S3 stage 1 with sports cat

[Pooley1]

Hi, Recently I have bought and fitted a full Milltek exhaust system with a sports cat.

I’ve been driving the car for a couple of months but just lately I’ve had an error code come up on the when I put my foot down I get an error message saying “Drive system fault” and it goes into limp mode.

I’ve taken the car to the garage and they say it’s saying “turbo overboost”. I will find out more shortly as the car is going in to get looked at.

what I want to know it could this issue be something to do with the sports cat? I’ve been told I need to go stage 2 by some people but I’d rather not do this as stage 1 seems sufficient to me and I don’t want to spend a fortune.

Is anyone else running a sports Cat with stage 1?

 

[Damo S]

A sports cat in theory is not compatible with a stage 1 which is for cars that are otherwise standard in all other areas (although it doesnt have to be). The reason being that the sports cat affects the readings of the post cat lambda sensor and it can throw a wobbly. Certainly on mine (stage 2) the post cat lambda has been disabled as I can see in the diagnostic app I use (even though I dont have a sports cat but that is just a standard thing done as part of their stage 2 remap).

I'm not sure about this turbo overboost issue they are talking about, but perhaps that is a problem as well.

 

[Houston]

I would assume that the overboost could likely be as a result of the improved flow from the sports cat over the stock one allowing it to spike and cause it to produce boost pressure above the currently deemed safe level.