Ok the manual says 85W90 or something like that. I was wondering if anyone has used the full synthetic version of this which cost like 3x more or the half syn version that is like $2 more than conventional, and if they see any improvement when using it?

 

I'm using Royal Purple 75w140, and I saw about 1 mpg increase, and it feels like there's not so much of a jolt when I suddenly accelerate, but that could be all in my head

 

Don't know how much I would attribute a thicker oil to increasing fuel mileage... My experience with moving to a heavier oil was a drop in mileage...

 

Haha well shoot...maybe I used 75w90...whatever you suggested in my old high mileage thread...it's been a while!