Easy way to lower the level of boost on wrx WG?

[mikewolf]

I have a wrx turbo and wg on my miata. I have read online that the stock waste gate limits boost to about 13.5psi. I think that is more than my internally stock miata engine will be able to handle. I know there are other factors in determining the boost level, but is there a way to make the stock waste gate open earlier?

[JoeT]

Undo the clip that holds the vacuum actuator on the actual wastegate arm, and reduce the preload on that arm.

Stock spring tension on the WRX is around 7 - 9 psi, not 13.5.

To reduce the preload, just unscrew the clevis about 1 - 2 turns.

[BryceD]

How do you control the boost currently? The Subaru boost control solenoid?

If you aren't using anything currently, why not a simple manual boost controller?

The WRX WG actuator arm is adjustable, and you could loosen it so the WG is always open a little bit, but a better solution would be a manual boost controller.

[mikewolf]

Thanks Joe,
7-9 should be better.

Bryce, I have yet to run the car boosted. I will likely use a manual boost controller, but from what I understand, they usually increase the boost pressure from stock, instead of decreasing it.

[BryceD]

I belive the actuator spring tension is closely matched to the 'WG Boost', so even if your wastegate was stuck wide open, the turbo would develop 6-7psig.

You can add a 'helper spring' to the wastegate to lower the effective actuator spring tension, as I don't believe you can easily take apart the existing actuator to replace the spring with a lighter one. The helper spring would open the wastegate sooner, but I don't think you will be able to get boost below that 6-7psig.

[Cavemanrjc]