Join Date: Aug 2006
Location: State of Confusion
89 is what you car should run best with.
If you use 87, you're computer may adjust the timing, so you may not hear the knock (which normally indicates that you need higher octane) but, when it does, it reduces your mileage and will not save any money.
If you really want to go with 87 to save money -- run several tanks of 87 and track your mileage. Then run several tanks of 89 (similar driving conditions) and track your mileage. If your mileage is as good or better with 87, then, by all means: use it.
'06 Charger RT (original owner)
Last edited by birddog; 07-05-2007 at 05:46 AM.