SKU: 19820516709

Competition Series 4" Catless Downpipe for the X1/X3/X4/Z4 N20 (4 Cylinder) Engine

Sale price$245.25 Regular price$272.50
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Description

Competition Series 4" Catless Downpipe for the X1/X3/X4/Z4 N20 (4 Cylinder) EngineIntroducing our Competition Series 4" Downpipes for the 2011 15 X1 s xDrive28i 20i 16i, 2011 17 s xDrive28i 20i 18i, 2014 18 X4 xDrive28i 20i 18i and 2011 16 Z4 sDrive28i 20i 18i N20 (4 Cylinder) Engine. Key Features: Made in the USA! Manufactured in house. Now available for the 2011 15 X1 s xDrive28i 20i 16i, X3 s xDrive28i 20i 18i, X4 xDrive28i 20i 18i and 2011 16 Z4 sDrive28i 20i 18i N20 Engines! Horsepower gains of 14 to 16whp average (gains will

Introducing our Competition Series 4" Downpipes for the 2011-15 X1 s/xDrive28i/20i/16i, 2011-17 s/xDrive28i/20i/18i, 2014-18 X4 xDrive28i/20i/18i and 2011-16 Z4 sDrive28i/20i/18i N20 (4 Cylinder) Engine.

Key Features:

  • Made in the USA!  Manufactured in house.
  • Now available for the 2011-15 X1 s/xDrive28i/20i/16i, X3 s/xDrive28i/20i/18i, X4 xDrive28i/20i/18i and 2011-16 Z4 sDrive28i/20i/18i 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: 19820516709

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4.1 ★★★★★
Based on 17 reviews
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Product Reviews
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gillabyte
Bozeman, US
★★★★★ 5
Amazing Oil!
Style: Restore & Protect, Size: 5 QT, Configuration: 5W-30
So far after first oil change it made my Toyota Tundra 5.7L with 255k miles run smoother and quieted the timing chain tensioner knock that I was quoted $5k and up to repair! Will be using from now on to 500k miles plus!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 14, 2026
K
Verified Purchase
Katharine Dow
Battle Creek, US
★★★★★ 5
A fascinating glimpse into the undoing of the Confederacy
Format: Paperback
This dense and and well-written book includes some really interesting insights into how the Confederacy was formed, but then ultimately challenged and destroyed by some of the people it excluded. In Confederate Reckoning, we get to learn about the epic political battle in which White women and slaves in the South helped to undermine the Confederacy and determine the outcome of the Civil War.
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Reviewed in the United States on November 29, 2025
D
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Darrell Criswell
Houston, US
★★★★★ 5
Excellent book!
Format: Paperback
I think this is a fabulous book. I have always been interested in the causes of the civil war and this book presents an interesting, almost fascinating perspective, which I havent' seen in other books. I have also been reading James Oakes fabulous "Freedom National" and the two books complement each other extremely well. McCurry's book is not of the quality that Oakes book is but not much is. I cannot understand the criticism of her writing. I find her writing to be very good...admittedly some of the sentences are too long and a few ill defined names but this is a very well written book. Although we have all studied some version of much of this material before I find it hard to believe that almost anyone won't be astonished by the magnitude of the task the confederacy was attempting to take and its inherent stupidity or maybe a better description would be craziness of these people. Good book!
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Reviewed in the United States on May 21, 2013
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gloine36
Fort Morgan, US
★★★★★ 4
Outstanding exploration of the Confederacy's domestic divisions which helped contribute to its ultimate defeat.
Format: Paperback
This is an extremely powerful interpretation of the political forces at play in the Civil War South. Like it or not, Stephanie McCurry delivers a careful exploration of the domestic forces which were occurring during the Civil War in the Confederacy. The result is illuminating and exposes issues with great depth that have been overlooked in the study of the conflict. Much as domestic issues influenced government policies in the United States during the war as well as constantly in US history, domestic issues played an important role in influencing the actions of the Confederate government. Despite the Confederacy being an attempt to create an elite class system of rule, those without a voice in government found a way to be heard partly through their own actions, but also due to the democratic nature of American government. McCurry, the Christopher H. Browne Distinguished Professor of History at the University of Pennsylvania has definitely opened a can of worms with the release of this book. It was a finalist for the Pulitzer Prize for History in 2011 losing out to Eric Foner’s The Fiery Trial: Abraham Lincoln and American Slavery, itself a great work on the Civil War. Just how important were the actions of women and slaves in the Confederacy during the Civil War? McCurry states that their actions helped drive government policies. Based upon her work as well as others I would say she was correct. Others disagree. I think the thing to consider here is that the Confederacy, despite setting up a government ruled by the elite class of slave owners, was still responsive to the majority of the people inhabiting it. While it was an attempt to create a new nation, it was still required to adhere to some of the principles of the American Revolution. In order to establish the nation, the slave owners were going to have to wage an insurrection and for that they needed the help of the non-slave owners who would compose the majority of its armies. McCurry notes this and shows that this was just the first example of the elites compromising to achieve their goals. No matter what the elites desired, it could only happen with the support of the people in the Confederacy. It would be that support which was critical for the survival of the Confederacy. Without it, the Confederacy had no chance. This is often overlooked. First, many people think the Confederacy enjoyed the support of the people of the slave states. They did not. Of the 15 slave states in 1860, only 11 would join the Confederacy. Of those 11 states, a full third of the white men in them actually opposed secession. From the very beginning, the Confederacy had to deal with an active resistance inside its borders from whites who rejected their authority and slaves who would contribute as little as possible to the Confederate war effort. Later, soldier wives would riot as well as shield deserters. McCurry wrote extensively about these features. Just how much these factors played in the ultimate defeat of the Confederacy is going to be a guess and is open to debate. Did they cause the Confederacy to lose? Not of their own accord, but they did contribute to the defeat of the South over time. There is no doubt that the use of slaves by the Confederate armies was challenged from the very beginning of the war to the final end of it. The facts are undeniable on this matter and McCurry is not the first historian to note this nor will she be the last. The inability of the Confederacy to use its manpower to the maximum capacity was a crippling factor. The issue of slave labor and slave soldiers reflects the deep divisions within the Confederacy and exposes the rotten foundation which the slave owners tried to build their nation upon. All in all I liked the book. As some of the other comments show, the writing style could have been better. She repeated herself in multiple spots. This I think is a reflection of her still emerging writing style. Confederate Reckoning is only her second published book. She has written many articles, but those are different methods of writing compared to books. It takes some time for historians to really find their voice when writing monographs. She does have a Coursera course available, “The History of the Slave South,” which was offered in both 2014 and 2015. I think McCurry does a good job in opening up our eyes to the domestic issues on the Confederate home front. The real question which will be debated is just how much impact they had. I suspect that will be the argument for many.
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Reviewed in the United States on December 13, 2015
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Lydia E. York
Whiting, US
★★★★★ 5
Hidden History
Format: Paperback
Dr. McCurry has no dog in this fight. She is Irish by birth, and raised in Canada. However, she brings a fresh perspective to the Confederate enterprise. From its foundation to the bitter end, the life of the Confederate state is documented in the words of the people who lived it. Dr. McCurry includes all the people embraced by the Confederacy, even if they weren't considered "citizens." This includes women and the enslaved people; two thirds of the Confederacy's population. The only battles documented are the struggles of an infant state professing to have perfected the US Constitution that had birthed into war. It didn't all work out as planned. But there are important lessons to be learned that aren't usually taught about the Civil War.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 18, 2020

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