Boost issues
 

I'm having boost issues. The boost is going too high. I just replaced my manifold because of an exhaust leak. I also checked my wastegate while I was changing the manifold and noticed it was missing the valve seat. I purchased a new valve seat and also changed out the spring to a Large blue and small blue (20psi) before I had a large Red spring (10psi). The funny thing is this started happening with the large red in there. It used to hold a steady 18psi with my boost controller on and on real cold days it would creep to 20psi and just hold...then eventually it would go to really high amounts to where ignition cut would save me (luckily I have mechanical preturbo water/meth injection) so I'm assuming that saved my ass...knock was still in the low 20s after this fiasco. I have the 20psi spring in there now, completely turned off the boost controller so it should be on just wastegate spring pressure, but it spiked again to ignition cut. What could cause this problem? I have a Greddy Profec B spec 2 boost controller and a Tial v44 wastegate. Thanks in advance for the help.

What boost level is your ign cut at?

around 28psi, although last night boost on the power fc read 2.00 so that's around 30psi, this is all happening at around 4200rpm

How did you connect the wastegate to your system? vacuum line wise? When are you experiencing boost cut (RPM wise)?

Are you running brick wall right into it at low rpms? are you slowly building pressure and hitting cut?

It doesn't seem to be a pattern as far as when it hits it, I haven't tried to floor it much now that I'm experiencing this problem constantly. If I roll into the throttle and build the boost up with the boost controller off and a 20psi spring, it'll still get to 25psi before I decide to let off to protect my motor. Its confusing me because it should only be at wastegate spring when everything is turned off. Plus when I took apart the wastegate the diaphragm was intact and everything was operating smoothly when I was moving the parts with my hand.

Do you have any leaks or cracks in your vacuum/boost lines yo the wg?

I'm not sure, I'll check in a bit when I get back home. I used silicone lines for those lines.

With the new 20PSI spring in there....has the boost ever been controlled? Perhaps the spring is too much for your application?

Did you plumb the vacuum hose directly to the wastegate (eliminate the variable of the boost controller)?

I would throw in a really weak spring in your wastegate if you have one and bypass the boost controller. If that works and holds boost steady you know the wastegate is functioning properly. I would then connect the boost controller and check function of that (with a less rated spring you can do all this at low PSI and no harm to motor). Then if that checks out, I would put in the other higher spring and see what happens.

I'll try this hopefully tomorrow, I need to get this sorted out before I get retuned for my higher boost goals

I don't know how I missed this when I took about the wastegate the first time, but there is a 1/4 inch slit in the diaphragm...I'm assuming that's the problem. So now I'm searching for a replacement diaphragm. Thanks for the help everyone.
http://sphotos-b.xx.fbcdn.net/hphoto...22402524_n.jpg

Good catch... Thats more than likely your problem

This fix it?

Sorry for the late response I didn't have a chance to test it out due to all the rain until last night. Yep, this fixed the problem, I put the 20psi spring back in and it holds at 21psi in forth gear in cold weather on just the spring...boost controller off. Thanks for the help everyone.