has anyone here read some of the threads at BITOG about the DI of N54 and fuel dilution with Mobil 1?
high air pressures - high fuel pressures - hot oil temps legitimate worries ... but no conclusions possible. We'll know the answer in hind-sight when these cars start reaching 100,000 miles. In the meanwhile, choose who you want to believe and follow their advice. (glad I'm leasing!)
As long as you drive 10 to 20 miles a day I wouldn't worry about it. I have been doing extended oil drains in various cars for 10+ years. I put the M1 0-40 in my 335 and My X3 just gets the dealer stuff and just had it's first ouil service at 18k miles and oil analysis showed that it still had some life left. My friends Porsche is every 20k miles with M1 and oil analysis on that is fine also.
remind me not to buy your X3 when you sell it.... j/k here's the link http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=981162&Board=48&fpart=all&gonew=1#UNREAD
I have torn down motors with over a 100k with extended drains and they have been fine. Just keep using up our oil for old time thinking.
Hmmm, hate to start a fight but.... I'm going to side with David on all this. I have also seen plenty of engines torn down with high mileage oil changes that look virtually new. I have built and raced everything from drag race engines to formula engines in everything from Saturday night specials to series winning professional teams. The whole change your oil every 3k miles is a big hoax to sell product. Yes, I know grandpa drove his Ford pickup for 300k miles by changing oil every 3K miles, that was then and this is now. The game has changed completely. Does anyone remember the Mobil 1 tests of the early eighties when they drove a BMW 3 series 1 million miles with no oil changes, just a filter change at the normal interval and a top up of M1? And that was with 30+ year old 1970's technology oils. I might change oil twice as frequently as BMW recommends if the car was regularly tracked (and then it would never be with the pseudo synthetic Castro BMW uses) but to equate oil changes with long engine life is not science it is pure 100% myth. BTW. while we are talking about the N54 engine, a lubrication engineer that works for a major syn. oil supplier told me that there is a slight advantage of more heat transfer to the oil when using a heavier weight synthetic oil for those afraid of the higher than normally aspirated temperatures of the 335i TT engines. Fight among yourselves...
I found that fascinating upon reading, so I researched it a bit and have found some information on the subject. I read that the oil was changed frequently during the test. The wear tolerances were all within BMW's specified range for new engines and the whole condition was essentially flawless. While searching for that article, I also came upon a thread on Bimmerforums about some guy who has his E30 over 500k miles. He attached pictures and lo and behold, we was speeding when he took the pic, so you know he didn't drive like a granny. lol
It is an interesting thread - I never thought oil analysis could be entertaining! But even assuming all the posts are honest and legit (always a concern on such forums, especially those sponsored by "big oil") there is a big problem with statistical power. We are hearing only the unusual experiences of a self-selected sample population. A very small sample population in repect to the large number of cars out there. The direct injection technology is still relatively new, it may present a whole new challenge for oil designers - but I think only time will tell. I admit that I would use a shorter oil change interval if I were planning to keep this car forever. I would also change it after a track event. But that is just my "old fart" thinking, based upon absolutely no science. I don't think BMW has the longevity answer with their "service interval indicator" algorithm, but I don't think anyone else has a better answer either (at least for now).
Mobil 1 tests Extended changes or no changes I remember that article and test being an extremely good read. I think it might have been in the Mid-eighties as I remember it was reprinted or referenced in the Roundel after 1985 sometime (when I became a member) I'll try to hunt it down. It may have been done several times as I also remember a test on a chassis dyno. A couple years earlier than that I had been working in advanced engine engineering at Ford and had witnessed some of the early testing of Mobil 1 Synthetic and what it had to offer over dino oil and it was very impressive, so impressive that many cases of unmarked M1 engine oil and other lubricants found there way to a few Ford race teams restricted to using the series sponsors dinosaur oil (Union 76 at the time) Now I am told that there are is a whole sub-industry at the large oil producers just developing special blends of synthetic lubricants for race qualifying, mileage runs, etc.
Right before the Indy 500 some race teams grabbed up some 0w40 M1 at my local Napa store. no sh!t it may give the HP edge for the race. Anyway I thought it was interesting.
His product was a 15w-50 weight BMW M car approved Synthetic ELF/Total but he was just referring to the fact that higher viscosity oils absorb and then dissipate slightly more heat Yes, lighter weight oil makes power and are more efficient I have heard some of these special recipe qualifying lubricants are scary thin.
I bought a semi custom boat back in the early 1990s and asked the rigger, an aussie who had worked on several offshore race boat teams about using M1 in my boat engine. He told me that the race team he was currently working for had switched to M1 that season, and that previously, they had needed to rebuild the engines after each race. After the switch, they were able to go at least three and sometimes four races without a rebuild. It really was a better oil back then, I assume the newer semi synth formula is still good, but I have switched to Royal Purple more recently in my track cars, though I really have no way of knowing if it is any better. Its just that a stronger oil should last longer, given accceptable filtration.
Yes. Several oil experts do have UOA's from Mobil1 0W-40 and other Synthetic oils that are BMW approved and show severe fuel dilution of the oil in N54 within as little as 1000 miles. It appears (my interpretation of the expert comments) that most DI engines in North America suffer some fuel dilution (some engines more than others) because of regulations that prevent leaner burning mixtures which increase No2 emissions. The DI technology leaves some unburned fuel around the lower cylinder walls where it gets into the oil and dilutes it... reducing flash point, and increasing wear. The N54 has according to these folks show to be particularly hard on oil both due to dilution and heat. DI engines in other parts of the world can be run in stratified mode where fuel mixture is lean in the lower part of the cylinder and richer near the plug. This significantly reduces dilution of the oil, at the expense of higher emissions. This is all very interesting and they strongly recommend a much shorter oil change interval than BMW recommends, feeling that BMW really hasn't done its homework regarding the oil needs of this engine. While the oil experts have made custom oil formulations that effectively combat the dilution and thermal issues and WILL stand up to longer OCI's, they are not BMW approved. So those of us who want to play it safe warranty-wise by not straying away from BMW approved oils basically have no choice but to reduce OCI's by at least half. One person even recommended no more than 5000 miles on approved oils. I am following that advice and reducing the OCI significantly. It's cheap insurance and piece of mind.
what you describe here about lean burn and emissions regulations is what is keeping the direct-injection versions of the normally-aspirated N52 engines out of the US.
