Date: 3 Mar 2005 21:14:11 GMT From: Dave Hinz <DaveHinznospamcop.net> Subject: Re: Saab 9-3: What octane to tank?
On 3 Mar 2005 12:36:35 -0800, R. Frist <fristnospamt.edu> wrote: > Just a thought: Is it not true that in order for the knock sensor to > work it must sense a knock? If so, it follows that running lower > octane in a turbo must cause a little more wear and tear than high > octane fuel. I suppose it depends on how often the knock sensor lets > the ignition and boost advance until another knock is detected. Makes sense, but no. No matter where the knock point is, it'll find it and set ignition and boost just short of there. > Another consideration may be carbon deposits. A friend of mine has a > Cadillac with signs "Use only premium fuel" all over it. He claims > that using premium is a waste and has only used 87 for the last 10,000 > miles. He now complains that the car keeps running on roughly after > turning off the ignition. Granted, the Cadillac is not a turbo and > has a higher compression ratio then turbo engines at atmospheric > pressure. Maybe this is not a problem with turbo engines. Does > anyone have any data? If he runs mostly city miles, no good long runs to burn the crap out of the engine, it'll build up. I don't know of that being related to octane, more of how the car is driven. People generally will drive a Cadillac differently than a Saab owner will drive a Saab. Dave Hinz