Anyone running synthetic actually see a mileage increase? If so, what oil/filter combo?

 

i have used the castrol synthetic blend,never noticed any better mileage just longer times between changes

 

I worked at Napa and Advanced Auto over the years. I used synthetic in my everyday driver and conventional in my race cars and off-roaders. The mileage increase is probable minimal less than a MPG. But I have seen on a dyno increases in horse power when synthetic fluids are used. I had a 5.o Mustang before that when changed motor, trans and gear fluids all to synthetic there was a 12hp increase. So its worth it if ur looking for power and motor life longevity its worth it. But if ur looking for MPG use conventional oil.

 

Syn is better, because you can use it in longer intervals.
so it pays for itself

 

the 4.0 runs best with high phosphorous oils.. i use castrol diesel 15w-40 and its given me the best results with my low-ish compression, oil control ring-leaking, blowby-prone, high miles motor.