no boost control?

[rtviper]

I was asked a question about my buick and did not have an answer. When I bought the car it had a modified stock computer with a chip. The car has a heavy duty stock style wastegate. I changed over to a Fast system. I was asked what controls my boost since the Fast system will not. Stupid me I thought you just turn the wastegate rod in or out to control boost. On the dyno it went from a low of 19 lbs to 24 lbs as the car was tuned. I was asked why the car did not just boost until it could boost no more without any controls. I am wondering that my self. Any ideas? It has a t76 turbo and a stage II motor. Damn you have to be an Einstein to run these cars and I have never been accused of that.

 

[Ormand]

The wastegate controls boost. It takes air from the turbo discharge, and uses that to open the puck, when boost gets more than the spring pre-load will handle. The stock chip/ecm also uses the wastegate solenoid to bleed off some of that pressure, and INCREASE boost above the spring setting. But, since the ecm doesn't have any data to know what boost is, it isn't really "controlling", it is just increasing. Lots of tuners bypass the solenoid, running "tuner style", and control just by setting the preload on the wastegate. If you were to shorten the rod too much, so that the wastegate would not open, THEN the engine would just keep boosting until something would break.