Originally Posted by Motion Lab

Recommended setting is based on the amount of boost you are setup for and how much vacuum is being produced at idle. If the setting is too soft you will suffer from the Hyundai Genesis syndrome (seemingly making boost at idle/fluttery bov operation). Also the piston may not be able to remain closed at idle. If it's set too hard, the valve will not open enough (or at all in some cases). If this happens you will incur compressor surge.

So basically you want to start at the softest setting and with the car running, turn the tension up a bit passed the point where the piston remains closed at idle. Then have a friend rev the car and make sure that the valve opens during the vacuum fluctuations and you're set.

Thanks,
Steven Watson
StevenW@motionlabtuning.com