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I have always used Mobil 1 15-50 Extended Performance oil in my 968. Now I can't find the Extended Performance. I just learned about Mobil 1 and the EPA requiring less zinc additives to oil. So Mobil 1 may no longer be good for my 968. I read some posts on Rennlist but am confused and could not find anything here.
What do racers use and recommend for oil in their 968 and how often to change it.
thanks
Dave
I run Brad Penn 20W50 semi with a very high ZDDP value and HTHS index of 6+ (I believe Porsche says 3,5 as a minimum). Most likely over the top for me but it feels good. I change every 10000 km or once a year if I'm able to keep the oil temps at a sensible level. If not, I'll change more often. My engine is virtually stock.
it is true the the formulation changed - i think it is changing again

it is true that ZDDP promotes engine life

many oils are excellent at providing lubrications and protection

many people use redline (i am using 10-40) i noticed a distinct improvement in freer revving and lower oil temps when changing from mobil 1 15-50

many people use royal purple - they swear by it

the same can be said of amsoil - there are tests out there that show amsoil as an excellent oil and perhaps better than the rest
If using Amsoil, would you recommend the series 2000 20-50 Racing oil?
If using Joe Gibbs racing oil, the XP-6 15-50?
If using Joe Gibbs and it has less detergents, how often would I need to change oil?
i am REALLY old when it comes to thoughts about oil - i come from the school of "if it's thick it's good - it it's thicker it's better" - it took me a lot to change that way of thinking and go to a multi-viscosity oil, let alone to a thinner one

that being said, your oil temperatures will tell you a lot - so will your pressures - when an oil gets hot, it thins - higher viscosity ratings provide more protection under higher temperatures, but you may or may not need a higher rating

so far, the 10-40 redline has never thinned out at full temp (about 265), but this is a street car, no matter how hard i drive it - i haven't actually run the amsoil, but am sure it is fine to run the 20-50, and probably better in a race car

i have no experience with joe gibbs outside the redskins
I've only run amsoil 20 50 synthetic in my 968 since I got it 3 years ago. Really impressed with the amsoil product, I know its subjective, but I can feel the difference. I used to use Mobil in my 944 then switched to amsoil and could feel the difference.
Recently switched to amsoil 5 40 european formula synthetic for colder temps this winter, but may keep for the summer as well.
I like it, for what that's worth. I don't race the car.
since none of us have the capacity to really test any of the oils, most of anything we have is anecdotal and subjective - the only "data" i have is limited to temperatures (and then only going from mobil 1 15-50 to redline 10-40) and a quicker revving, though i never quantified it - i can tell it's there, but can't tell you how much

the oil company websites that are out there with data, managed to skew the results enough by mismatched comparisons of oils to invalidate them as any real test

we have to rely on those who have tried different oils, hope that their scenarios are similar to ours, and go from there