i just installed a tial 38mm wastegate on my car and it's supposed to have a .4 bar spring (5.8psi) but i can't seem to boost over like 3-4psi. what might cause this? i have the side air fitting connected to the turbo. i bought it brand new, but i suppose it could have the wrong spring installed, i didn't check.

 

Sounds like you have the little yellow spring in there. That's what I originally had in my 35mm WG and I boosted to about 4 psi just off the WG.

That's my guess unless you have a boost leak somewhere.

 

Make sure you don't have an exhaust leak or a boost leak somewhere.

Also, jsut an FYI the standard (at least most common) way to hook up a wastegate without a boost controller is to leave the top port unconnected and put a standard vacuum source to the side. I don't think it will matter in your case though, but you can try it out.

 

i have an exhaust leak at the cat, but that shouldn't matter should it? my setup:

drag mani
.63/.60 t3
spoolin performance downpipe
tial 38mm wastegate

 

Check for exhaust carbon buildup (signifying a leak) from where the exhaust manifold meets the head, from there the wastegate meets the manifold and from where the turbo meets the manifold.

 

I still think it's the spring based on the amount of boost you're creating. Does it fluctuate at all or is it consistantly 4 psi?

 

i checked today and i do indeed have the red spring, which is the correct one. it seems like it fluctuates between 3-4 psi, but i've only driven with it for a couple days so i'm not 100% sure. i also noticed a bit of carbon on the manifold where the turbo inlet is. could a small leak make that big of a difference?