87 grand national

[dgreen]

86,000 miles mostly stock under hard acceleration pops and spits seems to be over boosting has digital gauge and aftermarket but seem to spike when this happens prev. Owner installed adj.waste gate how do I lower boost

 

[dgreen]

Vacuum hose from waste gate to boost sol. Is good

 

[DOUGGN]

If you have an adj. wastegate actuator you lower the boost by lengthening the rod. each full turn is approx. 1 pound of boost change.

 

[dgreen]

Thanks ill give it a try it seems to spark knock when it spits do you know how much boost it had stock ?

 

[DOUGGN]

around 12#. spark knock (detonation) is a very bad thing with a turbo car - I would keep out of boost until you know what is going on. first thing you should get is a scanmaster - will tell you a lot about what is going on in the motor.

 

[blackgn1]

How much boost is it running? +2 on the scanmaster. You need some way to monitor knock. SOON!!!

 

[dgreen]

87 gn

Checked car over today prev. owner had boost way too high, adjusted waste gate got boost down to about 13 psi. also checked fuel pressure (has adjustable reg.)was at 18 lbs. at idle re-adjusted to 39 psi at idle car runs great ! Thanks for all your help ! I dont want to race this thing i just want to have fun. Still get goose bumps everytime i open garage door and look at the car !!! (The wife is a little upset that her van has to stay outside and the GN and my truck get to stay in the garage, but i think she will get over it)

 

[blackgn1]

Don't forget the scanmaster.