Description 

Our Competition Series 4.5" Downpipes for your 2020+ M340i(x), as well as 2016+ M240i/340i/440i/540i and 2017+ X3/X4/X5 M40iX six cylinder B58 turbo engine

Features

• Fitment for the new BMW B58 Engine
• High Flow 200 cell metallic catalytic converter used
• Higher Max Horsepower Power Curve
• Higher Intial Torque Curve.  Torque curve hits faster, higher, and longer
• Better throttle response and faster turbo spool up times
• Mandrel Bent 4.5"/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
• Brush Finish (standard) or optional Polish 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)
• Compatible with the factory or aftermarket exhaust systems
• Track tested durability
• Includes all hardware for complete installation
• Limited Lifetime Warranty
• Made in the USA!

Thermal Coated Black 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 Sports Series 4" High Flow Metallic Catted Downpipe, more power is unleashed! 

The factory catalyter uses a 900 cell ceramic core. What the 900 cells means is that per every inch, there are 900 "cells" that the exhaust gas must pass through. We use a 200 cell metallic core. By having less cells per square inch, these individual "cells" are bigger in size thus allowing exhaust gas to pass through it more easily. Thus, the lower the cell count, the higher the flow. Higher flow = more power, faster turbo spool up (less turbocharger lag) and better throttle response. Bottom line, faster. The benefits of a metallic catalytic converter vs a ceramic like the factory is that it can take higher temperatures and is more durable (last longer). They are also lighter than their ceramic counterparts.

So Why 4.5" Piping? The new turbochargers on the B58 engines utilise a much larger 4.5" outlet compared to the 4" outlet on the older N55 engines. if we ran a 4" downpipe flange inlet so that we can use the 4" tubing, a "step" would be formed between the turbocharger outlet and downpipe inlet. Exhaust gas for the turbocharger would hit this "step" and a lot of turbulence would form at this point and cause backpressure. Backpressure this close to the turbocharger would greatly affect performance. Thus, to ensure that we get unobstructed flow from the turbocharger outlet to the downpipe outlet, we had to CNC machine a new 4.5" flange to match. This allows a seamless transition and eliminates any possible turbulance which would cause backpressure. Though this presented another challenge for us as 4.5" tubing is not readily available and hard to source. Our motto "Performance, No Compromise" prevailed at the end and through hard diligence and many phone calls, we finally found a souce for the material. Even though the material was considerably more expensive than the standard 4" stainless steel,we wanted to give our customers the best by producing the best product possible. 

Brush Finish 

Our Sports Series 4" High Flow Catted 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.  Since the outlet of the turbocharger is 4.5" and the factory exhaust system is 3", the factory downpipes reduces size using short transitions from 4" before the catalytic convert and 3" afterwards.  Due to space needed for the catalytic converter, the factory downpipes reduce in size using very short transitions.  Since our catless downpipes delete the catalytic converter, we have more space.  Thus, we use very long transitions.  These longer transitions allow the exhaust gas time to smoothly transition from the larger piping to the smaller.  This results in less exhaust turbulence and backpressure which again improves throttle response and increase turbocharger spool times (less turbocharger lag). 

The factory downpipe utilizes a flex bellow section that allows the exhaust system to move.  This eliminates undue stress on the exhaust components like the exhaust system, downpipe, turbocharger and exhaust manifold.  Many of our competitors do not feel it is important to keep this.  While you do not see any adverse affects right away, over time, the stresses caused by not having a flex section and having a rigid exhaust system will cause premature wear and tear.  Any stress failures like cracks will form quicker than usual on exhaust manifolds and exhaust components.  Also, without a flex section, the exhaust system cannot properly deflect impact.  Especially on lowered cars, whenever the exhaust system contacts the ground, the entire system gets pushed up.  Without a flex, you can imagine how much stress is put into exhaust components like the exhaust manifold when the exhaust is pushed upwards.  We fully understand that durability of our products is important.  Thus, like BMW, we incorporate a flex section into our downpipe.  Our flex sections are 100% stainless steel (cheap flex sections only have stainless steel center braids and steel caps) to ensure corrosion resistance.  

CNC Machined Billet Stainless Steel V-band Flange

Factory B58 Downpipe Flange

Our downpipes are designed to fit perfectly with either the factory exhaust system or your aftermarket exhaust system. There are no compatibility issues whatsover. The downpipes will come by default in Brushed Finished. We also offer Polished Finish as an option.

Options

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 absorbtion 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 high, resulting in lower backpressure. The ceramic coating also adds additional corrosion resistance. We utilise the best ceramic coating possible. Our thermal coating can resist up to 2000F of heat/ It is available in black only (all other colours cannot withstand the high levels of heat). 

Additional O2 Sensor Bung - An additional O2 sensor bung can be added so that you can easily add a wiseband O2 sensor nd gauges for you to monitor air/fuel ratios. The additional O2 sensor bung will come pre-installed with plug so that you do not need t run the O2 sesor 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.

CAUTION: This product is intended for OFF ROAD COMPETITION USE ONLY. Not legal for use on pollution controlled vehicles upon public road/highways. THIS PRODUCT IS FOR SALE FOR ALL 49 STATES EXCLUDING CALIFORNIA.  In addition to vehicle use verification, a Vehicle Compliance Waiver needs to be signed.

THIS ITEM IS NOT FOR SALE, INSTALLATION, OR USE ON LICENSED VEHILES IN THE STATE OF CALIFORNIA. 

Manufactured by

Evolution Racewerks 

Part Number

BM-EXH018SCAT

BM-EXH018PCAT

BM-EXH018TBCAT

Dimensions 

TBC

Weight

TBC