Active Autowerke BMW N55 F3X M235I 335I 435I F87 M2 Catted Downpipe

Active Autowerke BMW N55 Downpipe 

BMW introduced a new valvetronic, single turbo version of its direct-injection engine for the F-Chassis models beginning in 2012. The Active Autowerke N55 downpipe for the M235i, 335i, 435i and M2 helps unleash some of the potential that is restricted by the OEM downpipe.

Turbochargers are powered by spent exhaust gases created during the combustion process. The quicker these gases are evacuated, the better. Unfortunately, the factory down pipe in the N55 is quite restrictive, which results in slower exhaust gases and slower turbo spool.

The Active Autowerke F-Chassis N55 Signature down pipe utilizes 3.5” diameter stainless steel piping in order to provide more power, quicker spool, and extreme durability. 

This variant includes a 4.5" high flow GESI catalytic converter that will NOT produce a CEL!  GESI has stamped N/GBL/4389/1119 on these cats as required by the EPA. The number represents the following: N (New) GBL: GESI’s Manufacturer Code / 4389 is the part number registered with the EPA / 1119: Manufacturing Month and Year.  GESI can correctly claim that this specific technology has met test protocol 40CFR86, and has been verified by a third party laboratory, and most importantly has been registered with the EPA.

NOTE: Federal law prohibits the tampering of an emissions control device.  Mobile Source Enforcement Memorandum 1A, allows for aftermarket parts to be used in the repair or replacement of emissions control systems, provided the emissions aren’t adversely affected.  There is no mention or reference to cell density or converter volume dimension.  The GESI catalytic converter will produce emissions that will meet the standards set by the EPA, not CARB.

***Before your order ships you MUST sign and return the Off Road Use Only Waiver available HERE. Please email, fax or take a photo of the completed form. You can email it to your sales rep or to and you can fax it to us at (305) 253-8921***


  • NO CEL when using this downpipe
  • Designed to be as unrestrictive as possible
  • GESI EPA registered high flow and fully OBD2 compliant
  • High flow 4.50" GESI cat with 3.50" piping allows for maximum power output
  • Quicker turbo spool - improved power over stock
  • Rated for 500 to 850 hp applications
  • Withstands up to 1500° F
  • Can reach operational efficiency within 9 seconds of startup
  • Easily bolts-on – no cutting or welding required
  • Durable construction from TIG welded 304 stainless steel
  • Precise fitment
  • Modular design for later upgrades 
  • Made in Miami, Florida

Active Autowerke N55 Signature Downpipe Benefits

The speed of a turbo’s impeller wheel is limited by exhaust back pressure. A larger down pipe relieves some of this pressure, resulting in quicker and more efficient spool. With Active Autowerke’s Signature downpipe, your N55 can rev quicker, and deliver more horsepower and torque.

Minimizing back pressure while remaining daily drive-ability was the goal of our N55 downpipe. Owners can now upgrade to a product that is affordable, reliable, and easy to install. 

After months of research and development, our engineers settled on a 3.5” diameter pipe which utilizes the least number of bends possible. However, the Signature N55 down pipe still fits easily into the OEM location, with a painless installation process.

Constructed entirely from 304 stainless steel with 1.5MM wall thickness, we are confident that you’ll be pleased with how robust and durable this down pipe is. Trouble-free installation and a long lifespan ensure that you’ll enjoy many miles of performance with your N55!