Just want to chime in on this issue- We are also an independant Porsche facility in Florida that uses Mobil 1 15-50 (Technical Dimensions). We've used 15/50 for many years in both street and track cars as standard (all models through current and Audi as well). For cars that will be heading to a significantly colder climate we will instal the 0-40.

When 0-40 first became availible, we spoke with an engineer from Mobil 1 and here is the break down:
0-40 will flow as a zero weight down to -45F
15-50 flows as a 15 weight down to -39F (neither of which we will ever see in Florida..hopefully)

Both oils become thicker as they warm, both attaining their 40 or 50 weight properties by abt 150F and their starting 0 or 15 weight properties at ambient temp (engine cold, outside temp almost never below +30F) will be nearly identical.

We find that running the 15/50 in Florida is beneficial in that it's oil viscosity will be nearly the same as the 0-40 at the ambient temps we see regularly and as it warms provides additional protection, better oil pressure and less oil consumption. Also, the thicker viscosity oil will be less prone to leakage.

From a protection standpoint, the 15/50 has 1200ppm zinc-phosphorous vs 1000ppm in the 0-40. This is a primary anti-wear component of both oils. When asked directly, the Mobil 1 engineer i spoke with said that outside of the lower viscosity in super extreme cold weather, the zinc-phosporous was the primary differential between the 2 oils

In addition to high ambient temps regularly, many of our clients also track their cars and the 15/50 is certainly superior in that realm.

Hope this data helps answer a few questions

 

Blasphemy!!!


How dare you challenge the judgment of Porsche and the many posters on this forum and others? Posters, who have concluded that Mobil 0W40 is the BEST oil for their engine simple because the majority of other uninformed posters say it is.

In their imaginary world, here are several reasons that should persuade you why 15W50 will not work in a Porsche:

Too thick for variocam to operate
Too thick to flow through lifters
Won't reach critical engine components fast enough on start up
Produces too high an oil pressure
Can’t flow to various areas of the engine due to tight tolerances
Makes engine run too hot
Causes more engine wear
Not on the “pay to play” approval list.
Etc, etc.


You should immediately begin questioning what you are experiencing in the use of 15W50 oil. It does not appear to support what is on paper (web pages actually) and therefore must be incorrect. Do NOT accept your real world experience as true. Accept only what should be and not what is. Repent immediately and ask for forgiveness.




Personally, I know of few dealers and Indy’s that will use 0W40 (except in cold climates) in any of their cars or customer’s cars. Many began moving away from Mobil Water years ago after experiencing many of the problems you mentioned, including leaks and burning in addition to low oil pressure. Additional documented problems include premature bearing wear, valve and lifter wear and substantial wear to the plastic cam lifter guides.

Your mention of the zinc content is important and many have yet to realize this. I am sure as more miles are put on these engine, more and more side effects of using inferior oil be surface.

 

My point was not to berate anyone for using 0-40 but to highlight the reasons why we choose to use 15/50. If we were in New England we would be using 0-40 std and 15/50 for track cars. We have found many positive reasons to use 15/50 in our region. The thermal breakdown of both oils is pretty high anyway (435-445F) but all factors combined, i feel add up to a better level of overall protection for our customers. I can say for certain that swapping from 0-40 to 15/50 on the 996Twin Turbo models has def. reduced oil consumption on most customers cars.

 

Hello. The Mobil 1 website agrees w your listing of phosphorus levels 1200ppm vs 1000ppm 15-50 vs 0-40 oils. They show the Porsche approval of the latter. Mobil suggests the 15-50 for HT-HS applications (extreme conditions?) and for "flat tappet" equipped racing motors. Recent Excellence response to this question stated the need for the oil to run the internal hydraulics of these motors, ie the variocam, as well as cool and lubricate. They support using a Porsche approved low visc. oil for this reason. I do not wish to question your experience w this 15-50w oil and am glad you have seen no problems. I am sure there are benefits w.r.to oil comsumption as you state. My concern is specific to roadgoing ie non racing motors. If there is an engine failure requiring warranty claim and Porsche tests the oil (as I have read they do) there could possibly be a problem with out of spec oil. This is a non issue w a racing motor for the obvious reasons. I just don't know the answer to the warranty question if it exists in anyone's mind other than mine. Thank you for your well reasoned and congenial input. Were I in Fla I would drop by to discuss this. Here in NY 15 wt. oil seems like a far off dream