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Perrin Big Tube Equal Length Header 2002-2014 WRX / 2004-2021 STI

by Perrin
Original price $1,274.15 - Original price $1,274.15
Original price
$1,274.15 - $1,274.15
Current price $1,274.15

Create a smooth-sounding exhaust note while increasing horsepower and torque with the PERRIN Equal Length Header. Available in both Standard 1.5" or 1.625" Big-Tube Primaries.


The Perrin Equal Length Header comes with collectors that have been designed for better exhaust flow while allowing the headers to be constructed with increased accuracy. The improved exhaust flow and more precise construction increase power and reliability, while the low-profile design allows for excellent ground clearance.


Increase horsepower and torque without ECU recalibration or tune! This part is designed and tested to work safely on your vehicle without any tuning required! However, more power can be gained with proper ECU tuning! Confirm any tune or recalibration you add is specific for all modifications added to the vehicle. 


The equal length design of the Perrin Header produces smooth, balanced exhaust flow from the heads to the turbocharger giving you the best of two worlds: quicker turbo response as well as more horsepower and torque throughout the entire RPM band. While designed to fit the factory up-pipe, our header will also mate with an aftermarket up-pipe that fits the factory header and turbo, as well as any rotated turbo kits compatible with the factory header.


You won't see grossly over-sized tubing to make our header "look" impressive, this just slows exhaust gas flow and reduces response. Perrin headers use 1.5" and 1.625" (big-tube) primary tubing that is expanded at the flange to fit the Subaru exhaust port size. These tubing sizes are perfectly designed for cars up to about 400 horsepower and above 400 wheel horsepower, respectively. You can see from our dyno graphs that there is a significant gain in horsepower and torque across the entire RPM band compared to an OEM header.


Perrin flanges are CNC machined from 304 stainless steel and counterbored on the backside to make smoother transitions. Flange ports are sized properly to ensure exhaust coming out of the head has a smooth, unobstructed path to the tubes. The ports are not over-ported which would cause gaskets to burn out quickly. The tubes are expanded inside the flanges for a perfect fit and smooth flow of exhaust gases to the tubes.


Due to its equal length design, the Perrin header will alter the tone of your exhaust. The exhaust pulses from the engine are equalized and spread out producing a smoother, more refined sound. A byproduct of the equalization is a significant reduction in the volume of your exhaust sound. Some describe the sound as being similar to an inline four cylinder engine exhaust. 


Most headers collect on the passenger side of the engine, and due to space constraints, are not equal length and compromise exhaust flow. Because we use the added room provided by the oil pan (only on 2.5L turbo pans), we can create a smooth transition of the header primaries to the collectors, and collectors to up-pipe, providing more power and torque then the competition.

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