Date: Wed, 3 Mar 1999 09:32:01 -0500 From: "Eric Law" <elawnopsamexxx.com> Subject: Re: Can someone explain OCTANE?
GK, Justin provided a reasonably good explanation, but left out one very important factor that's near to the hearts of many Saab owners - turbocharging! The boost pressure that a turbo provides to an engine has an effect similar to raising the compression, e.g. it increases the engine's tendency to detonate or "knock". So, in a turbo motor, using a higher octane fuel will permit a higher boost pressure before knocking occurs. This equals more horsepower. You can see this effect easily in the Saab APC turbo cars (if the APC's working correctly!). If you go from high-octane to low-octane gas, the boost gauge will read lower and the car will not have as much power. This is because the knocking tendency has increased, and the APC system lowers the boost pressure to compensate. Eric Law