The Evolution Racewerks Sports Series 4" High Flow Catted Downpipe is engineered for maximum performance on BMW’s N55 6-cylinder engine. Featuring a high-flow 200 cell metallic catalytic converter, mandrel-bent 4" piping, precision CNC-machined V-band turbo flange, and stainless steel flex section, this downpipe delivers improved throttle response, quicker turbo spool, increased horsepower, and reduced backpressure.

Built in the USA and constructed from 100% 304 stainless steel with full TIG welding, this downpipe is designed for long-term durability, track-tested strength, and perfect compatibility with factory or aftermarket exhaust systems. Long gradual transitions allow smooth exhaust flow from 4" to 2.5", reducing turbulence and improving turbo efficiency.

Features

• Made in the USA and manufactured in-house

• High Flow 200 cell metallic catalytic converter

• Mandrel-bent 4" piping with smooth transitions

• 100% 304 stainless steel construction

• Stainless steel flex section for durability and reduced component stress

• 100% TIG-welded for superior welding quality

• Precision CNC-machined turbocharger V-band flange

• CNC-machined O2 sensor fittings and laser-cut brackets

• Brushed finish (standard) or optional polished finish

• Optional high-temp black ceramic thermal coating

• Optional additional O2 sensor bung (comes plugged)

• Optional EGT bung (comes plugged)

• Compatible with the factory or aftermarket exhaust systems

• Includes all required hardware

• Limited Lifetime Warranty

Performance Benefits

The factory downpipe uses a restrictive 400 cell ceramic catalytic converter with small honeycomb passages that slow exhaust flow and increase backpressure. The Evolution Racewerks 200 cell metallic core allows significantly higher flow, resulting in more power, quicker turbo spool, and improved throttle response. Metallic cores also withstand more heat and offer greater durability than ceramic cores.

By utilizing compact catalytic converters and extended transition sections, this downpipe reduces exhaust turbulence. This design maintains high exhaust velocity, reduces turbo lag, and ensures optimal exhaust energy delivery to the turbocharger.

Unlike many competitors, this downpipe includes a full stainless-steel flex section to protect against stress, vibration, and impact — especially important on lowered vehicles. This helps prevent premature cracks in turbochargers, manifolds, and exhaust components.

OPTIONS

• Ceramic Thermal Coating (Black Only)
  Reduces underhood temperatures, maintains exhaust gas energy, improves flow velocity, lowers backpressure, and adds corrosion resistance. Rated up to 2000°F.

• Additional O2 Sensor Bung
  For wideband O2 sensors and air/fuel monitoring gauges. Comes pre-installed with plug.

• Optional EGT Bung
  For EGT sensors and gauges. Comes pre-installed with plug.

Legal Notice

• For off-road competition use only.

• Not legal for use on pollution-controlled vehicles on public roads/highways.

• Not for sale, installation, or use on licensed vehicles in California.

• Available internationally without restriction.

Fitment

• 2011–2016 BMW 535i (F10) with N55 engine

• 2011–2016 BMW 640i (F12/F13) with N55 engine

• 2011–2015 BMW 740i (F01) with N55 engine