Quote:
Originally Posted by aerobod
There seems to be a particularly North American resistance to change based on experience elsewhere in embracing advances in technology. My knowledge of UK based BMWs, the use of 2-year oil change intervals (when using a proper Group III or IV synthetic, not most of the stuff that is allowed to be called "synthetic" in North America) and the lack of any major issues in BMW engined cars that have been using 0w20 oils now since at least 2015 (together with almost every other manufacturer, including Porsche now), lead me to the conclusion that quality 0w20 oils in a fairly low stressed engine like the B58 (low rev limit, conservative boost pressures as stock) actually work very well.
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The thing is UOA's don't lie and it still shows these FE oils don't protect as well because they keep prioritizing fuel economy.
2 year oci's would be a stretch, but with ll01 certificatations it might be doable because ll01 has insanely stringent oxidation standards. But with Pao heavy oils it probably won't make it 2 years because paos and esters oxidize too quickly, and why Castrol edge 0w30 and 0w40 don't have BMW ll01 certificatations because it can't meet the stringent oxidation tests.
I wouldn't call the b58 a low stressed engine, it's running a bit more boost than the n55 and n54 stock, it revs to 7k which is still really high compared to other engines on the market, and the main issue is that it still runs very hot oil and coolant temps (for efficiency) like the n5x engines did. So I wouldn't want to run an FE oil let alone a 20 weight FE oil in the 2.6 - 3.1 HTHS area. If 0w30 fe oil was considered to be not too good (with UOA's on BITOG) with an HTHS over 3.0 the 20 weight version isn't going to improve upon that, it likely would be even worse.