I've got it printed out and will digest it . . . and comment in a bit
First Comment is So what? Whats the big deal? This paper says kinda what we know already . . .
The bone I have with this is that it doesn't identify more chemically the differences between the variablity and what leads to the failures.
Looking at their 4 test oils, the Group IV 0W-30, the Group III/IV 5W-30, and the Group IV 0W-40 and the Group III/IV 5W-40 I think it becomes hard to determine anything more than a comparison to those very specific formulations.
The low polymer oils (lower visc modifier meaning the 0W-30 and 5W-30 oils) did much better. And that is as expected. The additive choices clearly are just as important as base stock.
The one thing that is clear is there were 2 Group III 5W-30 oils that peformed perfectly in the tests (these are off the shelf not blended for the tests like the ohter oils).
So what can we get out of it?
Well not much IMO.
The Petro Canada 0W-30 oil I am using is a Group III/IV blend, and the wear metals are very similar to the results I've gotten with a Group IV/V blend 0W-30 so I would feel reasonably comfortable saying that the oil is doing its job.
I've run a compression check a while ago and it was over 500 PSI across the board - no loss of compression - nearly as high as some xW-40 oils tested. That was between 80 and 90,000 miles on the ODO. so quite a few hours running the Group III/IV blend.
Yes Group III quality is variable. Hence my desire to avoid group III oils coming from anywhere other than Petro Canada's refineries. And my reluctance to reccomend Rotella T 5W-40 synthetic.
My other question I have from reading this paper is what does adding a Group V oil to the PAO do to the results? I know of only a very few PAO only oils on the market and they are there only (my guess) for limited (very) markets and are very low production batch oils.
What does this mean for the TDI? Well they ran a bunch of tests - and killed a boat load of TDI engines to write a short 7 page paper
with little meaning for the North American market
But it does questions quite significantly the intelligence of running a high polymer treat oil (PAO or Group III). 5W-40 doesn't look like a very good viscosity. So I might join Tbill in saying if you are down somewhere warm and can't grasp that a 0 or 5W-30 is perfectly acceptable irregardless of ambient temps (to run in the TDI) then run a 15W-40, not a 5W-40.
I'd also wager that 300,000 miles in Delvac-1 vs a sister engine run 300,000 miles with Amsoil Series 3000, will demonstrate significantly higher piston ring deposits and much MUCH lower merit scores. I would also feel confident that anyone running the Amsoil 10W-40 will see increased piston ring deposits over either the Series 3000, or Series 2000 0W-30 or even the 15W-40 HD oil.
As it was written here many moons ago by someone who had more to give and less to snipe about (at that time) 0W-30 is ideal for the Garret Turbo and with this evidence a 0w-30 or 5W-30 properly formulated oil is better for the rest of the engine.
(all opinions expressed in this post are mine, I have no connection to any monetary rewards from sales of oil or oil related products. These are opions, some based on more than others but that is it. take is for what it is and deal with it
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[ December 14, 2002, 09:20: Message edited by: GeWilli ]
