ShellRotellaT 5w-40, 3,777 mi, 07 Subaru Legacy GT

[bluesubie]

Here's a pdf of a uoa at 4,970 miles on RTS posted at subaruforester.org

The car is a Forester XT running a Cobb Stage II (ECM reflash, some exhaust mods).
Viscosity = 11.82
Z = 1177
P = 1020
Fuel = 1.3%

I guess the viscosity hit could be from the fuel in this case.
Driving conditions = Typical Subaru turbo driving.

Quote:
Oil was hot and I specifically drove it for about 20 minutes on the highway before draining. About 80% of my driving is stop and go though it's only 5 miles to work. I had done 30-40 hard pulls (I've got a really nice, little used 1 mile straight stretch near my house) on this oil, so I'm not surprised it sheared down.

-Dennis

 

[Jaymus]

How much Calcium did that one have, Bluesubie? I think you have to be a member to see it.

 

[bluesubie]

Originally Posted By: Jaymus
How much Calcium did that one have, Bluesubie? I think you have to be a member to see it.

2908

-Dennis

 

[07spec]

So it looks like my calcium is pretty low then for RTS.

 

[Gary Allan]

There could always be a batch variance, but this looks like a reading miscue. Blackstone may still have the sample. Point out the radical difference in expected results vs. indicated. They've been known to vary greatly on stuff like moly ..but this is the first time with calcium to my knowledge.

 

[bluesubie]

A WRX owner just posted an RTS uoa on nasioc with a calcium reading of 683. Something's fishy.

-Dennis

 

[addyguy]

I don't see what the issue is here - the lower Calcium level is augmented by the Magnesium detergent.

Just a different way of arriving at the same place....

 

[bluesubie]

Originally Posted By: addyguy
I don't see what the issue is here - the lower Calcium level is augmented by the Magnesium detergent.

Just a different way of arriving at the same place....

And this is Blackstone's response in regards to the WRX owner I mentioned above:

Quote:
The Shell Rotella T 5W/40 additive levels found in analysis have been known to fluctuate compared to most other oil. Calcium is a detergent/dispersant additive, and sometimes we find it at ~3000 ppm in this oil type, but in others we find it reading much lower. It looks like the Shell Rotella T 5W/40 formulation in your Subaru makes up for the lack of calcium with increased magnesium, which is also a detergent/dispersant additive. This discrepancy in additive levels for this oil type doesn't seem to have had any noticeable effect on performance. We don't know why two different "versions" of the same oil exist at the same time, but both seem to do the job very nicely. ...