Shear Stability of M1/EP vs M1/GF-4

[TooSlick]

EOT viscosities for the last five, 5w-30/10w-30, EP tests:

64.9 SUS
64.5 "
64.9 "
63.9 "
60.1 (turbo)


EOT viscosities for the last five 5w-30/10w-30, GF-4 tests:

62.4 SUS
59.1 SUS
58.4 SUS
58.1 " (turbo)
9.01 Cst

The new EP formulation is clearly more shear stable than the GF-4 chemistry. It's thickening because there is little or no polymer shearing to offset the normal oxidative thickening.

I call this the Amsoil "problem"...

 

[NewGuy]

TS -

Do you think that this increased viscosity stability of M1EP would improve the performance of M1 in LS1 based GM engines? I ran M1 10W30 in my 5.3L V-8 and it ran great.....up to 4K miles. After that I got a lot of valve noise which I would attribute to the material shearing??

M1 10W30 EP has a higher HTHS (3.21 vs. 3.14) regular M1 10W30. Any thoughts on whether the EP formulation would provide better wear protection for 5-7K OCIs?

Thanks for the insight.

 

[TooSlick]

Yes, I think it's MUCH better for all these GM Vortec engines (as well as the Chrysler Hemis) and the SAE 10w-30 grade would be marginally better than the 5w-30. I'd use one of these oils even in a brand new GM vehicle. NOBODY is going to care if you use an API SL, GF-3 rated formulation instead of an API SM, GF-4 rated formulation. In fact, the odds of your GM service manager knowing anything about API/SAE/ACEA oil specs are about 1000:1 - and I'm being charitable.

I can assure you that many, if not all of the ExxonMobill lube engineers are using this stuff (or Delvac 1, 5w-40) in their new personal vehicles - just like many of the Amsoil tech service guys run their Series 3000 "diesel" oil and not one of their gas engine formulations....

I should add that I specifically don't recommend using LC20 in these thicker M1 formulations. The last thing you want to do is keep it from thickening slightly over the course of a long service interval. You're actually getting better wear protection this way....

Tooslick
Dixie Synthetics

 

[haley10]

quote:

---

Originally posted by TooSlick:
NOBODY is going to care if you use an API SL, GF-3 rated formulation instead of an API SM, GF-4 rated formulation. In fact, the odds of your GM service manager knowing anything about API/SAE/ACEA oil specs are about 1000:1 - and I'm being charitable.

Tooslick
Dixie Synthetics

---

TS, my GM service manager absolutely knows the differences. Would he give you a problem? No. I doubt GM would issue an directives to do so either.

 

[surfstar]

how about a 50/50 mix of EP and GF-4? my only UOA was of M1 10w30 GF-3 (i believe - it was 9/04) and the viscosity was 64.0 after 4600 miles. a blend should give me shear stability and not too much thickening, right?

 

[TR3-2001SE]

Why are we calling a formulation that thickens up shear stable? I would call it viscosity challenged or unstable viscosity.

 

[Pablo]

Isla Vista dude - Unless your engine is burning oil at a good clip, the extra ZDDP in S3K will not have any impact on converter life/performance.

 

[IslaVistaMan]

Thanks, Pablo. My engine isn't burning any oil, so I think I'll give the Series 3000 5W-30 a shot next time around. I just dropped some of the 0W-30 in about 1,600 miles ago, so it won't be for a while yet.

I plan on doing UOAs through Blackstone at my next couple of oil changes, so it should be interesting to see if there are any real performance differences between the two oils.

 

[Jay]

I don't think you can make a good judgement about shear stability from one viscosity measuring point at the end of the OCI (unless you have VI).

A better indication of shear stability is a spacebears-type study where viscosity is measured every 1000 miles. In the spacebears study, Mobil 1 5w-30 proved more shear-stable than Amsoil ASL 5w-30, although both oils were very good in this regard.

3MP is testing M1 5w-30 again and unfortunately a viscosity abnormality (either is mistest of the virgin or a fluke batch) marred a possible shear stability result for the SM formulation.

 

[buster]

Actually what can happen in many cases, is the oil will shear, but thicken at the same time giving the impression that the oil isn't moving at all. This is the effect TS is referring too.

 

[oilyriser]

That explains why Mobil 1 lost the A5 rating. You can still get A5 rated 5w30's in Syntec and Synpower flavors, and they cost less than M1.

 

[TooSlick]

Jay,

I'd have to respectively disagree with your conclusions....

The other piece of data that I didn't include is the average total solids level for these EP samples (0.25%), which is low. So they aren't thickening due to contamination, it's just that they aren't shearing initially.

If you were to do an early UOA of the GF-4 and the EP versions of the Mobil 1, 5w-30 after 1k-2k miles, you'd see the the GF-4 stuff takes a quick dip in viscosity. This is done to help pass the fuel efficiency requirements of GF-4, which is measured twice during the standard test - I believe after 16 hrs and 96 hrs.

Mobil claims the EP chemistry can't meet these energy conserving specs, and after seeing some of these preliminary UOA's, it's easy to see why. A difference of 1.0 Cst in the API Sequence test would be enough to go from passing to failing.

I suspect this improvement in shear stability is due to the 50% more Supersyn that is mentioned by EOM. It's serving a secondary function as a shear stable, polymeric thickener.

 

[IslaVistaMan]

TS, I'd like to try the Series 3000 5W-30 in my RAV4's 2.4L VVT-i engine next change. I'm currently running the Series 2000 0W-30, but I think the 5W-30 would be better for this car. I like the lower volatility and better HTHS numbers of the "diesel" oil, and it's less expensive as well. The engine is spec'd for a 5W-30 or 10W-30, btw.

The only concern I have with the Series 3000 is the greater potential for converter poisoning from what I presume is a higher level of ZDDP. I live in San Diego, and long-term converter performance is critical to keeping a car on the road here.

 

[Blue99]

quote:

---

The new EP formulation is clearly more shear stable than the GF-4 chemistry. It's thickening because there is little or no polymer shearing to offset the normal oxidative thickening.

I call this the Amsoil "problem"...

---

Well, problem or benefit depends on which side of the fence the opinion is coming from.

Isn't this really just an example of oils designed to pass the GF-4 Sequence VIB fuel economy test by including some form of polymer in the blend that will shear during the 96 hours of the test?

I think it's great that the M1 EP line of oils has been readily accepted despite the lack of a GF-4 rating.