Cast Collector
The collector is thick walled cast 347 (321) stainless. The casting removes several welds, each weld removed is one less flow disruption (reduced turbulence). The casting has features milled into it that assure the primary tubes fit VERY concentric every time. Using a casting allows the collector to be designed as a true high velocity merge vs tubing that can only be formed a little bit, and not ideally. The casting is thicker/stronger than formed tube and also holds heat better.

Short Equal Length Primaries
The shortest possible length primaries you can have on an Equal Length header. Short means less header volume and quick spool up.

Symmetrical Primary Design
All primaries have a similar tube length AND bend geometry. This keeps the pulse velocities high and consistent compared to equal length headers with different (non-symmetrical) primary tubing geometry. Smooth Mandrel Bends. All of the bends utilize a mandrel for smooth non-restrictive flow. Not only that, we use the largest bends possible at every location. It would be cheaper to use 2” bends everywhere, like others do, but that’s not going to give the best performance.

Thick Walled 321 Stainless Steel Construction for Long Life
321 is alloyed with titanium, costs more, a lot more, but it’s the ideal material for high temperature turbocharged applications. Would 304 stainless work, yes, but the temperatures on our turbocharged cars can exceed the limits of 304 stainless enough to make them brittle and crack. 321 stainless steel has higher strength and toughness at elevated temperatures. It was developed by the aircraft industry specifically to address 304 stainless manifolds that were cracking. Killer B Motorsport is the only company that manufactures full 321 headers.321 stainless steel conducts less heat than 304 stainless steel. The short primaries and properly sized secondaries also pull less heat from the exhaust gasses increasing turbine efficiency. Large tubing headers expose the exhaust gasses to more surface area transmitting more heat and reducing exhaust energy. You can also ceramic coat or wrap our headers (and keep the warranty) without exceeding the temperature range like you can with 304 stainless.

V-Band Up-Pipe Connection
Why V-Band? Fast, easy, no gasket, no leaks, perfectly concentric alignment of tubes for no disruption of flow, what’s not to like!

Up-Pipe included
Of course it comes with an Up-Pipe! This header was designed as a complete system. Using other up-pipes would only compromise performance, and nobody wants that. ONLY on Traditional and EWG

Works with OEM EJ25 Oil Pans, and Killer B Motorsport Performance Aluminum Oil Pan! 

Fits All WRX & STi EJ Series Engines. Designed to work with OEM location turbo.