Evolution Racewerks (ER) BMW Mini B46 Competition Series 4" Catted Downpipe (X1, X2 & Mini Cooper S)

Evolution Racewerks (ER) BMW Mini B46 Competition Series 4" Catted Downpipe (X1, X2 & Mini Cooper S)

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Introducing our new Competition Series 4" Catted Downpipes for your BMW B46 four cylinder turbo engine!  Fits all 2016+ X1/X2, Mini Cooper S, Clubman, Cabrio and Countryman.


You may also wish to purchase an additional O2 Sensor Bung and/or an additional Exhaust Gas Temperature Bung


  • Now available for the 2015+ BMW X1/x2 B46 Engine!
  • Now available for the 2015+ Mini Cooper S, Clubman, Cabrio and Countryman.
  • Horsepower gains of 14 to 16whp average (gains will vary based on modifications of your vehicle).
  • Higher Max Horsepower Power Curve
  • Torque gains of 20 wtq average (stock boost) up to over 24 wtq (Software upgrade) (gains will vary based on modifications of your vehicle).
  • Higher Initial Torque Curve.  Torque curve hits faster and higher and longer.
  • Better throttle response and faster turbo spool up times.
  • Mandrel Bent 4" piping.  Smooth transition to the exhaust system.
  • 100% Stainless Steel Construction
  • 100% TIG welded for better quality welds
  • Precision CNC machined turbocharger V-Band flange.
  • Stainless steel flex section like factory that allows proper exhaust movement and flexibility.
  • Mirror polish or brush finish
  • Available with high temperature black thermal coating to reduce underhood temperatures.
  • Optional - Additional O2 sensor bung for wideband O2 sensors (comes with pre-installed plug)
  • Optional EGT sensor bung for EGT gauges (comes with pre-installed plug)
  • Retains all factory heat shields.
  • Compatible with the factory or aftermarket exhaust systems.
  • Track tested durability.
  • Includes all hardware for complete installation.
  • Limited Lifetime Warranty.


Evolution Racewerks (ER) B46 Mini Competition Series 4" Catless Downpipe (X1/X2) | Nforcd UK
Shown in Brush Finish 


Restrictions in the exhaust system robs horsepower and torque especially on turbocharged cars.  Thus, removing as much exhaust flow restrictions will increase horsepower and torque significantly.  The factory catalytic converter found in the factory downpipe is a big culprit of this and is a major exhaust flow restriction.  The factory catalytic converter is made up of catalyst material formed into "honeycomb" weaves.

Exhaust gas must pass through these tiny "honeycomb" weaves on their way to the exhaust system thus causing a major exhaust flow restriction.  It also causes turbulence after the catalytic converter which causes the exhaust flow to slow down (which increases restriction).  By replacing the factory downpipe/catalytic converter with our Competition Series 4" Catless Downpipe, more power is unleashed!  Our dyno testing has shown around 14-16whp average peak gains and upwards of 24wtq peak gains!  While peak horsepower is nice to look at on dyno charts, what's more important is the power curve.

If you look at the dyno charts, torque hits MUCH earlier and harder.  The torque curve is BROADER throughout the RPM band.  More usable power.  You have more time spent in the RPM band with higher horsepower and torque.  This equates to faster turbo spool up (less turbocharger lag) and better throttle response.  Bottom line, faster.  You will feel the difference instantly. 
Our Competition Series Catless Downpipes is constructed out of 100% 304 grade stainless steel and utilize mandrel bent piping.  They are 100% TIG welded by our in house fabricators and built in the USA.  

The factory turbocharger turbine housing utilizes a 4" V-Band flange which we have duplicated and CNC machined cut out of billet 304 stainless steel.  Stainless Steel CNC machined O2 sensor and laser cut brackets are TIG welded using stainless steel rods.  

The O2 sensor is positioned at the factory location. The factory turbocharger outlet is 4".  Many of our competitors machine a 4" outlet v-band to match the factory, but have a 3" opening at the flange so that they could use 3" piping to save money on manufacturing. This causes a "step" at the worst place possible, at the turbocharger outlet.  Our downpipe features a 4" inlet on the downpipe and 4" piping.  We reduce it further away from the turbocharger outlet. This results in less exhaust turbulence and back pressure which again improves throttle response and increase turbocharger spool times (less turbocharger lag). 


xDrive (AWD) Version

On xDrive all wheel drive models, there is a driveshaft running from the transfer case to the rear differential that the standard front wheel drive cars do not have. This driveshaft sits right underneath the downpipe and blocks the removal.  On a typical installation, you would need to disconnect the driveshaft (requires special driveshaft tool) or lower the front subframe to give enough clearance to remove the downpipe.  This add significant installation time and complication to the installation.  Our solution is the 2 piece xDrive version allows you to remove and install the downpipe without removing the driveshaft or lowering the front subframe.  This will save you considerable time (money) on installation and allows quicker, easier servicing.


Evolution Racewerks (ER) B46 Mini Competition Series 4" Catless Downpipe (X1/X2) | Nforcd UK


Ceramic Thermal Coating - The purpose of ceramic coating downpipes is to keep heat from the exhaust gases inside the downpipe from radiating out.  This keeps underhood temperatures lower and less heat absorption by nearby parts/surfaces.  Another added benefit is that by keeping in heat (energy) in the exhaust gases inside the downpipe, exhaust flow velocities stay up, resulting in lower back pressure.  The ceramic coating also adds additional corrosion resistance.  We utilize the best ceramic coating possible.  Our thermal coating can resist up to 2000F of heat.  It is available in black only (all the other colors cannot withstand heat that high).

Additional O2 Sensor Bung -  An additional O2 sensor bung can be added so that you can easily add a wideband o2 sensor and gauges so that you can monitor air/fuel ratios.  The additional O2 sensor bung will come pre-installed with a plug so that you do not need to run the o2 sensor right away.

Optional EGT (Exhaust Gas Temperature) Bung - An additional 1/8" NPT bung can be added so that you can easily add a EGT sensor and gauge.  The optional EGT sensor bung will come pre-installed with a plug so that you do not need to run the EGT sensor right away.



The B46 engine is found in all U.S. spec cars.  The downpipe is different than the B48 found in the EU / Asia spec cars.  You must get the correct downpipe for your car as they are not interchangeable.  


This product is intended for OFF ROAD COMPETITION USE ONLY. Not legal for use on pollution controlled vehicles upon public road/highways.


• 2016+ BMW F48 B46 X1

• 2016+ BMW F39 B46 X2

• 2016+ MINI F55 F56 B46 Mini Cooper S 




Manufactured by

Evolution Racewerks