The five cillinder sound is so great... I think another reason for its relative rareness is due to the fact that most countries outside Europe have little specialized people to work on engines such as these, so models for these engines must only be aiming either for european markets or for niche consumers in other markets.
In Brazil we had Audi A3s with 5 cillinders, as well as VW Jetta's with the 2.5 that was really fun to drive, and those faced a hard life when service was needed. But obviously the main thing was the Fiat Marea, which was a mass produced car with 5 cillinder engines (including a variation with a turbocompressor) in a very hot weather and, despite all adverse conditions with weather and all the fuel injection issues we had with poor gasoline quality, they worked very well until service was needed. It was then, when mechanics had to change timing belts, to fix the engine after a gasket was damaged or to try and salvage it from Fiat's team huge mistake (they basically said to consumers to only change oil every 20 thousand kilometers, in the 90s, on a weather much hotter than what they designed the engines to run). Most engines never recovered from the first time they were opened here, since trying to sync a different engine was basically witchcraft for mechanical workers at the time.
They already went through hell years before, trying to learn how to swap the timing chain on the first 16v DOHC engine of the Fiat Tempra. Fiat was innovating, but it didn't went so well... today, very few of those remain, and those that keep up smooth are almost impossible to spot. But the sound... it is impossible to not be happy when you hear it.
Well, it has been done in custom setups, with equal length runner intakes, but it's not exactly something practical for mass production in the same way equal length runner exhaust manifolds aren't practical for it.
Yes, that's a nice summary thank you 👍
Why the ignition order can't be 1-4-2-5-3? That would resolve the adjacent cylinder intake issue.
And would make the balance worse
Actually, yes, they can be carbureted; One carburetor per cylinder. The other option is to create a manifold with equal length runner tubes; Just like headers in an exhaust system.
So, how do I know? 🙂
SU carbs would do it.
He didn’t say they couldn’t be carbureted it’s that they wouldn’t be logical or economical for mass production
Audi had carburettor equipped 5 cylinder engines.
He covered the case of one carb per cylinder in the video.
@@nasserrafek9579 He covered this in the video as well (6:50), only in production for a short time as they weren't very good.
I had one in my GMC Canyon, Chevy also had one in the Colorado. I never had any problems with it. A radial engine is sort of like an inline engine with all cylinders on the same place on the crankshaft. That arrangement has equal spaed intakes. They were usually in 5, 7, and 9 cylinder rows..
4 stroke radial engines can only be an odd number of cylinders. Each time a cylinder fires, the next cylinder is on the exhaust stroke. So in 2 revolutions, each cylinder gets to fire. A 2 stroke wouldn't have that problem, and there is at least one example of of a 2 stroke radial with 2 banks of 4 cylinders.
I was told by a racing mechanic of the fifties to seventies who was trained by manufacturers of Weber and SU that while the Weber was able to be adjusted very finely it varied according to height and humidity so in sports car racing across country say Mille Miglia the variable needle in jet had advantage over multiple fixed jets of Weber.
As regards the six cylinder this engine took much time to develop originally as it had vibration periods which required a damper on the front of the crank to make them run smoothly. The five cylinder I think was first used with a four cylinder firing and the fifth cylinder as a supercharger to the other four which was a novelty but I cannot now recall who did it - a Continental manufacturer I think.
I must admit the two fives I owned were remarkably good engines, both injected as you say one was the Volvo which had prodigious power and the other a VW diesel which would ‘climb the side of a house’ as the saying goes. The power overlap was very good. It was a pity that it was never able to match up to the emission laws and I sold it 18 months ago with sadness.