CTS Turbo B5 Audi A4 High Flow Cat

The CTS B5 A4 1.8T High Flow Cat Pipe is the premier cat pipe for your Audi. Our test pipe is designed to seamlessly fit in place of your restrictive stock catalytic converter, which is situated immediately after the turbocharger.  Our test pipe features 3" stainless steel piping, smooth mandrel bends, two 02 sensor bungs with an option for a third.  Substantial power gains, improved exhaust flow and a more throaty sound are the main benefits from installing our test pipe.  Upon inspection you will notice a flare which is nearly 4", this flare then tapers to 3" and is designed to allow for optimal flow as the exhaust gas transitions from the turbocharger to the test pipe.  In addition to being one of the best bang for the buck performance upgrades for A4 owners our cat pipe is also a very attractive piece.  Each 3" test pipe is mandrel bent, hand tig welded.  Do you need an additional 02 bung for data logging?  Well that's no problem!  An additional 02 bung is included at no extra cost. Fitment: 1997-2001 B5 Audi A4 1.8T Product Details: T304 stainless steel construction Mandrel bent stainless steel Fully tig welded design Install hardware included Great power upgrade To remove the CEL that will occur, proper tuning software must be used. Use of stage 2 software upgrade is strongly recommended.

This part also goes by the following cross reference.

Cross Reference Part Number:

Fits These Vehicles 1 application

A4

Make	Model	Engine	Years
AUDI	A4 (B5)		1996–2001

Fitment data last updated: 2026-09-30

✓ Fits 1 vehicle applications Check vehicle fitment before ordering View fitment