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Old October 31st, 2018, 19:41   #3485
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Join Date: Oct 2014
Location: NorCal

Originally Posted by James & Son View Post
If you are trying to reduce or beat the TDT UOA you could probably easily do it with Bio-SynXtra HD SHP Motor Oil SAE 5W40 (10 TBN). To reduce iron wear you need the 185 VI which is attained without exccessive use of VI index modifying polymers which improves HTHS and flash point.
Thats likely what you were after with your combination and mix. But you lose out on the benefit of increased flow and reduced wear at startup. The other benefit at start up of all RLI products is the improved boundary or lubricity during start up and shut down.
The difference between Bio-SynXtra HD SHP Motor Oil SAE 5W40 (10 TBN) and the low ash version is a reduction in the amount of antiwear and TBN to attain the latters low ash( equal to CJ4). The advantage of the former( equal to a CJI) is you have the additional additives already and unnecessary use the 2% adder pack.
Just in case your interested I use the low ash 5w-40 and drive one year or 15000 miles, at month (6) I add 2% and then at month (9) I add another 2% in hope that I retain the CJ4 low ash qualitys without deminished wear additives.
I would expect with your '03 you would likely get to 15000 miles with no additives using the Bio-SynXtra HD SHP Motor Oil SAE 5W40 (10 TBN).
One of the reasons you can run the RLI out passed 10,000 miles is its tolerance for diesel fuel dilution.
Hi, James & Son.

I had two bottles of the booster pak which were ordered about a year ago. I am just using them up, 1/2 bottle (4oz) in my Golf and 2.8 Duramax at each OCI. I do not plan on buying anymore booster pak.

I created this mix of 10w30 & 15w40 because I got a bunch of the 10w30 CJ-4 for cheap and wanted to thicken it up a little. The 15w40 has great properties (Low NOACK, High VI, and High FP) so it seemed like the best option.

I had this "10w40" blend tested by Oil Analyzers, it is a "thin" 40wt and it has a VI of 172.
  1. 78.8 cSt @ 40c
  2. 13.3 cSt @ 100c
  3. NOACK 8.5% (11% + 6%/2 = 8.5%)
  4. 526 ppm of Sb
  5. ~1100 ppm of Phosphourus

As you can see it has superior cold flow (40c) properties at the mild temperatures we see here in CA. I don't need a low winter rating so 10w, 15w and even SAE 30 are fine here.

These higher winter rating blends use thicker base oils so the flash points are typically higher than a 5w.

I'm staying with the low-ash versions because I'm also using this in my 2.8 Duramax equipped with emissions controls. The 10 TBN CI-4+ version of the 5w40 is excessive SA. I also would be changing the oil once a year anyway so I don't really need to exceed a 10k mile interval as I have two vehicles. CJ-4 is fine for me.

I would also like to mix the 15w40 with the SAE 30 next as that would be even a lower NOACK (6.5%) and higher flash point. That is the next thing I will try if the Oil Analysis results are better than what I've seen with TDT and D1 ESP CJ-4 versions.

I'm attaching a copy of the OAI report for your reference:

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