Ive got the greddy spec II ebc, and i cant get it to boost past 10psi. this is on an 88 TII, stock ports, 3" exhaust, 3" tid, BNR stage 3 turbo, stock wastegate spring (5-6 psi)

on the ebc, the boost starts increasing from 5 psi at about 45%, to 10psi at about 55%, but then it stops increasing. ive tried up to 95%, and it holds steady at only 10psi.

i did some searching and saw something about not being about to boost more than twice the stock spring psi? the only thing i can think of is maybe exhaust back pressure pushing the wastegate flapper open?

 

sometimes you cant get it past twice the spring pressure, but that depends on the controller. looks like its time to ditch the bnr jamin!!

 

Yep, over the years I have read of people having this problem with stock hybrids pushing the internal wastegate open.

It has been fixed by adding spring tension to the WG actuator to keep the flapper on the seat.

I have seen puller springs added on between the flapper and wastegate acutator (seems like heat would relax the spring quickly.)

I have seen the actuator simply moved rear ward on the bracket so there is more initial spring pressure.

I have seen a turnbuckle added to the WG actuator rod so that more preload could be screwed in.

If you contact Bryan at BNR he will definitely help you out.

It is often a case of AF ratios and timing as well, so don't be discouraged if those are the first questions he asks about.

 

yep, i added a couple springs between the wg arm and the actuator..

now base boost is 9psi, and i was able to boost a lot higher with the EBC
THanks!