SI2NV

Help!!! Well I just put my Apexi AVC-R boost controller. I set the boost about 6psi what is stock for the wastegate a start point. The turbo is a greddy 18G on my 99 si. So I went for a ride to test it out. The turbo holds at 6psi but then around 6500rpm it start to build boost again to about 10psi. So I turned the boost controller off and it still did the same thing. Then I bypass the controller and hocked it the way it was before at the back of the manifold. Guess what it did the some thing. With the controller I have it hocked up after the intercooler before the throttle body Apexi told me that's the best place. Doe's anyone how I can fix the problem. I hope its something that I over looked. O one other thing about 6 months me and friend where turning up the boost buy adjusting the actuator the cheap way. It got to a point where we turned it in to much. Where it did the same thing 8psi then went to about 11psi. I set it back the way greddy had it and it was fine again.

Gotballcancer

I have an greddy kit on my itr and it creeps and spikes all the time. There is no real pattern to it and I have tried numerous ebc and mbc's. I'm going to weld in a 38mm tial onto the greddy manifold.

SI2NV

That's the thing before it would hold at 6psi all the way to redline. There was no creep a little bit of spike but no more then 1psi. But now as soon as 6500rpm comes around give or take 100rpm it start to build again boost not cool. Its like clock work. Its one hell of a ride first you get hit with the 6psi then VTEC last but not least the 10psi kicks in. Same thing is not right.

Gotballcancer

yes you are right and that something is the 28mm wastegate opening. Port it or go external. Something else that is wierd about the greddy setup is that for 4 months during the summer I was able to run 14 psi with a 3 psi spike but absolutely no creep. All of a sudden nothing I do can remedy the problem. Best of luck to you.