Vilhuer

928 engine design was done in early seventies. Back then these modern oils didn't even exist. Their excellent features are wasted in old engines. For example Porsche museum puts Valvoline 20W50 into cars they restore even though factory normally uses different brand oils based on sponsor deal they have done for production line use. Mobil, Shell whoever is current new car favorite provider don't seem to have right products for factory to use in 30 year old models.

gruffalo

Why? Why is a 10w40 better than a 0w40, for example?

dprantl

Because in order to make a 10W-40 oil for example, you start with a 10W oil and add viscosity modifiers so that the film strength hot is 40. As the oil is used and the modifiers wear away, hot film strength gets closer and closer to a 10W.

Dan
'91 928GT S/C 475hp/460lb.ft

Vilhuer

And in case of Mobil 0W it seem to cause premature wear in for example eighties BMW engine cam lobes. Not good at all for our old design engines.

FUSE69

Have any of you guy's tried Valvoline's VR1 10w-60 synthetic?

I've been using Valvoline's 20w-50 with good results, but it is a dino oil, so am wondering if it's worth switching to their synthetic...

Vilhuer

Friend uses it in his '90 GT as cheaper alternative for Castrol. He loaned it for me for Helsinki-Stockholm-Nurburgring trip last summer. 3k+ miles at motorways and autobahns and several laps at the 15 miles long old ring and only problem was too high for our liking consumption at the track. That can be expected even with Mann-Hummel setup. Oil was fine at short bursts up to 160mph and longer periods in 120-140mph at autobahn.

993turbo

I used Castrol 10w 60 ''M'' oil in my 928's earlier. No issues. I have now switched to ''Gulf Competition Racing Oil'' 10w 60 Synthetic Ester based. Very happy. :-)

FUSE69

How much do you estimate you used per lap and what was the oil pressure like once idling back to the carpark after a lap?

I have 20w50 here for the next oil change, so maybe for the change after that I will give the 10w60 a try...

gruffalo

I'm gonna give the Gulf 10w60 a try. This thread is inconclusive anyway. A 10w60 is:

-too thick
-too thin, since it's based on a 10
-too new, multigrade didn't exist back in the day...

Vilhuer

Maybe 5 laps and 1L was normal so its little over 1L/100km. It changed somewhat depenging on how much traffic there was at the track meaning was high rpm used all the time or not. Oil pressure remained same as always. At idle it is 2.5 bar IIRR and don't need much revs to go above 3 bar. Weather wasn't super hot though.