N20 Oil Pressure
Not sure how many others are tracking their BMW's with the N20, but figured I'd share some of my findings as it relates to oil pressure. I track my Z4 pretty heavily and in July had a bit of a surprise when running the Pocono Southeast course during MPACT when the car threw several codes related to intake and exhaust camshaft / crankshaft correlation faults. These codes are sets when the camshaft is not in the correct position due to a timing issue. The most common cause is a problem with the VANOS system. Since I hadn't seen these errors thrown previously, I decided to clear them and see if they reappeared under normal driving conditions (which they did not). This let me to believe that the most likely cause was a drop in oil pressure which caused the VANOS solenoids to be "late" vs what the DME had expected. Also, given that Pocono Southeast is comprised of mostly left turns unlike just about every other track in the Northeast, it seemed plausible that the root of the problem was caused by not enough oil in the pan at the pickup location while hard left hand cornering.
Since Pocono, I fitted an oil pressure sensor to the N20 and wired it up to my AIM MXL data logger. Then took the car out for a bit of testing at NJMP Thunderbolt to see if I could confirm my theory. I've attached images of the oil pressure sensor install (which is actually in the same location where BMW would have put a sensor in the oil filter assembly) along with screenshots of the AIM analysis measures and plots.
The first is x/y plot is oil pressure vs lateral acceleration (negative numbers are left turns), second is oil pressure vs longitudinal acceleration (negative numbers are braking) and the third is oil pressure vs RPM. These show oil pressure dropping off when either heavy breaking or turning left, I think it's coincidental that rpm's also happen to be below 3500 at the same time.
I'm not overly concerned about this as the number of samples below the 1.5 bar minimum operating oil pressure is rather low, but still planning on a solution for late November. I'll be working with a vendor that fabricates a good number of parts for BMW's on creating an oil pan baffle for the N20. The biggest challenge I think will be the fact that on non-Xdrive cars the oil pan is actually plastic, but hoping they can come up with something that will work without having to go through the effort (and expense) of manufacturing aluminum oil pans. With any luck once the prototype is fitted and tested in my car, they will start offering them for sale to anyone else who might be interested.
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