Perrin 2004-2007 Subaru STI True Equal Length Header

True Equal length header, proven gains of 20+WHP!

Reaching back to lessons learned by tuners in our past, PERRIN™ has grabbed a dramatic power increase that was previously bottled up by the factory manifolds. Whether normally aspirated or turbocharged, proper exhaust gas scavenging is vastly important. The turbocharger relies on energy from the exhaust flow to rotate its blades. By freeing up energy that was otherwise restricted by the factory manifold we can transfer that to the turbo to decrease spool up times and improve power.  Our R&D staff was able to manipulate the length and shape of each runner to allow easy installation and still maintain large power increases.

POWER 

As shown in our charts section, the header makes power in all situations. Stock STI, Legacy GT’s, and even heavily modified STIs. In the past headers were a trade-off.  Some top end power was gained where some low end power, and boost response was lost. Also the minimal gains made the cost vs. HP scenario not look so hot.  The equal length design of the PERRIN header, gives you the best of both worlds.  Tons of low end power gained and still the top end power.  We find a minimum of 30Ft-lbs of torque gained at lower RPM, and around 15ft-lbs everywhere else. Same goes for Wheel HP, roughly 30WHP at lower RPM,and about 15wHP every where else.  Talk about the cost vs. HP scenario looking good!

DESIGN

The design of the PERRIN equal length is very different from the rest.  You will not find huge oversized tubing here just to make it look cool.  You will find proper sized tubing designed for the perfect balance of response and HP for applications beyond 400WHP.   All of the 2.5L turbo engines come with an oil pan with a large cutout in the side. This allows for a truly equal length, and free flowing header. Many other headers collect on the passenger side of the engine, and due to space constraints can’t be truly equal length without compromising flow, and clearances.  Because we use the added room around the oil pan, we can create a smooth transition of the header primaries to the collectors, and from collectors to the uppipe connection. This is why our header makes power across the entire RPM band.

A small but important feature to our header is that it is designed to fit to the factory uppipe. This allows for simple installation to either an OEM uppipe, aftermarket uppipe, and our rotated turbo kits.This is important you can upgrade any part of the system when you choose to.

BOOST RESPONSE

Because of the design of the PERRIN equal length header boost response is also improved.  Most all cars will see about 300RPM quicker spool. This does many good things for the car.  More boost at lower RPM equals more torque, and more power. At the dragstrip you will notice quick 60ft times, 0-60 times will be greatly decrease, and the overall fun factor of the car is greatly improved. check out our charts section showing the boost response of a GT3582R.
 

SOUND

The only downfall with the header is the loss of the Subaru sound.  The lumpy, thumpy sound everyone has come to love becomes a nice smooth buttery sound, for everyone to fall in love with all over again.  Because of the unequal nature of the OEM header, the exhaust pulses are paired together causing that lump sound.  The PERRIN header changes the note of the exhaust because of it equal length design.  The sound pulses from the exhaust are equalized and spread out, causing the smoother, more refined sound coming from the exhaust.
 

Below is a test of our header on a 2005 Legacy GT. This car started asa stage 3 LGT with the PERRIN TMIc, and uppipe installed. Only the header was changed between runs. check out the torque!

Below is a test a Nasioc Member did on a stage 2 STI. This car had just an EcU flash and turbo back.  Between runs only the header was changed, no EcU retuning. 

Below is a tuned PERRIN GT3582R rotated turbo kit, running 21psi.Again just the header is changed between runs.  This test was done in the very public forums on NASIOc, by Tim Gentil.

 

 Below is the boost response change on a GT35R with only the PERRIN header changed between runs. Another great graph provided by NASIOc member Tim Gentil.

 

compatibility Note:

Fits all Subaru Turbo Models

2008+ WRX and 2008+ STi Fits NO mods! 

02-05 WRX models require a STi type oilpan and oil pickup for necessary clearance. (can be purchased from your local Subaru dealer. call or e-mail for more information!)

2004-05 FORRESTER XT models require the STI type oil pan, oil pickup and 2002-2004 WRX oil cooler, for necessary clearance. (can be purchased from your local Subaru dealer.  call or email for more information!) 

2006+ FORRESTER XT models require the 2002-2004 WRX oil cooler.  These models have the correct oil pan. Please call for further details.

06+ WRX's require modification to oil cooler. Please call for further details. 

Also fits all Automatic models as well. No interference.

Is not compatible with header wrap material and will void any warranty. Please call with further questions.