Tag Archives: Perrin

brembo, Cusco, Impreza, STi, Subaru, Turbo, WRX

Master Cylinder brace Install For STi/WRX

Master Cylinder brace Install For STi/WRX:

The brake master cylinder is located by the driver’s side strut tower and once you find it the rest is pretty self explanatory. I have a 2005 Subaru STi. Some later years might be slightly different.
Tools needed:
10 mm socket and wrenches
Zip tie (optional)

Master Cylinder Brace: A installed Cusco master cylinder brace.
Master Cylinder Brace: A installed Cusco master cylinder brace.

1.) Find the brake master cylinder located just inboard of the drivers side strut tower. The washer fluid bottle will be in the way so unbolt the two bolts and lean it forward, no need to disconnect it altogether.

2.) There are two brackets bolted to the strut tower visible in this picture. These are the two holes used to mount the brace. Unbolt these two holes.

Master Cylinder Brace: There are two brackets bolted to the strut tower visible in this picture.
Master Cylinder Brace: There are two brackets bolted to the strut tower visible in this picture.

3.)The lower bracket is not compatible with the master cylinder brace. Its best to remove the bracket, then zip tie the lines to the master cylinder brace at the end to keep them secure.

Master Cylinder Brace: Remove this bracket.
Master Cylinder Brace: Remove this bracket.

4.)The next bolt to take out is difficult to get a picture of but you will see it easily you can barely see it here, it is located slightly farther towards the back of the car, undo it as well.

Master Cylinder Brace: The hidden bolt is located slightly farther towards the back of the car, undo it as well.
Master Cylinder Brace: The hidden bolt is located slightly farther towards the back of the car, undo it as well.
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EJ25, EJ257, STi, Subaru, Tuning, Turbo, USDM, WRX

Pulley Subaru WRX/STi Rundown

The primary purpose of an aftermarket pulley is to reduce the size and/or mass of the stock unit. They serve two purposes: to reduce horsepower loss and increase throttle response. Notice the use of “reduce horsepower loss”. Pulleys DO NOT add horsepower, rather they free up horsepower due to the reduction of rotational mass.


Grimmspeed Lightweight Crank Pulley Black – Subaru All EJ Engines

A lightweight aftermarket perrin pulley.
A lightweight aftermarket perrin pulley.

HP gain is 5-10HP. These HP figures are a range as there have been very few before/after dyno runs with lightened or under driven pulleys.

What is a lightened pulley? Generally, it is an exact copy of the OEM pulley only CNC machined out of aircraft grade aluminum and powder coated for corrosion protection and aesthetic appeal.

What is an under driven pulley? This is a pulley that mimics the function of the OEM unit, but is smaller in diameter. This will reduce the duty cycle of the pulley and proportionally the parasitic drag on the engine.

Are under driven pulleys bad? It depends on the amount they are under driven. Some under driven pulleys can lead to reduced A/C output, lighting problems, stereo problems, and other voltage issues. Some are lightly under driven and some more so.

Isn’t replacing the stock harmonic damper (pulley) bad? Subarus do not come with a harmonic damper or balancer like some other vehicles do. For other manufacturers’ vehicles, this is a legitimate concern. Proof:

“Thank you for your patience as I checked with our Technical Services Department regarding your message below. They advised that the crank pulley is a pulley and nothing else. It is not used as a harmonic damper/balancer.

Thanks for the opportunity to be of assistance. If you need any future assistance, please feel free to contact us again.”

Best wishes,

John J. Mergen
Customer Service Department
Subaru of America, Inc.

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