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Custom Performance Single Step Headers for BMW E46 M3

SKU: SH001
OUT of STOCK. FREE SHIPPING.
Designed to maximize midrange torque while maintaining strong peak horse power. Dyno results: +12 to +15 HP at 7,500 RPM and +12 to +15 lbft of torque @ 4,300 RPM (at rear wheels).
Price: $1,095.00
Out of Stock
Custom Performance Single Step Headers for BMW E46 M3
Custom Performance Single Step Headers for BMW E46 M3
Custom Performance Single Step Headers for BMW E46 M3
Custom Performance Single Step Headers for BMW E46 M3
Custom Performance Single Step Headers for BMW E46 M3
Custom Performance Single Step Headers for BMW E46 M3
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Product Details

If you have been waiting for a reasonably priced, high quality stepped header for the BMW E46 M3, well your wait is over. The CPI Single Step Headers were designed to maximize midrange torque while maintaining strong peak horse power.  Dyno testing resulted in +15 horse power at 7,500 RPM and +12 pound/feet of torque @ 4,300 RPM over stock (at the rear wheels). On our test M3, with a software tune from TTFS, power output was 327 HP and 270 LBFT of torque at the rear wheels.  These headers are perfect for the street or track (SCCA and autocross).

KEY FEATURES of the CPI Single Step Headers 

  • The CPI Single Step Headers are all 321 stainless steel (with satin finish instead of high polish) and all joints are TIG welded. 
  • The single step design is unique in that the lead pipe is fitted into trailing pipe.  Other stepped header designs swedge the end of the lead pipe and fit it over the trailing pipe.  The CPI Single Step design provides for increase exhaust port scavenging and smoother exhaust flow.
  • The 3-way merge pipe is fitted into the exhaust collector pipe.  Other header merge pipes are swedge at the end to fit over the exhaust collector pipe.  The 3-way merge design provides for smoother exhaust flow into the collector pipe.
  • The primary pipes are integrated with the flanges so that there is no edge, lip or other exhaust flow obstructions at the engine exhaust port.
  • Two exhaust collector flanges (one fixed and one loose) that will connect to OE section 1 or any after market section 1 with the OE flange configuration.
  • Two O2 bungs on each header and one EGT bung on bank 2 header.

UNIQUE DESIGN ASPECTS

  • Single step lead pipe is 1.65" (42mm) OD - fits snugly into trailing pipe, which has a 1.78" (45mm) OD.


  • 3-way merge pipe is fitted into the exhaust collector pipe (which is 2.33" OD). 


  • Primary pipes are integrated with the flanges and have a 1.56" (40mm) ID which is slightly larger than the 1.52" (38mm) ID exhaust port on the engine head.  The header gaskets also have a 1.56" ID so they mate perfectly with the header flanges. 


  • Smooth transition to 3-way merge with proper O2 bung locations.


  • Max diameter on collect (2.36" OD) to mate to section 1.

 

  • Port matched flanges to maximize exhaust gas velocity.


  • Equal length and proportional steps to increase exhaust port scavenging.

 

  • All mandrel bent primary pipes.

 

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