Hello all,

I know this may be better suited in the "engine/turbo/drivetrain" forum, but 99% of those guys have never really driven their evo so I figured this would be a better forum.

I am currently running a full-race T4 twinscroll manifold with twin TiAL MVS wastegates. I run a hallman boost controller with the soft spring.

in the wastegates I am running 20 lbs of spring pressure.

with this setup I am getting some pretty large boost spikes while the motor is still cool (regular operating temp for the street). when the motor heats up I do not have this problem.

I was wondering if anyone else has run into this or a similar problem? I have a theory that as the wastegates heat soak, the springs become softer which in turn reduces my boost spikes.

I think that if I reduce the spring on the wastegate and rely more on the boost controller that this might reduce this problem.

FYI my target boost is 22-23 psi.

this graph is from a 20 minute session at NJMP

 

I had a Hallman MBC once. It stuck wide open and blew my head gasket. When I was having that diagnosed and replaced, the shop told me they see that quite a bit with the Hallman. So just my .02. I'm not running the $70 AMS one; super simplistic.

Some tuners will let the car spike and low boost to get the torque going. Have you asked your tuner about this? Or are you open-sourced?

 

I am the tuner lol

I usually do let the car boost spike to get the torque up, but not a 6-8 psi spike.

Noted about the Hallman, ill have to keep an eye on it.

 

Truthiness.

I tried running the stiffer springs, which required two, and didn't like it. I think I settled on the 10 lb or 14 lb single spring in the wastegate.

 

ya, im gonna pull one of the springs out, which will net me a 14lbs wastegate