Stock Wastegate act. question:

[TurboRegal84]

Why does our stock wastegate Act. have 2 vacume ports? I was wondering this, and I removed the hose from the port closest to the passenger side, and then plugged up the vac port up at the throttle body.

When I tested it...removing the line gave me about 2more psi of boost, and the turbo spooled up faster....are there any downsides to keeping the port open, and not applying Vac to it?

or is this one of those things that we still ask GM "What were you thinking"?

Thanks for your help!


FYI FYI...if anyone does this make sure it is the port closest to the pass side..if you remove the driver side then your car will have umlimited boost, and it will blow up!

 

[TType84]

theoretically extra vacuum along with boost on one side would let the wastegate react faster, and thus keep boost from spiking. I can think of no reason that you would gain 2psi from that..

 

[b4black]

I can't figure out why the vacuum port is there. My only guess is maybe it would help keep the WG closed in low boost applications (where spring tension is minimal). After all, these are aftermarket (Garret) turbos adapted to a factory use.

I find that the vacuum side of the actuator is usually leaking internally. I remove the vacuum line and cap off the engine's port. (Otherwise you have a BIG vacuum leak.)

I don't know how you would gain boost. Your WG should have kept it where it was set at. Unless your max boost is below your WG's setpoint.


The 86/87 doesn't have the second port. I ask Harry Hruska at Precision, he said you don't need it and to cap it off as well.