Blowby CFM

#1

Has anyone used a blow by sensor/gauge on their engines to monitor the health? i’m just wondering what a normal reading might be?

i got 1.5 CFM out the valve cover breather venting to atmosphere.

cheers

#2

Normally its measured with a manometer. You can use electronic ones, but they dont measure CFM.
I dont know what the limit is per BMW.

#3

what is measured with a manometer? measuring pressure in the system can be misleading for working out if there is too much blowby. i’m venting to atmosphere anyway (no sludge in intake ftw)

#4

Suggest you search web for how to do a leakdown test. Cliff notes, dual gage, cylinder at TDC, 100psi on first gage, read leakdown on second. Anything under 5 is excellent.