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- - Re-evaluating my oil choices (https://www.ft86club.com/forums/showthread.php?t=72305)

Re-evaluating my oil choices

Hey, so my buddy sent me this link that explains oils film strength and how it relates to valve train wear of flat tappets and cams. I know our car comes with roller rockers and coated pistons and what ever else is high tech these days, but I thought it was a good read. This guy seems a bit "ranty" but it's makes sense to me and based on his testing - Mobil 1 5W-30 was the best (#10 out of 150 something) off the shelf oil that didn't need any additives or needed to be special ordered. It's film strength is what really grabbed my attention and IMO all modern oils additive pack are all pretty good, so I'm not too concerned there. Btw I ran German Castrol for 30000km and was avg 8.0L/100 km, Mobil 1 0W-30 I was avg 7.9L/100 km for 5K. I'll let you know what I get with the Mobil 1 5W-30, but first impressions are really good. The engine seems a lot punchier, as well as with some WOT 1-5 pulls I'm already into 7.9L/100km at 240 km (just got it changed on Thursday).

I'm collecting samples and having them analysized and will post results when I get them all back. I also remember someone mentioning that the new WRX and Forester XT use Mobil 1 5W-30 from the factory so that also had some bearing on my decision. I didn't want to run a specialty brand either as I like knowing I can go to any store and buy a bottle or two if need be. Anyways, without further adue,

http://540ratblog.wordpress.com/2013...-test-ranking/

Funny all the WRX people reported prior to the 2015 their vehicles consumed Mobil 1 and that it was a bad choice for their engines. The word has always been that Rotella (yes, Diesel engine oil) seems to work best for factory boosted Subarus.

For the NA engine, the 0W20 is factory recommended probably due to low viscosity helping improve mileage.

My twin is not winter driven, so heavier viscosity not an issue. Currently using Mobil1 OW20, might switch. Will keep an eye open for your mileage results.

Quote:

Originally Posted by wbradley (Post 1902555)

Sorry I should've been more specific, I was only referring to the FA20 models. But ya that's what I've heard too. Mobil 1 0W-20 AFE is actually pretty good stuff according list as well.

That information means zero to how an oil performs inside an engine. Those tests were not conducted according to industry standard ASTM methods. The Forester and WRX come from the factory with a very thin 30 grade (or even a thick 20 grade) Idemitsu oil with boosted levels of molybdenum and ZDDP. The BRZ/FR-S factory fill is also Idemitsu, but the viscosity is slightly lower and the ZDDP is lower as well.

That said, any Resource Conserving xW-30 is just a bit more robust than most xW-20's but the operational HTHS and operational viscosity (and possibly oil pressure) of the xW-30 will actually be very similar since many xW-30's shear in viscosity to a 20 grade oil in severe conditions (this is why Mobil1 0W-40 is a better choice than M1 5W-30 for some applications).

As far as ZDDP goes, M1 0W-20 EP, 5W-20 EP, 5W-30 EP all have the same levels. Both the 0W-20 AFE and 0W-30 AFE have lower levels of ZDDP.
http://www.mobiloil.com/USA-English/...duct_Guide.pdf

The viscosity of the M1 5W-20's is just a bit thicker than the viscosity of the 0W-20's. The 5W-20's should be more stable as well since more viscosity modifiers are needed for 0W-20's and 5W-30's.

German Castrol is a very thick 0W-30 (and not Resource Conserving) and is thicker than any Mobil1 xW-30 at 100C, with Mobil1 10W-30 High Mileage being the closest to GC.

And some comments regarding the above link:

Quote:

he's using one parameter that if you reach it you have already failed in lubricating your engine to state that any given oil is better than any other.

His testing method is not representative of any place in any engine that you or I are ever going to see.

And his conclusions have absolutely nothing to do with the parameter of choice by which he ranks them.

Quote:

That statement makes absolutely no sense whatsoever. Testing oil in a running engine allows you to observe the actual characteristics of the lubricant in its designed operating environment. This means it has to deal with fuel dilution, contamination, acids/combustion products, varying levels of heat. It has to resist deposit formation, it has to resist baking into varnish, it has to be able to neutralize the acids and do this for whatever the designed oil change interval is.

NONE of these things are replicated by this testing machine. NONE of them. Because it represents a scenario that no engine will ever see: Extreme sliding interface pressure, the closest relation to which would be the cam lobe/lifter interface on a flat tappet engine or a diesel injector/cam interface which never see those types of pressures, ever. So where's the relevance?

If this type of lubricant testing made sense, the OEM's would be all over it. It is inexpensive; certainly FAR cheaper than building an engine, running it on a dyno for hundreds of hours and then tearing it down and meticulously inspecting and measuring every component. But they aren't. That should speak volumes as to the true relevance of this testing methodology.

His actual testing and the results are certainly done with the utmost care and I have no doubt in my mind that he followed the scientific method to a T. I'm not questioning his testing or the results. I'm sure the results are wholly and entirely accurate and were obtained following proper procedures. And they represent exactly what he says they do: The failure point of the film strength of the oils tested. They don't however in any way translate to the actual conditions experienced by oil in an engine, only testing in an actual engine does that. That's why tear-downs are performed. That's why millions of dollars are spent by OEM's doing just that. And that's why companies like Mercedes, Porsche, BMW....etc maintain lists of tested/approved lubricants for use in their engines. If they could just Timken-test them to get that information they'd be making a lot more money on their approval process.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=3124298
:burnrubber:
-Dennis