A bit of a long post...but might help someone out there...includes stats on several recent OA.
So let me defend the current formula of AMSoil a little. I've done a ton of research on this website and others before and after I purchased my Audi S4. I decided on 2 oils that meet the vw502 standard. GC and AMSoil Euro 5w40. I've done oil analysis each time I've changed the oil. After the engine was well broken in I did a comparison at ~2,500 miles between the GC and AMSoil. Blackstone did the analysis. The GC had a higher TBN number compared to the AMSoil...8.2 GC vs 6.2 AMSoil.
But the wear metals were slightly improved on the AMSoil. VW recommends 10,000 mile change intervals. I'm going to be doing 5,000 mile intervals for the time being until I see how the oil holds up over longer periods. I enjoy changing my own oil so early oil changes are not a big deal. The additive package on the AMSoil probably starts out about 5 points lower than the GC. I know AMSoil starts at 8 for a TBN where GC, I'm guessing is around a 12 or 13.
But for right now, since I'm going to do 5,000 mile OCI I'm not as concerned about a slightly lower TBN. I'm more concerned about the wear metals and the AMSoil, shearing or not, is beating what many people believe to be the end all be all in oil...GC.
Blackstone has commented that they LOVE both oils...both have benefits, maybe a newer formual of the AMSoil will improve on it's shortcomings, but for now, IMO, it's the best oil for my new S4.
Just my 2 cents...below are the Blackstone comments the results of all my OA on this car so far...
DAN: You can see the difference in oils by looking at the additive package. Here calcium, magnesium, phosphorous, and zinc are all at lower levels. If we compare this sample to the last one, we see that after a similar oil change interval, most wear metals improved. These aren't terribly big improvements, but every little bit helps, especially if this oil is cheaper. The TBN read 6.2, so it is likely the TBN doesn't start out as high, which fits with the lower levels of additive. Everything looks good here and we think you could easily go 4,500 miles next time.
1st number is the oil change at 7,636 miles (AMSoil Euro 5w40)
2nd number is oil change at 5,293 miles (GC)
3rd number is oil change at 2,850 miles (GC)
4th number is my first oil change at 1,566 miles (factory fill)
5th number is my S4 Average
6th number is the universal average for all S4's they've tested with the 3.0 TFSI engine.
Aluminum 2 3 3 5 3 3
Chromium 0 0 0 0 0 0
Iron 7 10 8 18 11 14
Copper 6 8 8 25 11 7
Lead 0 0 1 1 0 1
Tin 2 6 0 2 3 2
Molybdenum 0 0 1 0 0 24
Nickel 0 0 0 0 0 1
Manganese 1 2 3 12 4 2
Silver 0 0 0 0 0 0
Titanium 0 0 0 0 0 0
Potassium 0 2 1 4 2 2
Boron 45 4 11 58 24 34
Silicon 8 13 19 67 24 11
Sodium 3 4 3 5 4 5
Calcium 1736 2004 1749 1867 1872 1989
Magnesium 14 504 402 11 307 322
Phosphorus 747 933 862 735 842 812
Zinc 890 1231 1060 951 1073 1011
Barium 0 0 0 0 0 0
AMSoil Stats....
SUS Viscosity @ 210°F 63.4
cSt Viscosity @ 100°C 11.16
Flashpoint in °F 415 >365
Fuel % Antifreeze % 0.0 0.0
Water % 0.0 Insolubles % 0.2 TBN 6.2
