Wastegate signal

[nismo1003]

my wastegate set at 8 psi , the wastegate signal line hook up to turbo (i had the 300ZX T3 turbo), when it's WOT , it reach boost to only 7.5 psi, someone told me to put that signal line to the throttle body(behind) , is it that much different between the dfiffernt location?

Also my turbo spooled up to full boost ( 7.5 psi) at 2400- 2600 Rpm Range) , is it normal?

my setupT3 turbo35mm wastegateFMIC intercooler2.5 interppiping all the way3" exhaust

[Nathan]

If it's to the intake manifold, the turbo will effectively produce more boost, because it'll push throught the intercooler pressure drop (.5psi isnt enough to worry about imo). BUT, I've heard that it has bad consequences when a vacuum situation is produced, such as letting of the throttle at high rpms. I hope someone else can explain why

[nismo1003]

so can I just add a one way flow " adapter" or whatever it called ..so it only see boost but no vaccum.

[Nathan]

Beats me, I really dont understand the whole vacuum situation well enough to tell you

[nismo1003]

what's ur setup thou? to the turbo or to the throttle body? what about everyone on here ? what's ur setup

[Nathan]

I'm planning on using to the turbo, here's some info I found though: http://forums.nasioc.com/forum....html

Some info AGAINST the intake manifold: http://forums.nasioc.com/forum....htmlsorry for all the Nasioc links, they like to talk a lot it seems and its just what I ran across doing google searches

[C-Kwik]

Chances are, if you tested the pressure at the same place you are getting your wastegate signal from, you would see 8 psi there. The 7.5 psi is seen because of the pressure drop. Using the manifold signal will ensure you will see the actual boost setting of the wastegate at the manifold. The only real downside to referencing manifold pressure is that it will create more heat in the intercooler as it's more prone to a slight boost spike as it reaches peak boost. But the upside is slightly quicker spool-up since the wastegate will stay closed a bit longer. As long as you have a good working BOV, and vacuum issues will be negligible. Vacuum would only shut the wastegate immediately forcing all air through the turbine. With a system that has no BOV, this can kill a turbo a little quicker than running no BOV while using the compressor outlet as the reference pressure for the wastegate as surge spikes will force the wastegate to open and help slow the turbo a bit sooner.

[nof03]

could not have said it better. almost sounded like it was out of a book or something:D

[TurboKA37]

if you read the first post in the second link Nathan gave, i wonder how it was possible for that guy to have enough exhaust pressure to get his turbo to bush 15psi at part throttle. and at 15psi in the charge pipe he says he has 2psi in the manifold at part throttle. how would there only be 2 psi in the manifold with about 15psi on the other side of the partially open TB?

[Nathan]

I'm guessing he meant VERY partial throttle, such as barely opened at all. I think even 1/4 throttle would be enough to equalize the pressures pretty quickly. I too wondered how he was spooling the turbo up, however considering its a subie forum, if that was a stock turbo then they are decently small and spool decently quickly. Certainly faster than a t3/t04e.

[C-Kwik]

I didn't read the thread on the scoobie board until now, but as someone said in there, it comes down to having the proper type of BOV. One that works on a pressure differential will keep you from seeing boost spikes like that. I'm not sure if all BOV's work this way or not. I do know HKS says their Super-sequential one does.