Inliners International Forums General Discussion Blown and Injected TECH: How to lower PSI on wastegate acutator

I have a GM inline 250 with a Grand National T3 turbo. It has a factory HD wastegate that is rated at a factory PSI setting of 18-19 psi. On my test runs my boost would raise past 15psi and I would have to get off the throttle. For it to be safe, I wanted to lower it to a safe 5 psi so that I do not blow it up. I started to research how to lower PSI and came up with a mod that included a compression spring that "helped" the actuator rod extend. The directions were not very clear, so I decided to make a short video to visually explain how it works.

TECH: How to lower PSI on wastegate actuator

Good job! Good step in keeping all parts in the right place for the engine.
Start boost small and work up till your comfy. Tom

Boucher,
Nice, sorta what I had PM'd & sent you a pic about running an external spring.

Yours looks like a clean install..

I am not sure your actuator is a stock factory actuator if it goes to 18-19 psi, is that with tension on the wastegate valve?.
Meaning, do you have to pull the wastegate arm out to attach onto the wastegate arm?

Stock the GN's & T-Types run about 14 PSI of boost pressure.
I believe the factory ones are non adjustable, not sure.

If it is adjustable,you can set it to the lowest boost,, set the rod so there is no spring tension,that should net you aprrox 14 psi, but that would be too high still.

Your video on the actuator will work & guessing you want to start off w/ 5 psi?

You should be able to work your way up to 10 or so psi on pump gas & conservative timing.

Have you bought a intercooler & tubing kit yet? If not,,, get it, they are cheap on Ebay.

It's just a good way to cool down your intake charge & there are no moving parts on an Air to Air set-up.

An electric fan pushing through the intercooler is a nice addition for the stop & go traffic & stagging lanes if @ a track.



MBHD

Thats great, thanks for sharing!