Thinner oil, better MPG.

[KiwiBacon]

Has anyone had good mileage results going to thinner semi-synthetic oils?

My car came from the dealer with 20w50. After 10,000km I swapped to 5w30 (both within the manufacturers range, but opp ends of their scale).

Difference in fuel economy (if there is one) is soo small I can't tell.

[PGS 4WD]

It is true so much that the current Ford inline 6 cyl economy figures were supposedly only acheivable with thin oil, although my XR6 T never seems to get the quoted economy figures??

Joel

[Ruffy]

I think one of the best examples of this is the 1FZE engine.
When 80's were new i worked at a toyota dealer and had the ocassional customer comeback complaing of there car being sluggish after it was serviced. You could actually feel the difference driving it between the 20w-50 gtx2 and the 10w30 protec (i think). the engine revved much smoother.
I'm guessing as i have no stats, but that would have to effect fuel economy to.
You'll notice the difference more in tight tolerence twin cam engines and especially small capacity rather that the likes of a falcon engine.

[KiwiBacon]

You'll notice the difference more in tight tolerence twin cam engines and especially small capacity rather that the likes of a falcon engine.

Funny because that's my nissan wagons engine to a T. Twin cam 1.8 litre econobox.
But it does seem to be a bit of a freak fuel consumption wise.

Driving the nuts off it will drop it to 11 km/l, otherwise it's 12km/l on a slow trip or a fast trip or a hilly drive or a sedate flat drive.
Disconnecting EGR made absolutely no difference either.