View Full Version : Easy way to lower the level of boost on wrx WG?
mikewolf
03-22-2010, 11:11 AM
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?
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
03-22-2010, 11:25 AM
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
03-22-2010, 01:02 PM
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
03-22-2010, 02:09 PM
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
03-22-2010, 08:46 PM
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