No, the waste gate has an internal 5psi spring. The N75 is what keeps the waste gate closed, allowing the turbo to produce more than 5psi.

 

N75 is also what opens the wastegate...

It looks like if there was no power to the N75 it would be in a "no flow state" which would make overboosting impossible.

http://forums.audiworld.com/showthread.php?t=1476692

 

Well first off your a ndbw car which doesn't have a MAP sensor, so it is impossible for your car to go into limp mode because of a over boost issue.

I am very suprised no one else here pointed that fact out and the thread is nearly a week old.

Also there is no such thing as a longitude K03S. All you have is an updated version of your stock K03, doesn't really make more power then a stock ndbw K03.

Incorrect. You dont unplug the harness you bypass the N75 by putting the hose from the turbo and the hose from the WG actuator together. This allows the pressure to go directly to the actuator. Doing this will tell you exactly how much pressure is needed to open the WG by how much boost you get on your gauge while driving WOT.

 

According to Borg-Warner there is no such thing as a K03S period. But I think most people knew what I was talking about. It's not the identical to the stock K03. It has a different actuator and different turbine blades. Either way the car is very jumpy, jerky and overboosts since i Installed the new turbo... I'm Looking into a new N75 as we speak.

 

The K03S everyone talkes about is a K03 on the Transverse 1.8t.

The 2001+ A4 owners just call the their turbo a K03S because it has a different part number and thought it was the reason their car made 170hp stock. LOL

You might want to make sure your vac line isn't kinked, pinched or plugged. The K03 you have shouldn't over boost that bad, there are plenty of other ndbw A4 owners that have used the newer K03 on their car without any issues. Even my K03 off my 2000 dbw went onto a ndbw car and ran perfectly fine and I made 250chp with that turbo which is more then any other A4 owner has made with a K03.

What you seem to be having a problem is the fact that your car isn't setup for that much boost, most likely running very lean if your still running the stock injectors which are smaller then the injectors used on the DBW cars. Your stock injectors are 210cc vs 270cc for the dbw cars. This is why the tunes for he ndbw cars were at a much lower boost level then the DBW cars could be pushed at. The ndbw cars just didn't have enough fuel with the stock injectors to support really high boost.

 

Mike - You gave me the info I was looking for -Thank you!

This is so true -LOL!!


That's impressive. Are the cooling systems different on ndbw vs dbw?

 

Cooling system is the same. Sad part is our radiator is pretty much used on the S4 2.7t which is why they come stock with 3 fans and they tend to over heat when you put a FMIC on them.