Hey all, I have been reading up on porting wastegates. I have a 1987 Turbo II, will be porting the gate for the extra reliability. I am still confused on some things though.

• If i put in a 3" exhaust on, will the boost still creep?
• Will the boost build over to stock 6-9 psi? If so is there anything I can do to limit it, I do not want to upgrade my fuel system yet.

 

now that i think about it, i've never run a complete 3" exhaust on an S4 turbo. around here, we seem to end up putting cats on, because that way we get power and it smogs.
it probably creeps enough to hit the fuel cut, but not enough that you need a fuel system.

TL;DR? a small restriction in the exhaust will keep boost creep under control and doesn't hurt power.

if you do decide to port the wastegate there are plenty of guides, when i put mine together i ground the hole bigger like everyone does, and i also cleaned up all the radii. and the final thing is to look at how far the WG can open, and if needed notch the rear cover

 

With a full 3" exhaust, you will get boost creep and hit fuel cut. If you don't want to upgrade all the other systems to support the higher boost and power levels you need to add more restriction upstream or downstream of the engine.

You can try putting on the stock cat to your system if it still fits, or use an OEM cat that will fit. Even then it may not be enough restriction. I couldn't find a cat that fit my 3" exhaust so I have been running a 3" test pipe with a 1" restrictor plate. Everything else is stock and boost levels don't creep and I don't get anymore fuel cut.

 

Waste gate porting guide.
FC3S Pro v2.0: How-To - Zenki wastegate porting

You could upgrade the fuel pump. and make sure you have a good new fuel filter in place. and clean injectors will help provide just enough fuel.
I ran mine for a while this way but in the end went Haltech.
the FCD will only help so much.

The performance gains you get are huge with Exhaust changes compared to any other car. So be careful on pushing it too hard.