Killer B Motorsport 321 Stainless Holy Header/Up-Pipe
The Killer B Motorsport Holy Header was developed using state of the art CAD software & simulations to determine optimal design to increase power as much as possible throughout the rev range. Short as possible primaries with a single secondary decrease header volume significantly, allowing exhaust gas pressure to quickly build. Symmetrical 4-1 design maintains high and consistent exhaust velocity as RPMs rise. You can expect faster spool up time compared to long primary/double secondary designs. A difference that you will immediately notice in throttle/boost response and the ability to hold more power higher into the revs.
Cast Collector. The collector is thick walled cast 347 (321) stainless. The casting removes several welds, and 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 as opposed to 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 that 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 which costs more, a lot more, but it’s the ideal material for high temperature turbocharged applications. 304 stainless would 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, which is why 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.
High Heat Retention. 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 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.
Works with OEM EJ25 Oil Pans and Killer B Motorsport Performance Aluminum Oil Pans!
Fits All WRX & STi EJ Series Engines. Designed to work with OEM location turbo.
Made in the USA!
We do not warranty wrapped headers.
For installation instructions click here
SKU | HH4-1 |
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Vehicle Fitment | 2004+ STi, 2002-2014 WRX, 2004-2013 Forester XT, 2004-2009 Outback XT, 2004-2009 Legacy GT |
Standard Color | No |
Part Number | HH 4-1 |
Product Instruction | For installation instructions click here |
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Holy Header/Up-Pipe HH4-13/15/22Absolutely perfect Holy Header with Up-Pipe, material, workmanship... No repositioning during installation. thanks.
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you get what you pay for2/18/22These headers are so far ahead of everyone else's. They spool fast, great HP improvement across the graph. You can't beat the 321ss and the lifetime warranty.
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Have patience and save your money cause it’s worth it10/6/21I have a 2010 wrx and my friend has a 2011 and we literally have the same bolt on Grimm speed top mount invidia cattless down pipe and n1 cat back arm cold air intake and the only difference is the headers I have the killer b and he wen with the invidia headers and junior tuned both of are cars and they are totally different from how fast I spool up and get into boost and we have been driving with the same headers for over 5 years and he has had 2 cracks he had to deal with I on the other hand have headers that look like I just got them a few months ago they literally made a ridiculous difference in performance my car has 310whp and 306 wfpt he is in the 280 area but it is not just the numbers it’s how much faster I get into boost and just pull away from his car and listen I’m not a mechanic but I do know how to drive the shit out of my car and I promise you that you are going to be disappointed that you didn’t save up the extra $500 and get something that is better than the rest performance wise material quality durability
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Best headers period8/6/21My favorite headers. I push these on all of my customers. You can't beat the gains and the lifetime warranty. My only complaint is the wait. They need to stop being so cheap and hire more staff.