My dad ran top fuel and later top alcohol. I do more modern German engines; VW, Audi, BMW, etc. I learn MORE from Tony, than any of the contemporaries. My dad and the guys knew this stuff, but sucked at explaining it. Currently applying MANY things I’ve learned here to a modern efi, turbo car build. This applies to everything
I used special hi-performance spark plugs, carburetor, ignition, fuel and engine treatments. Every one gave me a few percentage points improvement in mileage. Eventually I got over 100% and I had to rig up a pump and an overflow tank to collect the excess gasoline created by simply driving my car.
Thanks Tony, I keep learning really usefull stuff from you. Apparantly the lack of valves is one of the big reasons rotary's aren't more efficient, it's also why they're so freaking loud; no exhaust valve to absorb heat energy from the exiting gasses. I'm guessing it also applies to 2strokes.
In the tuneup classes I took back in the 70s the instructors emphasized the importance of starting the tune up process with a combustion chamber cleaner. UT just explained why .
AC Delco X- 66 top end cyl (,spray or fluid , decarbon formula, on carburetor engines worked great following directions. & occasionally helped early EFi systems ( special port psi adapter tool required) . Still a good treatment if still available. Derivative of Naval cannon carbon cleaner distilled for automotive uses. Follow mfg.directions. Or seek those who know.... oil / filter change & Fresh⚡plugs After treatment etc. 💨💨💨
@@joekurtz8303 I used to use that or something like that from AC Delco. It was called "Top Engine Cleaner". You had to "choke out" the engine. Let it sit for 15 - 20 minutes, restart it and hold your breath. The neighbors thought I blew up the engine. I don't know if it helped the engine but there weren't many mosquitos around for a couple of days.😎😎
Back in the ‘70’s, some of my friends were obsessed with efficiency and mpg. I got pulled into the mix as well. I was driving a ‘65 Chevy, with an inline 6. A guy at work had bought a truckload of NOS carbs, 1, 2 and4 bbl, still in the box. He was selling them for $10/ barrel. I bought a number of them. I put a single throat Rochester, made for a stationary engine on my car, hoping to achieve maximum mpg. Bad move! Burned 2 exhaust valves. An engine will only do what it can.
My experience with a Chevy straight six was a 250 in a 1978 C10 stepside with three on the tree. They may have been reliable, but what a terrible engine. It’s got mileage like an eight, but had the power of a four. I didn’t keep that truck for very long. That truck helped me find uphill grades I never knew existed. I was driving on the highway and the truck was slowing down. I thought something was wrong, but then I realized I was climbing and it didn’t have the power to hold 70 mph
@@MrJeffcoley1 that's crazy. Your truck wasn't running right. I have the same exact setup but instead of 3 on the tree I have a th350 automatic. My truck doesn't spin tires but it's more than adequate. Rochester mono barrel
@@mikem5475 I had just bought the truck near Abilene, TX in 1989 or 1990 and was driving home to El Paso. It was firing on all cylinders. I didn’t recall if it had points or HEI, but according to the specs it made 115 hp in a 4000 lb truck. I’m sure I would have tuned it up but I don’t recall. The long uphill grade was Interstate 10 between Midland, TX and El Paso climbing out of the Permian basin. Usually there was a headwind as well. I was rolling along at 70 but when I hit that long, long climb speed dropped off to about 55. I actually pulled over to check the plugs and wires to make sure they were OK. They were.
@@MrJeffcoley1 I believe it the way you describe 100hp for 4000lb. Mine doesn't have any emissions equipment, and just a cherry bomb glass pack muffler. Engine bay looks very uncluttered. I wonder if the emissions stuff really messed it up or maybe my standards are just low for how fast something is
How fuel milage is affected by bore size is something that has never crossed my mind. I cannot wait for your upcoming video! This stuff is like old-time wisdom being passed down from generation to generation.
"Legacy knowledge". Something that is ery much disregarded by new guys. Particularly young engineers. It's a tremendous mistake and they rarely admit it.
@@whatyoumakeofit6635 Young engineering student here. So many things you won't learn if you never learn anything beyond what's in the textbook. Gotta get out in the world, get your hands dirty, learn from the guys who do more doing than speaking.
Well put Tony. I’m an old timer like you. I have a newer truck but my daily driver is a 1976 F150 4x4, 360 granny low 4 speed. I love that old truck. Yes it uses more gas than my new one and doesn’t handle as well. But it’s dead nuts reliable. And I can fix it if it needs anything which rarely happens at only about 5,000 miles per year. Your channel has helped me keep it on the road and I thank you, sir. I really appreciate your teaching style. Oh and guess which truck pops everyone’s eyes.... not the new one.
had a 1977 f100 flare side! had a 351w 2v with a c4! had hedders and a diy hi out put ignition and a recurved dizzy. got 20 mpg! loved it was a day to day driver! was simple and reliable!
I’m right there with ya, Brian. Tony has taught me so much with my older vehicles as well, albeit they are TBI rather than carbureted. But I too have a newer 2016 Silverado, but daily drive my 1987 C10 (although she’s undergoing a major project to upgrade the aging fuel system, brake system and replacing rusted components) and I get WAY more comments on that than my Silverado. But my 1986 Thunderbird is the ticket. I’ve had it all my life and rebuild the engine and trans last year. Being able to take Tony’s teachings has allowed me not only to keep that car running, but also increased the mpg’s from 23 on the highway, all the way up to 35 mpg if I’m not romping on it on the highway. And for both vehicles - anything wrong with them, it’s a simple turn of a wrench, adjust this, tweak that, and they are back on the road in no time.
@@brianhdueck3372 thanks man! I really enjoy them and take them to car shows too. The c10 has 123,000 miles but my thunderbird only has 46,000! However they are skyrocketing in value so I do drive them like a little old lady haha!
The thing to remember about efficiency and mileage is that there is only so much chemical energy available in every gallon of fuel, and it takes a set amount of energy to move a (x) mass at (y) acceleration against (z) resistance.
This basic fact is completely lost on way too many people, which is why we get 100mpg claims, hoardes of people using fuel additives and other bolt on nonsense to improve milage. The truth is starting with your basic premise, the losses in effieciency is through transmission, approx 30%auto/5%manual, rear axle, wind resistance, lack of overdrive gear etc. But most importantly, is ones driving style. Ive managed to have a "fuel sipping" 1.8 turbo diesel use as much fuel as a carbed 5.0L V8, because i drove it to where it gave the same performance. Who'd gave thought, full throttle, max turbo rpm would use that much fuel? Well, it does. Drive like a granny, and you'd use less. In other words, the "secret recepie" for great milage is to put a brick under your gas pedal.
Hey Uncle Tony, I received my two t-shirts today ! My FAVORITE item was the self drawn pic of you ! It's hanging on the wall in my shop so everyone can see it ! I totally LOVE it !!! Thank you !!!
This kind of reminds me about the discussion of outdoor wood boilers and hot air wood furnaces. Many thought that is the best way to burn wood…coal bed, fire burns upwards heats water or plenum. Then a downdraft burn gasification boiler principle came along. Same amount of wood consumed but twice the btus generated and recovered.
Funny you should mention that. I had the same urge a few days ago when I saw them while wandering around my local farm supply store. I bought 2 boxes of the blue ones.
Ha! I just ran out of my blue shop rags. Are there any better ones that don’t disintegrate when using lacquer thinner? I buy prep towels (blue ) and those are good but more money.
In the 1940s Nash had their "iso-thermal™" head on their 6 cylinder engines. They had no intake manifold. The carb mounted directly to the head. The air passage inside the head ran over the top of the exhaust ports. The theory was that heat would vaporize the incoming air/gas mixture and would evaporate the gas droplets into a pure vapor for combustion. I don't know if it contributed to the MPG, but I smog checked a 56 Nash in the 1970s and it was surprisingly clean burning for the time era.
@@hotrodray6802 Yeah, 0-60 was measured in minutes 😅 They advertised 23 mpg in 1953. They won the Mobil Gas mileage run that year. The Nash 600 advertised 30 mpg. Like today it's best-case scenarios. I got 19 on my 54 Ambassador in the 1970s but it dropped to about 13 nowadays with the sh't gasoline and all. In fact when I upgraded it to a 350 crate engine the mileage is still at 12. A little more peppy now.
@@Iconoclasher except I have a 400hp ls motor that gets 40mpg on the highway... And a Camry that frequently gets 50mpg. 30mph is not today's best case scenario lol
@@UFC_Buffalo I can understand that. My lovely 54 Nash Ambassador has a SBC 350 now. (can't hardly get parts for the old Ambassador 6 anymore) Now I'm getting 13 mpg. 😂
Well done Tony, love your channel. I am 64 and started my career right out of high school, when Techs were paid 60-40 flat rate, been an ASE Master for over 30 yrs, and have heard this "100 mile per gallon" nonsense my whole career. Its funny you mention the Smokey "vapor" engine. In the early 80's Nissan was installing a ceramic heater under the carburetor to vaporize the fuel, it worked well, until of course it burned out, and sent the ceramic into the combustion chambers 🤣🤣🤣
I'm in total love with this series of videos Uncle Tony! I kinda knew that carbon deposits could make an engine not run properly or lose gas mileage, but I had no idea about the science of it! Amazing video once again! o/
Intake carbon acts like a sponge & can create lean Pre- ign knock.( bad) Sacking Fuel/ air mix @ cyl.🌀💥💨 or cyl inefficiency🏁 good fuel= filter svc, some occasional additives for low octanes help . Correct base timing per spec depending on Mfg . & Year of production . Basics. (SuK-SQuiZ- B💥-.&B🌬💨)
Uncle Tony this was spot on, very informative, very technical, very interesting. Interesting how when you discussed the cam failures of the Gen III hemi, you caught a lot of flack, which was undeserved. Some folks out there unfairly dismissed your thoughts and used the term hack, which was not true then and you certainly proved it again today. I thought I knew a lot about cars and then you go through this lights just click on upstairs.
I had to hire 007 Bond to protect me from big oil, because they sent gang members out to bump me off, because my 6 times removed step brother had a friend that built the million mpg carb... It was so crazy. It was so reliable that 007 Bond had one on the DB5 he picked me up in!!!! I swear !.. great stuff tony, as usual!!
Ive used a can of Berryman B12 into 1/2 tank of gas $4 about every 5,000 miles. my favorite. 50 years ago we ran water injection made from a windshield washer tank. In the early 80s Holley sold a water injection kit for knock supression. Same thing. washer tank with nozzles and a vacuum switch. Worked well on the high compression 70 Corvette 350 hp 350.
i read a article that chrysler was supposed to have done a test and said that it was impossible to burn all the fuel in a bore dia over 4" now this was written back around 1980 if i remember corecttly and was supposed to be one of the reasons that they made the V-10
Home example. Aftrr frying. Put the frying pan in the sink and open the tap slightly. When the water hits the metal it instantly vaporizes. If the water hits a leftover piece of the eggs you fried it does not vaporize. Simple.
One of the big problems for fuel mileage is that it by definition, negates what MOST people want.......performance! One of the best economy tips is to learn to drive economically. We take the heat out of our fuel intake systems to gain 3 hp and wonder why we lose mileage. Soft tires make for a smooth ride but not good economy. 4.11 gears really get you off the line but suck for mileage. Everything is a compromise. How fast do you want to go? How much can you spend.
Really enjoy hearing you talk about the nitro motors , that's very very interesting stuff to me ... Back in the 90's when i was getting into mechanics i was taught running a motor @2500'ish rpms while dribbling water into the carb to steam carbon , also running transfluid in your gas would help break up carbon .... Would be a good video * differnt products that'd help clean your cumbust chamb etc etc ...
I love this. This was so intresting, I never read anything on the stages of temperatures encountered by the mixture between the carb and the cylinders. And I totaly not thought about the back part of the valves and top of the piston heating fuel, and that carbon deposit could act as a insulation. So cool. Thanks a lot.
NAY, the problem is dieseling, an indication that excessive amounts of fuel is used. There is an asymmetric bell curve you have to get past in terms of heat. When you add gaseous fuel then the problem becomes getting enough charge to make HP, at the other end of said curve ...the running crappy just indicates you're on the typical side of said curve. Smokey's contrivance was a cheater's attempt to get to the other side ...
The heat crossover is detrimental to making maximum horsepower. That's why it is blocked-off on stock heads if you're building an engine for racing and omitted on aftermarket performance cylinder heads as well as on the 426 Street HEMI (as seen in the video) originally designed for an engine to be used in competition, not street use, and therefore didn't need a heat crossover in the head. When Chrysler was forced to build the engine and put it in passenger cars it used a makeshift arrangement to heat the bottom of the intake manifold. The main idea behind the heat crossover is cold weather driveability, i.e., quick warm-up of the intake manifold. Once the engine reaches operating temperature, the heat crossover is not needed.
This is the Best! I don't think people understand, how much "Ideal Test Conditions" Go out the Window once you're flooring it? Going uphill? or towing something? You are not going to get that "great" a fuel economy on an Factory EFI system, Unless it really is designed to operate under wide open throttle and high loads? as much as pleasing the EPA Pencil Pushers. (yes I like Glaciers too, that's why we should make More Biofuels) Scotty Kilmer also dispels these myths too, mainly though doing so in comparisons of "Small engine Big trucks" Vs "Conventional natural aspirated V8s". I've studied: Engineering, thermodynamics, physics, my whole life! But I Didn't Know this stuff! until I dealt with it in practice, on cross-country road trips - and moving from the Great Plains / Gulf coast to the Mountains. Automobiles are a funny part of life! There's So much misinformation and marketing speak "False" information! It's no wonder why E.V.'s are taking over the market. "They just work" (well mostly), and their performance metrics & efficiency specs are self evident & can be taken at face value. IF it says on the sticker 0-60 in 1.8 sec? and 100 MPGe, You can bet it's going to get that! atleast until an Ice Age starts or the Battery explodes. ICE's are a Headache, but I think some of the best engineering leaps forward was done so very long ago... Newer generations don't remember it.
We also need consider Rod Ratio & stroke length. There are Tons of high horsepower High Compression Ratio - Very High Efficiency (in Power per displacement) Superbikes that only weigh a quarter Ton or so. But they can't beat a Honda Accord in MPG for daily driving. because? NO VTec? No. Honda bikes included. It's because the stroke to bore Ratio is so short most of your usable energy goes out the exhaust. Not something that matters in a Low Revving Muscle Car - but it is interesting? Combustion Dynamics.
Someone told me that they got 100mpg from a flat head but it burned a hole in all 8 pistons. The only part of the story I believe is that they probably leaned out an engine so much that they burned holes in the pistons.
I've always hated carbon in my engines whether it was from the pcv system or egr system. In my experience growing up in the 90's and dealing with those cars the egr system was always to blame for excess carbon build up but I never could really explain it well, but UT just summed it up perfectly.
A leaner, more vaporized, hotter mixture entering the carb with the atmosphere air that is drawn in and then a VERY HOT HIGH VOLTAGE SPARK with VERY WIDE GAP(54thousands) will greatly increase MPG. I DID IT. 1966 289 2 bbl automatic stock mustang went from 15.5 MPG to 21.5 MPG and ran like a racehorse! Daily driver. Ran it like that for 2 yrs. Still have the car but don't drive it much.
if you read my post on the page above i did this to a 1972 mustang! the factory had evry thing right but the timig curve and the fact it had points! got 27mpg! had a 77 f100 that got 20mpg with 351w! it is easy! with a 289 i know i could get 30! gm hei in 1974 specd .070!
my dad grew up in northern Michigan and what he did to a old 75 nova is cut a hole in the firewall and route the hose from the passenger side A?C to the exhaust gas recirculation tube on the carb, and hen doing 100 mph flip the A/c on full blast and would instantly boost to 130 mph due to the cold air and pressure, also he made a copper coil of 1/4 copper pipe in a spiral about 5 spirals and attach it next to the radiator and rout the fuel line to it over the engine so the gas was cold. COLD GAS AND COLD AIR at operating temps made more power!
Fuel vaporization from a carb principally occurs in the cruise. What happens is kinda cool really. High manifold vacuum substantially lowers the boiling point of fuel causing it to boil off into a fuel/air gas. Full throttle where there's hopefully no manifold vacuum has to have added fuel enrichment by various methods. My favorite carb will always be the Thermoquad. God I love those things. Faults, none! The perfect carb. (Maybe there's a few faults - I'm in love alright) Also anyone who's ever blown a headgasket knows that those pistons at the leak site are always spotlessly clean. A bit of water in the intake never hurt a gas engine, but don't think of trying it on a Diesel.
@@hotrodray6802 yes but the in-line motors are different. Sure you can run it with no intake heat. Even drag race it, but if it’s cold outside you won’t like it in traffic. I used to build in-line 6 kits and sell them professionally. The problem with an in-line is the intake is just hanging out in the wind. On a V block you still have some heat rising up from the valley with an air gap manifold. Not as big of a deal. If you use a normal intake on a V block the hot oil keeps the intake as warm as needed. The in-line blocks are a different animals. The intake on a in-line with no exhaust heater or hot water will Ice on you on cold days. Yes that may make the most horse power but tip in it or take off slowly it won’t like it. I sold kits with a carb tuned and ready to run. Never ever had a complaint. I was told how much better my set up ran in traffic than what they started with almost every time.
You need to check out Shell's 376mpg Opel. It follows along the same thought process as you were noting. They wrapped the whole engine in asbestos so it would run at 400 degrees f. Then they modified the most gas guzzling part of any car, the air filled tires were swapped out for solid rubber ones. Combined with a chain drive instead of a gear driven trans and no suspension, the mileage went higher and higher. Drive train inefficiency is the main reason cars don't get better mileage. It's the same reason why trains can get better gas mileage than a car, minimal drive train loss with steel wheels, and diesel/electric powering them.
you hit the nail on the head! if you built a engen to run a 1 speed more or less you could tune it to run more eficently then drive a gen set to send power to electric engine to drive weels! just like a traine! thre was a car 1915 -20s that did this a owen magnetic!
wow! stunning amount of knowledge right there! ty very helpful in consideration when changing from port injection to carburetors... I am plotting to motor swap a 2006/7 silverado classic to a vintage pump gas dd
when I was driving my 65 dart with the slant6 with original gaskets I had put quit a few miles on it and I started noticing it pinging going up hills ect. check the plugs timing points ect. noticed it did little puffs of smoke ever so often. took the head off and freshened it up and replaced the valve stem seals and found out the valves had a a thick layer of hard oily crust built up . after I got all the valves clean down to bare metal I polished the valves and put the engine back together and it was a huge difference how it ran and got better gas milage and the pinging went away ect.
On any V8 I build, I block off the heat stove completely. You notice it takes a while to warm up. But I never have problems with vapor lock and my alum manifold is still spotless after 90k miles. It’s a 350 Buick in a 66 Chevy pickup. I get 17mpg on the hiway. Never had an issue with spark plug fouling or performance. But on days when the temp is below 30 you do notice a bit of stubbornness.
Where I live we have the wonderful issue of the famous vapor locking. A lot of folks think taking the carb bowl vent off helped performance. Guess what happens when fuel percolates in the fuel bowl? Vapor locking.
Especially in inline 6 engines. I have a Ford with a 300. Offenhauser intake. Holley 4 Barrel. I live in Phoenix az. Have to run a radiator heater plate in the winter and have it off in the summer.
My late father was a combustion engineer and I once told him about a system I read or heard about that involved platinum and he just said, we tried that and it doesn't work, platinum is very expensive. If it was possible to do these things, there would be practically no way to stop it from getting it out.
Tony one thing that kills those high mile per gallon stories is there is that strange problem, engine cooling. There is only so many BTU's of energy in a specific volume of fuel and that would set a maximum MPG. Now that nasty cooling system sucks up quite a bit of energy, but it is necessary , If there was no cooling system you would get better energy conversion, while at the same time they would melt down into a huge metal lump. Those high mpg vehicles getting that tremendous numbers have no cooling and they run the engine at WFO for only a few seconds and it is disconnected and the vehicle coasts to a near stop then they repeat the cycle again. Not really effective for day to day driving.
My Hemi actually gets 110 mpg. This has been documented all over the place and everyone that owns one like mine gets the same mileage. OK, so it is a 49cc Chinese scooter BUT, it is indeed a hemi (hemispherical combustion chamber) and it really does get 110 mpg. It only does 44 mph top end but, around town that's all I need.
As kids we would put tuning kits on 49cc mopeds, 70cc cylinders, higher compression cylinder head, expansion chamber exhaust, large 24/26mm carbs, std was 16mm, and majorly ported intake runners, exhaust, enlarged ports and lightened piston. This in conjuction with max bored cylinders, for approx 74/75cc, really woke it up. Far higher max rpm than out of the box tuning kit, and it pulled hard up top. But milage really sucked, almost like a regular car. We found a toned down version without the high compression top, which broke pistons due to knock unless using octane boister + 98 octane gas, less expansion chamber, and standard carb, was best of both worlds. Essentially same as the first 1966 mustang had a 2 port carb on a 289. The added cubes gave most drivability.
Hi Uncle Tony, I have been watching your channel for a long time. I enjoyed your projects and comments. I wish to share a personal account about high gas millage. Stay with me ... this is not a story about a guy who new a guy that was on the bathroom wall in a gas station somewhere. So here I go and bear with me ... back in 1982 I went to a high millage seminar in Rochester, NY. The guy putting it on was a electrical engineer who was obsessed with getting the most gas millage that could be made out of a car. He shared a lot of history and many patents via slide show. He also handed out a hand book with documentation. Yes, he shared conspiracy theories and so called accounts about big oil stopping the production of efficient carbs. He also shared that he himself was given death threats. Yes I raised an eyebrow or two. Bottom line: He was very intelligent and went through fuel theory like a professor. He reviewed fuel ratio and atomization rules. ALso, he had on display multiple designs for the do-it-yourself guy to improve gas millage. He described the mild to wild attempts to get close to 100 mpg ... crazy as it sounds. He had preheaters, stew pot vaporization chambers, and ceramic high temp vaporization units. What was most interesting was after the seminar he took us out side to his 1974 Cadillac Eldorado 500 CI. Being an electrical engineer, he installed the most dangerous , yet most efficient system. He used two military fuel pumps (to maintain positive pressure without vapor bleed back) which pushed fuel into a inline ceramic heater that went directly down the top of the carb. He had the pumps on a variable controller in the cabin that he adjusted to increase rpm. How he operated the system was to start the car on the standard carb then after the car was warmed up and running he would switch over to the ceramic heater. He used this mainly on the highway. from florida to NY he recorded 80+ mpg. Believe it or not I personally saw the car running on this system. It was not however a turnkey operation but a science project and tricky to run. However his concept did work. Also, there was no smell out of the exhaust pipe. His claim was that he took it to an inspection station with the pollution sniffer and there was no readable hydrocarbons or fumes since the combustion was so efficient. Now I am a gear head from youth and believe there is nor replacement for displacement ... but I saw this with my own eyes. So my reason for sharing is that it can be achieved but not for the public but as a science project. Take this as it is ... believe it or not, sincerely, Jeff
I read some where the carter bbd 2 barrel flows at 280 cfm while the holley 2 barrel flow around 265 give or take . I think the best bang for the buck is the thermoquad since the primeries flow close to 200 cfm on the 2 barrel part of the carb while other 4 barrels flow at 400 cfm on the 2 barrel so your getting really good fuel economy from the thermoquad 4 barrel and the bbd 2 barrel . I also like my carter 1 barrel on my slant6 in my 65 dart . my car was mostly stock including the tires and the 7-1/4 had 2:92 gears . got really good gas milage . got a little better gas milage when I added a k& N filter and put a bigger exhaust pipe from the manifold back
The EXACT reason the spreadbore carbs were so popular! A Quadrajet CAN get better gas mileage than a stock 2 bbl. It never does because we all like to hear that sound!!!
I'm impressed with your knowledge and how easily you explain it. You are smarter than you look(I'm kidding). Lol! I'm going to refer to you as Professor Tony from now on. Today you taught me something that I did not know before.
Good stuff, as always. Who knew how complex that heat/fuel interaction was? Other than emission problems, I wonder if the better road to less fuel consumption is higher compression engines. Think Michael May's Fireball heads for the Jaguar. Somewhere in my pile is a Popular Mechanics (or Popular Science--I can never keep them straight) article from the 1970s of a German-developed 4-cylinder car with 16:1 compression that ran on regular gas. Better gas mileage and power to boot. Nitrous oxides emissions were a problem, though, which may be why the engine never took off. The idea still intrigues.
With direct injection compression ratios are on the rise again. I think the Mustang GT is like 12 to 1 on pump gas but the Ford Coyote uses VVT to help control combustion temperatures and limit NOx.
Uncle Tony when I would like to see these different methods that we can use to decarbonize the top of the piston and the valve what products can we pour down or spray down the carburetor to help the vehicle be more efficient with less carbon buildup thanks Steve
in old days, we'd take off the air cleaner, and trickle in water from a garden hose while the engine ran, until it nearly stalled out. nowadays i guess someone can use bottled water, but the classic tune up for the lil' old lady who only drove in the city was to go out on the highway and give it "the italian tune"--downshift and wind up the revs. Today's fuel is better refined and has more detergents in it--i'm not sure us up north even need dry gas anymore, with all the alcohol ADM sells us to put in fuel.
With the engine warmed up and running, air filter off, then use a spray bottle to mist water into the intake. Just enough to hear the idle drop a little. A few minutes on a few occasions should help
This is one of the reasons why EGR is detrimental to an engine over the long term. The amount of carbon build in the intake tract is insane. I've pulled diesel intake manifolds that had a 1/4" of carbon buildup on the insides of the ports on the manifold, and the head let alone the intake valve. And yes I know a newer diesel is direct inject so the fuel doesn't spend time in the ports. Regardless the amount of airflow restrictions is still noteworthy.
EGR on a gasoline engine is beneficial to fuel mileage if properly implemented. A throttled gas motor is variable compression, At light throttle, effective compression is low due to partial cylinder filling. Inducing inert gas brings the effective compression up.
Very interesting. It makes sense to use top tier gas to keep the valves as clean as possible so they can vaporize the fuel effectively. Thanks for this video. Joe
Sort of, yes. But that little miniscule part of a percent of alcohol they include at $15-18 premium per tank, can be bought for $2-3 a can which lasts 20-30 tanks, which would be a far better economical approach, but in essence, same result. "Top tier gas" is marketed towards people who don't understand this on purpose, and they overcharge quite alot for the tiny amount one get. Higher octane gas on the other hand, IF your vehicle can benefit from it, IS actually worth it.
@@Santor- ruclips.net/video/ystuUJWae0Y/видео.html. There are some other independent certified lab test videos that show benefits from the extra detergents in top tier gas. Cheap gas near me is around 10 cents less per gallon than top tier. Not that much difference. Most people don't bother getting fuel system cleaners, so it may be helpful to get the gas with extra detergent added in. I understand all of the base gas comes from the same refineries. Top tier stations and their own proprietary extra detergents to the tanker trucks before distribution to stations. Cheaper gas stations use base gas that meets minimum standards.
I remember when alot of folks used to put magnets and aluminum foil around their fuel line to save gas.🤣 used to tickle me when I'd trade for a old car and still find one in place!
My neighbour had a 1920's Fordson tractor that I believe had a vaporiser instead of a carburettor. Ran on kerosene or pretty much anything else that would burn, so the idea has been around for a while.
A lot of farm tractors up into the 60's could run on Kero. There was a small gasoline tank to get the engine running and warmed up then a second tank for kero. Some farm tractors ran on propane too.
Propane 360 powerwagon was gasified fuel. It made at best 10% more mpg. The biggest hurdle I can touch is rpm. I can build and fine tune well, then the sweet spot in rpm for torque will get 20-30% better mpg than 1000 rpm more.
The world record for auto gas mileage was set in October 1973 by a 1959 Opel station wagon with a highly modified engine. The car traveled 376.59 miles on a single gallon of gasoline during a Shell Oil Co.
Smokey used a turbocharger backwards to reverse homogenize the fuel and atomize and pre heat it into the intake track to get it to burn easier and more efficiently like kindling in a camp fire, dryer wood burns better than damp wood
In the 90's I was a Quadrajet wizard. I not only knew how they worked but why. I could make them run circles around a Holley..Next best thing to fuel injection in my opinion. I found through experimentation that the intake port layout affected the type of carb that would work better. On GMs and Mopars with Siamese ports, like a spreadbore and Ford type layouts respond better to square bore carbs. Back in my wrench turning days, we would see intake valves so dirty that it would screw with the mixture. Unburned fuel is nasty. Eventually sticks rings and heavy deposits lower the detonation threshold. For this reason, I regularly pour in a full can of Seafoam.
Interesting. What are your thoughts on the electronic quadrajet vs various aftermarket efi's? Wondering if such a carb could be good for a built motor in a classic, which would simplify things, and keep it out of proprietary controllers, but at the same time avoid cylinder wash and keep optimal afr, in the hands of a more novice carb tuner with limited time to apply to it. Now, I know in classuc car curcles most anything that complicates things is frowned upon, and especially electronics. And I get that on a race track a double pumper would be preferred, for quick changes etc. But as a driver, Im thinking this option may have been largely overlooked by the community. Any thoughts on the matter?
@@Santor- The E Quads were controlled by a rather primitive ECM that basically cycled the primary metering rods up and down and a oxygen sensor. For someone not familiar with the intricacies of carburation, the aftermarket EFI is the way to go. Those old carbs required knowledge of jets and metering rods. Spring tension controlled both the primary enrichment system and the opening of the secondary air doors. Misadjusted secondaries were the number one reason for the bad reputation. There were two sets of metering rods to play with as well as different hangers that varied the rate they exposed the jet. GM had many different rods, jets and hangers for different applications..my favorite trick was using a Ram air float from a GTO..it was smaller and allowed more fuel in the bowl. Having a GM chart was paramount for high performance tuning..so you can see, a novice tuner is better off with a plug and play system such as EFI
I'm a retired mechanic I had a 1965 Ford Galaxie four-door 289 V8 with a two-barrel carburetor Ford carburetor old motor compression was 120 down to 90 lb compression old motor I pulled a 5 x 10 trailer 100 lb tongue weight on the hitch I got 24 miles to the gallon going through Kansas and Missouri I modified the carburetor for better gas mileage got between 23 1/2 and 24 Mi to the gallon pulling that enclosed trailer I can also do the same modification with the Holley carburetor
That is a good point.... The intake valve will vaporize some of the gas. I have never thought about that. But I work with Diesels mostly so that is not happening in a Diesel engine. But here is how you can get more mileage from a gas engine. Use a Diesel injection pump to inject gas into the ports! The high pressure atomization will be fare superior to a carburetor or even to a low pressure fuel injection system. You will get more power and better MPGs, I guaranty it.
@@UFC_Buffalo Yes, of curse. Diesel injectors, because nothing else can handle that kind of pressure. I would also put about 5% Diesel into the fuel for lubrication of the pump.
One reason I like e85 for racing - it's a lot less prone to carboning up an engine. In fact, when I switched to E85 in a supercharged sbc I used to race it actually partially cleaned off the pistons and combustion chamber over time. Not perfectly, there was still a little carbon in there but nowhere near as much as with race gas.
Thermodynamics can predict the limits of efficiency of a motor based solely on compression ratio. This is pre friction, oil losses, etc. 100 mpg might is possible on with a tiny motor in a tiny car.
Lassi, you actually just made my point. A gas engine has about a 10 to 1 compression ratio, while a diesel runs about 18 to 1, or higher. Also diesel has many more btu per gallon.
So conventional wisdom says to block the heat crossovers in the heads for maximum performance but you just explained a benefit to increasing heat of the air/fuel mixture. In a future video can you elaborate on when it makes sense to block the heat cross over (like plan z) and when you should leave it open?
I had the same thought. UT had a vid a couple of years ago talking about blocking the heat crossover and how it helps keep the intake and as a result, the fuel in the carb, cooler. I know there's some beef between UT and the Roadkill guys, so I cautiously bring this up... they found in an episode of Engine Masters that a cool intake helps with increasing cylinder filling, not due to cooler air temp but effectively via cavitation... Cooler intake walls = lower pressure area Vs hotter area = high pressure area, so the mixture wants to find it's way to the lower pressure area, helping with cylinder filling. A hotter intake won't have time to heat up the mixture (too short of a duration) but it will create more resistance and slow down the mixture, whereas a cooler intake will provide less resistance, allowing more mixture to squeeze in. These are of course small differences. They found that cool fuel temp was more important. Air temp going into carb didn't make much difference. Cooler fuel means more energy in the same volume, so if for example an engine will pull through say 1 cubic inch of fuel, the cooler cube will contain more energy in that given volume, compared to the same size cube that's hotter. With more energy, rpm increases and the idle screw / jet can be adjusted down, to minimise the volume of fuel pulled through (in that example, maybe only a 0.9" cube needs to be drawn through). Then again, that sort of suggests that the same volume is being pulled from the tank in either case. As temp changes volume, the idle screw / jets are compensating for energy per volume changes. It's still the same amount of energy, just in a different size. A warmer fuel will take up more space, so idle screw / jets need to accommodate that same unit of energy coming through in a larger volume. In other words, if tank volume is X, but in the warmer under hood temp that volume is now X +10%, volume is relative, so a warmer fuel unit passing through the carb may be X+10% but in its cooler state at the tank, it's still pulling through volume X. So maybe, fuel temp doesn't change volume consumption (efficiency), only that the metering of it needs to change relative to how that energy packet changes in volume in order not use the incorrect amount i.e. bring in a cooler mix but leave the metering the same, resulting in a larger volume being pulled the through unnecessarily. So effectively there is a dynamic between fuel tank volume, temp, and fuel draw at carb draw. 2 different temps, changing the volume, but still the same volume being pulled the through from tank (when carb adjusted the right). The cooling of fuel effectively acts a compressor... The same amount comes from the tank and the same energy is used by engine but because it's in a smaller packet, the metering is reducedduces to pull the same energy through, just in a smaller packet. Possibly this is where hotter temps could be better... a hotter mix has more area between the molecules which requires a longer burn time (same as as lean idle mixture needing more time to burn), so this may suggest that a hotter mix would be able to release energy over a larger area in a given timeframe, creating more movement to act on the piston (it's already an expanded mix) and while it may push less (lower power), it would still push. And perhaps that's where economy from higher temps comes from... Using the minimal amount of effort to push the piston, but stil lmoving it, in exchange for lower power output. Back to cooling quickly - A high vacuum level (cruise and idle) will help drop temp (through characteristics of low pressure effect on temp... As pressure drops, temp drops) but also the higher vacuum helps atomise the fuel more. The more fuel that is atomised, the more heat is taken out of the surroundings, keep temp low. But you can't help think that a mixture that's as hot as possible, on the edge of combusting, is the best thing to put into a combustion chamber. That way very little change (work) is required to push the mixture into combustion, which is what would make it most efficient.
Ray-maybe I have it over simplified in my head but I always thought that the purpose of keeping the air/fuel mixture cool was that it was a denser charge in the same volume. You would cram more air and fuel into the same space and make more power. I never considered resistance to flow but I’d love to learn more.
The correct answer is what UT ignored. If you want to make power, you need to ATOMIZE the fuel a fine as you can get it, at the booster. Then you have to keep it as fine a you can until it hits the chamber. You need some fuel that is NOT vaporzied all the way to the chamber and into the chamber because converting the fuel to a gas (vaporization) drops the incoming charge temperature and that makes power. You can easily vaporize too much fuel and lose power. Also, I forget the temperature at which cast iron turns blue, it I know it’s more than 200 degrees and I’ve seen way too many cast iron intakes that were blue from way too much heat in the crossover. You use booster signal and design to atomize the fuel, and correct atomization leads to correct vaporization. And that makes power.
My dad ran top fuel and later top alcohol. I do more modern German engines; VW, Audi, BMW, etc. I learn MORE from Tony, than any of the contemporaries. My dad and the guys knew this stuff, but sucked at explaining it. Currently applying MANY things I’ve learned here to a modern efi, turbo car build. This applies to everything
Tony does have a very special gift, of the ability to explain things, doesn't he?! And the best part is: no B.S.! No hype! Just science and facts.
I'm like your dad. I can't explain shit. I can understand how something works, but Im absolutely terrible at articulating it
Christopher Sine I’m 51 btw. I suck at explaining things too lol
Tony is a seriously good teacher. Much respect from Australia.
@@wheelieking71 Uncle Tony would have made an excellent Auto Shop instructor.
I used special hi-performance spark plugs, carburetor, ignition, fuel and engine treatments. Every one gave me a few percentage points improvement in mileage. Eventually I got over 100% and I had to rig up a pump and an overflow tank to collect the excess gasoline created by simply driving my car.
Hahaha.... That's awesome
You too ?!!
Big brain
Stonks for sure
WHAT ?? 🤔
I use your info to help keep my daily driver F100 with a 223 running smoothly. Thank you for the “old school” knowledge!
Don’t copy him too much or you’ll have it pulled out rebuilding it every week
@@Terminxman 😂
Thanks Tony, I keep learning really usefull stuff from you. Apparantly the lack of valves is one of the big reasons rotary's aren't more efficient, it's also why they're so freaking loud; no exhaust valve to absorb heat energy from the exiting gasses. I'm guessing it also applies to 2strokes.
In the tuneup classes I took back in the 70s the instructors emphasized the importance of starting the tune up process with a combustion chamber cleaner. UT just explained why .
AC Delco X- 66 top end cyl (,spray or fluid , decarbon formula, on carburetor engines worked great following directions. & occasionally helped early EFi systems ( special port psi adapter tool required) . Still a good treatment if still available. Derivative of Naval cannon carbon cleaner distilled for automotive uses. Follow mfg.directions. Or seek those who know.... oil / filter change & Fresh⚡plugs After treatment etc. 💨💨💨
@@joekurtz8303 I used to use that or something like that from AC Delco. It was called "Top Engine Cleaner". You had to "choke out" the engine. Let it sit for 15 - 20 minutes, restart it and hold your breath. The neighbors thought I blew up the engine. I don't know if it helped the engine but there weren't many mosquitos around for a couple of days.😎😎
SeaFoam
Back in the ‘70’s, some of my friends were obsessed with efficiency and mpg. I got pulled into the mix as well. I was driving a ‘65 Chevy, with an inline 6. A guy at work had bought a truckload of NOS carbs, 1, 2 and4 bbl, still in the box. He was selling them for $10/ barrel. I bought a number of them. I put a single throat Rochester, made for a stationary engine on my car, hoping to achieve maximum mpg. Bad move! Burned 2 exhaust valves. An engine will only do what it can.
My experience with a Chevy straight six was a 250 in a 1978 C10 stepside with three on the tree. They may have been reliable, but what a terrible engine. It’s got mileage like an eight, but had the power of a four. I didn’t keep that truck for very long.
That truck helped me find uphill grades I never knew existed. I was driving on the highway and the truck was slowing down. I thought something was wrong, but then I realized I was climbing and it didn’t have the power to hold 70 mph
The engine is the pump.
@@MrJeffcoley1 that's crazy. Your truck wasn't running right. I have the same exact setup but instead of 3 on the tree I have a th350 automatic. My truck doesn't spin tires but it's more than adequate. Rochester mono barrel
@@mikem5475 I had just bought the truck near Abilene, TX in 1989 or 1990 and was driving home to El Paso. It was firing on all cylinders. I didn’t recall if it had points or HEI, but according to the specs it made 115 hp in a 4000 lb truck. I’m sure I would have tuned it up but I don’t recall. The long uphill grade was Interstate 10 between Midland, TX and El Paso climbing out of the Permian basin. Usually there was a headwind as well. I was rolling along at 70 but when I hit that long, long climb speed dropped off to about 55. I actually pulled over to check the plugs and wires to make sure they were OK. They were.
@@MrJeffcoley1 I believe it the way you describe 100hp for 4000lb. Mine doesn't have any emissions equipment, and just a cherry bomb glass pack muffler. Engine bay looks very uncluttered. I wonder if the emissions stuff really messed it up or maybe my standards are just low for how fast something is
Uncle Tony explaining physics. Love it! Simple words explaining complex processes. :)
Uncle Tony is the ultimate Auto Shop teacher! :-)
How fuel milage is affected by bore size is something that has never crossed my mind. I cannot wait for your upcoming video! This stuff is like old-time wisdom being passed down from generation to generation.
"Legacy knowledge". Something that is ery much disregarded by new guys. Particularly young engineers. It's a tremendous mistake and they rarely admit it.
Flame propagation speed is the key. It has to do with how quickly and efficiently the mixture 'lights up'.
@@whatyoumakeofit6635 Young engineering student here. So many things you won't learn if you never learn anything beyond what's in the textbook. Gotta get out in the world, get your hands dirty, learn from the guys who do more doing than speaking.
My friend built a hot vapor system for his 225 Duster. It ran and it moved. I was proud of him!
Show us a little video
@@gulfy09 It was 30 years ago LOL. It didn't really work out, but he proved his point it would run and move under its own power..
Well put Tony. I’m an old timer like you. I have a newer truck but my daily driver is a 1976 F150 4x4, 360 granny low 4 speed. I love that old truck. Yes it uses more gas than my new one and doesn’t handle as well. But it’s dead nuts reliable. And I can fix it if it needs anything which rarely happens at only about 5,000 miles per year. Your channel has helped me keep it on the road and I thank you, sir. I really appreciate your teaching style. Oh and guess which truck pops everyone’s eyes.... not the new one.
had a 1977 f100 flare side! had a 351w 2v with a c4! had hedders and a diy hi out put ignition and a recurved dizzy. got 20 mpg! loved it was a day to day driver! was simple and reliable!
I’m right there with ya, Brian. Tony has taught me so much with my older vehicles as well, albeit they are TBI rather than carbureted. But I too have a newer 2016 Silverado, but daily drive my 1987 C10 (although she’s undergoing a major project to upgrade the aging fuel system, brake system and replacing rusted components) and I get WAY more comments on that than my Silverado. But my 1986 Thunderbird is the ticket. I’ve had it all my life and rebuild the engine and trans last year. Being able to take Tony’s teachings has allowed me not only to keep that car running, but also increased the mpg’s from 23 on the highway, all the way up to 35 mpg if I’m not romping on it on the highway. And for both vehicles - anything wrong with them, it’s a simple turn of a wrench, adjust this, tweak that, and they are back on the road in no time.
You’got some sweet rides there! And thanks to Tony!
@@brianhdueck3372 thanks man! I really enjoy them and take them to car shows too. The c10 has 123,000 miles but my thunderbird only has 46,000! However they are skyrocketing in value so I do drive them like a little old lady haha!
The thing to remember about efficiency and mileage is that there is only so much chemical energy available in every gallon of fuel, and it takes a set amount of energy to move a (x) mass at (y) acceleration against (z) resistance.
Dammmm right
This basic fact is completely lost on way too many people, which is why we get 100mpg claims, hoardes of people using fuel additives and other bolt on nonsense to improve milage.
The truth is starting with your basic premise, the losses in effieciency is through transmission, approx 30%auto/5%manual, rear axle, wind resistance, lack of overdrive gear etc.
But most importantly, is ones driving style. Ive managed to have a "fuel sipping" 1.8 turbo diesel use as much fuel as a carbed 5.0L V8, because i drove it to where it gave the same performance. Who'd gave thought, full throttle, max turbo rpm would use that much fuel? Well, it does. Drive like a granny, and you'd use less.
In other words, the "secret recepie" for great milage is to put a brick under your gas pedal.
University of Uncle Tony , best education you’ll ever get
my cousin invented a string trimmer carburetor, he was knocked off by Small Oil
Never trust Small Oil when stroking your piston.
Hey Uncle Tony,
I received my two t-shirts today !
My FAVORITE item was the self drawn pic of you !
It's hanging on the wall in my shop so everyone can see it !
I totally LOVE it !!!
Thank you !!!
This kind of reminds me about the discussion of outdoor wood boilers and hot air wood furnaces. Many thought that is the best way to burn wood…coal bed, fire burns upwards heats water or plenum. Then a downdraft burn gasification boiler principle came along. Same amount of wood consumed but twice the btus generated and recovered.
Does anyone else have the urge to go out and buy Scott RAGS? I know its not product placement but wow now I want to buy!!
Funny you should mention that. I had the same urge a few days ago when I saw them while wandering around my local farm supply store. I bought 2 boxes of the blue ones.
Ha! I just ran out of my blue shop rags. Are there any better ones that don’t disintegrate when using lacquer thinner? I buy prep towels (blue ) and those are good but more money.
In the 1940s Nash had their "iso-thermal™" head on their 6 cylinder engines. They had no intake manifold. The carb mounted directly to the head. The air passage inside the head ran over the top of the exhaust ports. The theory was that heat would vaporize the incoming air/gas mixture and would evaporate the gas droplets into a pure vapor for combustion.
I don't know if it contributed to the MPG, but I smog checked a 56 Nash in the 1970s and it was surprisingly clean burning for the time era.
Nash advertised the highest gas mileage of standard sized cars.
Not tire burners.
@@hotrodray6802
Yeah, 0-60 was measured in minutes 😅 They advertised 23 mpg in 1953. They won the Mobil Gas mileage run that year. The Nash 600 advertised 30 mpg. Like today it's best-case scenarios. I got 19 on my 54 Ambassador in the 1970s but it dropped to about 13 nowadays with the sh't gasoline and all. In fact when I upgraded it to a 350 crate engine the mileage is still at 12. A little more peppy now.
@@Iconoclasher except I have a 400hp ls motor that gets 40mpg on the highway... And a Camry that frequently gets 50mpg.
30mph is not today's best case scenario lol
@@UFC_Buffalo
I can understand that. My lovely 54 Nash Ambassador has a SBC 350 now. (can't hardly get parts for the old Ambassador 6 anymore)
Now I'm getting 13 mpg. 😂
Well done Tony, love your channel. I am 64 and started my career right out of high school, when Techs were paid 60-40 flat rate, been an ASE Master for over 30 yrs, and have heard this "100 mile per gallon" nonsense my whole career. Its funny you mention the Smokey "vapor" engine. In the early 80's Nissan was installing a ceramic heater under the carburetor to vaporize the fuel, it worked well, until of course it burned out, and sent the ceramic into the combustion chambers 🤣🤣🤣
I'm in total love with this series of videos Uncle Tony! I kinda knew that carbon deposits could make an engine not run properly or lose gas mileage, but I had no idea about the science of it! Amazing video once again! o/
Intake carbon acts like a sponge & can create lean Pre- ign knock.( bad) Sacking Fuel/ air mix @ cyl.🌀💥💨 or cyl inefficiency🏁 good fuel= filter svc, some occasional additives for low octanes help . Correct base timing per spec depending on Mfg . & Year of production . Basics. (SuK-SQuiZ- B💥-.&B🌬💨)
Uncle Tony this was spot on, very informative, very technical, very interesting.
Interesting how when you discussed the cam failures of the Gen III hemi, you caught a lot of flack, which was undeserved. Some folks out there unfairly dismissed your thoughts and used the term hack, which was not true then and you certainly proved it again today.
I thought I knew a lot about cars and then you go through this lights just click on upstairs.
I had to hire 007 Bond to protect me from big oil, because they sent gang members out to bump me off, because my 6 times removed step brother had a friend that built the million mpg carb... It was so crazy. It was so reliable that 007 Bond had one on the DB5 he picked me up in!!!! I swear !.. great stuff tony, as usual!!
Ive used a can of Berryman B12 into 1/2 tank of gas $4 about every 5,000 miles. my favorite.
50 years ago we ran water injection made from a windshield washer tank.
In the early 80s Holley sold a water injection kit for knock supression.
Same thing. washer tank with nozzles and a vacuum switch.
Worked well on the high compression 70 Corvette 350 hp 350.
I keep seeing your comments and you have no idea what you're talking about...
I never considered carbon as an insulator to heat. Topics like this with great references keep us all thinking .
i read a article that chrysler was supposed to have done a test and said that it was impossible to burn all the fuel in a bore dia over 4" now this was written back around 1980 if i remember corecttly and was supposed to be one of the reasons that they made the V-10
Home example. Aftrr frying. Put the frying pan in the sink and open the tap slightly. When the water hits the metal it instantly vaporizes. If the water hits a leftover piece of the eggs you fried it does not vaporize. Simple.
One of the big problems for fuel mileage is that it by definition, negates what MOST people want.......performance! One of the best economy tips is to learn to drive economically. We take the heat out of our fuel intake systems to gain 3 hp and wonder why we lose mileage. Soft tires make for a smooth ride but not good economy. 4.11 gears really get you off the line but suck for mileage. Everything is a compromise. How fast do you want to go? How much can you spend.
Excellent points. Especially on the driving style.
This is actually my specialty uncle tony... you'd be surprised what I've learned and tested..
From deep in my mind the words, latent heat of evaporation, flew by. Temps dropping by atomization
Tony, I love listening to you. I’m hoping to share some of this with my grandsons, as soon as we can find a suitable project car.
Really enjoy hearing you talk about the nitro motors , that's very very interesting stuff to me ... Back in the 90's when i was getting into mechanics i was taught running a motor @2500'ish rpms while dribbling water into the carb to steam carbon , also running transfluid in your gas would help break up carbon .... Would be a good video * differnt products that'd help clean your cumbust chamb etc etc ...
I love this. This was so intresting, I never read anything on the stages of temperatures encountered by the mixture between the carb and the cylinders. And I totaly not thought about the back part of the valves and top of the piston heating fuel, and that carbon deposit could act as a insulation. So cool. Thanks a lot.
NAY, the problem is dieseling, an indication that excessive amounts of fuel is used. There is an asymmetric bell curve you have to get past in terms of heat. When you add gaseous fuel then the problem becomes getting enough charge to make HP, at the other end of said curve ...the running crappy just indicates you're on the typical side of said curve. Smokey's contrivance was a cheater's attempt to get to the other side ...
I was taught a lot of these things Tony speaks about way back in tech school back in the 1970's.
Gas, Mist, … I get the “Gist”!
When I was little and the tank was low, I was always told “we’re running on fumes” 😂
The heat crossover is detrimental to making maximum horsepower. That's why it is blocked-off on stock heads if you're building an engine for racing and omitted on aftermarket performance cylinder heads as well as on the 426 Street HEMI (as seen in the video) originally designed for an engine to be used in competition, not street use, and therefore didn't need a heat crossover in the head. When Chrysler was forced to build the engine and put it in passenger cars it used a makeshift arrangement to heat the bottom of the intake manifold.
The main idea behind the heat crossover is cold weather driveability, i.e., quick warm-up of the intake manifold. Once the engine reaches operating temperature, the heat crossover is not needed.
Just installed a replacement exhaust manifold on my 292 Chevy inline six. It has a exhaust heat chamber to heat the intake gas
YOU get an "A+"for the video TONY !! Job well done fella. ....😀
You're the man Uncle Tony
Nobody could explain this any better than uncle Tony all very easy to understand I definitely got something out of this one !
This is the Best! I don't think people understand, how much "Ideal Test Conditions" Go out the Window once you're flooring it? Going uphill? or towing something? You are not going to get that "great" a fuel economy on an Factory EFI system, Unless it really is designed to operate under wide open throttle and high loads? as much as pleasing the EPA Pencil Pushers. (yes I like Glaciers too, that's why we should make More Biofuels)
Scotty Kilmer also dispels these myths too, mainly though doing so in comparisons of "Small engine Big trucks" Vs "Conventional natural aspirated V8s".
I've studied: Engineering, thermodynamics, physics, my whole life! But I Didn't Know this stuff! until I dealt with it in practice, on cross-country road trips - and moving from the Great Plains / Gulf coast to the Mountains.
Automobiles are a funny part of life! There's So much misinformation and marketing speak "False" information! It's no wonder why E.V.'s are taking over the market. "They just work" (well mostly), and their performance metrics & efficiency specs are self evident & can be taken at face value. IF it says on the sticker 0-60 in 1.8 sec? and 100 MPGe, You can bet it's going to get that! atleast until an Ice Age starts or the Battery explodes.
ICE's are a Headache, but I think some of the best engineering leaps forward was done so very long ago... Newer generations don't remember it.
We also need consider Rod Ratio & stroke length. There are Tons of high horsepower High Compression Ratio - Very High Efficiency (in Power per displacement) Superbikes that only weigh a quarter Ton or so. But they can't beat a Honda Accord in MPG for daily driving. because? NO VTec? No. Honda bikes included. It's because the stroke to bore Ratio is so short most of your usable energy goes out the exhaust.
Not something that matters in a Low Revving Muscle Car - but it is interesting? Combustion Dynamics.
Someone told me that they got 100mpg from a flat head but it burned a hole in all 8 pistons. The only part of the story I believe is that they probably leaned out an engine so much that they burned holes in the pistons.
100 mpg downhill for 1 mile? The old lady's Buick Park Ave Ultra displays 99mpg average under those circumstances, and she gets all wound up over it ☺
I've always hated carbon in my engines whether it was from the pcv system or egr system. In my experience growing up in the 90's and dealing with those cars the egr system was always to blame for excess carbon build up but I never could really explain it well, but UT just summed it up perfectly.
I've heard this before, but it's never been explained this simple. Thanks uncle Tony
A leaner, more vaporized, hotter mixture entering the carb with the atmosphere air that is drawn in and then a VERY HOT HIGH VOLTAGE SPARK with VERY WIDE GAP(54thousands) will greatly increase MPG.
I DID IT.
1966 289 2 bbl automatic stock mustang went from 15.5 MPG to 21.5 MPG and ran like a racehorse!
Daily driver. Ran it like that for 2 yrs.
Still have the car but don't drive it much.
if you read my post on the page above i did this to a 1972 mustang! the factory had evry thing right but the timig curve and the fact it had points! got 27mpg! had a 77 f100 that got 20mpg with 351w! it is easy! with a 289 i know i could get 30! gm hei in 1974 specd .070!
my dad grew up in northern Michigan and what he did to a old 75 nova is cut a hole in the firewall and route the hose from the passenger side A?C to the exhaust gas recirculation tube on the carb, and hen doing 100 mph flip the A/c on full blast and would instantly boost to 130 mph due to the cold air and pressure, also he made a copper coil of 1/4 copper pipe in a spiral about 5 spirals and attach it next to the radiator and rout the fuel line to it over the engine so the gas was cold. COLD GAS AND COLD AIR at operating temps made more power!
Fuel vaporization from a carb principally occurs in the cruise. What happens is kinda cool really. High manifold vacuum substantially lowers the boiling point of fuel causing it to boil off into a fuel/air gas.
Full throttle where there's hopefully no manifold vacuum has to have added fuel enrichment by various methods. My favorite carb will always be the Thermoquad. God I love those things. Faults, none! The perfect carb. (Maybe there's a few faults - I'm in love alright)
Also anyone who's ever blown a headgasket knows that those pistons at the leak site are always spotlessly clean. A bit of water in the intake never hurt a gas engine, but don't think of trying it on a Diesel.
Thank you Tony for explaining the heat crossover. Many people are confused about that one.
intake gasket sets often come with blockoffs and many people block the heat risers.
@@hotrodray6802 yes but the in-line motors are different. Sure you can run it with no intake heat. Even drag race it, but if it’s cold outside you won’t like it in traffic. I used to build in-line 6 kits and sell them professionally. The problem with an in-line is the intake is just hanging out in the wind. On a V block you still have some heat rising up from the valley with an air gap manifold. Not as big of a deal. If you use a normal intake on a V block the hot oil keeps the intake as warm as needed. The in-line blocks are a different animals. The intake on a in-line with no exhaust heater or hot water will Ice on you on cold days. Yes that may make the most horse power but tip in it or take off slowly it won’t like it. I sold kits with a carb tuned and ready to run. Never ever had a complaint. I was told how much better my set up ran in traffic than what they started with almost every time.
amazing what I learn when I listen to Uncle Tony!
You need to check out Shell's 376mpg Opel. It follows along the same thought process as you were noting. They wrapped the whole engine in asbestos so it would run at 400 degrees f. Then they modified the most gas guzzling part of any car, the air filled tires were swapped out for solid rubber ones. Combined with a chain drive instead of a gear driven trans and no suspension, the mileage went higher and higher. Drive train inefficiency is the main reason cars don't get better mileage. It's the same reason why trains can get better gas mileage than a car, minimal drive train loss with steel wheels, and diesel/electric powering them.
you hit the nail on the head! if you built a engen to run a 1 speed more or less you could tune it to run more eficently then drive a gen set to send power to electric engine to drive weels! just like a traine! thre was a car 1915 -20s that did this a owen magnetic!
I got something. Thank you Tony. This was what I have been waiting for.
wow! stunning amount of knowledge right there! ty very helpful in consideration when changing from port injection to carburetors... I am plotting to motor swap a 2006/7 silverado classic to a vintage pump gas dd
when I was driving my 65 dart with the slant6 with original gaskets I had put quit a few miles on it and I started noticing it pinging going up hills ect. check the plugs timing points ect. noticed it did little puffs of smoke ever so often. took the head off and freshened it up and replaced the valve stem seals and found out the valves had a a thick layer of hard oily crust built up . after I got all the valves clean down to bare metal I polished the valves and put the engine back together and it was a huge difference how it ran and got better gas milage and the pinging went away ect.
The video of that blue GMC truck with the vapor carburetor seems to work really well. The title of the video is POC1 vapor carburetor or something.
This guy seems to know something
ruclips.net/video/Ke0MGmUr3SU/видео.html
On any V8 I build, I block off the heat stove completely. You notice it takes a while to warm up. But I never have problems with vapor lock and my alum manifold is still spotless after 90k miles. It’s a 350 Buick in a 66 Chevy pickup. I get 17mpg on the hiway. Never had an issue with spark plug fouling or performance. But on days when the temp is below 30 you do notice a bit of stubbornness.
Where I live we have the wonderful issue of the famous vapor locking. A lot of folks think taking the carb bowl vent off helped performance. Guess what happens when fuel percolates in the fuel bowl? Vapor locking.
Especially in inline 6 engines. I have a Ford with a 300. Offenhauser intake. Holley 4 Barrel. I live in Phoenix az. Have to run a radiator heater plate in the winter and have it off in the summer.
My late father was a combustion engineer and I once told him about a system I read or heard about that involved platinum and he just said, we tried that and it doesn't work, platinum is very expensive.
If it was possible to do these things, there would be practically no way to stop it from getting it out.
I'm just happy my vehicles still start.
Tony one thing that kills those high mile per gallon stories is there is that strange problem, engine cooling. There is only so many BTU's of energy in a specific volume of fuel and that would set a maximum MPG. Now that nasty cooling system sucks up quite a bit of energy, but it is necessary , If there was no cooling system you would get better energy conversion, while at the same time they would melt down into a huge metal lump. Those high mpg vehicles getting that tremendous numbers have no cooling and they run the engine at WFO for only a few seconds and it is disconnected and the vehicle coasts to a near stop then they repeat the cycle again. Not really effective for day to day driving.
My Hemi actually gets 110 mpg. This has been documented all over the place and everyone that owns one like mine gets the same mileage. OK, so it is a 49cc Chinese scooter BUT, it is indeed a hemi (hemispherical combustion chamber) and it really does get 110 mpg. It only does 44 mph top end but, around town that's all I need.
This is a lie. Everyone knows the human body can not withstand the forces of 44mph
As kids we would put tuning kits on 49cc mopeds, 70cc cylinders, higher compression cylinder head, expansion chamber exhaust, large 24/26mm carbs, std was 16mm, and majorly ported intake runners, exhaust, enlarged ports and lightened piston. This in conjuction with max bored cylinders, for approx 74/75cc, really woke it up. Far higher max rpm than out of the box tuning kit, and it pulled hard up top. But milage really sucked, almost like a regular car. We found a toned down version without the high compression top, which broke pistons due to knock unless using octane boister + 98 octane gas, less expansion chamber, and standard carb, was best of both worlds. Essentially same as the first 1966 mustang had a 2 port carb on a 289. The added cubes gave most drivability.
Hi Uncle Tony, I have been watching your channel for a long time. I enjoyed your projects and comments. I wish to share a personal account about high gas millage. Stay with me ... this is not a story about a guy who new a guy that was on the bathroom wall in a gas station somewhere.
So here I go and bear with me ... back in 1982 I went to a high millage seminar in Rochester, NY. The guy putting it on was a electrical engineer who was obsessed with getting the most gas millage that could be made out of a car. He shared a lot of history and many patents via slide show. He also handed out a hand book with documentation. Yes, he shared conspiracy theories and so called accounts about big oil stopping the production of efficient carbs. He also shared that he himself was given death threats. Yes I raised an eyebrow or two.
Bottom line: He was very intelligent and went through fuel theory like a professor. He reviewed fuel ratio and atomization rules. ALso, he had on display multiple designs for the do-it-yourself guy to improve gas millage. He described the mild to wild attempts to get close to 100 mpg ... crazy as it sounds. He had preheaters, stew pot vaporization chambers, and ceramic high temp vaporization units.
What was most interesting was after the seminar he took us out side to his 1974 Cadillac Eldorado 500 CI. Being an electrical engineer, he installed the most dangerous , yet most efficient system. He used two military fuel pumps (to maintain positive pressure without vapor bleed back) which pushed fuel into a inline ceramic heater that went directly down the top of the carb. He had the pumps on a variable controller in the cabin that he adjusted to increase rpm. How he operated the system was to start the car on the standard carb then after the car was warmed up and running he would switch over to the ceramic heater. He used this mainly on the highway. from florida to NY he recorded 80+ mpg.
Believe it or not I personally saw the car running on this system. It was not however a turnkey operation but a science project and tricky to run. However his concept did work. Also, there was no smell out of the exhaust pipe. His claim was that he took it to an inspection station with the pollution sniffer and there was no readable hydrocarbons or fumes since the combustion was so efficient.
Now I am a gear head from youth and believe there is nor replacement for displacement ... but I saw this with my own eyes. So my reason for sharing is that it can be achieved but not for the public but as a science project. Take this as it is ... believe it or not, sincerely, Jeff
I remember the car.👍👍
Exactly. Well said. I always thought it was about the cooling of the engine?
I read some where the carter bbd 2 barrel flows at 280 cfm while the holley 2 barrel flow around 265 give or take . I think the best bang for the buck is the thermoquad since the primeries flow close to 200 cfm on the 2 barrel part of the carb while other 4 barrels flow at 400 cfm on the 2 barrel so your getting really good fuel economy from the thermoquad 4 barrel and the bbd 2 barrel . I also like my carter 1 barrel on my slant6 in my 65 dart . my car was mostly stock including the tires and the 7-1/4 had 2:92 gears . got really good gas milage . got a little better gas milage when I added a k& N filter and put a bigger exhaust pipe from the manifold back
The EXACT reason the spreadbore carbs were so popular! A Quadrajet CAN get better gas mileage than a stock 2 bbl. It never does because we all like to hear that sound!!!
This independent test run with a 1938 for car which mechanics illustrated featured in its magazine was with the Proge carburetor
I came in chasing unicorns(100mpg carb) and left completely educated. Very nice.
I'm impressed with your knowledge and how easily you explain it. You are smarter than you look(I'm kidding). Lol! I'm going to refer to you as Professor Tony from now on. Today you taught me something that I did not know before.
Good stuff, as always. Who knew how complex that heat/fuel interaction was? Other than emission problems, I wonder if the better road to less fuel consumption is higher compression engines. Think Michael May's Fireball heads for the Jaguar. Somewhere in my pile is a Popular Mechanics (or Popular Science--I can never keep them straight) article from the 1970s of a German-developed 4-cylinder car with 16:1 compression that ran on regular gas. Better gas mileage and power to boot. Nitrous oxides emissions were a problem, though, which may be why the engine never took off. The idea still intrigues.
With direct injection compression ratios are on the rise again. I think the Mustang GT is like 12 to 1 on pump gas but the Ford Coyote uses VVT to help control combustion temperatures and limit NOx.
Yeah I heard that emissions really put a bottle neck on how much mpg you can get when designing an engine.
Uncle Tony is just an all around cool dude.
I'll have to watch this one several times.
Uncle Tony when I would like to see these different methods that we can use to decarbonize the top of the piston and the valve what products can we pour down or spray down the carburetor to help the vehicle be more efficient with less carbon buildup thanks Steve
in old days, we'd take off the air cleaner, and trickle in water from a garden hose while the engine ran, until it nearly stalled out. nowadays i guess someone can use bottled water, but the classic tune up for the lil' old lady who only drove in the city was to go out on the highway and give it "the italian tune"--downshift and wind up the revs. Today's fuel is better refined and has more detergents in it--i'm not sure us up north even need dry gas anymore, with all the alcohol ADM sells us to put in fuel.
With the engine warmed up and running, air filter off, then use a spray bottle to mist water into the intake. Just enough to hear the idle drop a little. A few minutes on a few occasions should help
Who ya preachin to. Man, man, still teaching. I was old ten years ago, I saw tons of that a”fake news”, totally dumb.
This is one of the reasons why EGR is detrimental to an engine over the long term. The amount of carbon build in the intake tract is insane. I've pulled diesel intake manifolds that had a 1/4" of carbon buildup on the insides of the ports on the manifold, and the head let alone the intake valve. And yes I know a newer diesel is direct inject so the fuel doesn't spend time in the ports. Regardless the amount of airflow restrictions is still noteworthy.
EGR on a gasoline engine is beneficial to fuel mileage if properly implemented. A throttled gas motor is variable compression, At light throttle, effective compression is low due to partial cylinder filling. Inducing inert gas brings the effective compression up.
Very interesting. It makes sense to use top tier gas to keep the valves as clean as possible so they can vaporize the fuel effectively. Thanks for this video. Joe
Its the PCV.
Sort of, yes. But that little miniscule part of a percent of alcohol they include at $15-18 premium per tank, can be bought for $2-3 a can which lasts 20-30 tanks, which would be a far better economical approach, but in essence, same result.
"Top tier gas" is marketed towards people who don't understand this on purpose, and they overcharge quite alot for the tiny amount one get. Higher octane gas on the other hand, IF your vehicle can benefit from it, IS actually worth it.
@@Santor- ruclips.net/video/ystuUJWae0Y/видео.html. There are some other independent certified lab test videos that show benefits from the extra detergents in top tier gas. Cheap gas near me is around 10 cents less per gallon than top tier. Not that much difference. Most people don't bother getting fuel system cleaners, so it may be helpful to get the gas with extra detergent added in. I understand all of the base gas comes from the same refineries. Top tier stations and their own proprietary extra detergents to the tanker trucks before distribution to stations. Cheaper gas stations use base gas that meets minimum standards.
I remember when alot of folks used to put magnets and aluminum foil around their fuel line to save gas.🤣 used to tickle me when I'd trade for a old car and still find one in place!
Wow! what a lesson ! Genius ! wish I learned this 30 years ago . do you want an apprentice ?
Damn, Tony. You impressed me with your knowledge of thermodynamics and mixture physics. Great lesson.
That flamingo in the backgrpund is majestic 🦩
The secret to Fuel economy is weight and aerodynamics.
This guy seems to know something
ruclips.net/video/Ke0MGmUr3SU/видео.html
Good simple basic science here that also gets incredibly complex.
It takes a certain amount of energy to move mass
Simple physics
AMEN - Amazing that a cup of diesel fuel can actually move a dump truck.
Damn, Tony! That's worth a second watch. I'm going to have to send it to my non gearhead friend so I can swipe his phone and like it twice.
My neighbour had a 1920's Fordson tractor that I believe had a vaporiser instead of a carburettor. Ran on kerosene or pretty much anything else that would burn, so the idea has been around for a while.
Seen a Fordson Tractor once @ ⛽station . Small-Stout and huge cast iron saddle seat. NorCal agriculture relic
A lot of farm tractors up into the 60's could run on Kero. There was a small gasoline tank to get the engine running and warmed up then a second tank for kero. Some farm tractors ran on propane too.
@@bobroberts2371 kerosene is basically diesel...
Propane 360 powerwagon was gasified fuel. It made at best 10% more mpg. The biggest hurdle I can touch is rpm. I can build and fine tune well, then the sweet spot in rpm for torque will get 20-30% better mpg than 1000 rpm more.
I always wondered why on my little spitfire 4cy… there was a water tube going to the intake manifold….interesting. (
Merry Christmas Tony & Kathy!
The world record for auto gas mileage was set in October 1973 by a 1959 Opel station wagon with a highly modified engine. The car traveled 376.59 miles on a single gallon of gasoline during a Shell Oil Co.
Wow, this is really interesting stuff. Looking forward to next program.
OMG! Uncle Tony, the science guy. Good stuff, man!
Smokey used a turbocharger backwards to reverse homogenize the fuel and atomize and pre heat it into the intake track to get it to burn easier and more efficiently like kindling in a camp fire, dryer wood burns better than damp wood
Dude, that was awesome. Thank you.
In the 90's I was a Quadrajet wizard. I not only knew how they worked but why. I could make them run circles around a Holley..Next best thing to fuel injection in my opinion. I found through experimentation that the intake port layout affected the type of carb that would work better. On GMs and Mopars with Siamese ports, like a spreadbore and Ford type layouts respond better to square bore carbs. Back in my wrench turning days, we would see intake valves so dirty that it would screw with the mixture. Unburned fuel is nasty. Eventually sticks rings and heavy deposits lower the detonation threshold. For this reason, I regularly pour in a full can of Seafoam.
Interesting. What are your thoughts on the electronic quadrajet vs various aftermarket efi's? Wondering if such a carb could be good for a built motor in a classic, which would simplify things, and keep it out of proprietary controllers, but at the same time avoid cylinder wash and keep optimal afr, in the hands of a more novice carb tuner with limited time to apply to it. Now, I know in classuc car curcles most anything that complicates things is frowned upon, and especially electronics. And I get that on a race track a double pumper would be preferred, for quick changes etc. But as a driver, Im thinking this option may have been largely overlooked by the community. Any thoughts on the matter?
@@Santor- The E Quads were controlled by a rather primitive ECM that basically cycled the primary metering rods up and down and a oxygen sensor. For someone not familiar with the intricacies of carburation, the aftermarket EFI is the way to go. Those old carbs required knowledge of jets and metering rods. Spring tension controlled both the primary enrichment system and the opening of the secondary air doors. Misadjusted secondaries were the number one reason for the bad reputation. There were two sets of metering rods to play with as well as different hangers that varied the rate they exposed the jet. GM had many different rods, jets and hangers for different applications..my favorite trick was using a Ram air float from a GTO..it was smaller and allowed more fuel in the bowl. Having a GM chart was paramount for high performance tuning..so you can see, a novice tuner is better off with a plug and play system such as EFI
Very good information Tony. Loved it. Kinda the same principals in a refrigeration system. Well, to a point....
I'm a retired mechanic I had a 1965 Ford Galaxie four-door 289 V8 with a two-barrel carburetor Ford carburetor old motor compression was 120 down to 90 lb compression old motor I pulled a 5 x 10 trailer 100 lb tongue weight on the hitch I got 24 miles to the gallon going through Kansas and Missouri I modified the carburetor for better gas mileage got between 23 1/2 and 24 Mi to the gallon pulling that enclosed trailer I can also do the same modification with the Holley carburetor
What kind of modifications were made to help get good mileage?
That is a good point....
The intake valve will vaporize some of the gas.
I have never thought about that.
But I work with Diesels mostly so that is not happening in a Diesel engine.
But here is how you can get more mileage from a gas engine.
Use a Diesel injection pump to inject gas into the ports!
The high pressure atomization will be fare superior to a carburetor or even to a low pressure fuel injection system. You will get more power and better MPGs, I guaranty it.
O just use diesel injectors huh?....
@@UFC_Buffalo Yes, of curse.
Diesel injectors, because nothing else can handle that kind of pressure.
I would also put about 5% Diesel into the fuel for lubrication of the pump.
Your talking my bag! I did find valve and Port tricks on lawnmower engines. Now it's time to put it on a v8. Not 100mpg but noticble.
One of the ways to help with mpg is go to a electronic ignition such as an Ignitor. You have a simple electronic ignition to replace the points.
One reason I like e85 for racing - it's a lot less prone to carboning up an engine. In fact, when I switched to E85 in a supercharged sbc I used to race it actually partially cleaned off the pistons and combustion chamber over time. Not perfectly, there was still a little carbon in there but nowhere near as much as with race gas.
What kind of supercharger?
@@UFC_Buffalo Weiand 177
Thunderhead289 lawnmower carb - Genius
383 magnum vs 383 Chevy stroker
Totally different bore and strokes
Which one is best for fuel economy and why?
Thermodynamics can predict the limits of efficiency of a motor based solely on compression ratio. This is pre friction, oil losses, etc. 100 mpg might is possible on with a tiny motor in a tiny car.
My old Geo Metro with the 3-cylinder liter engine and five-speed would get 50 mpg if I didn't flog it. I never had to hypermile it either.
Lassi, you actually just made my point. A gas engine has about a 10 to 1 compression ratio, while a diesel runs about 18 to 1, or higher. Also diesel has many more btu per gallon.
Have a look at the channel Robot Cantina they put some small engines into a car. The fuel mileage was not that great.
@Lassi Kinnunen 81 I posted this to show " put a lawn mower engine on a car and get 200 MPG " has limitations.
I was all aboard for the first couple minutes.
Got lost in the BS afterwards to try to explain it!
So conventional wisdom says to block the heat crossovers in the heads for maximum performance but you just explained a benefit to increasing heat of the air/fuel mixture. In a future video can you elaborate on when it makes sense to block the heat cross over (like plan z) and when you should leave it open?
I had the same thought. UT had a vid a couple of years ago talking about blocking the heat crossover and how it helps keep the intake and as a result, the fuel in the carb, cooler.
I know there's some beef between UT and the Roadkill guys, so I cautiously bring this up... they found in an episode of Engine Masters that a cool intake helps with increasing cylinder filling, not due to cooler air temp but effectively via cavitation... Cooler intake walls = lower pressure area Vs hotter area = high pressure area, so the mixture wants to find it's way to the lower pressure area, helping with cylinder filling.
A hotter intake won't have time to heat up the mixture (too short of a duration) but it will create more resistance and slow down the mixture, whereas a cooler intake will provide less resistance, allowing more mixture to squeeze in. These are of course small differences.
They found that cool fuel temp was more important. Air temp going into carb didn't make much difference.
Cooler fuel means more energy in the same volume, so if for example an engine will pull through say 1 cubic inch of fuel, the cooler cube will contain more energy in that given volume, compared to the same size cube that's hotter. With more energy, rpm increases and the idle screw / jet can be adjusted down, to minimise the volume of fuel pulled through (in that example, maybe only a 0.9" cube needs to be drawn through).
Then again, that sort of suggests that the same volume is being pulled from the tank in either case. As temp changes volume, the idle screw / jets are compensating for energy per volume changes. It's still the same amount of energy, just in a different size. A warmer fuel will take up more space, so idle screw / jets need to accommodate that same unit of energy coming through in a larger volume. In other words, if tank volume is X, but in the warmer under hood temp that volume is now X +10%, volume is relative, so a warmer fuel unit passing through the carb may be X+10% but in its cooler state at the tank, it's still pulling through volume X. So maybe, fuel temp doesn't change volume consumption (efficiency), only that the metering of it needs to change relative to how that energy packet changes in volume in order not use the incorrect amount i.e. bring in a cooler mix but leave the metering the same, resulting in a larger volume being pulled the through unnecessarily. So effectively there is a dynamic between fuel tank volume, temp, and fuel draw at carb draw. 2 different temps, changing the volume, but still the same volume being pulled the through from tank (when carb adjusted the right). The cooling of fuel effectively acts a compressor... The same amount comes from the tank and the same energy is used by engine but because it's in a smaller packet, the metering is reducedduces to pull the same energy through, just in a smaller packet.
Possibly this is where hotter temps could be better... a hotter mix has more area between the molecules which requires a longer burn time (same as as lean idle mixture needing more time to burn), so this may suggest that a hotter mix would be able to release energy over a larger area in a given timeframe, creating more movement to act on the piston (it's already an expanded mix) and while it may push less (lower power), it would still push. And perhaps that's where economy from higher temps comes from... Using the minimal amount of effort to push the piston, but stil lmoving it, in exchange for lower power output.
Back to cooling quickly - A high vacuum level (cruise and idle) will help drop temp (through characteristics of low pressure effect on temp... As pressure drops, temp drops) but also the higher vacuum helps atomise the fuel more. The more fuel that is atomised, the more heat is taken out of the surroundings, keep temp low.
But you can't help think that a mixture that's as hot as possible, on the edge of combusting, is the best thing to put into a combustion chamber. That way very little change (work) is required to push the mixture into combustion, which is what would make it most efficient.
Ray-maybe I have it over simplified in my head but I always thought that the purpose of keeping the air/fuel mixture cool was that it was a denser charge in the same volume. You would cram more air and fuel into the same space and make more power. I never considered resistance to flow but I’d love to learn more.
The correct answer is what UT ignored. If you want to make power, you need to ATOMIZE the fuel a fine as you can get it, at the booster. Then you have to keep it as fine a you can until it hits the chamber. You need some fuel that is NOT vaporzied all the way to the chamber and into the chamber because converting the fuel to a gas (vaporization) drops the incoming charge temperature and that makes power. You can easily vaporize too much fuel and lose power. Also, I forget the temperature at which cast iron turns blue, it I know it’s more than 200 degrees and I’ve seen way too many cast iron intakes that were blue from way too much heat in the crossover. You use booster signal and design to atomize the fuel, and correct atomization leads to correct vaporization. And that makes power.
Tony, you the true talkin dude.