I questioned the Techs servicing a friend's Club Sport at the track about oil. They said they use Mobil 1 0W40.

 

Ah, the old 2.5W45

 

You got it. I started mixing oil when i was tracking an Exige S. They had a bad habit of wiping cams. So i started mixing M1 0-50 race oil with M1 0-40 street oil. The race oil had 1800 zinc VS 1000 for street oil.
Mobil tech said as long as it was changed often it was fine. Race oils don't have the detergent package of street oil plus the Zinc kills cats over time.
That's why today's oils don't protect flat tappet motors like the high zinc-ZDDP oils.

When i sold the lotus i did a ECU dump. 123hrs @ 7500-8000 rpm (10,600 track miles)cams were perfect.

The 91A is basically a flat tappet engine . Most manufactures have gone to roller followers . The GT3's are having the same cam wiping problem as the lotus. I think a 9k RL is just past the design parameters of the 91A..
Porsche lowered the RL to8600 on the 991R interesting?? https://rennlist.com/forums/991-gt3-...-replaced.html
carl

 

I'm not debating merits of any oil, but Mobil 1 0w-40 Euro spec (Porsche approved oil) now has more Zinc in it than 1000 ppm. Maybe the additive formula has been changed over the years.

FWIW, I sent in virgin samples of DT40 and Mobil 1 0w-40 Euro to Blackstone about 10 days ago and will post the results on this forum. I'm sure it's been done by someone on here before but I wanted the results as a baseline for my own long-term oil experiment I'm doing with my 2 p-cars.

 

From what I have heard, this cam wiping phenomenon is present in the GT3 and RS even at low revs (they are working to address it with different cam profiles and DLC coatings). I think the reason the redline on the R and RS (4.0L) is lower than the GT3 (3.8L) is because the extra 200cc of the 4.0L is achieved with stroke and the lower redline retains similar piston speeds as the 3.8L (similar forces on reciprocating masses).

 

you are correct 0-40 is 1100ppm & 0-50 race oil is 1850.carl
https://mobiloil.com/~/media/amer/us...guide-2016.pdf

 

Is it possible to purchase this Euro Spec version? I searched and did see some hits, but is the Mobil 1 0W-40 European Car Formula the same thing?

 

This is the Porsche approved Mobil 1 in 0w-40 weight:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

"European Car Formula" across the front of the bottle.

 

Makes me wonder if the factory oil fill has a little more Zinc in it than commercially available Mobile 1 Euro 0w-40. My first GT4 oil drain @600 miles had 1200 ppm Zinc and 1000 phosphorous. I'm curious what the oil analysis will show for Zinc in the virgin Mobil 1 0w-40 Euro sample I sent in last week. My Blackstone report for the first GT4 drain is below. Note that I didn't tell them what the oil was, because in reality, I have no confirmation that Porsche uses the commercial version of Mobile 0w-40 for factory fill. I refilled with DT40 and will drain again at 2,000 miles.

 

Here's a photo of the Panorama article mentioned in posts 42, 43 and 45 of this thread: