With gas prices at an all-time high (don't bother telling me about the 1979 price adjusted for inflation--I wasn't buying gas at age 9) I'm looking to try some alternate ways of saving money. My '99 Pontiac Grand Prix GTP requires premium (91 or higher octane) due to the supercharger. Right now that means $3.05 to as high as $3.19 per gallon. I can't help but look at the regular prices of $2.85 to $2.99 and wish I could use that.

I know there are fuel additives that supposedly boost octane, but I know nothing about if or how they work. Could I fill up with regular and add some octane boost, achieving the required 91+ octane at lower cost?

I doubt it will make for lower costs. Just doing a quick search I found that a 15 oz bottle of Octane Booster costs about $8.50 and treats up to 25 gallons. So, best case (with those numbers) you're looking at an additional $.34/gallon. But most tanks don't hold that much so you're probably looking at double that (or you could just add half a bottle per fillup, but the costs still don't work to your benefit).

My tank holds 14 gallons, so half a bottle would work. That's $4.25/tank or $.30/gallon, which is more than the difference between regular and premium. So you are correct: no savings.

Thanks, Bill!

Well, before you go adding additives, you can run regular unleaded in your car. The thing is that the computer will retard the timing to prevent detonation (pre-ignition) which is a problem with super/turbocharged engines. The result will be some reduced performance but nothing really all that noticible unless you have a heavy foot.

A happy medium would be to use a mid-grade fuel.

Using too many additives can actually cause spark plug deposits - found out the hard way. :)

Keywords:unless you have a heavy foot. :D

A happy medium would be to use a mid-grade fuel. I'll give this a try next time I fill up.