Hi Guys, I have an 84 400i, and have set the ignition timing to the stock 8degrees BTDC. The car runs smooth, but if I advance it a bit I get more power all round. I am using 100 octane fuel and seem to get no pre-detonation , has anyone got any info on how much advance you can use. The car is an auto, so the engine never really labours as it could with a manual, so it is difficult for me to assess if it is pinking or not. I will check the advance curve on the distributer carefully when next possible (as suggested by a member before), but when I was last under the car it seemed to be ok as the timing light showed on the fly wheel. Regards, Tim.
Any possibility that you could make some temporary paint/chalk marks on the crankshaft front pulley or HD and rig up/use a temporary pointer or use a nearby feature as the pointer? You're just looking for a relative timing change and not an absolute timing position. Just a thought if "under the car" is cumbersome/ackward -- it sure sounds so
That was quick! Thanks for your reply. I have the use of a car lift so getting underneath is no problem. Also from memory the fly wheel is marked with the maximum advance position, and this is why I think this distributer is probably ok, as it advanced correctly when last checked (10 months ago). I am interested more in anyones experience running a bit more advance, and would be interested in any rolling road figures with power changes at different settings. Thanks again 91tr
Understood, but I was thinking that the shape of that advance curve would also need a measurement at 2000 RPM (crankshaft) as well. Anybody have a 400i WSM to check if the static + chart = 30 deg BTDC at 5000 RPM (crankshaft) -- i.e., the WSM doesn't have the OM discrepancy?
