Sputtering/stumbling after exhaust install -

[00Psst]

I recently installed at Jetex exhaust on my 99 Passat w/ AEB engine. I have a high flow cat, stock DP for now due to a miscommunication, and then 2.5" Jetex exhaust. I also have a K04 turbo, 5 bar fpr, stock injectors and UPsolute k04 software.

Since installing the exhaust, I have a nasty case of sputtering/stumbling/hesitation under hard acceleration. It seems to not be as severe if I am tip shifting in comparison to when I am in full auto shift mode.  Typically the stumbling comes when in 2nd, 3rd or 4th gear, and accelerating hard with boost levels above 12psi.  With my current set up I typcially can hold 18psi and peak at 21psi.  

Any ideas as to what might be causing this? I am going to change my plugs for colder temp range ones this weekend, and I'm thinking it can't hurt to clean the MAF and throttle body but any other ideas, suggestions are appreciated.  I'm going to do some data logs with my vagcom tonight hopefully to see if shows anything.  I'm thinking it might be a fuel issue but I am far from being an expert on this.

TIA.

Mike

[enginerd]

Whats with the 5 bar FPR? I have seen this from GIAC ko4 setups and now upsolute. 5 bar + 20 Psi of boost = 92.5 Psi fuel pressure. The stock fuel pump starts relieving pressure over 90 psi, and doesn't reseat properly untill you turn the pump off.

[00Psst]

Whats with the 5 bar FPR? I have seen this from GIAC ko4 setups and now upsolute. 5 bar + 20 Psi of boost = 92.5 Psi fuel pressure. The stock fuel pump starts relieving pressure over 90 psi, and doesn't reseat properly untill you turn the pump off.

Forgive my stupidity but are you saying that I'm starving for fuel then?  Would bigger injectors help here?  Do I need a larger fuel pump?  

When I went with the K04, I already had UPsolute's software for my K03 and based on the recommendation from UP opted for the 5bar fpr rather than bigger injectors.  The goal was more power and a reliable set up that I wouldn't have to worry about an adjustable FPR with.  Was I steered wrong on this do you think?

[enginerd]

5 bar FPR is no good for the stock pump. when you spike over 20 lbs, the pump has a relief valve that pops open and vents fuel back to tank.

There are several ways to add fuel a 5 bar FPR is not the way.

Bigger injectors or better software. I logged some upsolute stuff and it was total shit. lean as hell and then vomiting fuel. piss poor tuning.