Tuning

[Skiuuup]

Do you have to put 98 octane in a vf storm commodore if it is a 98 tune or will it still run good on 91 as well.

 

[Deuce]

If it truly is tuned for 98 and you run it on a lower octane it will ping/knock at certain spots in the rpm/load range.
You could get timing taken out of the tune in whichever spots it does this on lower octane, but of course this means you need to go back to your tuner once you know.

 

[someguy360]

The only benefit you will see from 98 is if the car is tuned to take advantage of it.

A stock car will run just as well on 91 as 98, the only time higher octane is required is A. if the vehicle has been tuned for it or B. the manufacturer specifies it which you can usually find behind the fuel filler door (usually due to a higher compression ratio on modern small engines).

If your car is tuned for 98 though then usually it's due to the fact the tuner has bumped up the timing in the maps to take advantage of better knock/denonation resistence, in that case you do really want to run it.

 

[Ginger Beer]

If tuned for 98, use 98

If you don't want to spend the extra couple of bucks using 98, get a retune for 91