ARM Motorsports Catless Downpipes
F01 · F02 750i · 750Li · Alpina B7 · F06 · F07 · F10 · F12 · F13 550i · 650i · Alpina B6 | 4.4L Turbo V8 [N63]

ARM Motorsports' new N63/N63TU downpipes for the 4.4L V8 Twin-Turbo powered 550i allows you to take your N63/N63TU engine to the next level. Made with full 304 Stainless Steel and 3" construction these downpipes provide a significant increase in power and torque over the OEM catted downpipes. In addition to the massive power gains, these downpipes open up an incredible exhaust sound from the turbocharged V8 that will shock and awe onlookers!

By replacing the OEM downpipes with the ARM Catless Downpipes, you'll be removing the restriction from the OEM converters which will reduce exhaust back-pressure and allow the exhaust from the turbochargers to flow more freely. This increase in exhaust flow allows for the turbos to spool faster, increasing power and torque throughout the RPM range of your 550i. Our test car was an N63-equipped 2012 550i GT optioned with the all-wheel drive xDrive system. It came with a Stage 2 tune installed making our baseline numbers 412awhp and 482awtq. After installing the ARM 3" Downpipes and Cold Air Intake, we recorded gains of 48whp and 43wtq over the standard Stage 2 tune for an impressive total of 460awhp and 525awtq.

As with all BMW's, everything is designed to fit in a very compact space, and the N63/N63TU 550i downpipes are no exception. However, BMW did an excellent job of engineering the downpipes to flow in the smoothest path from the turbocharges down to the mid pipe section. Our downpipes essentially followed the same exhaust flow path with a few small modifications to make installation easier. Consequently, the ARM N63/N63TU downpipes mount up to the turbos and midpipes with the same precision as you would expect from the factory 550i downpipes.

The ARM N63/N63TU 550i downpipes come with a flex section to relieve stress between the upper and lower portion of the downpipe from engine movement during aggressive driving. To further reduce any tension on the turbochargers, we have developed an upper and lower bracket, one being on the section of pipe above the flex joint where it secures to the engine block, and the other on the lower portion below the flex joint where it is secured to the transmission housing. These are the same points BMW designed their factory 550i downpipes to be secured, which means a strong and lasting connection safe for all the components on the vehicle.

The ARM N63/N63TU 550i Downpipes utilize two O2 sensor bungs on each downpipe to allow for reinstalling the O2 sensors in their factory locations. This not only allows for the accommodation of the factory heat shield, but also allows the correct O2 sensor data to be sent to the DME. This is essential for the DME to properly monitor the parameters in the exhaust that are critical to having your 550i motor running smoothly. The installation of catless downpipes on your N63/N63TU will result in an inevitable check engine light (CEL) as the DME will detect that emissions are not being burnt-up by the OEM catalyst. To remove this CEL without having to tune it out we offer the CEL Delete Kit which is comprised of two O2 sensor spacers specifically calibrated to comply with BMW's parameters for a functioning catalyst. These install into the post-catalyst O2 sensor bungs on each N63 Downpipe, effectively removing the CEL that would otherwise appear.

The ARM N63/TU Catless Downpipes are compatible with the cars on the list below that have a slip-fit style OEM downpipe only. The most reliable and accurate way is to simply look under your vehicle for the connection point between the downpipe and mid pipe. In most cases, this is visible without having to remove any undertrays or covers. If your connections look like the images below and your car is listed on the fitment chart, these will fit your vehicle.

Features:

• Gain up to +43whp / 48wtq
• Improved Turbo Spool
• Enhanced Exhaust Note
• Fully Reversible

What's Included:

• ARM Motorsports Catless Downpipes