Straight 50-weight oil for summer heat?

[Forza]

Yesterday, I was talking with a local indie Porsche mechanic, and he stated that straight 50-weight oil is an appropriate choice during the summer for 911s. He said that track day junkies and racers often use it and that it would be totally fine to use until Fall.

I guess I can see it's use on hot track days, but it isn't listed as a straight-weight option in my owner's manual, and a search of here and the greater Web have yielded little on the topic.

Just curious, is a straight 50, even if it's Brad Penn's, strictly verboten, or are there times it can be safely used for general use? What is the lower end of the straight-50 temp spectrum?

[arrivederci]

Interested in opinions on this as well. Went looking for VR-1 yesterday for my racecar and could only find straight 50.

[JFairman]

Straight 40 weight oil would be a better single weight choice than 50 weight in 90 degree summer temps in a good motor.

If mileage is high, oil clearances in the bearings and piston skirt to cylinder wall clearances have worn and are bigger, and temps are high than 50 weight would be a good choice.

That said, 50 weight oil won't flow as quickly as 20w-50 to the valve train, cams, and chain tensioners after a cold start.

[boxster03]

I would agree with the straight 40 over 50 especially in Boulder. It can turn cool at night on a dime there even in the middle of summer. If not mistaken in the old days Porsche recommended straight weight oil but it was likely 30w. 30w might be better yet for Boulder. But why risk it with such good oil technology just go with a good high ZDDP rated multiviscosity oil. Are you really saving that much?

[arrivederci]

In my case, a little time on the phone and I tracked down VR-1 20w50, so that's what I went with. I bought the 50w just in case and will return it.

[efhughes3]

Having the multi-weight oil is good for in the morning when the engine is cold. With 20/50, you're still covered at the higher temps.