Was thinking about this the other day.. What's the most HP you can squeeze out of a 50cc kit?
I know all engines are different, and there are SOOO many factors in play there there isn't a single answer.. But makes me wonder, what IS the limit of power on a 50cc?
Obviously your carb size, jetting, intake size, type of cylinder, exhaust tuning, gearing, etc etc etc will make a difference.. But it was something that intrigued me. lolz
What'yallz think?
How hard do you have to squeeze to get your eyes to pop out ?...
Hmm... maybe a few hundred pounds?
How many dollars can you squeeze in to it ?
Money isn't the object- just talking about the theory. There has to be a limitation/line drawn somewhere, right?
we have one with 21.6 hp at the crank just under 50cc water cooled custom cases etc start at 3grand and work up from there as far as costs
look at vintage race bikes, ive heard of nearly 50hp out of a 50cc. its a how long is a piece of string sort of question really
Yeah I'm realizing this is way too broad of a question to really have an answer.. lol
But damn 50hp is impressive!
the 50cc land speed setting modified Aprillia RS50 motor makes 27hp
ashley carter Wrote:
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> look at vintage race bikes, ive heard of nearly
> 50hp out of a 50cc. its a how long is a piece of
> string sort of question really
^
this is incorrect, 50cc GP had pretty harsh HP cut offs. 10hp was the max in 8-12 speed bikes. There are not any 50hp 50cc motors.
the 50cc land speed setting modified Aprillia RS50 motor makes 27hp (edited)
The land speed record Aprilia RS50 is a good benchmark...maybe like 30shp is possible for peak power, but it's gotta be somewhere in that range
Speed/Power is a question of $$ How fast can you go...
Jan Tiel (former engineer for aprilia's two stroke racing development team) states that a 29hp single cylinder 50cc engine is 100% doable - and 39hp from a 50cc twin...
50hp seem a bit to high... Maybe with four 12.5cc cylinders...
Speed costs money... how fast do you wanna go? - the question of my life
Suzuki had a 50cc 3 cylinder, 14 gears and 19 hp, but was never raced because rules changed and limited to 6 Gears.
Keep in mind that is hp at rpm so torque is only 20 percent more than something like an mb5. It isn't that much more "powerful"
Arnie Grape Wrote:
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> the 50cc land speed setting modified Aprillia RS50
> motor makes 27hp
now. mod the 29hp motor to run nitromethanol. no blower or supercharger either huhpf.......
14 high end 3.5cc rc engines in paralell = 49cc, will get you past 40hp. Good luck with that one!
Damn that's impressive!
Would be interesting to see four 12.5cc cylinders though.. hehe so tiny
I'm sure that's the biggest caveat to this: is that the HP is only at a certain RPM range.. which could be very short
HP sales shit, toque wins the race.
yeah it sounds cool until you realize the torque and power/ weight is basically the same as a fast moped
I'm at work but I seem to recall that land speed record was done with forced induction, and then another record set with nitrous on the same vehicle.
Crazy Wayne™ rocks your sister's niece's daughter's grandma Wrote:
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> HP sales shit, toque wins the race.
I work with vehicles that make 1650lbft of torque and 400hp and they wouldn't win any races, it's all in the application.
what I said was a bit disingenuous. more peak hp = more torque at the wheel with gearing. (edited)
48hp wankle motor xr50
Rotaries pull power from an alternate dimension though..
Ooh, I feel some math coming on...
Hokay, let's get HP as a function of BMEP, displacement and RPM. Easy.
HP=BMEPx(displacement/12)x(RPMx2/33000)
BMEP is in PSI and displacement is in cubic inches
If we take the crazy BMEP values some supercharged nitromethane dragsters are churning out (1450psi, which is absolutely mind boggling), and combine that with our displacement of 3.051 cubic inches, we get:
HP=1450x(3.051/12)x(RPMx2/33000)
HP=368.6625psi cu-ft x (RPM/16500)
But what shall we use for our RPM? Well, RPM as a function of mean piston speed and stroke is defined by the following:
RPM=(MPS/2xstroke)x60
I'm going to use metric for this one just to be that guy. Let's stick with a slightly less that average moped stroke length of 39mm. That will get you a slightly oversquare engine, but would not limit you overly in terms of porting. As for mean piston speed, we will again delve into the world of top fuel drag racing and F1 lunacy to pull the absolutely insane number of 30m/s out of our asses.
Note: I am aware that mean piston speed is not actually a particularly useful number for engine design. It is, however, a fuck of a lot easier to calculate than max piston acceleration which is what you actually want. It's good enough for napkin math.
RPM=(30000mm/s /2x39mm)x60
RPM=23077
If we stick that into our earlier equation, we get:
HP=368.6625psi cu-ft x (23077RPM/16500)
That leaves us with a grand total of...
515.61HP!
Disclaimer: that's a rough estimate on the back of an envelope and does not take into account air flow at all. It would be completely impossible to get anywhere near the amount of air required to do even 1/4 of that through the ports of a piston that small, even with ludicrous amounts of boost. It also doesn't take into account heat generation, which would probably require something like the cooling tower on a nuclear power plant to dissipate. It also also doesn't take into account the fact a piston or crank that would hold together at the peak acceleration generated by the piston speed we used would not be possible to construct with modern materials. I'd have to do that math, but I'd bet the acceleration would be in the ballpark of 10000g. So if you have a 100g piston, the force on the crank arm would be something like 10000N. Unless the internal bits of your engine are made of unobtanium, the sheer inertial forces would be enough to tear it apart. Finally, that number is the result of me cherry picking the highest numbers I could find from the kookiest corners of motorsports. Using these calculations, you could probably "prove" that your Civic can produce 4000HP.
But there you go, the maximum theoretical HP output of a single cylinder 50cc two stroke engine is 515. Assuming your crank and piston are made of magical pixie dust, you are running nitromethane, your engine is immersed in a bath of liquid nitrogen and there's a supercharger producing 500psi bolted to the side.
How many horsepower to run the 500psi supercharger ?
This thread just gets dumber and dumber.
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