Date: Fri, 16 Apr 1999 15:09:07 GMT From: "Manic" <MMManicnopsamail.com> Subject: Re: Higher octane improving performance?
I tried to fill up my tank 3 consecutive times with American super unleaded (93 octane) in my '98 900SE. The cost was about 25% more but I didn't really realize increased fuel economy or noticeable performance. Specifically, the car only felt slightly more powerful and the increase in mileage was only 8%-12% over the 3 tankfuls driving equally in city and moderately traffic-laden highway. I don't think the added cost of 93 over 87 octane benefited me and I think I will continue to fill up on "regular" from now on. The slight increase in performance wasn't very useful to me either since I usually drive on congested routes. For the record, I drive a little aggressively, but not like I am driving a Grand Prix racer. (I tried this test with my Honda Civic. Although gas mileage went up about 15%-20% on 3 tankfuls, the 25% higher cost didn't justify the need). Andreas van der Wal <andreasnopsamnt:want.spam.cost.se> wrote in message news:7f7hgf$jlk$1nopsamcola.tninet.se... > Hi, > > I have wondered in what way the octane corresponds to the performance of > the engine. I know that higher octane prevents knocking and therefore > can tolerate higher combustion which could lead to more hp. The question > is rather if I one time fill up my car with 95 octane fuel (european > values) and the next time with 98 octane fuel, how would that influence > the run of the engine. > > Suppose that higher octane gives me more hp, will that mean that I can > lower my fuel consumtion? > > Will it change the rpm where I get most hp? > > Will it only be effective when really giving full gas or also when I > drive like an "old lady"? > > If someone knows, I would really be interested. > > / Andreas >