JCL--thanks for the info. Just realized tonight that I have been filling up on 93 (or 100 RON if we're cruising around Geneva). There is an 18-pump high volume Hess station I frequent, so I am guessing all the gas is pretty fresh. You are suggesting go with 91? I only fill up about once every 10 days, so cost is a non-issue, but you make a pretty strong case that is still, effectively, a waste of money. Ditto with the 325ci? Better not be a test on all this...

No, no test at the end.

If you have a fuel that works, from a station that sells reasonable volumes, then I would say you are on to a good thing. Try the 91 if they offer it, and see if you can tell a difference. That would apply to both vehicles, unless you have modified the engine in some way such that a higher octane rating has some benefit.

I don't have a pet peeve against people using higher octane fuel than the engine requires. It is their money, not mine. It does bug me (just a little) when people suggest that doing so is somehow better for the engine. As enthusiasts, we should know better than that. At a time when the oil companies are making record profits, spending more than necessary just seems a little......wrong. It is a marketing campaign that has been going on for so long, many people have grown up with it and believe it.

Let us know if you can tell a difference on the 91. Give it a few tanks to settle in.

Jeff

Speaking of record profits, I'm not buying Exxon anymore...I'm all for a nice executive sendoff but 400mil when the market metrics are at your back? Obscene. Let's put 400mil into hydrogen fuel infrastructure. I thought we went through this with Richard Grasso and Phil Purcell. (oops--hijack warning just went off...)

Hess sells 89, 91, and 93. I will give the 91 a try and report back. To the incalcuble relief of some, both engines are "mod free". Three tanks may be awhile, my r/t commute is about 5 miles. Thanks again for the detailed info.