AP Formula 4 piston
 

Just finished installing the AP 4 Piston Formula kit (Thanks Essex parts!) Install went smoothly and all parts needed were in the kit. Took it out for a test drive and the brakes are much more responsive and feel just like the Brembos on my Evo X. The only thing I did notice about them is that the pedal travel has increased a bit. My first assumption was that we didn't bleed it right so I redid the bleeding but still same pedal travel. Has anyone installed these and gets the same longer pedal travel before it gets hard? My other thought is that bigger surface area of the AP pistons require more fluid hence the longer pedal movement. Here is a picture of the install.

FYI Keep an eye on clearance with the wheel weights. I've had the weights hit the caliper.

When you bleed the fronts the reservoir goes dry fast keep it super full. A little bit of extra travel is normal but if its much deeper, bleed again just to be sure.

Anyone looked into a different master cylinder that might work better with BBK's?

A properly designed BBK won't need a different master cylinder... just because there is more pistons doesn't mean there's more volume since each piston is smaller than stock. Most of the BBK's keep the fluid volume required very close to stock from what I've seen.

I had super long travel when I missed the step about bleeding the inside nipple first then the outside. I only did the outside. Make damn sure you bleed inside first, then outside.

Now my pedal is a rock and more like an on off button.

I tried asking in the official thread for these. Are these able to handle a car with FI on the track with wide sticky tires or is the Sprint or Endurance needed for that?

I like this kit because I can keep 17" wheels and want it but if it won't stand up to increased power and grip I guess I'll have to settle with a sprint kit and 18" :\

The AP Kit should be able to handle FI and sticky tires just fine. The limits of the power in these cars is still fairly low and the chassis is light. There are a lot of factors that could change that statement but for all intensive purposes it should work fine.

No long pedal here. ROCK hard actually. Like something else...

I am so jealous...

Will try bleeding inner then outer and get back to you guys. Otherwise I am loving it. Braking is out of this world. Amazing kit would highly recommend.

Depending on your driving skill, you're probably 100% fine with stock rotors and calipers, just upgrade to better fluid and pads.

Boost won't magically make you faster on a track, so you might not be carrying that much more speed into braking zones over a better driver with much less hp.

If there were larger MC options then it'd be ok though.. lots of OEM upgrades on other cars end up that way but aftermarket solutions usually don't.

My essex kit (not the formula of course) still has a solid pedal :thumbup:

Depends :)

I agree that they will work (as long as they can lock up those sticky tires blah blah blah) but if the car is fast enough it might overcome the ability of the formula system to hold and remove enough heat.. but that's going to be very car, driver and track specific so there's no "right" answer.