Ok, I am fully aware that this thread will attract various opinions and experiences. What i say is based soley on my personal experience with this motor, and its mating to an auto box in a GX81 Mark II.

Get rid of the clutch on the S/C!

I have done this in conjunction with a change in pulley size (EA air con pulley). Before the mod, i struggled to get 11L/100km driving full granny and trying not to engage the clutch unless absolutely necessary. Post mod, i have driven about half bogan, half granny. I have put 90L of fuel in and done 920km.

My reasoning for the improvement is;
- S/C is post TB so spins in vacuum at idle.
- While under vacuum engine is assisted in breathing for a small crank price, which seems more efficient than having to pull air through the small opening of the ABV until reaching ~ -1 psi where the clutch would engage.
- Inlet manifold pressures fluctuate more smoothly (no clutch, no sharp changes) so acceleration is more effecient.
- The car can be driven much more linearly on the pedal, so the driver can be more efficient.

Even if the economy was the same, the improvement in drivability makes it entirely worthwhile.

The price you pay is; more airflow through the S/C at increased average temps thus more wear on the lobe coating and lobe shaft bearings.