So before I dropped a new clutch into my 2000 OBW this past weekend I was averaging about 360-370mpg (totally topped off tank to gas light coming on). Mostly highway, as I work 32 miles from home- 64 miles round trip.

 

Before I noticed my clutch was slipping I had just fueled up but not quite topped off so the needle was just barely below the full line (not quite a full tank).

 

While I had the engine out I adjusted the valves too. Intake valves were all bueno but all the exhaust valves were tight. Plugs looked great but I changed them anyway...

 

Well fast-forward one week into breaking in the new clutch and I'm already pushing 400 miles and I'm barely below the 1/4 line! Keep in mind I didn't start with a completely topped off tank either.

I haven't done the math yet but that's a substantial increase in mileage!!! I know I have another 60 or so miles left from 1/4 tank before the light comes on.

 

So I'm not sure where the increase came from; clutch or valves or both, but I'm super stoked!

It is rather simple

More efficient drivetrain. Less energy is wasted on slipping clutch (to maintain same speed). And more bhp comes out when engine compresses better (leaking valves). Although I think valves are not making a gigantic change.

 

Well done!!! Always nice when the fuel prices are rising againg (at least in Europe they are)