race gas

i want to run my 400ex off race gas. how do i do this properly

[trx400ex]

buy a high comp piston and race gas

[kabd69667]

I run 110 in mine and all i have is the mods listed below.

[Chef]

you can run any octane you wish, but it doesnt help anything, unless you have the compression to burn it correctly....

[51]

well from my mechanical knowledge the only time you need race gas is when your compression is above 11.1 ... you need this because your combustion chamer is smaller and needs better detonation to get all the power out of you engine... so if you run race gas in a stock motor you wasting your $$ and time..unless you liek the cool smell:devil


ohh adn somebody correct me if i am wrong

[400exRacerX]

Yup you are 100% right, if you are buying race gas for a stock motor or a piston with a lower copression then 11:1 then you are wasting your money.

[thorspapa]

Hey fellows, here's a good rule of thumb:
Air cooled motors
Up tp 10.5:1 Premium pump gas
10.75:1 to 11.75:1 Half pump/half race fuel
anything over run at least 105 octane, and at 13:1 you may start considering the exotic stuff.
Water cooled:
up to 12:1 Premium pump gas
Anything higher, start buying race fuel.
Lots of variables affect this, but these are ballpark figures given out by Powroll for starters.
By the way, do you know how to figure compression ratios? here it is:
If you have , say a volume of 140cc in your cylinder when the piston is at bottom of stoke, and a volume of 20cc when the piston is at the top of it's stroke, then your ratio is 140/20 or 7/1 or 7:1.
With this you can figure your actual compression any time, using good 'ol math from your earlier school years.
:blah

thank yall for the helpfull info

what is the best hi compression piston and will it harm engine life

[400exRacerX]

Either JE or Wiseco makes great pistons and any engine mods harms the life of the motor.