85 Z octane

[slippy4]

Whats the highest octane i can run in my 85 Z? i was told its stock bore and has about 175psi compression?

[Tri-Z Pilot]

The higher the octane the cooler your piston runs

[slippy4]

alright, but what is the highest i can run before it starts to run wierd because its too much.

[J.D.]

I always ran 87 octane(regular). Your *supposed* to run premium gas in it, but I found no difference/harm changing between regular/premium. There is no need to buy expensive race gas for a stock engine. If you mill your head and do some porting you'll need it, but your wasting money buying expensive gas. If you want to do anything, just run premium. Don't go past that.

[slippy4]

premium is what 93 octane, what if id run around 100?

[J.D.]

If you ran 100 octane you'd jack your engine up, it would run terrible. Reason being is the higher octane burns slower. Your gas would be firing at the wrong time, etc.

[slippy4]

alright, i could get some 100octane gas for about the price of premium so id thought id ask first.

[J.D.]

If you really wanna run 100 octane, mill the head, add a boost port, enlarge the exhaust port, and put on a 38MM carb. Then you have a reason to run 100 octane ;)

[TimSr]

Mine is perfectly content with 87 octane. There are no benefits derived from running higher octane than what your motor requires, nor would it cause any damages. In other words, you can run 100 octane if it makes you feel better, but your Z wont run any better than it does on 87.