Need install info on GM boost solenoid with extenal wastegate. tryed to tune with my wastegate duty cycle set at 0 and i was still spiking out. all my vacume lines are place as directed but stillnot able to figure it out. i searched the forums but was not able to find anything using extrernal wastegate. any help will be great.

 

On the side of the solenoid that has 2 ports, one to intake/atmosphere and the other to WG — switch those 2 around and see if it helps.

 

ok ill try it

 

i figured it out and now need a better solenoid maxed out the GM solenoid

 

if that is the case you might need a stiffer wastegate spring. also check for boost leaks.

 

For a dual port external WG you should:

1) Run a boost source to the lower port.

2) Run the NC (normal closed) port of the GM solenoid to the top port.

100% Duty Cycle = Closed WG, full boost
0% Duty Cycle = Spring pressure

 

Are you running 40psi or something?

 

I use a Perrin BCS with a Tial 44mm / T04Z - 15psi spring running 35psi at the manifold.

Loop the BCS in the same way as you would a regular internal style wastegate and you should get good resolution and control.

 

That doesn't make any sense, I think something is wrong with your setup...