Anyone knows what would be a good diameter for a restrictor plate in the exhaust to avoid boost creep ?

I installed intake system this past weekend and with the setup in my sig I am having trouble keeping boost below 10psi, even with ProfecB dialed all the way back (whereas before it was set to 4 o'clock).

I read that 2 1/4" diameter worked for some (suprfast), but would like to get a second opinion. I will most likely install a high-flow cat next year.

 

On my FC, the DSV (stock boost controller) wasn't working, and I ran 5.5 lbs with an intake and full turbo-back exhaust. The wastegate was sprung at 5.5 psi.

I would try that, see if you can disable the stock boost controller (is there one?) and run it at the psi that the wastegate is sprung at.

 

Check this thread:
https://www.rx7club.com/forum/showth...threadid=26389

 

I should add that this isn't going to stop "creep" really (well, it might, as there's less air coming out at 5 lbs than 8 lbs), but it's going to at a minimum start you creeping from a lower psi than if you started creeping higher up, and you might end at 10 psi with a long 4th gear run or something.

 

My 2.25" exhaust restrictor plates I made to go after the DP didnt really help much.
After I put on the Resonated MP it solved the problem.

 

Port the waste gate and cure the problem . Why spend money on go fast parts and then choke it back down .

 

Nope, I don't want to port the wastegate atm.

 

I had a 2" restrictor in my exhaust for a while. It worked pretty well except when it was below 40F.

 

I was going to try the 2" diameter hole (since the 2.25" didnt help much) but again, as I previously stated. Get the Resonated MP. its anomoly! It flows well and stopped the spiking.

 

I didn't know resonated midpipe would stop spiking and boos creep. Can it be manually made ? Isn't it just a normal midpide with a hollow mid-muffler welded to it ? (sort of like hollowing the main cat)

 

Its a muffler with 3" piping going into it.
I was stoked by it.