Attention: TDR Forum Junkies Wayne,
I agree, there's not really any "problem" with the oil. But the data has so much scatter that I can't use it to "prove" which oil is really giving me the best overall protection. The wear rates on Samples 1, 2, 3 are clearly acceptable and decreasing on a "per mile" basis, but what was my wear rate between Samples 3 and 4? According to the data, the wear rate was negative; if I had added the 3. 5 quarts of oil and sampled again immediately at 14. 3k, I would have had more than 19 ppm - that's less than half of the 14. 3 k reading of 44 ppm. The "make up" oil should have "diluted" me back to about 30 ppm, and then the extra miles should have added a little to that number. What this leaves me with is "good oil, acceptable protection, but the numbers may be +/- 10 ppm per sample. " That's a big enough difference that drawing conclusions of "Amsoil beats Delvac" or "15W-40 beats 5W-30" is going to be iffy at best.
I'm off to vacation now, but I think you're right, when I get back I should just call the lab on this one and see if they have any additional insights for me. Thanks to all for the input! (I'll let this thread die unless I learn something useful I can share. )
HC
I agree, there's not really any "problem" with the oil. But the data has so much scatter that I can't use it to "prove" which oil is really giving me the best overall protection. The wear rates on Samples 1, 2, 3 are clearly acceptable and decreasing on a "per mile" basis, but what was my wear rate between Samples 3 and 4? According to the data, the wear rate was negative; if I had added the 3. 5 quarts of oil and sampled again immediately at 14. 3k, I would have had more than 19 ppm - that's less than half of the 14. 3 k reading of 44 ppm. The "make up" oil should have "diluted" me back to about 30 ppm, and then the extra miles should have added a little to that number. What this leaves me with is "good oil, acceptable protection, but the numbers may be +/- 10 ppm per sample. " That's a big enough difference that drawing conclusions of "Amsoil beats Delvac" or "15W-40 beats 5W-30" is going to be iffy at best.
I'm off to vacation now, but I think you're right, when I get back I should just call the lab on this one and see if they have any additional insights for me. Thanks to all for the input! (I'll let this thread die unless I learn something useful I can share. )
HC
