gtreng1

Mobil 1 racing oil is finally not available. Should I go with Royal Purple 5W-30 or Mobil 1 extended performance 5W-30? I live in FL, so no need for winter oil. Just want highest performance

ryoung

Now that the M1 0w-30R is no longer available, I went back to M1 0w-40.

chenishead

Bloody dealer says something different, store is different. Confusion...

99A8Q

M1 0-40 European. All temps, all climates.

Hex168

I'm still under warranty and am reluctant to use a non-API oil. Still, this stuff appears to be the best out there. Note that the RS4 data is for a more demanding situation; the D2 4.2 is less demanding. However, oil analysis on my 2002 shows some fuel dilution, and Iwill consider switching oils once my CPO runs out.

See:
http://www.renewablelube.com/motor%20pricing.htm

http://www.renewablelube.com/products/pdf/Bio-Synthetic%20HD%20SHP%20SAE%205W40%20Motor%20Oil.pd f

http://www.renewablelube.com/products/pdf/Bio-Synthetic%20SHP%20SAE%200W30%20PCMO.pdf<ul><li><a href="http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&amp;Number=893022#Post 893022">Renewable Lube 5w-40</a></li></ul>

Hex168

My M1 0W-40 oil analysis indicated good wear but some fuel dilution and reduction in viscosity. Switched to M1 5W-40 to resist the viscosity reduction. Since my engine showed no serious problems, I'm not planning on another oil analysis any time soon.

Zumkopf

I love people who love their cars, but specialty oils are simply a waste of money for street cars. A petrochemical background is helpful here, but not necessary. The key is the API specification. Modern oil (especially the synthetics) has extraordinarily good protective capacity, and the difference in the grades being discussed in the climates we live in is marginal. Sure, 0w-30 flows slightly better in very cold weather than 10w-30, but the latter is fine just about anywhere in CONUS, especially for those who care about their cars and don't run them to redline from a dead cold start. Keep in mind that most diesel motors use 15w-40 dino oil, easily start in subzero temperatures given good glowplugs, and routinely run 300k+ miles before rebuilds.

Synthetic does have a measurable edge over dino oil, especially if you seek a wide multigrade coverage. Dino oil makes the stretch with additives; a wide-span dino oil (say, 5w-40) can be as much as one-third additives. Additives ain't oil, and they break down long before the oil molecules do. Synthetic accomplishes the same using precise control of the length of the oil molecule chain (long chain = better protection at high temperatures; short chain = better flow at low temperatures). But the difference between the flow of 0w and 10w in synthetic oil, in our climates, is essentially irrelevant for automobile applications. (If you live in Minnesota, Alberta, Saskatchewan, or anywhere where you routinely see really bitter cold, twenty and thirty below farenheit, my answer would be different. Virginia, Florida, Massachusetts, Illinois, Oregon, no.)

At the top end, synthetic 30 weight does a very good job at even summer temperatures. Even 20 weight synthetic does; Ford specifies 5w-20 for many of its motors, mainly for fuel efficiency reasons, but it maintains adequate engine protection. I personally wouldn't go as far as Ford, and would agree that for very heavy load at very high temperatures (e.g., trailer towing in August Phoenix stop-and-go traffic), you could profit from 40 or 50 weight at the top end.

Racing oil specs are for engines under tremendous stress at extraordinary RPMs. You simply don't get anywhere close with a road car. Not even as a club racer. I'm happy for you to enrich Exxon-Mobil, Shell, Sunoco, and me by buying very expensive oil, but it's a waste of your money. (I should also add that racing engines are routinely torn down, after very short intervals. If you're really going to stress a motor, the oil won't save you.)

When *your* car fails, it won't be because you used 10w-40 instead of 5w-40 or 0w-30 or 20w-50. It won't be because you used civilian oil in your S8 instead of racing oil. And if you don't change your oil and filter regularly, it doesn't matter how good the oil is you put in.

Zumkopf
'98 A8Q 95k (M1 5w-40)

P.S. Besides frequent O/F changes, IMHO the most effective things you can do to extend engine life -- far more important than the oil grade -- are (1) install a pre-oiler, to pump up pressure before you start the motor; and/or (2) install a good engine heater. The latter also has the advantage of making you toasty warm from the moment you start your car.

P.P.S. If you insist on 0 weight viscosity levels for winter conditions, and 50 weight for summer, pick a summer oil and a winter oil; avoid very wide spread viscosity oils. To get the wide viscosity spreads, the refiner has to make compromises in the oil composition. Again, this is particulary true with dino oils, which require a lot of additives to do this; with synthetic, the only real downside is that the oil ends up being a blend of cold-optimized oil and hot-optimized oil, and ideal for neither application. However, I still maintain 10w-40 will serve your needs year round just fine.

gtreng1

...The documented test out there are pretty conclusive that there were higher hp gains (may not be noticeable) from using M1 Racing over the standard M1 oil. Im finiding great things about the AMSOIL too vs. M1 extended performance. Being the creators of synthetic oil, I'll probably go that direction. If I had to rank what I base the selection on, it would be anti-wear additives, performance, cost. I know first hand that not all oils are created the same, its almost like saying theres no difference between running 87 gas and 93 gas.