Originally Posted by Surly73
There are lab results for an Audi S4, I believe, with DI that nukes it's oil in only 1,000km. The BMW factory intervals are particularly horrifying in light of that. Without careful lab analysis, I'd probably run synthetic in any of the DI turbo cars (N54, N55) and probably change 2-3x as often as the BMW interval (if it were mine)
Those lab results were probably either from the N54 or the RS6 (see reply #61 above).
And yes, the factory set intervals are indeed horrifying. Here's what Terry Dyson himself has to say about the N54 in general:
I have customers running BMW5w30, M1 0w40 all with the same effect, the wear control is good if we change the oil at 1000 mile intervals but the deposit formation from REAL volatility issues are slowly damaging the engines. I just worked a 07 335 Biturbo yesterday USING ASTM lab tests on the used oil and M1 0w40 went from VOA flash of 430+F to 240 F in 1150 miles, oil sheared to 12.1 cSt and fuel was at 1.99% by IR. Amsoil has not been tested in this engine yet. Because Amsoil is a traditional based PAO I predict similar results to the M1 0w40 which is still one of few M1 products that can perform reasonably well.
RLI BIOSYN is the only oil I am seeing work well in DI RS4 or 2.0 Audi or the BMW bi turbo 3.0 I6 in the 335I. They both are killing every oil I used to recommend. I am not kidding and have no interest in promoting one oil over the other.
The M1 0w40 should not be run longer than 1000 miles to be safe.. Audi and BMW know they are having problems but are marketing tied to certain LARGE oil company that sponsors BITOG thus they cannot speak out about it.
GC 0w30 green might work well here but the fuels chemistries have changed so much that it may be out of date to protect as well as I would want to see.
This is why I didn't even bother with M1 0w40, GC, Redline, Amsoil, etc. and went straight to RLI.