Norm Peterson

5W20 is for mpg reasons. Obviously when you're running hard out on a road course, mpg only matters to the extent that you don't run out in the middle of a session. Better protection is the game then.

FWIW, I've heard that 5W50 shears down to 5W40 or possibly lower in a relatively short time. Don't know how reliable that is, but it's something to consider where 5W40 is still a little more viscous at temperature even if it runs a little bit hotter.


Norm

jz78817

If you think the difference between 47.3 and 48.8 cSt matters at all, I don't know what to tell you. There's a lot more to wear protection than viscosity.

WJBertrand

I've been using the Mobil 1 5w-30 extended service oil in my GT. The engine does not seem to use any oil between changes (7500-9000 miles depending on when the oil life monitor tells me it's time).

SCCAGT

Yes, the whole tolerances thing requiring a thinner oil is BS. Always has been. Always will be. The next round of API ratings will bring it from a 20 to a 16. Its all for the sake of CAFE numbers.

yourmyboybh1026

I've always ran 5w-20 M1 full synthetic in my car and just started getting into HPDE events. Would you say its smart to switch to 5w-30 or 5w-50? I ride her pretty hard at the track for 25-30 minutes at a time with about an hour and a half between sessions. I haven't seen any signs of excessive ware and I tend to change all fluids after a track weekend.

Norm Peterson

Step up at least to 5W30.

I've been using Motorcraft full syn in that grade, and so far, so good. But I don't do track days where the temperature is predicted to get into the 80's (a heat exhaustion thing), which might tip your decision toward a little more hot viscosity if your track days run more than a few degrees warmer than that.


Norm

yourmyboybh1026

Well both HPDE events I went to were at Sebring in late May, so yeah it was hot! I'll step up for my next event in October.

Does anyone have any experience with aftermarket oil coolers?