killerEX500stnt

I have been wondering for a long time if higher octain fuel in the fiddy would be any better. bc in stuntlife someone said that 4-strokes need fast burning fuel (87) octain. THAT'S A LIE. Well last weekend i filled up with cam2 (112) octain. I have been checking the carb and sparkplug to make sure everything in good. it liiks good to me so far so i'm going to keep running it in the fiddy. with the upgrades that i have done it has shown me some performance that i have really been looking for. Does anyone know anything that it can do to my fiddy in the long run. or have any input????????? THANKS

Brett256

Here is what I know....


Back in my drag racing days it was always said that a vehicle will not need a high octane fuel unless cylinder pressure and or heat are above the levels that a low octane gas can handle. If the cylinder pressure/heat levels are too high for a low octane fuel it will cause preignition also known as detonation. Detonation occurs when the air/fuel mixture temp is high enough to ignite without a sourse of ignition (spark). Detonation usually occurs in an application where a high horespower vehicle with a high compression ratio or forced induction is not running a high enough octane fuel.

So.... I don't think a basically stock xr50 motor with 2.5 hp needs a high octane fuel. xr50's are not are not finicky high compression motors or force inducted the last time I checked. Actually low octane fuel should give you MORE horsepower because the air/fuel mixture will....
a)be easier to ignite with the given ignition spark
b)cause a more efficient/rapid explosion in the combustion chamber.

Speedy

Yeah what he said

Bray

yea..what he said...listen to 91vempo seems like he knows what hes talkin about

Tick_9se7en3

I believe the manual says to use 87...I could be wrong.

MXgraham044

i wonder what would happen if you put some nitro methane in a fiddy.

dblnaknak

My friends and I got ahold of some methanol alcohol. All we did was mix the ratio 4/1 and it ran a whole lot better. Even feels like I gained more horsepower. We got arenacross on the 20th I will let you guys know how it runs.

binder929rr

it won't help running higher octane. you won't find a gain unless you alter something like running higher compression or advanced timing.

you'll probably run better on 87 because that's what the engine is made for, or at least until you mod it out pretty good. to get the best performence run the lowest octane you can without causing detonation.

binder929rr

nevermind, i checked the manual and it says 91 so 91 will get the best performence.

fab5fiddy

dont try it. gasoline burns at a rato of 14.7 parts air to 1 part gasoline. and honda jets the bike accrdingly. nitro burns at a rate of almost 1:1 that means, u need to shove almost as much gas in it as u are air. which will ever happen the way it is jetted. so, if u can get it to run, which i dout, u will lean it out so bad u will probably blow a hole through your piston. cool huh?

fab5fiddy

binder929rr

damn, someone put the smack down on the facts