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CONSTRUCTION

The ARM N55 Catless Downpipe is built with mandrel bent SS304 stainless steel and backed by the ARM Motorsports Lifetime Warranty.  The ARM N55 Downpipe starts with a 4" diameter at the precision CNC machined turbo v-band connection and gradually reduces to a flared joint to optimize exhaust flow while matching up to the stock midpipe v-band connection perfectly.    

The ARM N55 Downpipe features two O2 sensor bungs to allow for reinstallation of the OEM oxygen sensors.  The O2 sensor bungs are located higher up on the ARM downpipe to avoid stretching the O2 sensor wires during installation.  A tune or CEL Delete will be required to avoid a check engine light from displaying on instrument panel.

FLASHING STAGE 2+

 By improving exhaust flow the ARM N55 Downpipe prepares your F-Series BMW for the higher boost tunes.  If you already have a software program for your N55 chances are these tune files are already pre-loaded into your software waiting for you to flash after your downpipe installation.  Most tunes require an upgraded downpipe and FMIC to run properly, if you don't also have an intercooler upgrade check out our F3X FMIC.  Stage 2 N55's can see power around 400whp and 400wtq.

IMPROVED EXHAUST SOUND

In addition to helping your N55 make more power and torque, it significantly improves the exhaust sound.  While the downpipe only accounts for approximately 20% of the entire exhaust system, upgrading it will produce a noticeable increase in volume, especially under full throttle and on cold starts.  If you're looking for a more extreme sound, you can pair the ARM downpipe will a full exhaust.  The ARM N55 downpipe is compatible with any aftermarket exhaust that can connect to the stock N55 downpipe.

IN THE BOX

FITMENT GUIDE