Sorry to thread jump here, I'm running an EFR 8374 with the .92 IWG on my 3.0ltr R32 GT-R and having similar problems to what Anton has with the standard BW hard canister Wastegate, I can only get to 20psi boost due to high back pressure (still a little unsure how this is so, I have a straight through 3.5" custom exhaust....?)
When we tried winding more preload on the factory hard WG spring, we ended up with boost spikes, and could only get to 20psi with the BC at 100% load.
Thread to my car is here if you want to read up on it
I have tried to purchase a Perrin WG, but they are not making them yet, I have bought a Forge dual port WG off Full-Race and have a Mac 4 port BC to see if it will fix the problem.
Question for Anton, I've read through the whole thread on here and Your build thread, and saw that had problems with the Forge WG leaking, but then before you put the Mac 4 port on you were having similar problems with the Perrin unit dropping boost......due to being unable to get a Perrin WG, do you think with the Mac 4 port and the Forge with the Red Spring I might be able to run the same dual boost setting numbers you are?
Thanks for your time.