if im filling up 90 octane fuel on my car, can i use 91 octane performance tune? sometimes i fill up my car with 88.5 octane fuel (because of gas prices), can i use 89 octane performance tune on 88.5 octane fuel?

 

To be honest, there will be little to no difference in performance eithe way, just save your money and use 87 octane, higher octane is only useful on higher powered vehicles.

 

i run 87. and never noticed a difference with 89 or 91. unless ur car is pumping out horse then just go with 87