Fun fact: The 6-port engine in the Rx-8 actually has 5 intake modes! Idle - 3250rpm = Only the 2 ports in the middle iron are open 3250 - 5500rpm = Secondary shutter valve opens, allowing airflow in the lower ports in the end housings 5500 - 6250rpm = Variable fresh air duct opens on the airbox (shorter intake length before filter) 6250 - 7500rpm = Auxiliary port valve opens, allowing airflow in the upper ports in the end housings 7500 - Redline = Variable dynamic intake valve opens, opening a shorter intake resonance path Mazda went to town on this one.
Thanks for watching everyone! If you happened to be one of the 900 people who saw this on Wednesday - sorry for the "repost." I had no intentions of releasing two videos on Wednesday and messed up the scheduling. If you're interested in more rotary content, here's a detailed explanation including advantages (ruclips.net/video/sd6pJtR4PaY/видео.html) and here's more detail on why they're not currently in production (ruclips.net/video/v3uGJGzUYCI/видео.html). Hope everyone's having a great weekend!
+Engineering Explained, While you're on the topic of wankel engines, is there a chance you'll be doing a video on how mazda's hydrogen rotary engine works and how it could possibly be the one thing that keeps the wankel engine alive in the future?
Don't certain Honda vtecs use different intake runners to achieve the same effect? I believe they use a rotating drum inside the intake to direct airflow
I just wanted to thank you for your genuinely made videos that are the most humble I've seen anyone set the bar at. Your love for mechanics makes me happy. Thank you for all the time and effort you put into teaching so clearly and vividly.
+Wall Russ You do know that skyactiv is designed for fuel efficiency and power and is currently not implemented in rotary engines. The ports that enable more air flow in rotary engines are called "AUX" ports and are either vacuum or electronically controlled. Skyactiv didn't kick in. Aux ports did.
+Rotary LOLSmiles Assuming they didn't wire open the Aux ports like most young people do. I just built an engine starting with turbo housings so I didn't have to deal with Aux ports and could get a better shape to start with for the bridgeport.
@@jordandyar5967 aux ports r usually called headphones jacks. Jesus christ apple. Even the rotary has a headphone jack. The people at apple r dumbass's
+Engineering Explained - I feel you missed a big part of the VIS on the Renesis, as well as some piston engines like the BEAMS toyota/yamaha engines. Not only do the ports open to affect port velocities, but the actuators are situated in the intake manifold so as to change effective runner length, greatly increasing VE.
Another rotor video ! , its great to educate people about them as for the better part their a little unknown and people simply bash on them with no concept of how they work or just how good they can be, for the better part im sure they've never driven one that rev's to over 9000 rpm and so smoothly... its like nothing else. Thanks for uploading !
I think it's fascinating that after watching this video, that some still think the Rotary engine has pistons. Show how little they pay attention to what they see. Or how little they know about engines or what a piston really looks like.
You are very knowledgeable when it comes to the rotary engine .With that being said I could almost guarantee that you could make changes to make that wonderful little power plant more economical and efficient .
I would like you to demonstrate us more about Wankel's basic characteristics, like geometry, basic fuctionality, materials engineering,etc. Also, give people a clue about its true potential and ofcourse how many brands did actually give it a try on their vehicles and how far did they go. Ofcourse, you can mention Wankel's history in racing. I am very fond of these engines and feel that they were left behind due to certain economic circumstances.
2 stroke engines have a very similar technology in their exhaust called a power valve. You can distinctly feel when they open, and can significantly change the shape of the power curve by changing when they open.
So, rotary engines do have valves? In this case, the intake valves (shown at 1:57 ) - though they are outside the engine. In the video at 1:30, we could also claim that's a sleeve valve of sorts for the auxiliary port? That's inside the engine... Killing the myth that rotary engines, including the Wankel rotary engine design used by Mazda, do indeed have valves.
Interesting stuff. Cant wait to see what the next rotary has in store to increase thermal efficiency, mpg and emissions.... Direct injection alone would be huge for the rotary. Being able to precisely control the amount of fuel should help overall performance. And hopefully mazda can incorporate laser ignition for a more complete burn of the af mixture.
+RickTrajan My dads mate sold one for scrap value £300 2 years ago and sold the engine for £150 a week ago.... he was trying to make an RX7 mini but then wanted to "Make the money back" so he could restore a muscle car to 100% OEM parts...
I heard something about someone creating a ceramic type rotary engine that apparently is more efficient and reliable and can run multiple fuel types. What are your thoughts on that?
What I've been thinking about is having a full PP port and a rotary valve which can then do variable intake timing. Eliminate the center iron. Every rotary needs at least one turbo because the exiting exhaust is too hot.
It's not a solenoid that opens up the secondary ports. It is the speed of the exhaust gasses creating a vacuum effect in the lines attached to the secondaries that causes them to open. A solenoid is an electrical device.
+Jack Stewart the porting on the Naturally Aspirated rotaries affects all aspects of induction characteristic. The 'top' port he is explaining, is not only giving greater port area, but greater duration of the intake opening in relation to 'crank degrees' and therefor has the same effect or function.
+Jack Stewart A Valve is a device that opens and closes, in my perception, the Vtec is those two variable intake ports shown in the video. It's just one other type of valve management that makes the similar effect.
Next explain bridge (or other)proting please. You really have talant in explaining stuff and it would be really nice to know what you think about porting an rotary engine. Thanks
The variable length intact tracts used on the rotary engine make more power or TQ by changing the length and also speed of the incoming pressure waves , depending on length. The RX7 FC S4 N/A engines 86-88 are called 6 port engines. These engines have 2 primary intake ports and only use these primary ports before 3800 rpm. At 3800 rpm the S4 N/A engines open 2 more intake tracts, as well as 2 more oil injectors start working and the remaining 2 barrels of the 3 barrel 115MM TB also open up. The 86-88 S4 Turbo engine is a 4 port engine and does not have the variable intact tracts.Changes were made for the 89-91 N/A S5 engine, now Mazda added a VDI, which started to work at 7200 rpm and allowed these engines to produce power up to 7800 rpm stock. The 89-91 block for the S5 turbo engine is the same as previous years. This only applies to 2nd generation RX7,s
Your video doesn't detail any pulse-wave tuning of the intake or exhaust manifold, talking about air-flow only. I've never really thought about it in the context of rotary engines, but the varying lengths of the effective intake must have an affect on the intake pressures at certain rpms? Could you do us a video on variable intake lengths and their affects on typical vs rotary engines?
they are "stackable" if you will it usually just requires a longer eccentric shaft ususally a 3 peice in the case of 4 rotors 26b and longer reinforced studs but the engine has to be balanced and perfectly aligned to make sure it doesnt twist while running and break itself essentially . and they can be "v-mounted" in the case of the 12 rotor engine. how that works i really dont know. custom brackets to hold each set of rotors along with each eccentric shaft having its own pulley and a complex drive belt system from what i saw in the video of it . along with a costom i take manifold to feed all the "blocks" if you will. im sure its very complicated tho and took tons of time to develope.
I wonder if anyone has tried this kind of tech in a 2 stroke engine. I know 2 stroke is a dying breed. But they do pack power and would love a comeback.
It's vaccum controlled on the 85 you were showing. no solenoids. it's like a little vaccum chamber that as it collapses at high vaccum it rotates that shaft. just pulled all that stuff off mine, they were locked up.
The RX8 engine diagram is a bit off. No butterfly valves. You have a single SSV valve that actuates. It rotates to different positions to open and close the intakes. The positioning also allows cross flow from rotor to rotor. basically as on rotor closes it's ports a pressure wave heads back through the intake and into the other half of the engine. Mazda claims it makes for a sort of supercharging effect. Sort of. The pressure wave just shoves a little more air/fuel in. They claim it's good for a few HP. Not sure how much they say it is.
Toyota 4AGE had TVIS. This was a dual intake runner system with a simple gate for the second runner on each cylinder. At around 4500 rpm (someone will correct me on this cause I can't remember exact rpm) the second runners would open up. To those not sure why you want it closed at all, at low rpm you still want intake velocity to stay high but if both are open then the air will sort of stagnate at the intake valve since only a certain amount can go in the cylinder. Anywho, cool to learn that Mazda did something similar on the rotary. The unique design really does change everything so every problem has to be assessed in a new way instead of having tons of examples to learn from.
+Evan Moon opel have same system: The Twinport Ecotech engine is the second generation of the GM Family 0 engine technology (also called Family Zero ... haha, could even be "Family Zed" in the right parts of the world, eh?). It works by having the ability to close off one of the two intake ports near the intake valve at low engine speeds, which speeds up the air entering the cylinder and causes a swirl of the air fuel mixture as it enters. This produces better low end torque. Coupled with advanced exhaust gas recirculation allows for better gas mileage without engine misfires (from the extra exhaust gas). As the engine speeds up, the secondary port is opened. Here is an image of how the air flows into the engine with (left) and without (right) the port open:
+Evan Moon I've literally had T-VIS throw me off the road in the rain, mid-corner idiocy on my part in an MR2. :D Taurus SHO 3.0/3.2 engines had a similar system to T-VIS. Mazda also had VRIS on several v6 engines which worked similar to this rotary style VIS with 3 stages and 4 different intakes, (on different vehicles,) that worked in different rpm ranges. The BMW M5 and Porsche 959 also had variable intake systems.
+Evan Moon Everybody was playing with variable intake systems in the 80s. As fuel economy rules tightened up, manufacturers began designing smaller engines that could rev higher, and so needed larger port diameters to accommodate their high-end breathing needs. However, at low RPM, port velocity is too slow with such large ports and such small displacements, so manufacturers did what they could with what they had. Variable intake systems were often vacuum-actuated, not relying on the limited computing power of fuel injection systems of the day. For example, Nissan used several similar schemes whereby a vacuum actuator would open and close butterfly valves in secondary ports, or block off part of an intake port, including the Secondary Butterfly System used on the CA and RB series engines. These relied on manifold vacuum alone. At idle, the high vacuum condition closes the ports. As vacuum decreases or boost builds, the butterflies open up. Mazda's variable intake systems were similar, as were Toyota's. Of course, in the early 90s, variable valve timing and lift came along and changed the game, rendering many VIS systems obsolete.
Are these multiple intake ports a necessity because of the carburetor? I wonder if you could just use all three intake ports all the time with a fuel-injection system. But in 1985, I'm pretty sure Mazda used carburators on their RX-7s.
I just would like the point out that not all rotaries are this way. 12a engines only have 4 intake ports. 13b engines can either be 4 port or 6 port. In the 4 port engines many people do something called porting where they grind down the intake ports to allow for more airflow and subsequently more power. Not all of the engines have this "VTEC" system. Just something I thought I'd share!
1985 RX7 with a 13b, must of been the GSL-SE. Loved mine. Put 150k on it in 3 years. Those Rotors are the best, Higher mass and best for a turbo engine.
The real doktorbimmer Obsolete? Guess you don't know about the RX8 or RX Vision they are currently working on. As for the GSL-SE rotors, Atkins carries them.
And still works and is being put into a current vehicle, the RX Vision. Also with it's age, that has to say something for the tech then. It still beats anything with the same if not more displacement. When it was racing it was pitted against vehicles twice it's displacement, still taking that class in GTU.
I've personally beat Mustang 5.0's with my little 1.3L. I used to love when they caught up at the next light and asked "How many cylinders does that have?" and I'd say "None" that look of bewilderment was priceless.
I've experienced cruising in a Nissan with a continuously variable transmission (CVT). The extraordinarily low engine RPM at cruising speed made for some impressive fuel economy. I'm wondering if pairing a CVT with a Wankel operating at low RPM would be light weight enough to be economical. So, I guess my question is, since I understand that piston engines tend to bog down at low RPMs, is Wankel efficient enough to run that slowly? Looks like a marriage made in heaven to me.
doktorbimmer rotary engines are actually far superior to piston engines when it comes to insustrial needs due to their cost and size versus their power output
+Punchy LightBeer Supra is the best car I have owned. A series 2 VVTi 6 speed Supra turbo and I couldn't imagine owning anything else. I have only ever owned Toyota and I have had two supra's and my first car was a celica. I am an enthusiast and I care about fuel, I used literally a tank of premium in one day, I find myself filling up most morning after being out racing until late.
+Jake Gelly and its done on purpose. There have been better engines made that have more fuel economy, less parts, and same if not more power but the big companies snuff them out.
+Raoul G Bot 280hp out of an 1.3L in the case of the RX7 FD, shows the engineers got it right. We don't care about the 17mpg when we're leaving that Mustang 5..0 which by the way gets the same MPG in the 80's and 90's.
Hey I know you did a few videos back on Nissans' lmp1 car, but could you explain the hybrid system on that car? From what I'm getting they don't use a conventional system. If you have explained it, could you tell me which video? might have missed it
I filmed a video with Nismo which they were going to upload on their channel. Unfortunately I don't think that video will ever come out, and they have all the footage. :/
I actually hope Mazda will revive the rotary, they already announced a pretty realistic concept car at Tokio Motor Show. Who joins the hypetrain with me?? ^^
Very interesting and well explained. The emissions effectively killed this wonderful engine and the difficult seals, so if in the future one could solve these problems, it may be competitive again, right? Diesel has oil in the fuel mixture, would that not be sufficient to lubricate the tips of the rotors and avoid having to inject oil to burn and ruin the emissions? I know NSU, Mercedes, Fiat and even Norton motorcycles have dabbled with the Rotary engine and given up, therefore I am sure they must have considered all the options before relinquish their interest. Thank you for the info.
I just recently watched the video on the 4 reasons why the rotary is dead, and the main problem was fuel economy. That being said, with only one port open at low RPMS, does that mean that it is getting worse gas mileage at higher RPMS because all the ports are open, or does it compensate for the faster turning of the rotor?
I have a 13b with a carburetor conversion but there is nothing to link up to the variable air on the outside of intake manifold? what forum can I use to answer this question? im new to the rotary world
+Blehtubezz Aus VTEC main thing is change intake duration, because high rpm needed more time to the same air flow. This system open/close channels for more air but duration ? This system for me look more like viariable intake (only open/close Chanel for better air velocity, like OPEL TWIN PORT, TOYOTA T-VIS P..S me old opel have dual ram system, also have 3 stages (or 4, if idle stage), but it is different thing vs vtec,-working in "different section" , yes it increase air flow, but not change duration.
+fregis on a rotary the port shape is essentially the camshaft profile. having multiple ports that open at different times is like having multiple cam profiles on demand. rotary engines (at least the rx8 version) also have multiple length intake tracts as well on the intake manifold.
i think about that (different position vs rotor), but Engineering Explained only talk about intake velocity, just more air.... Port form, number opened increase time intake, ok like vtec system, or more i-vtec
Excuse him he knows nothing about Wankels. He says they are not reliable but they won the 24 hours of Le Mans in 1991 or 1992.. Also the Cannonball run back in1983.
so if the valves are controlled by a solenoid, then is would mean they would be either open or closed? Do you know if anyone (not that anyone other than Mazda has put much into rotatory) has made a variable system?
In the 13B engine I'm showing, yes, it's an "on/off." Dunno if they vary it with later models, doesn't seem like it would be hard to do with the later model engines.
my aux ports and vdi are open only cause they were seized shut lost a little bit of low end but i went to a gtu s diff which is a 4.30 vs the normal 4.10 so didn't notice a difference
not quite sure what the difference is between air flow and air velocity... something like pressure vs speed ? tyvm nice one (even though i dont quite understand!)
+Guillaume Breton Flow is the cross sectional area of the inside of the intake multiplied by the velocity. So they have a direct relationship most of the time. However, the total cross sectional area increases when the extra ports open so the velocity of the air in the intake doesn't increase at the same rate even though your overall flow is going up considerably. Hope that made any sense...
+Osvaldo Morales You are partially correct in that it is to increase horsepower but only that those auxiliary ports are closed to promote more stable engine operation at low speeds and of course gas mileage. When you climb the RPMs, the other valves open and you get increased airflow and more fuel to maximize the efficiency of the engine. Btw, the last naturally aspirated rotary made (86-91 RX-7) only put out 146-160 hp. The Renesis puts out anywhere from 230-240 hp. And they have the same gas mileage.
Thats pretty neat, my cousin had an FC rx7 and that valve you were twisting open you can buy upgraded versions that are affordable and he claimed it was a very noticeable difference. I love rotary engines and how they sound. especially with a nice port job. One of the things though is i've been told the rx8 rotary engine is among the worst rotary engines every made. is there a specific reason for that ?
answering the question thats used as the title of this video, yes, definitely...... rotary engines, specifically the more common 13B, uses the best type of VTEC, however Mazda calls the technology Twin Sequential Turbos, lol..... in all seriousness, no, the more common uses of rotaries are to make an insanely light and small displacement engine and then slapping as many turbos onto the engine as they can. has Mazda designed and utilized something SIMILAR that acts like VTEC/VVT/etc? yes, but definitely not the same because rotary engines dont have CAM SHAFTS. in their naturally aspirated (non-turbo) engines, they added 1 additional intake and 1 additional exhaust port, and used crank shaft sensors and computers to actuate these valves; off of what rev youre at, throttle input, etc.... that technically isnt a traditional variable valve timing mechanism though, because traditional versions are actuated via retarding/advancing the cam shafts (which is the part that opens/closes your valves), and like i said earlier, rotaries dont have cam shafts. that is all. farewell. stay frosty.
that was sarcasm dude.. lol.. VTEC was essentially designed to mimic a turbo setup; when off boost, youre not consuming much MPG, when your boost kicks in, you use more fuel.. VTEC is like that in a sense, when out of VTEC, you're not consuming much fuel, when VTEC kicks in, you're putting your engine in "turbo boost mode".... so, in a sense, Mazda's VTEC is the best kind because it utilizes twin turbos lol
Im still wondering why there are less/smaller exhaust valves than air/fuel inlet valves. Because hot air expands and needs more room in my mind. Could someone get my mind clear? :D
Fun fact: The 6-port engine in the Rx-8 actually has 5 intake modes!
Idle - 3250rpm = Only the 2 ports in the middle iron are open
3250 - 5500rpm = Secondary shutter valve opens, allowing airflow in the lower ports in the end housings
5500 - 6250rpm = Variable fresh air duct opens on the airbox (shorter intake length before filter)
6250 - 7500rpm = Auxiliary port valve opens, allowing airflow in the upper ports in the end housings
7500 - Redline = Variable dynamic intake valve opens, opening a shorter intake resonance path
Mazda went to town on this one.
I like how the exhaust in the whiteboard diagram is shooting flames
+Marius G I Lol'd when Jason showed the whiteboard
That's because rotary's don't burn all the fuel pumped in and often shoot flames when they hit the rev limiter
Do you know why he did that?
Correct.
i mean u kinda need to label which pipe is the exhaust lol
Thanks for watching everyone! If you happened to be one of the 900 people who saw this on Wednesday - sorry for the "repost." I had no intentions of releasing two videos on Wednesday and messed up the scheduling. If you're interested in more rotary content, here's a detailed explanation including advantages (ruclips.net/video/sd6pJtR4PaY/видео.html) and here's more detail on why they're not currently in production (ruclips.net/video/v3uGJGzUYCI/видео.html). Hope everyone's having a great weekend!
+Engineering Explained HEHE I got to see the pre-release! I'm special!
I also got to see it!!!
how about Chrysler turbine car (u probably wont)
+Engineering Explained, While you're on the topic of wankel engines, is there a chance you'll be doing a video on how mazda's hydrogen rotary engine works and how it could possibly be the one thing that keeps the wankel engine alive in the future?
Don't certain Honda vtecs use different intake runners to achieve the same effect? I believe they use a rotating drum inside the intake to direct airflow
That explains a lot. The "High Power Package" on the Renesis for the RX-8 makes it rev OVER 9000!!!!!
I just wanted to thank you for your genuinely made videos that are the most humble I've seen anyone set the bar at. Your love for mechanics makes me happy. Thank you for all the time and effort you put into teaching so clearly and vividly.
And erroneously.
Engineers are very creative. Imagine how long it took for engineers to come up with these complex machines?
Around 5,500 years
+Taylor Jenkins That's a good approximation!
The real doktorbimmer lol. How you been? Haven't been in a conversation with you for a while.
The real doktorbimmer Wow. What an inspiring response!
the more you make rotary engine videos the more I fall in love with it
Thanks for the info in Rotary Engines. Knowledge is important in life. Always appreciated
SKYACTIV KICKED IN FAM TBH
+Wall Russ I'M DEAD XD
+Wall Russ You do know that skyactiv is designed for fuel efficiency and power and is currently not implemented in rotary engines. The ports that enable more air flow in rotary engines are called "AUX" ports and are either vacuum or electronically controlled. Skyactiv didn't kick in. Aux ports did.
+Rotary LOLSmiles Assuming they didn't wire open the Aux ports like most young people do. I just built an engine starting with turbo housings so I didn't have to deal with Aux ports and could get a better shape to start with for the bridgeport.
@@jordandyar5967 aux ports r usually called headphones jacks. Jesus christ apple. Even the rotary has a headphone jack. The people at apple r dumbass's
Love that you took the time to draw the flames coming out of the exhaust. Has to be a realistic representation.
so did vtec kick in YO ?
This video is great! Please come back more with rotary engine episodes!!
He knows little about Wankels.
Only a 3 minute video and I already understand it. Quality video!
+Engineering Explained - I feel you missed a big part of the VIS on the Renesis, as well as some piston engines like the BEAMS toyota/yamaha engines.
Not only do the ports open to affect port velocities, but the actuators are situated in the intake manifold so as to change effective runner length, greatly increasing VE.
Great video!
Reminds me more of an intake runner control system. Especially when you described the one on the Rx-8. Love your videos!
Perfect! ... a small 3 minute vid straight to the point bite sized info job done! Thank you again!
It's great to know how engines work in detail. Great video
Love your rotary videos.
i find the rotary engine very fascinating great vids 👍👍
I laughed so hard when I saw Rotary VTEC in the thumbnail lol
Believe me you really notice when the SSV comes open about 5k RPM in an RX-8.
rotary-tech kicked in, yo
I Suggest Next Video Should Be About Different Types Of Porting.
Another rotor video ! , its great to educate people about them as for the better part their a little unknown and people simply bash on them with no concept of how they work or just how good they can be, for the better part im sure they've never driven one that rev's to over 9000 rpm and so smoothly... its like nothing else.
Thanks for uploading !
I love your wankel series. Keep it up!
I think it's fascinating that after watching this video, that some still think the Rotary engine has pistons. Show how little they pay attention to what they see. Or how little they know about engines or what a piston really looks like.
You are very knowledgeable when it comes to the rotary engine .With that being said I could almost guarantee that you could make changes to make that wonderful little power plant more economical and efficient .
THIS ENGINE IS A HEAD OF ITS TIME
Can you do one about old aircraft piston rotary engines and how their blip system works?
I would like you to demonstrate us more about Wankel's basic characteristics, like geometry, basic fuctionality, materials engineering,etc. Also, give people a clue about its true potential and ofcourse how many brands did actually give it a try on their vehicles and how far did they go. Ofcourse, you can mention Wankel's history in racing. I am very fond of these engines and feel that they were left behind due to certain economic circumstances.
2 stroke engines have a very similar technology in their exhaust called a power valve. You can distinctly feel when they open, and can significantly change the shape of the power curve by changing when they open.
So, rotary engines do have valves? In this case, the intake valves (shown at 1:57 ) - though they are outside the engine. In the video at 1:30, we could also claim that's a sleeve valve of sorts for the auxiliary port? That's inside the engine... Killing the myth that rotary engines, including the Wankel rotary engine design used by Mazda, do indeed have valves.
Interesting stuff. Cant wait to see what the next rotary has in store to increase thermal efficiency, mpg and emissions.... Direct injection alone would be huge for the rotary. Being able to precisely control the amount of fuel should help overall performance. And hopefully mazda can incorporate laser ignition for a more complete burn of the af mixture.
All these rotor vids, watch this man buy an rx7
rx7 became too expensive too fast
+RickTrajan My dads mate sold one for scrap value £300 2 years ago and sold the engine for £150 a week ago.... he was trying to make an RX7 mini but then wanted to "Make the money back" so he could restore a muscle car to 100% OEM parts...
+GHOST it ain't a muscle car, and 1~2 years ago their price were decent in canada. maybe it's the hype or age.
RickTrajan No he sold the RX7 engine to restore A muscle car... not the rx7 you derp... also in the UK the prices are insane for RX7's
+GHOST XD thanks. I love the look of rx7 fd it's on the top of my dream cars.
Had no idea, very cool
hmmmm.. I didn't think they did, but the way they achieved it appears very simple. Definitely learning something new everyday, thank you, :-).
Dude, love the videos, and the new shirt and 'do :P
Jason. It would be cool to see a renesis (13B-MSP) vs the older style rotary comparison video.
I heard something about someone creating a ceramic type rotary engine that apparently is more efficient and reliable and can run multiple fuel types. What are your thoughts on that?
Rotaries are a lot of fun to rev. My rx-8 really starts to pull above 4k rpm, it's a similar feeling to a turbo spooling up.
+Graceful Shanks
no, it does not. a serious turbocharged car will feel totally different (at least one, were the turbo starts to spool up a 4k rpm).
Do a video on the speculated technologies of the upcoming 16x rotary engine.
hey. nice job with the explanation. by any chance can u do a video on the principles 5 stroke and 6 stroke engines.
What I've been thinking about is having a full PP port and a rotary valve which can then do variable intake timing. Eliminate the center iron. Every rotary needs at least one turbo because the exiting exhaust is too hot.
It's not a solenoid that opens up the secondary ports. It is the speed of the exhaust gasses creating a vacuum effect in the lines attached to the secondaries that causes them to open. A solenoid is an electrical device.
is VTEC not variable valve timing. if so how could a rotary engine have VTEC
+Jack Stewart Also alters lift, as in the area for which air can flow into the engine (at high RPM).
+Engineering Explained wouldnt what Mazda implemented in their motors be more in the realms of tuned induction as opposed to a Hondas variant of vvt?
+Jack Stewart the porting on the Naturally Aspirated rotaries affects all aspects of induction characteristic. The 'top' port he is explaining, is not only giving greater port area, but greater duration of the intake opening in relation to 'crank degrees' and therefor has the same effect or function.
+Jack Stewart A Valve is a device that opens and closes, in my perception, the Vtec is those two variable intake ports shown in the video.
It's just one other type of valve management that makes the similar effect.
on the 13b mazda was the first to introduce this kind of air induction into a car. also known as "6th port"
FB rx7 is life, wish mine was a 13B EFI GSL-SE but I got the 12A.
Next explain bridge (or other)proting please. You really have talant in explaining stuff and it would be really nice to know what you think about porting an rotary engine. Thanks
The variable length intact tracts used on the rotary engine make more power or TQ by changing the length and also speed of the incoming pressure waves , depending on length. The RX7 FC S4 N/A engines 86-88 are called 6 port engines. These engines have 2 primary intake ports and only use these primary ports before 3800 rpm. At 3800 rpm the S4 N/A engines open 2 more intake tracts, as well as 2 more oil injectors start working and the remaining 2 barrels of the 3 barrel 115MM TB also open up. The 86-88 S4 Turbo engine is a 4 port engine and does not have the variable intact tracts.Changes were made for the 89-91 N/A S5 engine, now Mazda added a VDI, which started to work at 7200 rpm and allowed these engines to produce power up to 7800 rpm stock. The 89-91 block for the S5 turbo engine is the same as previous years. This only applies to 2nd generation RX7,s
Your video doesn't detail any pulse-wave tuning of the intake or exhaust manifold, talking about air-flow only. I've never really thought about it in the context of rotary engines, but the varying lengths of the effective intake must have an affect on the intake pressures at certain rpms? Could you do us a video on variable intake lengths and their affects on typical vs rotary engines?
+Engineering Explained Couldn't you make a Review about the Maxda RX-7 (advantages and disadvantages) ? Thank you for reading
cool! many 2 stroke bike engine use a similar sistem for the exhaust port
they are "stackable" if you will it usually just requires a longer eccentric shaft ususally a 3 peice in the case of 4 rotors 26b and longer reinforced studs but the engine has to be balanced and perfectly aligned to make sure it doesnt twist while running and break itself essentially . and they can be "v-mounted" in the case of the 12 rotor engine. how that works i really dont know. custom brackets to hold each set of rotors along with each eccentric shaft having its own pulley and a complex drive belt system from what i saw in the video of it . along with a costom i take manifold to feed all the "blocks" if you will. im sure its very complicated tho and took tons of time to develope.
Can you please also explain what is bridge port and the pros and cons thank you
I wonder if anyone has tried this kind of tech in a 2 stroke engine. I know 2 stroke is a dying breed. But they do pack power and would love a comeback.
This reminds me of the YPVS engine's in old Yamaha two stroke bikes
Can't wait to see if they apply this to the new rotary that they varified sep6 2017
Very good explanation. Maybe a working Demonstration could help people conceptualize better 🤔
Hey Jason, do you have a video on Desmodromic valve drive?
It's vaccum controlled on the 85 you were showing. no solenoids. it's like a little vaccum chamber that as it collapses at high vaccum it rotates that shaft. just pulled all that stuff off mine, they were locked up.
Lock them open. It's like running with 4 barrels open had one called the Hemi Stomper
The RX8 engine diagram is a bit off. No butterfly valves. You have a single SSV valve that actuates. It rotates to different positions to open and close the intakes. The positioning also allows cross flow from rotor to rotor. basically as on rotor closes it's ports a pressure wave heads back through the intake and into the other half of the engine. Mazda claims it makes for a sort of supercharging effect. Sort of. The pressure wave just shoves a little more air/fuel in. They claim it's good for a few HP. Not sure how much they say it is.
You should partner up with James May for a show. You guys could be best buds.
Can you do a video on blow off valves please
Toyota 4AGE had TVIS. This was a dual intake runner system with a simple gate for the second runner on each cylinder. At around 4500 rpm (someone will correct me on this cause I can't remember exact rpm) the second runners would open up.
To those not sure why you want it closed at all, at low rpm you still want intake velocity to stay high but if both are open then the air will sort of stagnate at the intake valve since only a certain amount can go in the cylinder.
Anywho, cool to learn that Mazda did something similar on the rotary. The unique design really does change everything so every problem has to be assessed in a new way instead of having tons of examples to learn from.
+Evan Moon opel have same system:
The Twinport Ecotech engine is the second generation of the GM Family 0 engine technology (also called Family Zero ... haha, could even be "Family Zed" in the right parts of the world, eh?). It works by having the ability to close off one of the two intake ports near the intake valve at low engine speeds, which speeds up the air entering the cylinder and causes a swirl of the air fuel mixture as it enters. This produces better low end torque. Coupled with advanced exhaust gas recirculation allows for better gas mileage without engine misfires (from the extra exhaust gas). As the engine speeds up, the secondary port is opened. Here is an image of how the air flows into the engine with (left) and without (right) the port open:
+Evan Moon I've literally had T-VIS throw me off the road in the rain, mid-corner idiocy on my part in an MR2. :D Taurus SHO 3.0/3.2 engines had a similar system to T-VIS. Mazda also had VRIS on several v6 engines which worked similar to this rotary style VIS with 3 stages and 4 different intakes, (on different vehicles,) that worked in different rpm ranges. The BMW M5 and Porsche 959 also had variable intake systems.
+Evan Moon Everybody was playing with variable intake systems in the 80s. As fuel economy rules tightened up, manufacturers began designing smaller engines that could rev higher, and so needed larger port diameters to accommodate their high-end breathing needs. However, at low RPM, port velocity is too slow with such large ports and such small displacements, so manufacturers did what they could with what they had. Variable intake systems were often vacuum-actuated, not relying on the limited computing power of fuel injection systems of the day. For example, Nissan used several similar schemes whereby a vacuum actuator would open and close butterfly valves in secondary ports, or block off part of an intake port, including the Secondary Butterfly System used on the CA and RB series engines. These relied on manifold vacuum alone. At idle, the high vacuum condition closes the ports. As vacuum decreases or boost builds, the butterflies open up. Mazda's variable intake systems were similar, as were Toyota's. Of course, in the early 90s, variable valve timing and lift came along and changed the game, rendering many VIS systems obsolete.
Mazda's VRIS was ECU controlled vacuum solenoids and lived on to 2002. My favorite was the one for the M5.
My first car had this exact engine... Good times where had.
Oh and... who can reasonably say "my car is older than me"? :D
+Pyrrha Nikos i love cars that are older than me :)
My car is about twice as old as me
Are these multiple intake ports a necessity because of the carburetor? I wonder if you could just use all three intake ports all the time with a fuel-injection system. But in 1985, I'm pretty sure Mazda used carburators on their RX-7s.
GSL SE
I just would like the point out that not all rotaries are this way.
12a engines only have 4 intake ports. 13b engines can either be 4 port or 6 port.
In the 4 port engines many people do something called porting where they grind down the intake ports to allow for more airflow and subsequently more power.
Not all of the engines have this "VTEC" system. Just something I thought I'd share!
+Nick White Pretty much from 86+, rotaries have had this system in place. 6 ports primarily.
Can you please make a comparison of different engine types (rotary, boxer, v-engines) concerning horsepower per weight/volume/dollar.
🏁
Can you explain how variable length Intakes (like the 787 had) work and what exactly do they do?
1985 RX7 with a 13b, must of been the GSL-SE. Loved mine. Put 150k on it in 3 years. Those Rotors are the best, Higher mass and best for a turbo engine.
The real doktorbimmer
Obsolete? Guess you don't know about the RX8 or RX Vision they are currently working on. As for the GSL-SE rotors, Atkins carries them.
The real doktorbimmer
I currently own an 1993 RX7 and keep up with the technology.
And still works and is being put into a current vehicle, the RX Vision.
Also with it's age, that has to say something for the tech then. It still beats anything with the same if not more displacement. When it was racing it was pitted against vehicles twice it's displacement, still taking that class in GTU.
Ignorance is bliss.
I've personally beat Mustang 5.0's with my little 1.3L.
I used to love when they caught up at the next light and asked "How many cylinders does that have?" and I'd say "None" that look of bewilderment was priceless.
Rotary goodness!
I've experienced cruising in a Nissan with a continuously variable transmission (CVT). The extraordinarily low engine RPM at cruising speed made for some impressive fuel economy.
I'm wondering if pairing a CVT with a Wankel operating at low RPM would be light weight enough to be economical. So, I guess my question is, since I understand that piston engines tend to bog down at low RPMs, is Wankel efficient enough to run that slowly?
Looks like a marriage made in heaven to me.
Any idea why the rotary engine design isn't used in refeigeration?
Can you make a video on How VVT works ?
Can forced induction and placing a 3rd ignitor at the middle of the combustion stroke would be of any help to burn the mixture properly ?
Sounds a lot like TVIS from the MR2 AW11 rather than any other kind of VVT variation.
Could you do a video on the Koenigsegg V8 engine used in the Agera? How did they achieve over 1000HP with half the cylinders of the W16?
cant wait for the next generation of rotaries
doktorbimmer hahah mah boy, you should look at the news, rotarys are back your little hater
doktorbimmer rotary engines are actually far superior to piston engines when it comes to insustrial needs due to their cost and size versus their power output
so much engineering effort and so little fuel economy
+Punchy LightBeer Supra is the best car I have owned. A series 2 VVTi 6 speed Supra turbo and I couldn't imagine owning anything else.
I have only ever owned Toyota and I have had two supra's and my first car was a celica.
I am an enthusiast and I care about fuel, I used literally a tank of premium in one day, I find myself filling up most morning after being out racing until late.
+Punchy LightBeer 22L/100km is not 9.4 Gallons per mile. You probably meant 9.4 miles per gallon which would be more accurate.
+Jake Gelly There is more to life than fuel economy... :-D
+Jake Gelly and its done on purpose. There have been better engines made that have more fuel economy, less parts, and same if not more power but the big companies snuff them out.
+Raoul G Bot 280hp out of an 1.3L in the case of the RX7 FD, shows the engineers got it right. We don't care about the 17mpg when we're leaving that Mustang 5..0 which by the way gets the same MPG in the 80's and 90's.
Hey I know you did a few videos back on Nissans' lmp1 car, but could you explain the hybrid system on that car? From what I'm getting they don't use a conventional system. If you have explained it, could you tell me which video? might have missed it
I filmed a video with Nismo which they were going to upload on their channel. Unfortunately I don't think that video will ever come out, and they have all the footage. :/
makes me want a rotary just so I can impress my friends
I actually hope Mazda will revive the rotary, they already announced a pretty realistic concept car at Tokio Motor Show. Who joins the hypetrain with me?? ^^
Had a 1973 RX3 Mazda 2200 pounds 8 mpg new spark plugs every 1000 miles new seals at 10,000 miles. What a POS
Very interesting and well explained. The emissions effectively killed this wonderful engine and the difficult seals, so if in the future one could solve these problems, it may be competitive again, right? Diesel has oil in the fuel mixture, would that not be sufficient to lubricate the tips of the rotors and avoid having to inject oil to burn and ruin the emissions? I know NSU, Mercedes, Fiat and even Norton motorcycles have dabbled with the Rotary engine and given up, therefore I am sure they must have considered all the options before relinquish their interest. Thank you for the info.
I just recently watched the video on the 4 reasons why the rotary is dead, and the main problem was fuel economy. That being said, with only one port open at low RPMS, does that mean that it is getting worse gas mileage at higher RPMS because all the ports are open, or does it compensate for the faster turning of the rotor?
Look at Jason's later vids on the rotary, especially the hydrogen one.
these look relatively easy to work on. Anyone ever rebuilt one?
I have a 13b with a carburetor conversion but there is nothing to link up to the variable air on the outside of intake manifold? what forum can I use to answer this question? im new to the rotary world
do you prefer/like the rotary engine better or vtec engine more?
Is just variable intake, So you wrote VTEC just for show? only get better ratting?
+Blehtubezz Aus VTEC main thing is change intake duration, because high rpm needed more time to the same air flow.
This system open/close channels for more air but duration ? This system for me look more like viariable intake (only open/close Chanel for better air velocity, like OPEL TWIN PORT, TOYOTA T-VIS
P..S me old opel have dual ram system, also have 3 stages (or 4, if idle stage), but it is different thing vs vtec,-working in "different section" , yes it increase air flow, but not change duration.
+fregis on a rotary the port shape is essentially the camshaft profile. having multiple ports that open at different times is like having multiple cam profiles on demand. rotary engines (at least the rx8 version) also have multiple length intake tracts as well on the intake manifold.
i think about that (different position vs rotor), but Engineering Explained only talk about intake velocity, just more air.... Port form, number opened increase time intake, ok like vtec system, or more i-vtec
Excuse him he knows nothing about Wankels. He says they are not reliable but they won the 24 hours of Le Mans in 1991 or 1992.. Also the Cannonball run back in1983.
You see people doing dual engine builds... imagine dual rotary engines!!! One in the front and one in the back.
so if the valves are controlled by a solenoid, then is would mean they would be either open or closed? Do you know if anyone (not that anyone other than Mazda has put much into rotatory) has made a variable system?
In the 13B engine I'm showing, yes, it's an "on/off." Dunno if they vary it with later models, doesn't seem like it would be hard to do with the later model engines.
my aux ports and vdi are open only cause they were seized shut lost a little bit of low end but i went to a gtu s diff which is a 4.30 vs the normal 4.10 so didn't notice a difference
not quite sure what the difference is between air flow and air velocity... something like pressure vs speed ? tyvm nice one (even though i dont quite understand!)
+Guillaume Breton Flow is the cross sectional area of the inside of the intake multiplied by the velocity. So they have a direct relationship most of the time. However, the total cross sectional area increases when the extra ports open so the velocity of the air in the intake doesn't increase at the same rate even though your overall flow is going up considerably. Hope that made any sense...
why not just use one valve then automatically adjust the valve based on speed like using governor to control the valve?
how do f1 engines Rev so high?
+Joshua Lee Chee ruclips.net/video/SJs_64Aj4Ho/видео.html
+Engineering Explained thank you
Super short stoke has a great deal to do with it as well
compressed nitrogen as valve springs too I see from the video
Shorter stroke.
Is this done more to increase fuel economy/efficiency than to increase horsepower? The waknel isn't known for it's MPGs.
+Osvaldo Morales You are partially correct in that it is to increase horsepower but only that those auxiliary ports are closed to promote more stable engine operation at low speeds and of course gas mileage. When you climb the RPMs, the other valves open and you get increased airflow and more fuel to maximize the efficiency of the engine. Btw, the last naturally aspirated rotary made (86-91 RX-7) only put out 146-160 hp. The Renesis puts out anywhere from 230-240 hp. And they have the same gas mileage.
VTEC kicked in YO!
Thats pretty neat, my cousin had an FC rx7 and that valve you were twisting open you can buy upgraded versions that are affordable and he claimed it was a very noticeable difference.
I love rotary engines and how they sound. especially with a nice port job. One of the things though is i've been told the rx8 rotary engine is among the worst rotary engines every made. is there a specific reason for that ?
answering the question thats used as the title of this video, yes, definitely...... rotary engines, specifically the more common 13B, uses the best type of VTEC, however Mazda calls the technology Twin Sequential Turbos, lol..... in all seriousness, no, the more common uses of rotaries are to make an insanely light and small displacement engine and then slapping as many turbos onto the engine as they can. has Mazda designed and utilized something SIMILAR that acts like VTEC/VVT/etc? yes, but definitely not the same because rotary engines dont have CAM SHAFTS. in their naturally aspirated (non-turbo) engines, they added 1 additional intake and 1 additional exhaust port, and used crank shaft sensors and computers to actuate these valves; off of what rev youre at, throttle input, etc.... that technically isnt a traditional variable valve timing mechanism though, because traditional versions are actuated via retarding/advancing the cam shafts (which is the part that opens/closes your valves), and like i said earlier, rotaries dont have cam shafts.
that is all.
farewell.
stay frosty.
that was sarcasm dude.. lol.. VTEC was essentially designed to mimic a turbo setup; when off boost, youre not consuming much MPG, when your boost kicks in, you use more fuel.. VTEC is like that in a sense, when out of VTEC, you're not consuming much fuel, when VTEC kicks in, you're putting your engine in "turbo boost mode".... so, in a sense, Mazda's VTEC is the best kind because it utilizes twin turbos lol
Im still wondering why there are less/smaller exhaust valves than air/fuel inlet valves. Because hot air expands and needs more room in my mind. Could someone get my mind clear? :D
Is it for sale?