Wastegate GTP38R/PowerMax

DEEZUZ

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First off, when did the GTP38R get dubbed "PowerMax"? I always knew it as just the GTP38R...?


I have installed a few of these, even on my truck, but I did one yesterday and had noticed something weird about the waste gate. I had put about 5 PSI to the gate and it started to open and by about 15 psi it was fully open...

I thought this was weird, so I got on the phone with our sister shop and see what they thought and they informed me that it should start opening right at about 5.5 PSI...

Ok. How does this work when its in the truck and under load? I still hooked up the red line since its a customers truck. Does the regulating valve have ultimate say in when it opens? It seems to me the damn gate would be open all the time if it start to open at 5 psi....

On my truck I just left is disconnected...
 

PSD POWER007

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When I had mine, I tightened the actuator arm all the way down so that it couldn't open. On anything less than a 180cc injector, the gate isn't really needed. I made around 38 psi and exhaust back pressure was always within 8-10 psi in the upper boost range. But usually stayed bretty close to 1:1. This is with 180/80's
If the gate is opening that soon, I'd guess exhaust pressure over comes the spring pressure pretty easily and EGTs get up and you probably won't see more than 15 psi of boost.
 

Justin@DP-Tuner

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First off, when did the GTP38R get dubbed "PowerMax"? I always knew it as just the GTP38R...?


I have installed a few of these, even on my truck, but I did one yesterday and had noticed something weird about the waste gate. I had put about 5 PSI to the gate and it started to open and by about 15 psi it was fully open...

I thought this was weird, so I got on the phone with our sister shop and see what they thought and they informed me that it should start opening right at about 5.5 PSI...

Ok. How does this work when its in the truck and under load? I still hooked up the red line since its a customers truck. Does the regulating valve have ultimate say in when it opens? It seems to me the damn gate would be open all the time if it start to open at 5 psi....

On my truck I just left is disconnected...

Every GTP38R comes with the wastegate set extremely loose. We get calls about this all the time. Mostly people wondering why they can't build boost and higher EGT's.

Not sure why Garrett is setting them so loose. IIRC when I got mine 4 years ago, it started opening at about 15psi.
 

DEEZUZ

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Well the truck felt good and he had crappy tunes so I let it go loose
 

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