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I was leaning towards the 5W-50 M1 myself, but recently found out that Porsche recommends 0W-40 M1 in their 991 cup cars from the Rennlist GT3 Cup subforum. Confirmed by the 991 GT3 Cup technical manual below.
I will be sticking with 0w-40 M1
FWIW: Cup car engines get rebuilt frequently and 0w40 will have slightly higher hp (in theory) than a heavier oil.
I think both are fine and have been running 0w40 in my 993 with some zddp additive now (and ran it for years in my land rovers), but I am thinking 5w50 is probably a little better.
I think both are fine and have been running 0w40 in my 993 with some zddp additive now (and ran it for years in my land rovers), but I am thinking 5w50 is probably a little better.
Really - never heard of using 0W in an air cooled. Usually 15W50 or something thick for the wider tolerance bearings...
Really - never heard of using 0W in an air cooled. Usually 15W50 or something thick for the wider tolerance bearings...
Even though the Rennlist aircooled people hate 0w40, it looks like my car has had it most of its life (it did get one 5w50 oil change) and it is what Porsche recommends for the 993 and so its easy to get.
I changed the oil at 250 miles on my 991.2 GT3 with Motul 8100 5W40. Mobil 1 0W40 does not have the greatest stability at high temps (I would call it "water like"). Although both are rated as a 40W at high temps, the Motul will perform better one that heat level is reached.
Changing oil again at 1,250 miles. Will continue with Motul 5W40.
I changed the oil at 250 miles on my 991.2 GT3 with Motul 8100 5W40. Mobil 1 0W40 does not have the greatest stability at high temps (I would call it "water like"). Although both are rated as a 40W at high temps, the Motul will perform better one that heat level is reached.
Changing oil again at 1,250 miles. Will continue with Motul 5W40.
Hmm.. wonder where you got the information that M1 0w40 is water-like compared to Motul 8100 5w40. Based on Blackstone testing their thickness are almost the same or very close at 212F and based on their data sheets, both have the same exact viscosity at 150C or around 300F.
The more important fact is that M1 has on average about 200-300 ppm more zinc/zddp in addition to moly. The latter is completely missing in the Motul. I’d say M1 has by far the better additive package for wear protection. My last virgin 0w40 m1 showed 1200 ppm zinc (compare that to Motul’s 850-950); that’s what protects engines. And we are talking about the SN rated 0w40 m1.
Edit: other reasons why I will continue to use M1 0w40 1) recommended by Porsche. 2) it’s the same oil used in Porsche Cup cars for racing.
If you want to use thicker oil go with M1 5w50
02-26-2018, 08:09 PM
