TSOA Where Is the UOA for M1 15W50 in your car and one of Castrol 5W50 For Comparison

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I personally don't believe there is anything inherently wrong with a group III oil, except for the fact that it may be not quite as good as a group IV or group V, costs less to produce than the IV and V and the companies charge full price for it. Looking at the Shell 5w-40 for $3.25 quart at walmart (when bought by the gallon) and the Group III looks like a good deal. Also, many people don't realize it, but BMW sells the 5w-30 group III Castrol (which does not appear to be the 5w-30 syntect given its nearly 40 weight CST when new) for less than $4.00 quart. The only problem with the BMW oil appears to be BMW's insistance on pushing it to 15,000 miles when it is more realistically a 10,000 mile oil (I guess that extra $1 quart for the Mobil 1 buys you the extra 5,000 miles)

While I am not a fan of the Castrol 5w-50, I believe it has turned in some pretty decent UOA's. For me, I am sticking with Mobil 1 or Redline. For my father-in-law's 91 Mercedes (who is bad about maintence), I am putting in the Shell Group III because I feel comfortable it will go 7500-10,000 miles in better shape than mineral, while not breaking the bank.

Cary
 
Hi,
yes, in Porsche racing circles some "mistakes" have been made regarding viscosity choices

Some "failures" have occurred when using M1 0w-30(etc) and when even the manufacturer has never recommended such a grade for normal use.

A brief study of the oil Brands and viscosity used in all failures referred showed no brand specific bias - no Brand ( including M1 15w-50 and Castrol ) was better or worse than the next - but see below

Some circumstantial data exists of crank failures due to cavitation and also starvation under high G cornering forces. Some have occurred at continuous readings of 6500+rpm - way above factory recommended maximums!
These are technical issues - not lubricant issues
Some are lubrication issues!

The oil of course is not to blame in these cases but it is viewed as such by some "experts". Many of these people do not have any quantifiable data such as core oil temp, actual oil pressures ( they use the existing OP gauge ), some use gauges that can only read to 30% below relief valve setting and etc. The real data is mostly non existent, especially "running data" recorded in real time on an ECM or PC.

M1 0w-30 does show an OP loss above a 15w-50 when racing and why not? M1 is oft mentioned in this regard. Choosing the correct viscosity is critical to oil durability as is its HTHS viscosity and volatility

Ester based race oils of higher viscosity do show some excellent results especially where excessive fuel dilution occurs and, the M1 race oils used in most "serious" sponsored race team's cars is indeed a special brew - and why not?

Racing improves the end product for all of us

Regards
MY89 Porsche 928S4 5.0l V8
MY98 BMW Z3 2.8
MY02 Subaru Outback 2.5
( all on Delvac 1 5w-40 )
 
Just a thought...

Is it not possible that Syntec 5W50 might hold up maybe just a little bit better than M1 15w50 in the EXTREME case of an air-cooled Porsche engine on a road course for extended periods of time. Maybe at VERY HIGH oil temps Syntec is slightly thicker than M1, and this is the difference between finishing or catastrophic failure?

Pure speculation on my part...

PS - I personally don't buy Castrol anything, and actually use M1, but I am intelligent enough to know (and admit!) that M1 may not be appropriate in every situation, particularily the 30 weights.

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Geeman, I asked if he used it, 5w-50 was his answer to everything. It is what he runs in all his 8 street cars, one being a Model 2002 with a M3 engine in it. Pretty quick car. I know he uses Valvoline Racing for some non-turbo cars, changing at 1500 miles and the Syntec at 2000 miles. He will not use 0w oils, poor oil pressure and low film strength at start-up (noisy valvetrain) and lack of "cling" to engine internals is his justification. He uses GTX HD 15w-40 all-seasons in customers cars and said it is still working fine in my Mom's garaged Passat 2.0l, a year later. Does he know his shyt, yes. Is he old-school, definately. Is that always a bad thing, no. Will I still use 0w-30 Syntec, yes.
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Well, then I do not believe that there was any harm to the engines using M-1 15-50, else ACEA A3 would also read "may be unsuitable for use in some engines".

That said, my car ran better with Syntec 5-50 than M-1 15-50 and I challenge anyone here to try the same test. This may be what the mechanic is referring to. However, it's a farce that this viscosity blows engines.
 
Well, inferring the cause of engine failure from the brand of oil found in the trunk is akin to concluding that the presence of baby formula in a refrigerator caused a baby. There's no way that one can state that any oil caused an engine failure without a UOA, engine teardown, and inspection. And as for my(equally valid) anecdotal evidence? I've used M1 15W-50 in my BMW M30, M42, M52, and S38 engines. All but the M52 were tracked on a regular basis. The track events involved engine speeds in the range of 3500-7000 rpm-mostly at full throttle- for 30+ minutes at a time. At 300000 miles the M30 engine needed a head gasket due to oil seepage, so I'm guessing that using Castrol 5W-50 would have averted that expense? The other engines are still running strong at mileages ranging from 83000 to 120000.
 
Wimpy little BMW engines don't need Castrol, only those Porsche engines do!
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MAYBE those Porsche air-cooled and/or turbos really punish the oil on the track, and 5W50 Syntec has higher viscosity at elevated temps.

Oh yeah...doesn't BMW have their own issue with under hood grenades...in certain M3's ?? I think their solution was ... THICKER!!! oil, in the form of Castrol 10W60.

Thick vs thin...continues!

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Maybe we are on the wrong track. Maybe the porsche engines can't tolerate a 50wt oil, and since the syntec probably shears to a 30 on the first lap, it works better
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M1 15W-50 is in my opinion one of the best motoroils out there. It has a stouter additive package than even Harley motor oil (even more additives than M1 20W-50 harley Oil !!!) and HTHS @150C of 5.11 !!!

Most oils in the 5W-30 to 10W-30 visc. have no more than HTHS @150C of 3.5

If I'd live in the South or hot climates, this is THE oil I'd run.
 
I think if we go back to TsoA original post we may learn something. I believe there is something in this specific application that makes the Castrol a better choice than the Mobil 1. At least one person who seems to be very knowledgable on Porches seems to agree with his
mechanic. This seems to be specific to Porches pushed to the limits in road racing. An air cooled engine is a different animal to begin with and road racing puts oil through abuse to the max. I just think his mechanic may be on to something. Remember that experience thing "experience is the best teacher" Let try to keep an open mind on this and maybe learn something.
 
Hi,
not all Porsche engines are the same! Some have dry sumps some don't. Some have oil coolers some don't. They come in 4,6,8 and 10 cylinder versions. Some are "flat" some "in line" some are "vee"s. Some are great, some good and some marginal!
Some like air to cool them, some like air and oil, some like coolant! What a mix!

But then you all know these things

People with lots of exposure to air -cooled 911's ( not me in recent years - since 1971 ) suggest Mobil 1 15w-50 for post '89 engines

For pre-'89 911s Valvoline Turbo and Kendall GT1 are highly praised

The correct viscosity is very important and the following extract from a 911 specialist builder'a article in "Excellence" April 2003 may assist;

"Oil temperature usually runs between 180F and 240F. Many 911's run toward the hot end..."

"For pre-1989 911's and all 944's use 20w-50 in the USA unless you live in Alaska - use 10w-40 there, and in Canada as well. Use 10w-40 for the 924 and 20w-50 for the 924 Turbo"

The statistical failure rate of engines using M1 may actually be very low - it is the most common synthetic both Worldwide and inside Porsche engines.
It usually gets slammed without concise and replicated facts to back up the claims

I do not use M1

Regards

[ November 25, 2003, 08:37 PM: Message edited by: Doug Hillary ]
 
Mcompact and SBC350Gearhead, I am likeing each post!!! LMAO!!! Seeing how Syntec 5W50 shears down to the viscosityof hot tap water after 2000-3000 miles I find it diffacult to belive it could protect anything turning over 5000 RPM's or turbo charged.

I also find is absoulutely funny that Syntec-Blend has been out performing regular Syntec. The irony is just great!

I also wanted to remind everyone that 5W50 Syntec is loaded with viscosity improvers. The thickest GIII that can be made with out viscosity improvers is 30Wt.
 
John, the answer is the blown engines were NOT using the 15-50...but, most likely the 5-30.
 
Hi,
Dr T - you are indeed "on the right tram"!

This is what I am finding doing some "Porsche research" and as mentioned earlier. People use the wrong viscosity with gay abandon and without realising the possible consequences

And then they blame THE OIL when things cut loose!

Regards
 
Again, I was directed to the hatch area of the 944t, it had the Mobil Red Label 15w-50 jug within. I did not say, "Mobil 1 blows engines" I said "engines blow ON Mobil 1" subtle difference.
 
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