Well that would explain it... Of COURSE you're seeing high boost with a fully modified exhaust. And that is boost creep, by the way. Your exhaust is flowing too efficiently for the computer and boost pill to maintain boost at ~10-11 psi. When you stomp down on the gas, you're "overriding" the stock boost control, essentially.

I'm hoping (from your reported 13 psi) that you still have a stock intercooler, and/or intake because if you had a large SMIC or FMIC, you'd probably be spiking to 18+ psi and that'd be all she wrote.

You need a boost controller of some type or a reprogrammed ECU (or both), and you need them YESTERDAY. Unless you've got the fuel to back it up, or some way to control it, you're living on borrowed time.

 

OK this post started out as just another rather stupid nubie comment and got very good. Now I’m hoping to move it into the final phase many threads never get to... options to fix the problem we diagnosed…

In this specific case we have a car with stock fuel system, stock turbo and intake, but fully free flowing exhaust. The problem is his boost is uncontrolled and creeping beyond it's set limits. This is caused by air taking the path of least resistance as it always does. The air from his exhaust would rather go through the compressor then try squeezing through the hole in his wastegate... The problem with that is it causes an over boost condition and there is not adequate fuel to keep the engine happy.

What are the ways to fix the wastegate problem? I can think of 2 that I’m sure will work and be moral practice on an RX-7.
Enlarge the wastegate flapper and hole.
This will effectively change the path of least resistance from through the turbine to through the wastegate and bring the system back into control. now if not enlarged enough, future mods on the intake may switch the system back out of control causing creep.

Another viable option, have more restriction in the exhaust. This will cause greater backpressure on the turbo making it harder to turn the turbine during high flow conditions and changing the path of least resistance, to through the less restrictive wastegate...

Aside from restricting the intake on the secondary turbo, I don’t know any other options. Does anyone else know of any?

The first option is probably the best overall solution.

Option 2 is the easiest and for now most cost effective. The restriction in the exhaust could be as simple as a 2.75" hole in a plate inserted at the flange for the midpipe.

 

Hahaha

 

your best remedy is just to run more boost and get your fuel mods in order, ie. new ecu with some sort of boost controller. Buy teh PFC or AEM and be done with it, but don't drive it like that.