Guest Tom Scala Posted July 18, 2001 Share Posted July 18, 2001 I wanted to raise the boost on my 78Z w/SDS injection but don't have an IC installed yet so I figured 9 psi was a safe max level. I tried making the wastegate rod adjustable by cutting and threading it and shortened it 3 turns. From all I've heard 1 turn will equal 1 lb. boost. This raised the boost from just under 6 to just under 7. I shortened it 2 more full turns and only got about 7.5 psi. I don't want to shorten it any more since I have to pull it out of the diaphram housing quite a bit to get it on the wastegate. My turbo is a hybrid with a stock Buick GN compressor side and the t3 exhaust housing with a clipped wheel. The wastegate outlet is ported. I'm running a 2.5" mandrel bent downpipe and a mandrel bent 2.5" exhaust to a Dynomax Super Turbo muffler. No cat. In ScottyMIZs' post it was suggested exhaust backressure was limiting his boost. Could this be my problem? Should I just get a dial-a-boost and forget it? Quote Link to comment Share on other sites More sharing options...
Guest Tom Scala Posted July 18, 2001 Share Posted July 18, 2001 Oh yea, one more thing. The GN's run 14psi stock with this compressor and regularly go as high as 20 so I'm pretty sure thats not what is limiting my boost. Thanks. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 19, 2001 Share Posted July 19, 2001 If that is the original wastegate cannister, I would check the diaphragm. Only way I know is to use some sort of a pump and put pressure to it and watch for the rod to move. Make certain when you adjust the rod that you disconnect it from the lever to relieve the sring preload, else you can damage the diaphragm. Quote Link to comment Share on other sites More sharing options...
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