My Car = 1986 328 - USA Spec Anyone got rough estimate of engine vacuum at idle speed. Below are my numbers. Warm idle = 1,000 rpm Vacuum at plenum where brake booster connects = 13-14 Lbs. fluctuates within 1lb Location = Central SC - USA. Approx 300 Feet above sea level I have read posts regarding the GTSI cars that say as low as 10lbs and these cars may run lower vacuum than most..? Also read the 308 WSM indicates, but can't find in my 328 WSM...?
Hmmm, good question...that vacuum reading at idle would be too low for most OEM engines, indicating a possible vacuum leak or a problem with worn rings but maybe 180 degree crankshaft motors like the Ferraris generate less vacuum at idle; I have no experience at all working on/with 180 motors and I have never done a vac check on my 328 so can't even offer a comparison. It will be interesting to get more information!
On a Euro 308 QV you should see around 12-14 inches of vacuum. I think your 328 should be in that range.
