KermaTDI 2.5 Inch Stainless "J" Downpipe for Mk4 TDI

What It Is
A 2.5 inch downpipe made from 304 stainless steel, built in the UK, that serves as the starting point for a full turbo-back exhaust on Mk4 TDI cars. It uses a precision ball and socket flange, similar to the style BMW uses, so the pipe can be adjusted up, down, left, or right for a clean fit before final installation.

What's Included

• 36 inch section of 2.5 inch 304 stainless straight pipe, useful on its own for a straight-pipe, resonator, or high-flow cat install
• 2.5 inch to 2.25 inch stainless reducer, so the downpipe connects to factory cat or cat-back piping if you're not ready to upgrade the rest of the exhaust yet
• O2 sensor bung built in for BEW engines, so the same downpipe works on either ALH or BEW cars

Why the Ball and Socket Flange Matters
Rigid flanges only line up one way. This adjustable flange lets you fine-tune the pipe's angle during install, which makes fitment easier and more forgiving, especially if you're building the exhaust in stages.

Fitment

• 1999-2003 Mk4 Golf, Jetta, and New Beetle TDI with the ALH engine code
• 2004-2006 Mk4 Golf and New Beetle TDI, and 2004-2005.5 Jetta TDI, with the BEW engine code
• 2002-2006 Jetta Wagon TDI with either ALH or BEW
• Pre-2007 vehicles only. Not for cars equipped with a Diesel Particulate Filter
• Not CARB certified for use in California

Building a Full System
This downpipe is meant to be the first piece of a complete 2.5 inch turbo-back exhaust. Add a resonator, high-flow catalytic converter, and cat-back piping as your budget and goals allow, KermaTDI recommends its own 2.5 inch Magnaflow high-flow cat as the next step.

FAQ

Will this fit my car if it has a DPF?
No. This downpipe is for pre-2007 Mk4 TDI models without a Diesel Particulate Filter. DPF-equipped cars need a different setup.

Does one downpipe work for both ALH and BEW engines?
Yes. It includes the O2 sensor bung needed for BEW cars, so the same part fits either engine code.

Can I run this with my factory catalytic converter?
Yes. The included 2.5 inch to 2.25 inch reducer lets you connect to factory cat or cat-back piping, so you can upgrade the rest of the exhaust later.

Is this legal in California?
No. This part is not CARB certified for use in California.

Do I need anything else to install this?
Just the downpipe bolts up on its own. If you want a full turbo-back system, add a resonator, high-flow cat, and cat-back piping separately.