Different results from 3 labs - Brad Penn

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Jan 9, 2009
Menlo Park, ca
First as of now Brad Penn didn't have their new 15w40 out yet so I mixed equally some 10w30 and 20w50 to achieve 15w40. This was done after consulting with Brad Penn.

Prior to the mix I had sent a sample of virgin 20w50 to Peterson Cat labs. Then I mixed the above numbers and put the 15w40 mix into the car running it 100 miles. So yes the 15w40 is not real virgin but for the purpose of this test, I was only really after the zinc and Phos numbers. This mix went to both Blackstone and Polaris.

Here's the numbers

..................... Zinc - Phos - Sodium ----Miles on oil
Peterson Cat (20w50)---1049----952----339---------0
Blackstone (15w40)-----1107----938----319-------100
Polaris (15w40)--------1600---1226----388-------100

Both Blackstone commented on how high the Sodium level is pointing to either it is because it's a newly rebuilt engine or it's an additive. Note that Peterson had similar numbers and that oil was virgin. So I am pointing to an additive.

But what got me is Polaris's high zinc and phos's numbers.
Assuming the 10w30 has same or less zddp than the 20w50, which is very likely, then Polaris must be way off.

Nice to hear an oil company comfirm the creation of a 15w40 by mixing 10w30 with 20w50, presumably they said 50 50 mix.
Polaris Labs meets the highest level of accreditation attainable by a testing lab with the ISO/IEC 17025:2005 - A2LA. That doesn’t mean they don’t make mistakes or never have made a mistake. However, getting two different lab results – one from Blackstone and then one from Polaris and then placing the doubt on the highly accredited lab (Polaris) seems a bit flip flopped.

Remember we have seen Blackstone VOA reports on this board that have proven to be low on the ZDDP numbers.
All of the labs will report different results in many ASTM standard tests. When they submit their test results for a round robin comparison for certification, they are considered for a pass/fail grade for each standard based on what the mean average results were from the other labs submitting their results. So, unless you get a copy of the ASTM ISDO0707-Interlaboratory cross check program results for your lab, you really don't know how accurate they are for ZDDP reporting, or any of the ASTM standards for that matter. From the results I've seen, you don't have to pass every test to get the ISO/IEC 17025:2005 certification.

As a personal experience note, I once complained to an oil company about additive levels seeming to be lower than I would expect from one of their products and sent them a VOA from Blackstone to illustrate my concern. They told me to start using Polaris Labs and I would be happier with the additive levels!

Moral of the story...if you want higher additives, use Polaris Labs!
The other moral might be to stick with one lab and learn to see and interpret the trends there. Well, assuming you can count on the result being consistent, at least.

This is why I have started getting VOAs on everything I use. That gives me the baseline start for both the batch and the brand I'm going to UOA later. I know that's not anything new and is generally good advice, but it doesn't appear that all that many BITOGers practice it. Until recently, that included me. What do they say about the newly converted being the most outspokenly fervent....?

Anyway, these days, I'm even less concerned with proving that my oil's better than yours, and more with getting the most from my money.
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Originally Posted By: INDYMAC

Moral of the story...if you want higher additives, use Polaris Labs!

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