Here's something I don't know - Boost Controller/wastegate spring

[4felix20]

say i buy the greddy profec B spec II and hook it up to my 38mm wastegate which has a 10psi spring.

can i use the profec to lower boost? would i be able to run 5psi?

for some reason, i'm thinking you can only go higher in PSI than the current spring inside the wastegate with a boost controller.

[WDRacing]

Nope, you can't lower the boost past the spring or diaphram if its internal. But they do sell springs that go as low as 4 psi. You should be using a BC if you are ready to increase the boost.

WD

[hannibal]

Boost controller restricts the boost pressure signal from the wastegate until the boost controller reaches its set pressure. If you set your BC to 5psi, it would wait til you hit 5psi, then allow the WG to see the 5psi signal. Your WG would just ignore this 5psi, and wait til boost reaches 10psi to open.

As WD said, you can only uses a BC to raise your boost setting.

[Florida240sx]

They already explained it..........I got a small spring.Think it's 5.? spring. On mine it was 4.7ish psi but was receiving wastegate signal of hotpipe not fpr. I'll sell it to you cheap.

[4felix20]

would it fit a tial 38mm? see, i'm parting together another turbo setup and i'm not sure if i want to buy this one guy's tial yet.