Hi Everyone

I am experiencing some boost creep with my current setup.
It holds 7 psi until 7000rpm and then it creeps to 19psi over 7000rpm.
I am running pump gas so do not want to boost more than 14psi on 95 Octane.
I currently have a cheap chinese manifold on the car and the wastegate priority is incorrect.

I am going to get a custom manifold built soon to correct all of this.

Do you guys prefer 2x wastegates over 1 wastegate?
I am thinking of running a single 45mm/50mm wastegate and welding it on to the exhaust housing for optimum boost control.

Pic of current exhaust manifold below

 

Most important part of this whole thing is what turbo are you using...

 

I will be putting in a GT35r from Rx7store. Bought the car with that turbo. Oil seals were shot so got a new core, want to get a bigger exhaust housing put on it and then run that turbo. Currently got a gtx45 with 1.58 AR rear housing. Way too much turbo for my application

 

That's a turbo that will get you into space... what gate are you currently using? With the turbo you're wanting to use, a single 50mm will be plenty. Your current issue is likely the jet engine you have just being too much for the current gate to handle

 

External waste gates are a nightmare and I can't imagine having 2.

You may be too deep to change gears, but the internal wastegated B-W 8374's are total winners.

Dale

 

Also want to mention whatever your boost control set up is.. if you have it. If you're just going off spring pressure then that's contributing to this situation as well.

 

Your issue is the manifold and the wastegate runner design. I'm running a Gleaseman manifold with dual 40mm wastegates and have no issues controlling 8 psi to redline or 30 psi. This is with a 4 port solenoid and a GT35 sized turbo.

 

Well no.... the reason you have the control you have is because of the combination of parts you have there. Switch to a single 40mm gate with a 15psi spring on the same manifold with a gt40 and see how difficult it is to control boost.

We don't have all the information we need to determine the issue but im willing to bet just the same its a combination of the things he's using. His massive turbo and likely small wastegate in addition to whatever he's using or not using for boost control is whats causing such an issue with his boost. Just going with an appropriately sized turbo would likely fix his boost problem entirely.

 

100% correct. There is not much you can do with that manifold. No offense but it's garbage. If you are using a twin scroll turbo, a high quality dual gate manifold is going to work great and have way better control then a single gate manifold even if it is actually designed well.

 

No boost controller connected. Running off Spring pressure.

 

Yea...you have a combination of issues here. What spring is in your wastegate and what size is it?

 

get a proper manifold and throw this garbage in the trash were it belongs.

 

The less boost you try to run and the less exhaust restriction, the more wastegate flow you need.

 

I have a 60mm wastegate with a 10 or 11psi spring in it.