[BulletZero]

Whats the highest compression our C32's can run on 92 octane? A B18B1 can run a 9.3c/r on 87-89 octane. Yet, we are running 9.6c/r on 92 octane. What else comes into play when calculating octane to higher compression? The plan is to bump my C/R up to 11:1 on forged pistons, but I dont wanna drive to Sunaco (110 oct) to fill up. Is there an alternative to increase octane?

Also does higher C/R increase ny likeyhood to fail emmissions?

 

[Mike Diaz]

you can run on 92 as always, but you will have to put some octane booster from the parts store pretty much every time you fill up. there's always increased cost with a high HP engine in regards to gas $$.

 

[cdndvl]

No Rule

There is no set rule about octane and compression... It is generally accepted that any engine under 11:1 can run on 94 octane and lower... Also engine requirements change as it gets older or how much carbon has built up (Carbon will both increase your compression a bit and keep the heat so it will be easier to pre-ignite.). The only for sure way to give your engine what it needs is to fill it up with a tank of the gas you have already been using, keep a log of what mileage you filled up at and how much you put in, and go for a drive... Does it feel like you have the same/less power than before (Better if you have a GTech pro ) and mark the mileage down... Then repeat with different levels of octane until you find the right one. I would also tell you to listen for pinging (a sign of pre-ignition), but I think your car may be equipped with knock sensors and you won't hear any because it retards the timing to prevent pre-ignition.

Sorry it's such a long explanation, but I hope it helps you.... It won't hurt the car for the short period it takes...