SKU: 82631229225

Sports Series 4" High Flow Catted Downpipe for the X5/X6 Series N55 (6 Cylinder) Engine

Sale price$447.75 Regular price$497.50
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Ships within 48 hours · Estimated delivery Aug 17 - Aug 22

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Description

Sports Series 4" High Flow Catted Downpipe for the X5/X6 Series N55 (6 Cylinder) EngineOur Competition Series 4" Downpipes for your 2011 13 X5 X6 35i (E70 E71) and 2014 17 X5 X6 35i (F15 F16). Key Features: Made in the USA! Manufactured in house. Available for the 2011 13 BMW X5 35i (E70) with the N55 Engine. Available for the 2011 13 BMW X6 35i (E71) with the N55 Engine. Available for the 2013 18 BMW X5 35i (F15) with the N55 Engine. Available for the 2013 18 BMW X6 35i (F16) with the N55 Engine. Better throttle response and faster

Our Competition Series 4" Downpipes for your 2011-13 X5/X6 35i (E70/E71) and 2014-17 X5/X6 35i (F15/F16).

Key Features:

  • Made in the USA!  Manufactured in house.
  • Available for the 2011-13 BMW X5 35i (E70) with the N55 Engine.
  • Available for the 2011-13 BMW X6 35i (E71) with the N55 Engine.
  • Available for the 2013-18 BMW X5 35i (F15) with the N55 Engine.
  • Available for the 2013-18 BMW X6 35i (F16) with the N55 Engine.
  • Better throttle response and faster turbo spool up times.
  • Mandrel Bent 4" piping.  Smooth transition to the exhaust system.
  • 100% Stainless Steel Construction
  • Stainless Steel Flex Section
  • 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.

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 200 Cell Metallic Catted Downpipes, more power is unleashed! 

The factory catalytic uses a 400 cell ceramic core.  What the 400 cells means is that per every inch, there are 400 "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 easier.  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 more heat and is more durable (last longer).  They are also lighter than their ceramic counterparts.

Our Sports Series 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" and the factory exhaust system is 2.5", the factory downpipes reduce size using short transitions from 4" before the catalytic convert and 2.5" afterwards.  Due to space needed for the catalytic converter, the factory downpipes reduce in size using very short transitions.  Since our catted downpipes utilize a s more compact 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 effects 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/turbocharger 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. 

Our downpipes are designed to fit perfectly with either the factory exhaust system or your aftermarket exhaust system. There are no compatibility issues whatsoever.  The downpipes will come by default in Brushed Finish.  We also offer a 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 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 backpressure. 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 the high levels of heat).

Additional O2 Sensor Bung - An additional O2 sensor bung can be added so that you can easily add a wideband O2 sensor and gauges for you to 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.  This is not required for a normal standard installation.

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.  This is not required for a normal standard installation.

CAUTIONThis 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. 

The item is for sale for international customers without restriction.

Please contact us at [email protected] or call us at (626) 334-6609

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 82631229225

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Size: Medium, Color: (348) Silica Green / Silica Green / Hydro Green
I have them in every color and used to get them from Sams, but they stopped selling them and I was lucky to find them on Amazon. Got all colors again. They stay, it's all I'm gonna say! And don't show in any of my tennis shoes. Absolutely love them and wear them until they get holes. They last a LONG time too. They're on the thin side and my foot loves them because they tend to get hot. There's no shrinking, they wash great with exception of the white ones I couldn't manage to keep white - they turned a bit greyish.
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Reviewed in the United States on January 4, 2026
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Christy F
Charlottesville, US
★★★★★ 5
Great socks
Size: Medium, Color: Pink - 647
Well-made and comfortable to wear. Great for golf and other outdoor activities. Like them because they do not show above shoes.
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Cait E
Whiting, US
★★★★★ 5
These ACTUALLY stay put all day long - I was skeptical, but am so glad I took a chance on these
Size: Medium, Color: (014) Halo Gray / Halo Gray / Castlerock
I was so skeptical about whether these would stay on my feet all day without sliding down into my shoe - I’ve tried so many socks in the past with the silicone strip on the heel which failed. I’ve owned these for a couple months now and they have never slipped down - they stay put all day! I love the variety of colors to choose from, and the value per pack is great since six pairs come per pack (I thought it was only three when I first purchased and was pleasantly surprised by the additional pairs). They also have perfect thickness - not too warm to wear during the summer months with sneakers; I live in a tropical climate, though, so I’m not sure how they will do in cooler climates. I’ve washed each pair once or twice and the color and quality of the silicone has stayed so far (knock on wood). Overall: high recommend based on my experience so far!
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Maggie Vega
Los Angeles, US
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Great fit!
Size: Medium, Color: (403) Washed Navy / Washed Navy / Blue Smoke
Great quality!
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