Thread: Only 5psi?

Avenir setup in a b14, stock everything with a jwt ecu (other than the intake of course).

I just rerouted the wastegate vacuum line to the turbo outlet and now my boost gauge only reads 5psi. Before, it was routed to the intake mani & read 8 psi (my gauge reads 1 psi LOW).

The throttle response feels better, less lag, car feels faster.... Just wondering why it reads 5 psi now?

Is there any way to adjust the stock wastegate?

Oh, and boost gauge is routed off the fpr vacuum line. Still, 8 psi before, 5 psi now.

You usually see higher PSI's closer to the compressor. This is why it's suggested to use a connection closer to the intake manifold.

^+1.

stratton.

^+2. good advice vad

Because you are sending higher pressure to the wastegate, yet still reading from the same place.

When the air passes through the charge pipes and intercooler it cools and the pressure drops. Also, there is an inevitable additional pressure drop when the air passes through the relatively turbulent intercooler.

This means that the pressure at the outlet of the turbo is usually a couple psi higher than the pressure seen at the throttle body or intake manifold.

You used to be sending pressure from around the throttle body to your wastegate. Once you got about 8 psi the wastegate would open. However, you'd always had about 11 psi readings at the outlet of the turbo. You following me?

So now you have fed the wastegate from the higher pressure area. Once that area gets to 8 psi your wastegate opens, yet you're reading your boost pressure from around the intake manifold so you're going to see about 3 psi less pressure there. That is why you're seeing 5 psi.

If you can, I'd recommend getting your boost gauge signal from somewhere else. The FPR vacuum line is too important and sensitive to mess with both introducing changes of failure and modifying the signals the FPR gets.

I see, so its basically the same pressure, just reading from 2 ends of the intake....

You are actually running 3 psi less boost than you were before. You are doing that, because you're telling the wastegate to open sooner than it did before, by sending it a signal from a higher pressure source than you did before.

I need a mbc haha. Maybe Ill take the regulator off the end of my air compressor and use that for free.