OverBOOSTing

hmmm, seems I have an overboost issue and it seems to be more of a problem then crazy levels of boost. Basically when it goes crazy (pretty much always) it seems to overboost to about 17psi and then my engine sort of stutters (maybe a fuel cut) requiring me to back off. This means I've never even hit redline in it yet as it normally overboosts way before then (say at least by 6k) and then the engine stutter.

This morning to see if it was overboosting or if my boost controller was just set too high I turned it down a whole third of what it previously was, but it really made no difference. So following that I decided that it must be overboosting and that must be what is causing the stutter. I'm guessing (based on talking to REACT members) that it could be the MircoTECH detecting the overboost and as a result cutting fuel to try and protect it.

So why would it be overboosting? Well it's an S4 high flow turbo with a 3" straight through exhaust system with no catalytic converter. Now S4 turbos have very small wastegates and are thereby notorious for overboosting - it makes me wonder why ppl high flow them. That combined with the free flowing exhaust is just making it crazy.

My current plan is yet decided but there are two options as I see it. Get a new turbo (Garret) with internal wastegate that will be more suitable; or modify my current turbo so that the internal wastegate is disabled (welded shut) and then rigged up with an external one. This second option could end up costing as much as the first option and the first seems more elegant. However the cost of the first one could be blown out if I need to redo tubing (exhaust and/or intercooler). So just checking out the options for now, but might also have a chat with my mechanic - when I get the clutch fixed.

(Oh yeah, I realise an option might be to modify my exhaust, but that doesn't really seem the best idea when I'd then have to sacrafice potential power. :D )