420A Turbo 420a spiking to 9 psi

[Riceboy]

Hey i just turboed my 420a about 2 months ago. My motor has about 170,000 miles on it. I've got a t3/t3 turbo with a .70a/r compressor housing and a .48a/r turbine housing, I get about 8-9 p.s.i. at about 3800-4200 rpm's. I have absouletly no fuel management, all it is is the turbo and the fmic. It is externally wastegated, i have a 4 pound small yellow spring in it but some how get 9 psi?

Weird idk, I heard external wastegates don't spike, if so, why am I spiking so bad? My motor still runs fine except when I blow my intercooler pipe off like once every other day.

When you guys turboed ## car did anyone notice their idle surging before coming to a complete stop? I idle at about 1800 rpm's until i come to a complete stop. Thnx for any help guys
Terry

 

[BigRand]

I have absouletly no fuel management, all it is is the turbo and the fmic. It is externally wastegated, i have a 4 pound small yellow spring in it but some how get 9 psi?

Weird idk, I heard external wastegates don't spike, if so, why am I spiking so bad? My motor still runs fine except when I blow my intercooler pipe off like once every other day.

When you guys turboed ## car did anyone notice their idle surging before coming to a complete stop? I idle at about 1800 rpm's until i come to a complete stop. Thnx for any help guys
Terry

Well if your not running a boost controller, than you can assume that you either have the wrong spring or there is something wrong with yours.

When you say you have no fuel managment, do u mean like no fmu, injectors, fuel pump or anything? That could be a part of your boosting problem. Also make sure your boost gauge is sourced at the intake manifold and not your turbo, they are two different readings.

You should really buy real intercooler pipe couplers, (GSgoingfast explains his trouble with home depot ones in his write up)

As for the idle, I dunno, My car never comes right back down to 800-900 idle after I get on it. The ECU likes to hold the idle up a lil higher like 1200 for like a couple of seconds before bringing it all the way down. But 1800 sounds a lil high but then again that could be your lack of fuel mangement.