I have a t04e setup with an HKS Racing wastegate. I'm using a EVC III boost controller that has no problems keeping boost rock solid from 10-13 psi, but I get 1-2 psi spikes when I have it set from 13-15. I know the wastegate spring comes from the factory set to 10 psi.

If I adjust the spring tension on the wastegate to set it closer to 13-15 psi, would the boost controller have an easier time holding boost at those pressures?

 

Can the hks racing unit's spring tension be adjusted? I did not know this but would love to know.

 

You can change out the springs; they make a 1 kg/m2 spring (14.7 psi) that I would consider getting if it would eliminate spiking.