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Is it true that a dirt bike produces more power per cc than any other vehicle?

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I heard this and am not sure if it is entirely true. I wouldn't be surprised though. But to be fair you would have to convert the bikes cc to ci to compare with other engines.

Does anyone know?

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Not more than any other engine, but more than the majority of mass produced reciprocating internal combustion engines availible to the public. Look at it this way, the new 5.0 mustang is praised in the car world for it's performance from the factory. It is making 82hp per liter at the crank. All of the 250F mx bikes make around 170hp per liter at the crank.

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Not more than any other engine, but more than the majority of mass produced reciprocating internal combustion engines availible to the public. Look at it this way, the new 5.0 mustang is praised in the car worled for it's performance from the factory. It is making 82hp per liter at the crank. All of the 250F mx bikes make around 170hp per liter at the crank.

Well I am just including racing vehicles and public consumer vehicles. I am excluding military vehicles, and other specialty vehicles that is not available to the public (besides racing).

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I'm thinking F1 cars are higher.

And top fuel dragsters.

Top fuel engines make around 1000hp per liter, F1 cars are around 275hp per liter. Both are quite a bit more than a dirt bike.

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Power per CC, two stroke dirt bikes are WAY up there. Forget a 250f, a 125 is around 336p per liter at the crank. Shifter cart engines are based on dirt bike engines, only more highly tuned and with their power in a narrower band, so they are a little higher. Around 400hp per liter or more.

Probably some of the highest hp per cc for naturally aspirated gasoline powered engines.

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RC nitro engines must be pretty hight, plane or car. I thought the little plane engine i had produced like 1.5 HP at 20000 RPM. It had about a 3/4" bore and about the same stroke. Could be wrong on the rpm.

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When you say dirtbikes, you really need to focus on just 2 strokes, they are the only ones that can compare to other top tier engines. a 250 cc 4 stroke makes roughly 38hp...where a 125 cc 2 stroke makes about 36hp. a KTM 250cc 2 stroke makes about 50hp. so you can see at least in the dirtbike world, a 4 stroke cant even compare to a 2 stroke based on output per cc. A 125cc 2 stroke is about the best power per liter at 288 hp/liter out of any bikes.

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You would have to convert the bikes cc to ci to compare with other engines.

Haha! This isn't 1972. Every automobile engine is rated in cc.

You need to separate 2stroke from 4stroke, they're nearly as different as piston and turbine engines. If you're talking mass produced 4stroke engines dirtbikes and sportbikes are about equal in hp per liter and are much higher than any other vehicle. Of course 2stroke engines kill it with massive hp per liter. Making any higher hp/liter requires very high revs and results in greatly reduced engine life so you only see it in race engines that get frequent rebuilds.

Lesson learned: If you want very high hp/liter without daily engine rebuilds get a 2stroke.

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Glad to see some folks are chiming in here with some reality lol.

Physics is physics. The answer is incredibly complex if you wanted every engine composition and fuel to air ratio, listed out along with material stress life span and all the other tiny little things that make one engine different from the other.

So to answer the OP's question simply, the answer is no. There is nothing special about dirt bike engines that make them more powerful than any other internal combustion engine in the world.

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If you compare all commercially available engines. I dont think you will find anything that can beat out a 125cc 2 stroke. at its roughly 280hp/liter output...a 600cc crotch rocket is at about 220hp/liter. Off the top of my head I cant think of anything else that comes close...

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2 stroke ftw! Love everything about them. However, I would think the little nitro cars (relatively) are the most insanely powerful per liter....If you had one to scale you wouldn't even be able to ride in it. It would knock you unconcious on take off like a jet.

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125 2 stroke motogp engines make around 55hp at 13000rpm. So thats 440hp/L.

Although not a dirt bike engine, it is still a carburetted 125 2 stroke.

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I heard this and am not sure if it is entirely true. I wouldn't be surprised though. But to be fair you would have to convert the bikes cc to ci to compare with other engines.

Does anyone know?

Please define 'vehicle' :bonk:

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The only thing specific output is good for, is bragging to your buddies. Power per displacement is a useless measurement.

Power/Weight or Power/Size is a far more useful measurement.

That being said, dirt bike engines, even two-strokes do not have that special of a HP/CC ratio. Top Fuel Dragster engines are over 1000HP/L. There are some Nitro N/A RC car engines that are also around 700-1000HP/L

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If you set criteria that the engine had to perform on 'pump' gas, it makes 2 strokes and bike engines seem impressive, but you could set any criteria to make anything look good. Methanol/nitro does weird things for engines. I know F1 engines have to run on pretty normal octane fuel.

A better question would be, 'Is it true that dirt bikes produce the most hp/cc as a mass produced recreational engine'.

In which case the answer is, they are probably up there.

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