Killer B Motorsport 4-1 Holy Header Coated - Subaru EJ Models (inc. 2002-2014 WRX / 2004-2021 STI)
Killer B Motorsport 4-1 Holy Header Coated - Subaru EJ Models (inc. 2002-2014 WRX / 2004-2021 STI)
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Killer B Motorsport
Killer B Motorsport 4-1 Holy Header Coated - Subaru EJ Models (inc. 2002-2014 WRX / 2004-2021 STI)
Killer B Motorsport 4-1 Holy Header Coated - Subaru EJ Models (inc. 2002-2014 WRX / 2004-2021 STI)
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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 you will immediately notice in throttle response and the ability to hold more power higher into the revs.
NOTE: Unless stock status shows "in stock" coated versions are usually built to order. Adding the coating option could add 2-3 months to your order.
It is recommended that you order a new set of gaskets to complete the install.
The Killer B Motorsport Holy Header was developed using state of the art CAD software & simulations to determine optimal design to increase power in the mid to high RPM range. Short as possible primaries with a single secondary significantly decrease header volume allowing exhaust gas pressure to build quickly.
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 you will immediately notice in throttle response and the ability to hold more power higher into the revs.
Features include:
- 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, they 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 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.
- High Heat Retention. 321 stainless steel conducts less heat than 304 stainless steel. The short primaries and properly sized secondary’s 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. Ceramic coating does not exceed the max temperature 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.
- Weighs only 17 pounds (vs. OEM weighs 25 pounds)
- Works with OEM EJ25 Oil Pans, and Killer B Motorsport Performance Aluminum Oil Pan!
- Made in the USA and Killer B quality!

| Specification | Value |
|---|---|
| Includes Catalytic Converter | No |
| Manifold Design | Equal Length |
| Piping Coating | Yes |
| Piping Material | 321 Stainless Steel |
The ceramic coated headers/up-pipe look and sound incredible. Do some research and you may find that many enthusiasts agree - these are the best performing headers available for the STI. The ELH completely changes the tune of the car: under light/moderate acceleration, the exhaust note is smooth and refined like a purring kitten. Under WOT it sounds straight up NASTY, and is sure to turn heads. I absolutely love these, but be warned - this kit DOES NOT come with ANY new hardware. You will need to re-use the bolts that connect the up-pipe to the headers (from your stock exhaust) and you will need to buy new gaskets all around. Worst of all, the up-pipe does not come with studs installed for the connection to the turbo. This means you will need to either buy new studs, or attempt to re-use the ones from your current up-pipe. If you are running the stock pipe and your car is not brand new, get ready for a fight - the studs do not come out easy (sometimes not at all). I found this out the hard way, and was only able to recover two studs from my stock up-pipe, meaning I had to source new studs while my car was already in pieces. Plan ahead and just buy new studs. They really should put a note about this in the product description >.>
Over all, great product and totally worth the price.