Originally Posted By: 69GTX
Originally Posted By: BrocLuno
I have a relationship with RAT. His "problem statement" is about race engines loosing cams and lifters in classes that require flat tappet style valve trains. Race engines run very aggressive lobe ramps and high rate springs to control valve float and bounce.
His testing was for clients that are not your average OEM engines. He extrapolates a LOT, does not run tests to verify repeat-ability in samples, etc. And he carries his math to extremes to separate oils that would be judged here on BITOG as equivalent. And he measures at only one temp mostly. So we really don't know what cold oil performance is on his rig...
But, saying all that - I find that even if his data is somewhat questionable (and it may be), it's a another look at oils and that is a good thing. There is nothing wrong with any of the oils in his to 1/3. There are concerns with oils in his lower 1/3 for performance engine applications.
For OEM engines, his rational may not apply to well ...
you can gain some more insight here:
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4045499/1 But, like lot of BITOG threads it has wandered
If "race" and/or flat tappet performance engines are RAT's focus, why is the #1 rated oil on the list a 5W-20? And why are the 40 grade oils as well as a lot of boutique racing oils in the bottom 1/2? Those results don't seem consistent to me. And to confuse things even more, their top 2 ranked oils (QSUD 5w-20 and M1 5w-30) perform average or worse at elevated oil temps of 275 deg F....about where a performance/racing engine might operate for extended periods. I didn't spend the time to thoroughly check the list for where the first MB 229.5 and Porsche A40 spec'd oils first show up. But M1 0w-40 is one of them (ranked #89 or bottom 1/3). Castrol Edge 0w-40 Euro can't be ranked much lower than it is at #135.
That is what his testing machine shows. That is what I get from the testing. Remember the temperatures of the oil can be much higher at the friction points than the sump temperatures. Like the oil filters tests that have been posted would the best filters really allow your engine to live longer when the engines with care and some luck out last the transmissions and body.