Date: 28 Oct 2001 15:52:28 +0100 From: Arne Adli <adli+nnopsamlid.ed.ntnu.no> Subject: Re: Which grade of fuel for 98 900SE Turbo?
"Walt Kienzle" <wkienzlenopsam.com> writes: > > If you get knock there is something wrong with the engine, the ECU will > > adapt to the fuel grade before knocking occures. > > That is not quite true. The original reply was more accurate. You might > not get audible knock or continuous knock, but the engine has to knock at > least once for the knock sensor (or knock sensing components of the DI > system) to pick something up, send that info to the ECU, and have the ECU > react to it. The ECU isn't psychic and can't anticipate "before knocking > occures (sic)." Well, the original reply stated that the NG turbo is supposed to run on premium. That is not true. It also statet that you migth get knock under acceleration if using lower grade fuel. That is only true for the first few accelerations until the ECU has adapted, and in general, you should not expect knock. The point of my post was to clarify that the NG turbo not is supposed to run specificly on premium, but I see that due to my erroneous simplification, the point maybe got lost... Arne > > Walt Kienzle > 1991 9000T > > "Arne Adli" <adli+nnopsamlid.ed.ntnu.no> wrote in message > news:s0nbsiuk094.fsfnopsamtel.no... > > Just Bob <uctraingnopsamanet.com> writes: > > > > > On Fri, 26 Oct 2001 02:36:38 GMT, "Harry Davis" > > > <harryedavisnopsamediaone.net> wrote: > > > > > > >I don't know about the NG900's but in our 3 9000's and my wife's 9-3, > we > > > >found that the mid-range worked the best. > > > > > > An NG turbo is supposed to run on premium. > > > > The NG Turbo is made to run on on a broad specter of octane. Since it > > has knock-detection, it easily adapts to the fuel grade. Running on > > Normal is no problem > > > > > If you use lower grade, it > > > may knock under acceleration. When that happens, the engine will > > > retard the timing to stop the knock so you get worse performance. > > > You will compensate by opening the throttle more and using more > > > gas as a result. > > > > If you get knock there is something wrong with the engine, the ECU will > > adapt to the fuel grade before knocking occures. > > > > The perfomance will of course be better with higher grade fuel. > > > > -- > > Arne Adli > > '96 Saab 900 SE Turbo > > -- Arne Adli '96 Saab 900 SE Turbo
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