Date: Fri, 26 Oct 2001 10:57:51 -0500 From: "Walt Kienzle" <wkienzlenopsam.com> Subject: Re: Which grade of fuel for 98 900SE Turbo?
> 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)." 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