Phokaioglaukos

The approved oils for the GT3 according to RennTEch are:

Castrol Syntec 5W-40
Mobil 1 0W-40 (factory fill)
Mobil 1 5W-40
Mobil 1 5W-50
Pennzoil Sythetic European Formula 5W-40
Quaker State Full Synthetic European Formula 5W-40

I have used the Mobil 1 0W-40 factory fill, and plan to do so this winter, but maybe Ishould go heavier for next summer, especially for track use?

SPR

what tranny fluid?

rockitman

hmmm, what's heavier 5w-50 or 15w-50 ? They are the same at operating temperature (50 viscosity weight). The 15w is heavier when cold. Why would one want to start their car with a heavier oil (15W) ? Since the most wear occurs at startup, seems to me that the thinner less honey like oil (5w) will get to the moving parts faster. The tolerances are very close between the moving parts on the motor. I cannot understand why one would want more wear at startup. I use 0w-40. In my neck of the woods when it's hot, I am happy with 40 weight on the upper end. Just my 2 cents.

BBGT2

I use the factory fill Mobil 1. Thinking about going to Mobil 1 5W40 next service.


BBGT2

FixedWing

I guess the historic thinking was that a wider spread in the oil required more additives. This necessarily meant less oil and less stability in the weights as the additives broke down. But I completely agree with you -- especially with today's synthetics which start with a broader weight band.

Stephen

FixedWing

The list is a little longer than this:

Engine Oils Approved by Porsche, TSB 1701, 7-09-04 (in PDF)

I think this is the most up to date listing.

Note that all oils are either 0W or 5W (only 0W oils are approved for very cold conditions) and all oils are 40 weight with the one exception of Mobil 1 5W-50. What's that about? Politics maybe? Mobil One is the factory fill so ExxonMobil obviously has pull with Porsche AG. In any case, if you want a 50 weight oil that is approved then this is the only choice.

Also Castrol Syntec 0W-30 (so-called German Castrol) is missing from the list even though it is an ACEA A3 oil. More confusingly, the bottle labelling even claims that it is "Porsche Approved"! The labelling can be seen here:

Castrol Syntec 0W-30

On the other hand, Castrol's Product Data Sheet doesn't claim Porsche approval. So I really don't know what's going on there. If it were approved then I would seriously consider this oil as the ideal oil in colder climates for minimum oil pumping power losses. I've seen some very good oil analysis results on this oil in other brand cars.

Stephen

cosmos

ok, now the question is what is recommended for the GT3 RS and the GT3 Cup cars??

FixedWing

The TSB states that:

The TSB is dated 7-9-04.

Stephen

cosmos

Wow, thats a really broad range for all types of engines.

Phokaioglaukos

Anything new on this front?

Austin

They all use 15w50. Mobil 1 is the preferred brand although plenty of people use the purple brand, Redline, etc. in their Cup, R, RS, RSR, and Street production cars. The thin viscosity recommendations are for smog reasons (including catalytic converter preservation).

Porsche 96.7+ series (even 993, 964 and previous) engines should run 15w50 for best protection at high performance driving and racing conditions. All 996 GT3 cars have the 96.7 series engines.

The regular 996, 997 guys (not the same engine as the GT3, GT2, TT and previous) are supposed to use the really thin stuff, probably due to less heavy duty internals or coatings.