I have a evo9 with a 91oct tune i was wondering if i put 100oct in what is the hp difference? if there isnt why not ?maybe the tune?
thanks

 

You would need to get a 100octane tune to realize any performance increase, other than maybe some added knock suppression. You could throw some 100 in there and turn the boost up a little but again a tune is needed to realize the fuels full potential.

 

ya i know i have to get a 100oct tune to see real hp difference but i was just wondering if a little hp can be added by just putting it in but thanks for the info

 

By just adding in 100 octane, you probably wouldn't notice any significant HP gains without a tune. Like stated above, you could add 100 octane and raise your boost a few psi.

 

OK well thanks for the input