MAGK944

I've used it for over 20 years in the same 944 but I don't have a cat. I guess any oil with the high zddp content our cars require will eventually eat the cat. It's one of the reasons oil companies reduced the content of zddp. However, I would rather replace a cat than rebuild my top end.

Fara

What's a catalyst? I've never seen such a thing on my car

f1rocks

Millers Racing Oil Harry King/Karl Poetl.
Not cheap but I get a full season (8 race weekends/3 DE weekends) and it still tests like new.

ggrecian

thanks gentlemen.i am going with the vr-1 20w-50.i had success with the 20w-50 penzoil.i appreciate your time