SKU: 63496985702

Competition Series 4" Catless Downpipe for the 2011-16 528i N20 (4 Cylinder) Engine

Sale price$245.25 Regular price$272.50
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Ships within 48 hours · Estimated delivery Aug 9 - Aug 14

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Description

Competition Series 4" Catless Downpipe for the 2011-16 528i N20 (4 Cylinder) EngineIntroducing our Competition Series 4" Downpipes for the 2011 16 528i N20 (4 Cylinder) Engine. Key Features: Made in the USA! Manufactured in house. Now available for the 2011 16 BMW 528i N20 Engines! Horsepower gains of 14 to 16whp average (gains will vary based on modifications of your vehicle). Higher Max Horsepower Power Curve Torque gains of 16wtq average (stock boost) up to over 24 wtq (Software upgrade) (gains will vary based on modifications of

Introducing our Competition Series 4" Downpipes for the 2011-16 528i N20 (4 Cylinder) Engine.

Key Features:

  • Made in the USA!  Manufactured in house.
  • Now available for the 2011-16 BMW 528i N20 Engines!
  • Horsepower gains of 14 to 16whp average (gains will vary based on modifications of your vehicle).
  • Higher Max Horsepower Power Curve
  • Torque gains of 16wtq 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)
  • 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 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. 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 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 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 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 with either brushed or polished finish.

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: 63496985702

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★★★★★ 5
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Reviewed in the United States on January 30, 2026
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RadcoCorp.
Houston, US
★★★★★ 5
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Style: CF10374 Classic, Style: CF10374 Classic
YEEEEEEAHHHHH! This went straight from the mailman's hand to my 2010 Tacoma. -Fits better than OEM and Replacements! -AC smells so fresh now! -Easy installation without any complications. -Has a foam gasket around the filter that makes it fit like a glove, thight and secure! -Very Well Made and quality materials. Won't be returning this one, will actually buy it for the rest of my cars! ⭐️⭐️⭐️⭐️⭐️
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Reviewed in the United States on May 11, 2026
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Amazon Customer
Lexington, US
★★★★★ 5
**Perfect Fit for My 2008 Acura TL**
**Perfect Fit for My 2008 Acura TL** I bought this cabin air filter as a replacement for my 2008 Acura TL, and it fit perfectly 👌. Installation was quick and easy—no issues at all. The build quality feels solid, and the activated carbon is a nice bonus for helping reduce odors and improve air quality inside the cabin. For the price, it's a great value compared to dealership options. Highly recommend this if you're looking for a simple and reliable replacement!
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Reviewed in the United States on August 5, 2025
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Kenneth F.
Natrona Heights, US
★★★★★ 5
Just what my vehicle's A/C, heat system needed ..
Good fit, and quality. Easy to change. You might be surprised how changing the cabin air filter can improve the airflow in your vehicles A/C, and heat system.
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Reviewed in the United States on April 13, 2026
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gb147
Los Angeles, US
★★★★★ 5
Perfect fit, Easy install, Better than taking it to a dealer.
This filter fits perfectly and easily. Unlike the dealer-installed filter (which I assume was an OEM filter but maybe not), it has arrows that indicate which side and orientation should be facing outward. The dealer-installed one does not have this and, as you can see from the photo, it was installed incorrectly. It should not be folded in on the sides. The old filter in the photo is after about 20K miles if that is a useful reference for you. Also, if you watch any YouTube videos, you will see a reference to releasing a plunger as the first step in releasing the glovebox door. For my 2018 Honda Accord Touring, there was no plunger, and that was confusing to me. If you don't see one, just go to the next step -- squeezing in the top, back corners of the glove box to fold it down. After that, everything goes like in the videos. Getting back to this filter -- it seems like it's better quality than the dealer-installed one. Shipping was fast. I would buy it again but, because this only takes a couple of minutes, next time I would do both the cabin and engine air filter at the same time so you might save a little money buying the combo set. Again, a very easy install and you don't risk having a dealer doing it incorrectly.
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