2008 -2015 Harley Twin-Cam Gets More Power with a K&N Street Metal Intake

HARLEY DAVIDSON FLTRXS ROAD GLIDE K&N Air Intake

The K&N RK-3947X Street Metal high-flow intake system is engineered to improve performance on the Harley V-Twin.

Back in 1916, General Jack Pershing used a small fleet of Harley-Davidson® motorcycles to combat Pancho Villa and his Raiders. These two-wheeled machines were cutting-edge technology at the time, and they even featured side cars with built-in machine guns. The U.S. Army was so impressed with the performance of the Harley®, they used 20,000 of them in the First World War, and 60,000 in the second. Decades later, those rugged military bikes live on with a line of big-bore street bikes that are as American as beer and apple pie.

HARLEY DAVIDSON FLTRXS ROAD GLIDE Air Intake

The K&N Street Metal intake adds power and looks great on a Harley-Davidson Twin Cam 96 V-Twin and Harley-Davidson Twin Cam 103 V-Twin.

The 2008-2011 Harley-Davidson Twin Cam 96 V-Twin and 2009-2015 Harley-Davidson Twin Cam 103 V-Twin power such road monsters as the Harley Road King, the Harley Electra Glide, and the Harley Freewheeler. Those two giant cylinders provide a tsunami of torque in any gear, so you can cruise without a care in the world. But if you'd like your hog to see an estimated increase of 8.1 horsepower and 8.82 lb-ft of torque, you're going to need a K&N RK-3947X Street Metal intake system.

Like every internal combustion engine, your H-D® Twin Cam has to inject air into the cylinders so the fuel can burn. The air comes in through a tiny hole behind that fancy chrome cover which sits between the cylinders. A thick paper filter then removes most of the contaminants before sending the air on to the throttle body. Unfortunately, the stock Harley intake system slows the airflow and causes it to heat up before it reaches the motor. This reduces the amount of power that the engine can make, because slow moving warm air contains a lot less oxygen molecules than cold air. The K&N RK-3947X Street Metal high-flow intake system on the other hand, is designed to collect and deliver a much higher volume of oxygen-rich cold air. Plus, the reusable K&N performance air filter cleans more dirt from the air, and it can go up to 100,000 miles before it needs to be cleaned (depending on road conditions).

HARLEY DAVIDSON FLTRXS ROAD GLIDE K&N Air Intake Dyno Chart

Dyno results for the K&N RK-3947X Street Metal high-flow intake installed on a 2015 Harley-Davidson Street Glide Twin Cam 103 V-Twin.

The secret to the K&N RK-3947X Street Metal intake system is in its design. A sturdy aluminum mounting bracket attaches directly to the throttle body (there's also a gasket to absorb vibrations), followed by a special velocity stack, the large K&N filter, and a nickel finished aluminum cover. The exposed filter element is able to collect significantly more air than the OE Harley-Davidson air filter, and the velocity stack helps it to gain momentum, so the engine has a smooth, steady flow of cold air to ingest. This helps that Harley Twin Cam V-Twin to make more horsepower and torque at lower RPMs, resulting in faster throttle response, and more power throughout the rev range. To prove its effectiveness, we installed the system on a bone stock 2015 Harley-Davidson Street Glide 103ci, and dyno testing revealed an estimated increase of 8.1 horsepower and 8.82 lb-ft of torque. However, your individual results may vary, due to the mileage, modifications, and condition of your specific H-D.

Don’t forget, K&N makes an entire line of Harley-Davidson performance parts, which you can view by using the search by vehicle tool or you can find a K&N dealer near you using the dealer locator tool.

Features & Benefits of the K&N RK-3947X Street Metal high-flow intake system

  • Engineered for the 2008-2011 Harley-Davidson Twin Cam 96 V-Twin and 2009-2015 Harley-Davidson Twin Cam 103 V-Twin
  • Guaranteed to increase horsepower
  • Guaranteed to increase torque
  • Sharpens throttle response
  • Increased airflow helps the engine to make more power at lower RPMs
  • Provides better engine sound
  • Aluminum mounting plate and cover
  • Reusable K&N performance air filter can go up to 100,000 miles before it needs to be cleaned (depending on driving conditions)
  • Installation takes around 90 minutes
  • Covered by the K&N 10-Year/Million Mile Limited Warranty

The following bikes can benefit from the RK-3947X intake system

2015 HARLEY DAVIDSON FLTRXS ROAD GLIDE SPECIAL 103 CI - All
2015 HARLEY DAVIDSON FLTRX ROAD GLIDE 103 CI - All
2015 HARLEY DAVIDSON FLRT FREEWHEELER 103 CI - All
2015 HARLEY DAVIDSON FLHXS STREET GLIDE SPECIAL 103 CI - All
2015 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI - All
2015 HARLEY DAVIDSON FLHTKL ULTRA LIMITED LOW 103 CI - All
2015 HARLEY DAVIDSON FLHTK ULTRA LIMITED 103 CI - All
2015 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA 103 CI - All
2015 HARLEY DAVIDSON FLHTCUL ELECTRA GLIDE ULTRA CLASSIC LOW 103 CI - All
2015 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 103 CI - All
2015 HARLEY DAVIDSON FLHR ROAD KING 103 CI - All
2014 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI - All
2014 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI - All
2014 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA 103 CI - All
2014 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 103 CI - All
2014 HARLEY DAVIDSON FLHR ROAD KING 103 CI - All
2013 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 103 CI - All
2013 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 103 CI - All
2013 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI - All
2013 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI - All
2013 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI - All
2013 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 103 CI - All
2013 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 103 CI - All
2013 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 103 CI - All
2013 HARLEY DAVIDSON FLHR ROAD KING 103 CI - All
2012 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 103 CI - All
2012 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 103 CI - All
2012 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI - All
2012 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI - All
2012 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI - All
2012 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 103 CI - All
2012 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 103 CI - All
2012 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 103 CI - All
2012 HARLEY DAVIDSON FLHR ROAD KING 103 CI - All
2011 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 96 CI - All
2011 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 103 CI - All
2011 HARLEY DAVIDSON FLHXXX STREET GLIDE TRIKE 103 CI - All
2011 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI - All
2011 HARLEY DAVIDSON FLHTP ELECTRA GLIDE POLICE 103 CI - All
2011 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI - All
2011 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI - All
2011 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI - All
2011 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI - All
2011 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 103 CI - All
2011 HARLEY DAVIDSON FLHR ROAD KING 96 CI - All
2011 HARLEY DAVIDSON FLHP ROAD KING POLICE 103 CI - All
2010 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 96 CI - All
2010 HARLEY DAVIDSON FLHXXX STREET GLIDE TRIKE 103 CI - All
2010 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI - All
2010 HARLEY DAVIDSON FLHTP ELECTRA GLIDE POLICE 103 CI - All
2010 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI - All
2010 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI - All
2010 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI - All
2010 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI - All
2010 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 96 CI - All
2010 HARLEY DAVIDSON FLHR ROAD KING 96 CI - All
2010 HARLEY DAVIDSON FLHP ROAD KING POLICE 103 CI - All
2009 HARLEY DAVIDSON FLTR ROAD GLIDE 96 CI - All
2009 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI - All
2009 HARLEY DAVIDSON FLHTP ELECTRA GLIDE POLICE 103 CI - All
2009 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI - All
2009 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI - All
2009 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI - All
2009 HARLEY DAVIDSON FLHT ELECTRA GLIDE STANDARD 96 CI - All
2009 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 96 CI - All
2009 HARLEY DAVIDSON FLHR ROAD KING 96 CI - All
2009 HARLEY DAVIDSON FLHP ROAD KING POLICE 103 CI - All
2008 HARLEY DAVIDSON FLTR ROAD GLIDE 96 CI - All
2008 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI - All
2008 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI - All
2008 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI - All
2008 HARLEY DAVIDSON FLHT ELECTRA GLIDE STANDARD 96 CI - All
2008 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 96 CI - All
2008 HARLEY DAVIDSON FLHR ROAD KING 96 CI - All

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