Let us know when the result is in. I'm curious!

 

Just to throw in another brand . . . I am using Royal Purple, but considering AMSoil or Redline at the next change.

 

*blink*

What? How does that work?

Serious question. Once a long-chain hydrocarbon is cut, it's cut, unless you go way out of your way to rebuild it (e.g. create some "new" synthetic oil out of it) ... right? Am I missing something?


Thanks!

 

^ He probably meant that it first shears out of grade and then it starts turning into sludge, lol.

 

You're right on the $.

As long as the wear averages, TBN, TAN, dilution, etc. are within the average for this engine, you shouldn't need to worry.

 

I noticed a couple of things.
PP 10w30 is actually just about as thin (63.4) as M1 5w30 (64.8) at 40* but slightly thinner at 100* (10.5 vs 11.3)
M1 0w40 is significantly thicker at both 40* (78.3) and 100* (14) than both PP 10w30 and M1 5w30.
Valvoline SynPower 5w30, which is an approved oil, is rated at 59 at 40* and 10.5 at 100*. This means that it is a thinner oil than PP 10w30 at 40*.
I came across a very well documented and detailed sequence of UOAs on BITOG performed on the same year MCS as mine using 0w40 M1 and the oil held up just fine even up to 12K miles. Driving conditions are the unknown factor in that equation. It's tempting, but I'll first try PP and see how it does.

 

Something wrong with Royal Purple? I've used Amsoil in other cars and I wasn't impressed. Never used Redline, but I'm running Royal Purple in my MINI. Probably just my imagination, but when I first changed to Royal Purple my MINI felt a little more zippy.

 

I've been using M1 0w-40 and 10w-30 in my VW New Beetle (1.8 Turbo with 1.0 Bar program). Based on UOAs, they are both quite good to ~10,000 miles (with some room left); the filter is 2x bigger than the Mini's and has a factory recommend life of ~18,600 miles. Environment: SoCal year round, 50/50 city/hwy. If it was more Hwy use, the oil should last till 15,000 miles. I've seen M1 UOA for this engine at ~15-18,000 miles

The only thing I don't like about M1 oil (for this motor) is the consumption along the way to 10,000 miles - about 1.5-2 quarts, even when new! If using Dino oil and changing every 5000 miles, there was little to no consumption. By design, Synth oil shouldn't evaporate faster than Dino... maybe it's sliding pass the rings?

Anyway, I had to replace the valve-cover gasket recently at 155,00 miles. The surface of the cam lobes, tappets, and the head has NO varnishing. Don't know about the Turbo though... hoping it'll last to 250,000+ miles.

Due to the age of the motor (160,000 miles), I've switched to 10w-40 grade now. Will see what happens.

 

Rotella T Synth is designed for turbocharged Diesel engines but does have API SM gasoline engine rating, but is not a GF 4 rated oil. There seems to be quite a following among gas turbocharged car owners, especially Subie WRX'ers. The anti-wear additive Zinc/Phosphorus is 35-40% higher than most synthetic oils made for gas engines, which mayl shorten the life of the catalytic converter if your engine burns oil.

If my MCSc doesn't consume oil in the 7.5k-10k range, I might try Rotella T Synth after my warranty is over.

More details: http://www.iwsti.com/forums/2-5-lite...-t-5w40-4.html

This is a sample UOA for a '5 WRX Sti. Previous 2 samples are from Mobil 1 5w-30 at 2589 and 3000 miles...

 

I'm not going to comment on RT beyond the fact that I'd rather stick to an oil package designed for gas engines and the fact that most of the arguments people uphold are statements by Terry Dyson which have been "urban legend"-ified (I checked with him regarding this). RT is not friction modified. Expect a drop in mpg. I have gotten better results than some RT runs on PP. I have zero reason or incentive to switch.
My dad's RAM 3500 Cummins trashed that oil in about 8K miles, so he had to do shorter OCI. He's a driver, he tows routinely at the truck's max load capacity.
That said, RT is a robust oil, just that there's no way to know how it truly does without a UOA, if you're into that kind of thing. Anecdotal evidence points to the fact that results won't be the same across the board. As far as I'm concerned it's more or less "the latest fad on BITOG".

 

Of course, UOAs are needed (and assumed in this thread) to see how an oil performs in a particular engine.

Rotella T Synth 5w40 is now gas-approved... just not BMW approved. Keep in mind that a some M1 and Redline oils (for gasoline engine) also have high Zinc content.