Originally Posted by stocktake (Post 2851531)

On all the failed motors I have replaced/repaired it has always depended on what position the valves have failed in as to what the owner experiences, either better/smoother delivery of power, or better mpg, or a little of both. Most common by far is the feeling of no power lowdown in the rev range and this is always the case if the balance vis fails in the closed position.

Originally Posted by vitesse (Post 2851516)

OK bit of translating time ....

1. At low rpm the balance valve and valve controlling the effect duct is closed. This causes the engine to breathe as two 3 cylinder engines each with its own separate mixing chamber and long power ducts, which means that the engine reaches peak torque at 2700 rpm.
2. To improve torque in the medium range the balance valve is opened while the power valve remains closed. Max torque is now reached at 3750 rpm (2.5 ltr) and 4000 rpm (2.0 ltr).
3. At higher engine speeds both the balance and power valve are open. Achieving now a range of torque upwards from 4000 rpm to a maximum of 6250 rpm (2.5) and 6500 rpm (2.0).