FQS (fuel quality switch) What are the settings

[HAVIC]

Hello all

i have a 325is with a motronic 073 ecu. my FQS is set to position 7. there are 8 settings to play with (0-7). My mate who has a porche 944 with a very similer ecu has his on number 5 for max power and timing advance. dose anybody have any ideas on what we put our ecu on. I want more power, because in australia ( where i live) we have 98ron fuel and i want to make the most of it. thanks

Michael

[Julien]

wtf? never heard of that on US spec cars.. do tell/show/explain

[cthulu703]

I had never heard of that switch, but I imagine it controls the ignition advance curve, the lower the octane fuel, the less advance you can run. Alot of people, myself included, that run performance chips have to run 92 or 93 octane, because it advances the ignition curve so much. You could play with the switch, creeping up on the highest setting and turning it down a notch when you get detonation.

[rs4pro3]

The 021 eta ECU's also have it
Can't remeber the link, But I've seen it posted on the E28 boards a few times.

[rs4pro3]

Here is the Link

http://bimmer.roadfly.org/bmw/forums/e28/4589094-1.html