Mobil 1 use to be the best. I wonder if they had changed the quality or if other oil raised the bar

 

Since the introduction of Mobil 1, it has had problems with burning off in the engine and leakage. Problems go back for decades. The 0W40 us just their latest introduction which turns out to be even worse as far as oil consumption and leakage.

 

Aren't most dealer running mobile 1? So most people bring their own oil or change by themselves with something else. I wonder what is the best oil for our cars?

 

If an oil analysis shows very little viscosity degredation and molecular decomposition under extreme pressure, one could probably assume that the oil will do a good job of protecting the motor. So I do think there's some benefit(s) that can be extrapolated from the above-mentioned test.

But if I happen to run across a more comprehensive test that thoroughly compares all of the qualites you listed, I'll be sure to post it. For now, though...this is all I've got.

 

Verry Verry interesting.
I think the person who stated the test was a parlor trick hit the nail on the head. All this article / test brings to the table is more questions from us users. Many great points from every one, degredation, decompositon, heat transfer, residue left ____ ............................ This whole thread made my butt pucker, wondering if I am using the right oil for my car.

 

Just go with what Porsche recommends. You're going to have to
come up with a fairly big conspiracy theory to think Porsche isn't
in the best position to know the facts and make the best
recommendation... "Porsche execs get such big kickbacks from
Mobil that they don't mind a few oil-related failures in their high
profile cars"... Sure... Mobil-1 used to be good but they changed
it to take advantage of the sellers market for trans-fats...
For what's it's worth, oil consumption is not one of the critical
judgements of oil. It depends on the viscosity for one, and two
10-30 oils are usually not identical in viscosity. The spec allows
a significant range for a given designation. Viscosity is *not* good,
per se. In the main, you want *flow*, not thickness. As long as
the oil film thickness is sufficient for your motor tolerances (the finer
they are, the thinner your oil should be), thick is bad. *Pressure*
is not good, flow is good. As long as your pressure is enough to get
the circulation rate, more just means wasted energy and heat.
Oil degrades due to heat, and the bad temperature is just about
independent of the viscosity, but thicker oil heats itself more when
it's forced through a given gap than a thin one.

Who are you going to trust? You make your choice.
Joe

 

Virtually every Duc shop I've been to pours Silkolene.

Prior to that virtually everyone used Agip due to the race team sponsorships.

As to this test, by the look if it it's largely bunk and the results have no practical application to an engine oil system.

 

I have to diagree. Pressure is VERY important in an engine's oiling system other than simply circulating the oil.as this is what keeps moving parts from touching, without enough of it, bearings would be scored and spun and valves would seize along with lifters, etc. Obviously you cannot have more volume without more pressure, anyway.

This, IMO, is part of where the 0W40 is lacking in proper protection of the engine. Oil pressure drops substantially at low engine speeds, as low as 6 -7 psi. Any hiccup of the engine, be it a misfire, abrupt movement due to acceleration, etc, greatly increases the chance that the crank will hit a bearing along with binding of lifters and valve. The film thickness in lab tests may be within requirements, but, as the test in this thread demonstrates, it is not strong enough to keep componants apart.

A choice of oil is always a compromise. Less drag, less protection; better protection, more drag; good for seal, bad for seals, etc. For the average driver who does not mind burning and leaking oil, a Mobil 1 would probably not be a problem, but for those that want to protect the engine long term and get the most performance out of the engine without adding a quart every other time you fill up, I sure wouldn't use it.

I think more and more people are realizing the negatives of Mobil 0W40 and are slowly moving to a higher viscocity oil. They are also learning that 0W40 is NOT the only grade or brand of oil approved and have moved on to others.

 

Is it common for these TT's to burn oil? I noticed that mine was a little low yesterday...

 

Yes. In the past, PAG/PCNA would say that 1 quart every 1000 miles is 'acceptable'. But since the introduction of the Cayenne Turbo, that number has dropped to 1 quart every 600 miles.

 

And is the reason they burn more and more oil because of poor workmanship in the engine or it it because they are coming from the factory with Mobil Water?

 

Hi. Pressure is important for flow, but pressure is not what keeps
parts from touching. That is film strength/shear resistence, which
does relate to viscosity, but the oil has to be thin enough to get
into the gap to begin with, and has to be flowing through fast enough
to carry heat away, and not stay there and get cooked. Pressure
itself is never used to lift parts. Typically a bearing has oil pressure
all around the shaft, not just in one place liting it off the bearing
surface, so the pressure cancels itself all around. You want a thick-
enough oil, but no thicker, and flowing fast enough to stay cool
under pressure at peak engine loads so parts don't expand because
of heat and cause interferance contact. Friction = heat. Viscosity =
liquid friction.

Yep. That's why we hear about so many Porsche motors failing.
What you want is an oil that gets to the dry parts as fast as possible
at startup. That's why the "0-" part is so important. If your motor
has such loose tolerances that a hiccup means a lot of banging
around in the bearing races, then gear-case oils would be better.

We disagree on les drag equalling less protection. Why not try
a 90-wt? What are you referring to regarding good-for-seal/bad-for-seal?

It's anecdotal, but I have one of the first 996tts in the country (August
2000) and have used my car harder than most everyone on this list, I'll
bet. I take complete notes. Since purchase, I have averaged 8 mpg!
I have used 1 qt of mobil-1 per 1000 miles, and almost all of them have
been in competition.

As you wish. It all depends on who you trust, and what you actually
do with the car. For most people, oil is like underwear, Gucci or Target,
it's more to do with how often you change. Post to the RennList race
group about how many still use thin untrustworthy Mobil-1, and about all
their inexplicable lack of oil-related failures.
Joe

 

I also use the european spec 5w-40 from amsoil. If you havent researched amsoil as an alternative to mobil 1 please do so....if u simply look at just the 4 ball wear test analysis it will open your eyes...if anyone is interested in ordering amsoil feel free to pm me...cheers!

 

Actually a good question. It is probably the engineering tolerances
being greater (looser fit). And oil consumption isn't dangerous per se
though it can be irritating if it becomes a chore to keep the level up.
You can always top it off if the rate is reasonable, and if using a
thinner oil means you're getting better flow and protection where/when
you need it, that's perhaps a good compromise. PorschePHD has said
that his rebuilt engines burn much less oil than stock motors.
Hand-tolerancing parts makes the difference, but the burning is not
necessarily indicative of any functional problem. I have .45 pistols that
have been hand-fitted and I have other cheaper ones that are just as
reliable, but all their non-critical gaps and tolerances have been left as-is,
and you can get audible rattles from them if you shake them side-to-side.
Nevertheless, they always put a big slug nicely downrange when you
shoot them, so no worries...
I think Porsche does have a range of engineering precision, and the
relatively mass-audience Cayenne is probably built to last, but not to
be as tight as a racing motor would be.
Joe

 

Last time I checked, Porsche made money from selling more cars, not recommending the best oil. There is such a thing as built-in obsolescence, or a finite lifespan for that matter. If all Porsche engines, bodies, trannys, etc etc etc lasted 500k miles, they'd be broke. It's like the lightbulb that lasts for 20 years - it can be done, but why would anyone produce it? I'm sure Mobil-1 or whatever they recommend is good enough to give a long enough lifespan to make clients just happy enough to shell out bucks for their next $100k+ car. Ignorance is bliss...