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PROFILE

The ARM E-Series N55 Downpipe is designed to increase power and performance of your N55 equipped BMW by optimizing exhaust flow and reducing back pressure. 
Upgrading the downpipe on  your N55 increases power, improves turbo spool, and allows you to run stage 2+ tuning, all while making your 135i or 335i sound better.  The ARM N55 Downpipe is compatible with OEM and aftermarket midpipes, designed for a direct fit with the 80mm V-Band flange that accommodates both standard and upgraded turbo setups.  An N55 downpipe upgrade is the first hardware upgrade every N55 owner should invest in for more power!   

IMPROVED EXHAUST SOUND

In addition to helping your N55 make more power and torque, the ARM N55 Downpipe significantly improves the exhaust sound.  Thanks to it’s 4.5″ middle section, the ARM N55 Downpipe will produce a deeper and more aggressive exhaust note, especially under full throttle and on cold starts. 

CONSTRUCTION

The ARM N55 Downpipe is built with high-quality TIG welded SS304 stainless steel.  It begins with a precision CNC machined 80mm V-Band flange which fits both the OEM N55 turbo as well as many N55 turbo upgrades.  The V-Band flange is welded directly to a flex section to alleviate stress from the N55’s turbo during aggressive driving.  

One unique feature of the ARM N55 Downpipe is the 4.5″ middle section, which transforms the sound of your N55 beyond a standard 3″ downpipe upgrade.  The downpipe transitions from the 4.5″ diameter at the middle section to dual 2.5″ diameter flanges at the midpipe connection.  This allows for seamless integration with OEM and aftermarket midpipes that fit the OEM N55 downpipe.

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.  

IN THE BOX

FITMENT GUIDE