Here are the instructions from Perrin themselves. Very detailed and easy to follow.
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Perrin Subaru Performance
Up pipe Installation
Warning: Offroad Race Use Only.

Thank you for purchasing the PSP stainless, catless up pipe. You will find this is a very high quality part, made for your Subaru WRX. The PSP catless up pipe has been designed to remove a very restrictive catalytic converter from the pipe before the turbo. Because this pipe removes one of the many catalytic converters on the WRX, it is for off-road use only.
I recommend having professional mechanics to do the install or help with the install. If you choose to do the install, I have provided very in-depth, step-by-step instructions for ease of installment.

Please read through all the instructions before performing the work. This isn¡'t the easiest thing to install, but with experienced help, it can be in a matter of a few hours.

Warning! Make sure you spray all the bolts with liquid wrench or equivalent. The nuts and bolts that hold the exhaust to the turbo, and the manifold to the up pipe and crossover pipe, have been know to seize together. Let the liquid wrench sit for a few hours before you remove them.

Tools you need:
O2 sensor wrench
3/8 drive ratchet
1/2 drive ratchet
Assorted extensions for 3/8 and 1/2 drive ratchets
10, 12, 14mm 3/8 sockets
12, 14mm 1/2 sockets
2- 14mm open-ended wrenches or gear wrenches
2- 12 mm open-ended wrenches or gear wrenches
10mm open-ended wrenches or gear wrench
Flat head screw drivers
Liquid wrench/ or equivalent
Assorted pliers

Let car cool off and prep for install.

1- While letting the car cool, remove:
Lower plastic splash guard (3 1mm bolts and 4 popits)



The air cleaner and box (2 12 mm bolts down low on the chassis)



Blow off valve. (2 12mm bolts)
Intercooler (2 12mm bolts and 3 hose clamps)



1. Intercooler bracket (2 12mm bolts)



Turbo heatsheild (7 10mm bolts, some of these are tricky to remove)
You will need to cut part of the turbo heatshield away, to make room for the relocated EGT bung.(Indicated by the black line on the turbo heatshield)






Front 02 sensor wire bracket- mounted on #3 cylinder coil (1 12mm bolt)



Front 02 sensor. (The sensor can be most easily access via a port on the passenger side wheel well. This port is covered with a 4 popit shield. It is a good idea to get an O2 Sensor socket for easy removal)




Lower exhaust manifold heat shield (4 12mm bolts)




It is a good idea to spray all of the bolts on the turbo and manifold with liquid wrench or WD40. (There are 5 bolts on the downpipe side of the turbo, and 7 on the lower exhaust manifold.) Let the bolts soak for at least 30 mins, the longer the better.

2- Remove the 5 bolts that attach the turbo to the exhaust downpipe ( 5 14mm bolts )
3- Remove the 7 bolts on the lower exhaust manifold ( 3 14mm nuts, 4 14mm nuts and bolts )
4- The exhaust manifold can now be removed. This is a good time to tap for an EGT sensor if you plan on installing one.
5- Remove the exhaust down pipe, and 2 midpipes. [Stock Exhaust. Aftermarket exhaust could be different] (5 14mm bolts (turbo) ,1 14mm bolt to tranny case, and assorted 12/14mm bolts on the 2 midpipes. Be sure to support the mid pipe that contains the rear O2 Sensor.
6- Remove the lower turbo heat shield. (mounted to up pipe with 2 10mm bolts)
7- Remove the 5 14mm nuts that bolt the turbo to the up pipe and larger bracket. ( 3 for the turbo, 2 for the bracket )





8- IT may be helpful to loosen the one bolts on the larger bracket that hold the bracket to the block. This will make things come out a little easier.
9- Unplug the EGT sensor connector located on the shock tower. (blue and black wire)
10- Remove the Passenger side motor mount nut/washer.



11- Using a jack and block of wood, jack the engine up enough for the uppipe to be removed out the bottom. You should only need to lift the engine approximately 2 inches. Be careful not to hit the EGT sensor on the way out.
12- Lower the engine, and tighten the motor mount nut.
13- Now that the up pipe is out, spray the EGT bung with liquid wrench.
14- Remove the EGT sensor and install it in the PSP up pipe. Use some antiseize on the threads when installing.
15- Place the old gaskets on the PSP up pipe.
16- Tighten all bolts flush with flange. (17mm heads)




17- Slide PSP up pipe into the car from the top. (This should be easier than the removal, since the PSP up pipe has more clearance )
18- Place PSP up pipe in the turbo bracket, use one of the nuts to hold it there.
19- Reinstall the lower exhaust manifold with the old gaskets. Don¡'t tighten all the nuts and bolts. ( 3 14mm nuts, 4 14mm nuts and bolts )
20- Snug all nuts and bolts down on the manifold, up pipe and crossover pipe, and brackets.



21- Install and tighten nut on the small turbo bracket ( 1 14mm nut )
22- Torque the nuts and bolts in this order:
Manifold to cross over pipe ( 2 14mm bolts )
Manifold to up pipe ( 2 14mm bolts )
Manifold to block ( 3 14mm nuts )
Finally turbo to up pipe ( 3 14mm nut )
23- Proceed backwards from step 9, reinstalling parts.

You have now completed the installation of you new Perrin Subaru Performance Uppipe!

Start the car to let it warm up and listen for exhaust leaks.
There may be a more noticeable engine noise coming from the PSP up pipe due to the lack of a catalytic converter and heat shield.

Thanks for purchasing the PSP up pipe!

Jeff Perrin
9855 sw serena way
Tigard, Or 97224
Jeff@perrinperformance.com
503-643-4677