Compression and race gas

[cdwood37]

ok i am already running 110 octane race fuel, i just built my motor and want to run pretty high compression because i am running 110 octane with plus 5 timing how high can i go compression wise with the plus 5 timing?

[Wallrat]

What kinda crank are you running?

[cdwood37]

a 4mm stroker

[sheenut05mx]

I wouldn't run any thing over 155psi 10.5:1 static, any thing higher and you'll want to run 116 octane.

Edited April 23, 2006 by sheenut05mx

[blueshee03]

ok i am already running 110 octane race fuel, i just built my motor and want to run pretty high compression because i am running 110 octane with plus 5 timing how high can i go compression wise with the plus 5 timing?

506304[/snapback]

 

 

what is your altitude . one of the main things to take into consideration when determining type of fuel to use with compression and timing is your altitude.remember also ,the higher you go on your compression the more you loose on top end.

[Ducman]

Depends on how high your exhaust ports have been raised. If you have a doon or drag type port then your static compression will be quite a bit lower. Example: my old motor was a +4mm dune port, exhaust ports raised A LOT. I had 19cc stroker domes, .035 squish, and I was measuring 145 psi when the motor was fresh. I ran +6 timing and could use 100 octane at 400+ ft elevation btu not at sea level. Then I needed 110. I think you could get away with 19cc domes for sure running 110, possibly 18cc.

[cdwood37]

I am a little above 5000 feet. i am already running 150 psi and the cylinders are cubs and they are factory with a touch up port.

[fastbanshee4u]

I have run up to 210lbs compression with + 4 timing on aviation gas all summer.Yea the fuel alot of people ,say" its junk".I refuse to spend six dollars a gallon on fuel.