ltc

Is Mobil Motorsport 15W-50 different than the M1 15W-50 that we get here in the States?
http://www.lufteknic.com/Merchant2/m...ode=lubricants

bgiere

That is old stock M1.

Heirsh

What concerns me about broad ranging policies like saying 0w-40 is good for all engines back to whenever is they weren't designed with that oil in mind. It may be completely true that this oil is fine in them, but I'm very hesitant to believe that. I'm goign to post some of my concerns so perhaps someone with more oil knowledge than I will allay my fears.

1. New cars are water cooled, and while I don't have anything to point at to prove it, I believe they are much better temperature controlled than the air cooled we run. This means to me that the oil we use should be able to handle higher peak temperatures and still protect.

2. Oil consumption itself doesnt bother me. It could be that you can correlate oil consumption with protection, but i've not seen anything about this. Is there any proof of this out there?

3. The hydraulic lifters in newer cars need to fill up very quickly. This time is minimized by using a thin oil. We have solid lifters. I havent analyzed it, but I would imagine the stresses in a solid lifter system are higher than with a hydraulic system due to its damping ability. So, to me this means we need more protection at peak times than a hydraulic system.

4. What about the bearing clearances? They have been tightened up through the years for many reasons in general. Are our clearances small enough that a thin oil is ok? Does anyone have the clearance data on modern porsche engines vs ours? I can dig ours up, but I dont have a reference for the modern ones.

Again, these are just some of my thoughts and why I personally, right now, would never consider sticking in 0w anything in my engine. If you look at the viscosity ratings of oils at diff temp's you will find the first numbers control the high temp viscosity a LOT more than is led to believe.

Anyway, I'd love to see some discussion of this stuff.

SimonExtreme

Maybe I have misread the data but I have never seen that. Have you any links to this, please. I am really trying to learn as much as possible about this as I believe it is more important than fuel and is a worthwhile "investment" of time as I intend to keep my car for many years.

SimonExtreme

I take the liberty of posting something written by "Simon the Oil Man" on another forum. Hope it is of some use. I will, as time permits, try to post some other references.

ltc

What does the new stock 15-50W M1 look like and where do you buy it?

Heirsh

Thanks for the link Simone. I'm hoping to learn more as well.

My basis for that statement is a search through the records of various oil sellers and a compilation of their data. I was looking for an oil with a high high temp viscosity at the time. Here is a couple figures. What you have above is more comprehensive. Also I made a mistake by using non specific terms such as a "lot".

M1 stuff, 0w=14.3, 5w=14.8, 15w=15.6

Thats almost 10% diff at the high viscosity. And for what benefit? We dont have tiny oil valleys and we don't have hydraulic lifters, and I can spare 2hp for better protection... That seems like a lot to me, but thinking about it more I can see where it isnt large to someone else.

A couple other poitns of interest to me.

brand.............weight............cSt@40C.........cSt@100C
M1.................15w-50.............133................18.2
Castrol............20w-50.............97..................19.7
Valvoline........20w-50............155.................21
Castrol TWS..10w-60..............170.................24.1

bgiere

New M1 15w50 is available at Wal-Mart, Autozone, etc...is is the M1 Extended Performance version...rumors are that it has changed to a Group III oil....

Christer

Just to point out, as my car is not standard it was recommended to me to run the 10-60W. I can also spare 5hp for better high temp protection. I am however going to have a look around now for other options.

SimonExtreme

I think the problem is that we don't know, and probably never will know, what other changes there are other than the cold temp viscosity. For instance from my figures above, Motul 300V goes from 13.80 to 14.0 with the change from 5w to 10w.

On another matter all together, does higher viscisty mean better protection? My first reaction is yes, but then I got to think that it's probably swings and roundabouts. If lower viscosity didn't protect so well, why do modern engines last so long?

I think that I am happy with the lower viscosity and am more concerned about whether the oil is likely to break down and reduce protection. I am therefore trying to stick to poa/ester blends.

Adrian

Heirsh,
Why don't you read the latest Porsche oil recommendations for the 964. I used 5W 30 and then 0W 40 in my 964. In its entire life it only used these two oil grades. It now has a new home in Germany and is still running strong.
Porsche said I could use 0W 40 in it so I did and had no problems. My 964 has been all over Europe in the middle of summer and I never struck any problems. I also use 0W 40 in my 996.
I am always amazed at how in one breath people say that "Porsche" make the best cars around and they are highly engineered and yet in the next breath (and yes I know you did not say this) they say Porsche don't know what they are talking about when it comes to their oil recommendations.
Just in case you don't have them, here they are from 2005.
Ciao,
Adrian.

PS: These recommendations are for standard engines of course. If you have something special follow your rebuilders/suppliers recommendations especially during their warranty period.

Heirsh

Adrian,

Thanks for bulletin. This is just one of those cases where someone (me) has their own train of thought on a subject. I was hoping someone might give some specific evidence or links to the concerns I listed. Simon pointed me to a nice compilation of data.

For me, so far, I get less engine wear with the heavier oils. Specifically I have so far gotten less metal wear in my oil analyses especially lead, cutting it to nearly 1/4 of its original value. This is just my engine, but it shows me enough to stick to the heavier oils. I will continue to try some diff oils, but lighter doesnt seem prudent given my results for my engine.

edit: Removed the specific %'s as I dont have enough data to really backup anything concrete. Its just trends right now.

ltc

FWIW, my dealer also put M1 0W-40 in my 968 Cab.....sorry, it's a water pumper with the engine in the wrong place.

Adrian

Heirsh,
There is no data nor proof. All you can rely on is past experience and manufacturers recommendations. I have worked with engines all my life and the one thing I learned a long time ago was that those who make them know more about them than I do, for me to second guess them.
When it's all said and done I am pretty secure in saying that no-one could ever provide any data proving that one oil makes an engine last longer than another.
What I do know is that when my engine is cold I like the oil to get where it is needed as fast as possible. For the Porsches with hydraulic valve lifters oil is crucial and the thinner the better on a cold start.
I do not operate my engine anywhere near maximum temperatures at any time so the top end temperature wear is less of a concern.
For racing car drivers well that's a different issue and they use heavier oils for top end protection because that is where they are operating. Mind you their engine life is much shorter than road cars.
If a normal daily or weekend driver Porsche is operating in the upper temperature limits I recommend a check of the cooling systems be carried out.
You are right it is personal and you travel the route that you wish. However if I am offering advice to somebody who doesn't have this experience then it is always; "use the manufacturers recommendations".
By the way I do not bother with oil analysis. I was involved with this for years and we found that it was somewhat unreliable to purely use the results to base maintenance upon.
You mention lead, where is it coming from?
Ciao,
Adrian.

JasonAndreas

HERE is the latest 2006 Approved Oil List TSB from Porsche.