15w50? Thats pretty thick. I would run the m1 ow-40 next time

 

Lots of boost and I live in Phoenix...

 

i use Shell 5w30

 

I would still run the 0w-40. What sort of temps are you seeing?

 

Royal Purple 10-40w.

 

used frying oil..works wonders!

 

I used to use Castrol SYNTEC 5W30, than when to Royal Purple 5W30, and now I use AMSOIL 5W30.

 

If your living and driving in a hot climate, the 1st number doesn't matter.
The W stands for Winter. NOT Weight.

Therefore 15W-40, and 0W-40 in Arizona would basically the same.

 

Yes W stands for winter weight but that figure also represents the viscosity the oil flows at when it's not warmed up yet.

Redlude97 could also be advocating the 0W40 because this particular weight type has been seeing much better oil analysis results than the others.

 

Who said anything about that weight? I was specifically addressing the 15w-50 ttrank was running, those would not be the same
Try and keep up

 

I don't want to start a **** show here, but the W does stand for winter. I spent an entire semester learning about oil, and oils testing.