Is M! T&SUV's VI on the low side or is that mileading?

Doug Hillary · May 17, 2005

Hi,
many new base fluids are being developed (or already have been) that will require us to rethink our own views on Viscosity Index, HTHS viscosities and etc. FUCHS GT1 0w-20 being a part of this progression!

It is interesting to note that the most widely used engine oil amongst Porsche owners worldwide in M1 in either 5w-50 or 15w-50 grades

M1 5w-50 is by far the most popular synthetic oil sold in Australia. As most of you know we have an ambient that ranges from -20C to over 50C. We have one State without an open road speed limit and many roads where there are straights that last for 60-70kms. It is quite common to travel 1200kms (890 miles) in one day here (I do it often) and the ambient will change from -10C to 40C!

I have never heard of a bad report on M1 5w-50!

The first "wide spread" multigrade oil (a 20w-50) was produced by Duckhams for the BMC Mini in 1958
It was later followed by Castrol. These mineral oils were not too shear stabile in the combined engine-transmission used in the Mini but it was still good enough to last for 2-3k miles. An oil like Castrol's XL 20w-30 (of that time) would be good for about 1.5k miles in the i application and would leak everywhere (they did anyway - you could almost hear the drops)

These oils quickly became a benchmark for English cars but Euro makers always aimed at slightly lower viscosities - usually settling for recommending a 10w30, 10w-40 or 15w40, or typically a 20w-20 or 20w-30 or 30 Oil

We must keep our minds open to the development of new lubricant technologies as the World struggles with the crude oil problems of demand, supply and depletion

Regards
Doug

y_p_w · May 17, 2005

quote:

Originally posted by moribundman:
Can we agree that a high VI Index should not be achieved by adding massive quantities of VIIs, but rather by using a high quality oil? And can we also agree that VIIs are commonly used to achieve viscosity spreads, and that the average consumer cannot tell if an oil has a "naturally" high VI Index by looking at the VI Index number?

The average consumer wouldn't even know where to look for a spec sheet, doesn't know what VI is, and shops based on brand name, cost, SAE viscosity, and that little API donut and starburst. Asking for 0w30 at a parts store a few years back, the employee asked back, "Isn't that like water?"

Also - VI improver in and of itself isn't bad. I hear there are more expensive ones that resist shearing better than others. I doubt there are massive quantities of VI improver used these days with all of the higher VI base oils.

quote:

Also, because you obviously know a lot in this area, would you mind addressing V8Blitz's question, as you surely have the answer he is seeking, and I would like to hear it. Here is his question again:

quote:

It seems that alot of other 5W-40 and 0W-40 synthetics (and even 0W-30) have a higher VI. This seems a little low for such a supposedly fantastic, ester based 5W-40 wt. synthetic.

Click to expand...

It's already been answered. It's thicker at 40ºC (102 cSt) than most other 0W-40 or 5W-40, and that's why the VI is lower. 5W-40 only means it meets the 5W cold pumping requirements and the 40 wt operating temp requirement; that's only two sample points. The target audience for Delvac-1 is OTR tractors where cold start performance is less of an issue although at 40ºC I doubt that thick an oil has any problems starting.

Here are the (almost identical) spec sheets:

http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_1_Truck_SUV_5W-40.asp
http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobil_Delvac_1_5W-40.asp

smthrj53 · May 17, 2005

Perhaps this is the time to ask what is confusing me about M1 TSUV. The spec sheets show almost no moly, while most other M1 formulas do have moly. What is it about the target application for this version that would cause the moly to be left out?

Audi Junkie · May 17, 2005

quote:

Perhaps this is the time to ask what is confusing me about M1 TSUV. The spec sheets show almost no moly, while most other M1 formulas do have moly. What is it about the target application for this version that would cause the moly to be left out?

The rest of the Mobil 1 line, Supersyn (PAO) is a completely different formulation than D1/T&S (ester) and would contain a different additive package, likely relying on esters for AW and FM over the use of moly

moribundman · May 17, 2005

quote:

Also - VI improver in and of itself isn't bad. I hear there are more expensive ones that resist shearing better than others. I doubt there are massive quantities of VI improver used these days with all of the higher VI base oils.

I'm sure you realize I never said VIIs were bad? I'm the one who used 5W-50 for about 100k miles with very good results. Could have needed you around when people jumped on me for using 5W-50, which was "loaded with VIIs."

I'm simply saying that a high Viscosity Index does not necessarily indicate a higher quality oil, which is what the first post in this thread was really about. I better shuffle off now, if I can get my Audi engine to crank over with that thick tractor oil fill.

V8Blitz · May 17, 2005

quote:

Originally posted by moribundman:

quote:

Also - VI improver in and of itself isn't bad. I hear there are more expensive ones that resist shearing better than others. I doubt there are massive quantities of VI improver used these days with all of the higher VI base oils.

Click to expand...

I'm sure you realize I never said VIIs were bad? I'm the one who used 5W-50 for about 100k miles with very good results. Could have needed you around when people jumped on me for using 5W-50, which was "loaded with VIIs."

I'm simply saying that a high Viscosity Index does not necessarily indicate a higher quality oil, which is what the first post in this thread was really about. I better shuffle off now, if I can get my Audi engine to crank over with that thick tractor oil fill.

I sort of understand your point about VI and the reasons it can be misleading. However, RL 5W-40, which supposedly has a similar base stock and naturally high VI has a VI of >170. Why is there this discrepancy between the two. It would again seem that the T&S would have a higher "naturally" occuring VI, no?

moribundman · May 17, 2005

quote:

I sort of understand your point about VI and the reasons it can be misleading. However, RL 5W-40, which supposedly has a similar base stock and naturally high VI has a VI of >170. Why is there this discrepancy between the two. It would again seem that the T&S would have a higher "naturally" occuring VI, no?

RL 5W-40

Vis @40 C, 94
Vis @100 C, 15.1
HTHS @150 C, 4.6
VI Index, 170

M1 5W-40

Vis @40 C, 102
Vis @100 C, 14.8
HTHS @150 C, 4.1
VI Index, 151

All I can tell from those numbers is this: 14.8:4.1=3.6 and that 15.1:4.6=3.2. This means that Red Line 5W-40, which has the higher Viscosity Index, is, at least on paper, a bit more shear-stable than M1 5W-40. I refuse to speculate regarding viscosity improver content.

You yourself said that the quality of VIIs varied. This makes it impossible to come to conclusions by comparing oils only by the numbers.

y_p_w · May 17, 2005

quote:

Originally posted by moribundman:

quote:

Also - VI improver in and of itself isn't bad. I hear there are more expensive ones that resist shearing better than others. I doubt there are massive quantities of VI improver used these days with all of the higher VI base oils.

Click to expand...

I'm sure you realize I never said VIIs were bad? I'm the one who used 5W-50 for about 100k miles with very good results. Could have needed you around when people jumped on me for using 5W-50, which was "loaded with VIIs."

I'm simply saying that a high Viscosity Index does not necessarily indicate a higher quality oil, which is what the first post in this thread was really about. I better shuffle off now, if I can get my Audi engine to crank over with that thick tractor oil fill.

And that's why a lot of people post their UOA results along with the VOA results to judge how much the viscosity might have changes. It seems apparent that M1 0W-40 contains a little bit of VII as it shears down to a heavy 30 weight after use. M1 5w30 and 10w30 doesn't, and the UOA results seem to indicate that it stays that way for a long, long time.

moribundman · May 17, 2005

quote:

And that's why a lot of people post their UOA results along with the VOA results to judge how much the viscosity might have changes.

Oh, you mean like my UOA of M1 5W-40 after an 8k mile OCI?

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=002330#000000

D1 5W-40 VOA (Can't find M1 5W-40 VOA right now):
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=11;t=000055#000015

y_p_w · May 17, 2005

quote:

Originally posted by moribundman:

quote:

And that's why a lot of people post their UOA results along with the VOA results to judge how much the viscosity might have changes.

Click to expand...

Oh, you mean like my UOA of M1 5W-40 after an 8k mile OCI?

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=002330#000000

D1 5W-40 VOA (Can't find M1 5W-40 VOA right now):
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=11;t=000055#000015

I don't know how to judge that one, since it used a whopping 4 quarts between changes.

BTW - I meant "changed" - not "changes".

moribundman · May 17, 2005

I'm getting out of this -- or I'll let fly like Mussolini from the balcony.

Is M! T&SUV's VI on the low side or is that mileading?

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