So I've been driving with 3" exhaust for a while and in turn hitting fuel cut.
I did a little experiment. I unhooked the linkage from the WG and drove around. Naturally it took a little longer to build boost but, the N/A block kind of makes up for it.

With the WG hooked up normal I can see on my boost gauge that it opens at around 6-7 PSI and then creeps like crazy to the fuel cut. Now, with the linkage unhooked it acts the gauge reads about 8-9 PSI then starts to creep. But the nice thing (and the reason for doing this) is that by the time I'm going to hit the cut I'm at 7000 RPM and ready to shift. As opposed to hitting the fuel cut at 5000RPM.

So the question is.....is it possible that my WG isn't opening far enough with the linkage hooked up or is that just the way it is?

 

you're better off using some sort of fuel cut defenser...

 

I'm planning on getting an Rrtek chip but even after that I don't want to boost much more than 8 or 9 PSI.

And another question The S5 turbo has a better wastegate. Yes?
Would it be able to bypass enough exhaust to keep my boost down?
Or do I need an external wastegate?

 

you need an external wastegate OR possibly port the stock wastegate enough to releive the extra boost pressure. That is why it creeps up the stock "hole" is too small to relieve the rpessure.

Had to do this on a different type of engine after we put on a better downpipe.

 

The problem with an external WG is that I'll need a different manifold therefore a different turbo!!!!

 

Yeah just port your wastegate.

 

i thought the s5 mainifold was design to help prevent boost creep, i thought that was a more common problem in s4's

 

I have an S4. I'm planning on getting an S5 turbo/manifold.

 

it's not worth it. Just port your s4 wastegate. If you port it correctly you will have no problems