Do U agree with my theory, if not what do U think?

[boraticus]

Originally Posted By: Robenstein
Originally Posted By: boraticus
How could a slipping clutch improve mileage?


Unless it slipped only during a hard acceleration and not when under a softer load cruising around.


Possibly. However, as previously stated, unless the OP takes a more scientific approach to measurements, there will be no conclusive evidence to confirm that either oil performs substantially differently from the other.

 

[Robenstein]

I agree a few more hard twists on the throttle can make a world of difference.

 

[Cujet]

I can notice a small HP change with various oil viscosities. Dyno tests show a tiny, but measurable difference. So, It's not all in my head.

However, once oil is up to operating temperature, regardless of stated viscosity, it's very thin and has only a small affect on economy. Maybe on the order of a few percent or on a 40MPG motorcycle, maybe 1MPG, from worst to best. 20-50 vs. 0-20.

Slipping clutches are generally easy to diagnose. The engine revs up. Clutch slip is especially noticeable when the clutch is released under high power. As the engine will continue to rev for a time.