Part #: HH4 - 1. The Killer B Motorsport Holy Header for Subaru WRX / STI is a top - notch exhaust upgrade. Developed with advanced CAD software and simulations, it's designed to boost power in the mid - to - high RPM range. Its short primaries and single secondary reduce header volume, enabling quick exhaust gas pressure build - up. The symmetrical 4 - 1 design maintains high and steady exhaust velocity as RPMs climb, resulting in faster spool - up compared to long primary/double secondary designs. You'll instantly notice improved throttle response and more power at higher revs.
Features:
- Short Equal Length Primaries: The shortest possible on an equal - length header, less volume, quick spool - up.
- Symmetrical Primary Design: Similar tube length and bend geometry for consistent pulse velocities.
- Smooth Mandrel Bends: Use mandrels for unrestricted flow and large bends for best performance.
- Thick - Walled 321 Stainless Steel: Alloyed with titanium, ideal for high - temp turbo apps, stronger and tougher than 304 stainless.
- High Heat Retention: Conducts less heat, short primaries and proper secondaries increase turbine efficiency.
- V - Band Up - Pipe Connection: Fast, easy, no gasket, no leaks, perfect alignment.
- Up - Pipe Included: Designed as a complete system for optimal performance.
- Lightweight: Only 17 pounds compared to OEM's 25 pounds.
- Compatible: Works with OEM EJ25 oil pans and Killer B Motorsport Performance Aluminum Oil Pan.
- Made in USA: With Killer B quality.
- Wide Fitment: Fits all WRX & STi EJ Series Engines, works with OEM location turbo, rotated setups need an adapter.
Fitment:
2002 - 2014 WRX, 2004 - 2017 STI, 2005 - 2009 Legacy GT, 2005 - 2009 Outback XT, 2004 - 2013 Forester XT.
Notes:
02 - 05 wrx may require 2.5l sti oil pan. 06 - 07 wrx needs sti oil cooler and sti oil pan. Not legal for sale or use in California on emission - controlled motor vehicles.
Using the Killer B Holy Headers is straightforward. First, make sure to check your vehicle's compatibility as listed in the fitment details. If you have a 2002 - 2005 WRX, you may need a 2.5L STI oil pan, and a 2006 - 2007 WRX requires an STI oil cooler and oil pan. Installation is a technical job, so it's recommended to have it done by a professional mechanic. The V - band up - pipe connection makes the installation relatively easy and ensures a leak - free fit.
When it comes to maintenance, the 321 stainless - steel construction is durable, but it's still a good idea to check for any signs of damage regularly. Look for cracks or loose connections, especially after long drives or rough use. You can clean the headers with a mild automotive cleaner to keep them looking good.
Remember, this product is not legal for sale or use in California on any emission - controlled motor vehicle, so always comply with local regulations.
