HKS Stainless Steel Front Pipe - Single Scroll

Features

• It was developed based on long time know-how of turbo technology.
• The connection portion with turbine is made by lost wax casting that enables flat surface between flange and pipe.
• Improved exhaust efficiency without catalytic converter. (Off-road use only)
• For improvement of exhaust efficiency, diameter of the pipe is Φ75.
  If it is used with the specified muffler (31008-BF001)(*), whole exhaust system will be Φ75.
  * Front Pipe and Muffler system set (31008-BF002) is available.
  (This item can be used with other exhaust systems. A Flange Adaptor is included to fit to Φ65 spherical flange.)

Whole front pipe will be changed from stock Φ60 to Φ75. It reduces secondary exhaust gas back pressure that is a common problem of EJ engines.

BB Tune

BB Tune is...
"Boxer's Balance Tune" and it is a project of HKS to analyze completely about typical problems of EJ20 engine due to its boxer engine layout. Previously, EJ20 engine had been considered as it was easy to be damaged. To find out the cause, the engine was analyzed on test bench at HKS and found out that reducing back pressure is the point to prevent knocking and the know-how changed EJ tuning in Japan. Since EJ25 has the same engine layout, reducing back pressure is effective for safe tuning. 
To reduce secondary back pressure, replacement of front pipe will be required for further tuning.

For over 40 years, HKS products have been put to the test in drag racing, road racing, rallying, and top speed trials. HKS equipped vehicles have captured numerous racing championships and hold claim to a myriad of competition records using many “off the shelf”, race proven HKS components. As a result, HKS has been synonymous with “performance” in the automotive aftermarket industry for the past 40+ years.