[Alpina_B3_Lux]

Originally Posted by doughboy

Great Stuff Marcel,

I've been using the Titan Pro-S 5W-40 since 8000 miles old (now 38,000 & 5 changes since then), glad to see its still No.1! Remember the 335i runs hot, and hot oil weights are measures at 100degC, they are thinner still at 120 of course, so any leaks or pressure loss will be amplified with thinner standard oil.

You're correct, it is a full ester synthetic, not a mixed or modified mineral oil which many lesser 'synthetics' atually are (Castrol Included).

Originally Posted by doughboy

Kevin Bird told me to stick with OE spec oil for the Quaife? but I suppose any superior geared diff oil should be ok?

As as you correctly say NEVER use Limited Slip Diff Oil, as the quaife is not a clutch LSD but a geared ATB.

Well, Birds apparently use the Mobil 1 I quoted in my post, but which does not seem easily available to the public. Which is why I wrote to Opie who mentioned the Fuchs oil - if I understood them correctly the specs of both oils are quite similar so I don't think that it will make any big difference. Opie apparently got the information on the Fuchs oil from Quaife themselves.

Originally Posted by doughboy

PS - Did you know that Birds are now selling a specially made finned heatsink-type diff rear cover for the 335i? (like M3 / M5) good for track work apparently to prevent oil breakdown - sounds like your kind of thing Marcel

No, I didn't know that (they're not mentioned on their website I believe) - but it seems to be very similar (if not identical?) to the VAC cover that I'll be installing on my car in a few weeks (see my original post).

Alpina_B3_Lux