2 stroke car?

[[email protected]]

While I was reading carb and intake mods and motorcycle carbs, I thought of my old dirt bike. Two stroke designs are very simple, just wondering if any ever existed beyond the very early days. With a 2.0L engine like ours, you could get 2X the HP easily. ...of course the trade of would be rebuilding the top of the engine occassionally and failing emissions. But hey, we do that anyway, right? : )

[cardoc33]

2 strokers don't have much of a torque curve. Don't need one on a bike that weighs 300lbs. Not so good on a 3000lbs car.

[pimp86LX]

lol yeah the curve is insane

no torque....no torque....no torque....ALL THE TORQUE RIGHT NOW WEEEEEEEEEEEEEEEEEEEEEEE!


Ah the fond memories of my first RD-350.

[kraftaroni]

Yea a rd350 or 400 doesnt have much torque but new dirtbikes do. Old rd's didnt even have power valves. They also had terrible reeds that made the low end miserable. Plus now they have the technology of properly timed ports for an all around powerband.
One of the first Subaru's was called the Subaru 360 it was a two stroke 356cc motor,"360", Suzuki, Mitsubishi all had two stroke cars.
Think about it in order for 4 stroke motorcycles to compete witht the two strokes they have to give them double the displacement. Even with that difference in displacment they still only make 2 more hp and 5 more ft pounds of torque.
Check this article out you may see more two stroke cars sooner than you think.
http://www.findarticles.com/p/articles/mi_m3165/is_n7_v28/ai_12485781
They even have a two stroke motor that isn't a total loss system for oil it has a crankcase with oil in it that doesnt get mixed with the fuel. The #1 problem with internal combustion engines is leakage and the valve-train.

[ZackieDarko]

lol yeah the curve is insane
no torque....no torque....no torque....ALL THE TORQUE RIGHT NOW WEEEEEEEEEEEEEEEEEEEEEEE!
Ah the fond memories of my first RD-350.
:bowrofl: :bowrofl: :bowrofl:

[[email protected]]

300lb bike? How about a 40 ton train? http://www.looksmartsacramento.com/p/articles/mi_m1215/is_3_206/ai_n13629194

Torque isn't the problem. Keep in mind people regularly use racing/lightened flywheels which reduces torque.

** I stand corrected: torque is not reduced. A flywheel will only help maintain a consistent output ...or something like that.

[[email protected]]

I did a little homework after I read the posts. I expected to get one or two replies, but it seems I'm not the only one interested in different ideas. Like anything else involing engineering, it's cost - R&D, market, etc.

The answer about torque is mostly right. So how does a 2 stroke move 40 tons? Beats the hell out of me but it ain't by revving the engine to 12K and dumping the clutch, lol. What I've read about auto applications is that a loosely designed 2 stroke is put in a car and the results are usually not so good. In the 60's, the Berkeley 500 was built for racing which had enormous output, but burned pistons or fouled points, etc on a regular basis. This is common for two strokes (any bike manual) and is another reason why they didn't gain popularity. While the design is simple, the components are more critcal so... what you get in a typical weedeater is cheap fabrication for a device that won't usually see more than a 100 hours of use. Compare that to a company that only develops 2 stroke engines for it's railway diesel engines and you have a much different outlook on market and R&D.

While torque seems like the obvious answer, the orginal reason was probably emissions. After finding about the train, it appears emissions have greatly been reduced over the years, just like the diesel. At this point, it's hard to see 2 strokes become popular in such a 4 stroke saturated environment (cars), but they still exist in certain niches where they flourish. While comparing apples and oranges, either one can always outperform the other given unlimited R&D and budget. It's like the ricer/muscle car arguement that goes on, and on, and on... To me a four stroke car is the obvious choice today, but that's like saying Microsoft is the O/S of choice. It's not like anyone has a choice really. It's what happened to work out at the time and what we've come to live with. Cheers!

[Accordtheory]

2 stroke, supercharging, and direct in cylinder injection=the future

...at least before fuel cells and ultra high power density capacitors take over..imagine, the 900whp electric car, you'll see that, no doubt..

[Accordtheory]

direct injection so you don't get fuel in the exhaust on the overlap cycle, of course. that's how 2 stroke diesels already work..

If you want to learn more about this , look at how the engines on huge cruise ships are set up. 2 stroke diesels running insane boost levels, like 50-70psi..

How's this for a question, why can't a diesel engine run on gasoline?

[Accordtheory]

Keep in mind people regularly use racing/lightened flywheels which reduces torque.

How could a flywheel possibly reduce torque. You're talking about inertia. Once your clutch is engaged, your car is faster with a lighter flywheel. That will show up on an acceleration dyno too.

[[email protected]]

I want to see 900whp ...parked in my garage!! : )

I noticed all the turbocharging. Pretty cool, but expensive obviously. Direct injection, 2 strokes, super/turbo-charging seems to have more potential, but what do I know...

I would think diesels can't run on gas for many reasons. For one, there is no true spark. Also, I think it would be too hot for the engine design. Never thought about it much though. Give me the answers!! : )

You're right. I'm talking about inertia... which manages torque. It doesn't effectively increase/decrease the inherent torque of an engine, but it stabilizes the output. A lighter flywheel will reduce the time it takes to accelerate, but a heavier one maintains a consistent output more effectively. So, off the line at a given rpm, a heavier flywheel will maintain the energy the engine has created better than a lighter flywheel. That was my point. I'm all about lighter flywheels and acceleration. : )

[AccordDX86]

Diesels cant run on gas, there is no true spark because diesels dont need any heat initially (unless really cold, which the glow plug is there for). Diesel explodes when compressed, like an oil boiler in your house.

[[email protected]]

Did you see the 3 wheeler car on Discovery yet? It uses a front end like a bike, but has a 2-3 person cab which rotates at some point near the rear (up to 45 degrees). It looked like lots of negative camber and independent suspension, which would make the handling interesting to say the least. Can't remember if it was gas or electric.

[Accordtheory]

I don't even have cable tv..ugh..

I would love for someone to give me a definitive answer on why a diesel "can't" run on gasoline.. I do have a couple of my own theories though as far as why an existing diesel can't run on gasoline, but I see no reason why a compression ignition gasoline engine couldn't be built, with the right technology. I think it would all come down to the injector, you would need to get the fuel out into the chamber extremely quickly because of the much higher rate of flame propagation as compared with diesel, but you could do some really awesome shit with this style of engine. Stratified charge combustion with over a 23:1 static compression ratio. Put that in a 5600lb denali, get 30mpg..

I Seriously believe that there are forces in the industry, car companies, oil interests, etc, that are holding back the advancement of technology for their own financial sake. Just look at the shit endyn was building in the 80s, they built pro stock engines that ran over 23:1 compression on race gas, and that trickled down to street engines in the form of cam and piston kits designed to raise the compression and burn the mixture only on the exhaust side of the chamber. (cam profile tailored to avoid piston to valve contact with the raised dome on the intake side. The raised dome would push the mixture into the exhaust side of the chamber) We Still dont have that on production engines. They're halfway there, adding 'quench area' in the chamber, (edelbrock's sbc 'e-tec' heads are a good example of quench with a flat top piston) but they haven't taken it the rest of the way.
one more thing.. I don't know if you know, but saab came out with a variable compression ratio engine years ago. Very simple concept, the cylinders pivot slightly on an axist adjacent to the bottom of the cylinders. I remember thinking that was amazing when it came out, but now I know that concept is obsolete..by lowering the compression that way, you lose the quench, actually increasing your propensity of detonation, while of course lowering your efficiency..

Electric cars are the future, I need to design that ultra capacitor, damn it..Batteries and their associated energy losses will always hold the electric car back. Fuel cells, ultra high energy density capacitors, and electric motors will be the combination for the next 100 years.

[snoopyloopy]

The answer about torque is mostly right. So how does a 2 stroke move 40 tons? Beats the hell out of me but it ain't by revving the engine to 12K and dumping the clutch, lol.
no, lol, certainly is not. they idle under 300, and usually run a little under 1000. they work by powering a generator which then powers electric motors in the trucks.
http://travel.howstuffworks.com/diesel-locomotive.htm

[[email protected]]

Thanks for the link snoopyloopy.

Absolutely agree about the industry being held back. I've heard all kind of stories as I'm sure everyone else has about inventions that were bought out or banned. Not a fan of politics, big gov, etc and that's probably the reason. It kills me up how foolish the SUV craze has become ...people paying $100 a week to take their kids to school and buy groceries. The gas/diesel 2 stroke efficiency might a "Myth Busters" episode? (Junkyard Wars is a great show if you havn't seen it.)

Here is an insteresting article: "If diesel engines are more efficient, why do most cars have gasoline engines?" http://auto.howstuffworks.com/question399.htm
It seems that most of these reasons can or have been overcome. Still we use gas...

Probably the biggest reason newer concepts haven't broken through is consumer demand. As long as people are still buying the same SUV's and new cars every year nothing will change. You are right about batteries and their ineffiency. A friend, electrical engineer, where I work was telling me the other day about a chinese engineer that has come up with a battery that apparently puts out 64V and last up to 8 times longer than a standard battery. Who knows how long it will take to reach the market and if it will be affordable though. Obviously that would benefit electric or hybrid cars, but what about all the gas/diesel/stroke/injection designs that would be better than what we already use?

[Xulfiqar]

I don't even have cable tv..ugh..
I would love for someone to give me a definitive answer on why a diesel "can't" run on gasoline.. I do have a couple of my own theories though as far as why an existing diesel can't run on gasoline, but I see no reason why a compression ignition gasoline engine couldn't be built, with the right technology. I think it would all come down to the injector, you would need to get the fuel out into the chamber extremely quickly because of the much higher rate of flame propagation as compared with diesel, but you could do some really awesome shit with this style of engine. Stratified charge combustion with over a 23:1 static compression ratio. Put that in a 5600lb denali, get 30mpg..
I Seriously believe that there are forces in the industry, car companies, oil interests, etc, that are holding back the advancement of technology for their own financial sake. Just look at the shit endyn was building in the 80s, they built pro stock engines that ran over 23:1 compression on race gas, and that trickled down to street engines in the form of cam and piston kits designed to raise the compression and burn the mixture only on the exhaust side of the chamber. (cam profile tailored to avoid piston to valve contact with the raised dome on the intake side. The raised dome would push the mixture into the exhaust side of the chamber) We Still dont have that on production engines. They're halfway there, adding 'quench area' in the chamber, (edelbrock's sbc 'e-tec' heads are a good example of quench with a flat top piston) but they haven't taken it the rest of the way.
one more thing.. I don't know if you know, but saab came out with a variable compression ratio engine years ago. Very simple concept, the cylinders pivot slightly on an axist adjacent to the bottom of the cylinders. I remember thinking that was amazing when it came out, but now I know that concept is obsolete..by lowering the compression that way, you lose the quench, actually increasing your propensity of detonation, while of course lowering your efficiency..
Electric cars are the future, I need to design that ultra capacitor, damn it..Batteries and their associated energy losses will always hold the electric car back. Fuel cells, ultra high energy density capacitors, and electric motors will be the combination for the next 100 years.

firstly diesel engines work on the detonation principle, and secondly diesel fuel burns slowly, unlike gasoline when mixed with air becomes a bomb.

Ive seen the saab VCR engine white papers, its a very simple design, the CR is varied from 14.5:1 to 8.0:1 throughout the rev range, boost is provided by a lysholm supercharger driven 30% overdrive.

[AccordDX86]

I think hydrogen cars are the future. After all, they dont pollute, and making the fuel doesnt cause pollution, unlike electric cars.

[my86dx4dr]

Yea a rd350 or 400 doesnt have much torque
but a ktm 450exc does, and a couple of old 80's xr250s do to

4 stroke Owns 2 stroke

[Ichiban]

Accordtheory, it is my experience and belief that a diesel won't run on gasoline because gas lacks the lubricity for the injectors/pump/ring seal required for the engine to function. also, i think that gasolines higher resistance to detonation has something to do with it, as it is a fuel that's designed to burn, not detonate like diesel. an example of this is premium vs regular fuel. premium is composed of slightly more "light" ends of the petroleum "spectrum" than regular fuel which is closer to the "tar or heavy" side of things. premium thusly has a higher resistance to detonation and slightly less combustive energy per unit of volume than regular gas. Now look farther down the spectrum (towards the heavy end) and you find diesel, with far more combustive energy, and a way higher propensity for detonation. in fact, the quality of diesel is marked by Cetane rating, usually between 30-70. this is indicative of "wax" content. why? in winter the higher wax fuels will gel more quickly, so a lower wax fuel is used, however the higher wax fuels will give more power. I've heard that worn out detroit diesels that are burning oil make incredible power until they explode, because the engine oil being a "heavy" fuel burns with the diesel and adds a fair amount of energy to the whole process. summing up, gasoline is too weak, won't detonate easily enough, and lacks the lubricity to run a conventional diesel engine.

i hope some of this made some sense...

[thegreatdane]

Bosch is currently introducing the second version of thier direct injection gasoline system. This direct injection system will make a very high A/F ratio possible and create a much more effective combustion. In terms of regular gasoline engines this will be the future.

[2drSE-i]

i hope they make a kit for 3geez :D

[Accordtheory]

I don't think a diesel engine runs by "detonation". How can a gasoline engine get completely blown apart in a matter of seconds from that, and a cummins diesel in a dodge truck can go easily 200k miles? I don't buy that at all. I think it's just a matter of the injectors.
And to people who think diesel has a higher propensity for detonation than gasoline, you can't even Begin to run the type of boost and compression on a gasoline engine that you can on a diesel without encountering detonation well before the spark event takes place.

[2drSE-i]

werd, anyone wonder why 90% of semis are turbo'd deisels?

[Xulfiqar]

I don't think a diesel engine runs by "detonation". How can a gasoline engine get completely blown apart in a matter of seconds from that, and a cummins diesel in a dodge truck can go easily 200k miles? I don't buy that at all. I think it's just a matter of the injectors.
And to people who think diesel has a higher propensity for detonation than gasoline, you can't even Begin to run the type of boost and compression on a gasoline engine that you can on a diesel without encountering detonation well before the spark event takes place.

diesels do actually run on the detonation principle, just try putting a burning match into a bucket of diesel, it will extinguish, (dont try it on gasoline). Slow burn, try throwing diesel on a red hot iron bar, (FIRE)

diesels have a two part combustion chamber one to start the fire and one to shove the piston with the heat (as you may know that compressing air makes it hot, diesels compress is to an extent that it becomes so hot it rapidly ignites fuel upon spray), and fuel is not introduced into the intake stroke, it is injected upon TDC at compression, that is also the reason diesels dont have a throttle blade, lean burn induces detonation.

[Brons2]

Accordtheory, it is my experience and belief that a diesel won't run on gasoline because gas lacks the lubricity for the injectors/pump/ring seal required for the engine to function. also, i think that gasolines higher resistance to detonation has something to do with it, as it is a fuel that's designed to burn, not detonate like diesel. an example of this is premium vs regular fuel. premium is composed of slightly more "light" ends of the petroleum "spectrum" than regular fuel which is closer to the "tar or heavy" side of things. premium thusly has a higher resistance to detonation and slightly less combustive energy per unit of volume than regular gas. Now look farther down the spectrum (towards the heavy end) and you find diesel, with far more combustive energy, and a way higher propensity for detonation. in fact, the quality of diesel is marked by Cetane rating, usually between 30-70. this is indicative of "wax" content. why? in winter the higher wax fuels will gel more quickly, so a lower wax fuel is used, however the higher wax fuels will give more power. I've heard that worn out detroit diesels that are burning oil make incredible power until they explode, because the engine oil being a "heavy" fuel burns with the diesel and adds a fair amount of energy to the whole process. summing up, gasoline is too weak, won't detonate easily enough, and lacks the lubricity to run a conventional diesel engine.
i hope some of this made some sense...


Wrong...gasoline is far more volatile than diesel. Go get a gallon of diesel and pour it on your driveway and then take a match to it. It won't burn.

The correct answer is: Gasoline cannot be used in a compression like a diesel because it is too volatile. The combustion of it cannot be easily controlled at high compression ratios.

[Vanilla Sky]

i know this has been threadjacked and now we're talking about diesel and diesel engines, but aren't rotaries considered 2-stroke?

[Brons2]

i know this has been threadjacked and now we're talking about diesel and diesel engines, but aren't rotaries considered 2-stroke?

No.

They have intake, compression, power, and exhaust stages.

The thing that makes them more efficient vis a vis displacement is that the rotor can have multiple stages going on in different parts of the rotor.

[Accordtheory]

The reason I brought up the diesel thing is that since in a diesel engine the injector sprays directly into the cylinder, that is a way you can efficiently use the 2 stroke cycle without any fuel going out the exhaust. That of course led into me wondering why you can't have a compression ignition gasoline engine. I still totally believe it is possible, and that it comes down to injector design almost 100%. But no, you wouldn't need compression ignition to have a 2 stroke gasoline engine. You would just need a supercharger.

..I thought volatility was a measure of a liquid's properties of evaporation, not combustibilty..time to go look in a chemistry book, I guess..

[[email protected]]

Wow, haven't been back in a while. Certainly some interesting reading...

Great Dane, can you elaborate? Btw, nice car!

[gp02a0083]

hell, makes me wonder about the rotery engine , we all know the TQ rating is shit but high HP gains are easy, only reason that i like this engine (from an enginnering standpoint and engine rebuilder) is that there is no valve train at all , its mostly the degree angle and other characteristics of the ports on the engine that act liek valves, thus a light weight engine with fewer moving parts, now only of they could fix the TQ problem and make the engine run better on gas cuz sometimes thos roterys are pigs on gas

[Accordtheory]

How do you seal the rotors without burning oil? I don't get it. And the rx-7 engine only lasts about 80k before it needs a rebuild..but better oiling/materials/construction will probably be applied to rotaries of the future. How is the engine in the rx-8, other than not turbo?


..the rx-8 is the gayest looking pseudo sports car I can think of, next to the eclipse after like 99 or whatever. Ugh, imagine if the rx-8 and the new eclipse had gay buttsex and produced an offspring..man, that would be a Gay looking car!
..whoa, sorry there for the hation..

[Ichiban]

excuse me? i never indicated that diesel was more "volatile" than gas.
go read the post again.
The diesel detonates when it is injected at or near tdc of the power stroke. this is TIMED DIRECT INJECTION. diesel engines can't "pre-ignite" because of high compression or boost levels because the fuel isn't even in the cylinder yet, as soon as it is, it detonates. its supposed to. go look up "diesel engine principles of operation". it will all make sense. Spark event? diesel engines do not have spark plugs. some have glow plugs, but they are not required.

....also, ever heard a gas engine "diesel" after you shut it off? My chev did it constantly. if the ignition is shut off and it's still running but sounds like a 6.2L diesel than it must be detonating....

The argument that gasoline is "too volatile and it's combustion cannot be controlled at high compression ratios" makes no sense. it WILL detonate. however diesel will detonate more easily, despite being LESS volatile. Volatility refers to how a substance evaporates, or produces fumes, having nothing to do with detonation. Gasoline is made really to not detonate, so why use it?

I'm not making this shit up. go read a friggen book on it if you don't believe me.

[Xulfiqar]

[QUOTE=Accordtheory]How do you seal the rotors without burning oil? I don't get it. And the rx-7 engine only lasts about 80k before it needs a rebuild..but better oiling/materials/construction will probably be applied to rotaries of the future. How is the engine in the rx-8, other than not turbo?
..the rx-8 is the gayest looking pseudo sports car I can think of, next to the eclipse after like 99 or whatever. Ugh, imagine if the rx-8 and the new eclipse had gay buttsex and produced an offspring..man, that would be a Gay looking car!
..whoa, sorry there for the hation..[/QUOTE

wankels do inject a small quantity of oil to lubricate the apex seals, otherwise you would cut right through the nikasil coating, thats why its in the owner manual of the mazda/eunos cosmo to top up the engine oil level.

but the rotary engine can last well past 100K miles if you take care of it, Ive seen a 1g RX7 with its 12A engine clock past 200,000 kms and still it fires up on first start and runs like new.

[Brons2]

How do you seal the rotors without burning oil? I don't get it. And the rx-7 engine only lasts about 80k before it needs a rebuild..but better oiling/materials/construction will probably be applied to rotaries of the future. How is the engine in the rx-8, other than not turbo?
..the rx-8 is the gayest looking pseudo sports car I can think of, next to the eclipse after like 99 or whatever. Ugh, imagine if the rx-8 and the new eclipse had gay buttsex and produced an offspring..man, that would be a Gay looking car!
..whoa, sorry there for the hation..

The rotor uses "apex seals" at the corners. Indeed oil control can be a problem on worn engines. The rotary is also designed to burn a small amount of oil to keep the apex seals lubricated and pliant, thereby mandating the use of conventional and not synthetic oils. Some racers who want to use synoil will hook up an external tank to the rotor oil injectors and fill the tank with conventional or even 2 stroke oil.

As for it needing rebuilds after 80K...not true. One caveat being, the rotary is ill suited for short trip operation. OTOH, it can be better than a reciprocating engine for sustained high speed operations because everything is going the same direction all the time, not unlike a turbine. There are some sites detailing the use of rotary engines in small aircraft, and they are run at 5000+ RPM for hours at a time using a reduction gearbox. They are well suited for this sort of operation.

If you ever drive a rotary, one thing you will notice how smooth the engine is at high RPM. I had a friend in high school who raced RX-3's and RX-7's, and the engines were smooth as a baby's butt at 8000+ RPM's.

As to why it is ill suited for short trip operations...Even in the fuel injected versions, it is possible to flood the engine if you turn it off too soon after a cold start. Once a rotary engine is flooded, you are in a world of hurt. Unlike a standard reciprocating engine, it is not merely a matter of supplying the engine a leaner fuel mixture until it starts. The process goes like this: if the engine is turned off shortly after a cold start, the engine will be running rich which will cause the apex seals to become wet with fuel, reducing their effectiveness to seal the different stages (intake, compression, power, exhaust). A rich mixture will be reintroduced on a subsequent restart. If starting is hard and enough extra fuel goes into the chamber, it is *possible* that the apex seals can get wet enough with gas that effective compression is no longer possible, rendering the engine flooded. In this extreme example, the only fix to get the engine running again is to remove the spark plugs, squirt a few ounces of oil into the chamber, and then crank it over again. If it doesn't start within 15-20 seconds, repeat. Keep this routine until it does start. (PITA, I know...)

Some reading on this here: http://www.rx7.com/techarticles_unfloodFC.html

People mostly experience these sorts of problems when moving the vehicle. For example, they will start the engine cold, move it out of the driveway, and then turn it back off. They go back later, or the next day, to a no-start condition. To avoid these sorts of problems, it is recommended to always run the rotary engine to full operating temperatures after a cold start. This is actually detailed in the owner's manual of Mazda rotaries. One method around this is to run the engine at 3000 RPM for 10 seconds before turning it off. Another procedure I found is here: http://www.rx7.com/techarticles_floodprev.html

You may ask yourself, why bother with all this rotary crap? Well, the engine can be very rewarding in it's smooth and powerful operation. It's not a good engine for people who are not particularly attentive to vehicle ownership, however.

[jonrichert]

but a ktm 450exc does, and a couple of old 80's xr250s do to
4 stroke Owns 2 stroke

way off topic but i got a wr450 this year and sh!t i never want to set foot on a 2-smoker again. the thing is a rocket.

[Ichiban]

Accordtheory, i think i finally see your point with the direct injection 2 stroke gasoline engine. you want to use a supercharged setup with forced induction and an oil-lubricated bottom end (a la detroit diesel) instead of an oilburning or oil-injected crankcase induction system (a la chainsaw).

before those of you out there decide to correct me, ask and i can describe in great detail how each system functions, as well as how and why different fuels do what they do.

[Cant Stop]

the japanese have 2 stroke cars usually about 490 cc which fits their insurance bracket that is why our 3g's are not 2.0 liters but rather 1955? it falls short of 2000 cc so it is in a cheaper insurance/registry bracket, the 2 strokers are small as in cvcc small.
got pics just need a scanner of cars in jap junkyard circa 1986!

[Cant Stop]

HA SAW it again!!
sorry guys but what is PITA? please pretty please!