After analyzing all the data and discussing different oil properties and related subjects (that were not part of my "oil study") with some of the enginners at a few of the oil companies, I have made up my mind which oil I will be using in the M3.
My viscosity grade choices were the 0W-30, 5W-30, 5W-40, 10W-30 and 10W-40 oils. My "short list" choice of product manufacturers were Amsoil, Redline and Mobil.
I have elected to use Amsoil's 0W-30 oil.
The reasons for my choice are many.
In discussions with Mr. Darren Wallace (Technical Design Engineer and Chemist) of Amsoil Company, he suggested strongly I use the 0W-30 in the M3 for street and track. His suggestion rather suprised me! I asked him, "track too" and he said "most definitely." I will only lightly attempt to explain why he made his suggestion to me.
He explained that BMW engines, as are most others, had very tight engine tolerances for their bearings, etc. He said using the Amsoil 0W-30 would protect these bearings (and the entire engine) better than ANY 30 weight grade oil they have ever tested, including their other 30 weight multi-vis grade oils they offer. The anti-wear additive package for this 0W-30 oil, he said, is simply the best they have ever seen! The chemical make-up of the other Amsoil oils don't allow this same anti-wear package to be used. He also explained this particular oil is better at dealing with the contaminents (hydrocarbons left from combustion), dirt and corrosion, etc. than the other oils.
He said using the 0W-30 would offer unheard of protection at dry start-up where the anti-wear properties, only found in Amsoil's 0W-30, would virtually eliminate the metal-on-metal damage incurred when first cranking up an engine. He further explained that damage results whenever an engine is first cranked up, even if the ambient temperature is 100 degrees F.
There is much more to the anti-wear abilities of this "one oil" but I won't attempt to even try to cover it all. He did admit that no other oil that they have in their line of products, as good as they all are, has the characteristics, properties, abilities, traits and technology that the 0W-30 does. In fact, the way he put it was, "the Amsoil 0W-30 could be five years ahead of the competition!"
He also added that all 0W oils are more expensive to produce and this is the reason most other synthetic oil producers don't offer 0W oils. In the future, he said, this will change in his opinion.
Mr. Wallace further said that this oil is highly recommended not only for street use in the M3 but also in the most demanding and continous high rpm, high temperature, high abuse conditions! He explained many SCCA entries (and other forms of racing) are using it. And that the oil's film-strength, shear/tear properties, anti-wiping protection, lubricating ability, engine cooling, etc. are the best.
Keep in mind that the second number of an oil's viscosity grade (30 in this case) is the steady weight of the oil when at 100 degrees C (212 degrees F) and it compares with any other 30 weight grade oil, in thickness, regardless whether it's a 0W-30, 5W-30 or 10W-30. This is a A.S.E standard test which must be passed to be called a particular viscosity grade oil. (Don't let the "0W" verses the more common 5W or 10W confuse you.) This particular oil's ability to remain a 30 weight oil in very abusive engine temperatures at well over 150 degrees C (302 degrees F) allows it to be a strong and safe oil for street, strip and track.
He explained that using a heavier weight oil is not necessary or desired "unless" the engine is built losely (with wide bearing tolerances) which BMW's engine's are not. Also, he stated that car manufacturer's recommendations for using a heavier "petroleum" based oil such as 15W-40 or 15W-50 was only recommended because of the protection those petroleum weight oils could offer. Using lighter synthetic oils in lieu of hevier petroleum based oils offers "more" engine protection while also offering better wear protection too. It's a win-win situation.
Anyway, for those who have asked me about which oil I intend on using in my M3, I have made my choice!
His email (or used to be a year ago) is:
Hope this helps