I have a t3/t4 hybrid with tial 35mm (9 psi spring) and profec B. When I gun it (with the boost controller off), the boost will spike to 15psi and settle back in 9psi. I use to connect the vacuum from wastegate (side) to the intake manifold and now I switch it to the charge pipe and the boost still spikes occasionally. Is my wastegate too small for my application? Any other thoughts?

 

dont connect the vacumme part up. only use the boost

 

what do you mean??

 

i did not know what i was doing when i first went turbo. i hooked up the wg wrong. unless you are using a boost controler made for an external wg you dont use the top part of the wg. disconnect it and see what happens.

 

I have an EBC.

 

Any one have a clue????

 

From what I understand, profec b and external wastegate goes like this:

Black Box In - vacuum source on intake manifold
Black Box Out - top port of wastegate
Wastegate side port - vacuum source on intake manifold

Is this correct?

 

here is my configuration...
Black box in --- Manifold
Black box out-- top of the wastegate
(now)Side port of wastegate-- Charger pipe
(before) side of wastegate---- Manifold

Could it be my wastegate(35mm) is just not efficent enough?

 

What happens when the boost controller is turned on?

 

same thing, it will spike up a little, 3-4 psi and settle back down to whatever it should be.

 

From what your describing, it SEEMS like your wastegate obviously isn't regulating the boost. However, if I were you I would disconnect the the profec b all together, run the top port open, and run the side to the intake manifold-correct me if I'm wrong. That way you'll be able to check if it has to do with the boost contoller. If boost holds steady at 9 psi then I'm assuming theres something wrong with your profec b.