AP Racing brake systems in development

[JRitt]

You pretty much nailed it Matt, I did not have any method of determining actual rotor temps, but they were very blued and cracking as mentioned. I actually noticed after two days of running the car bone stock, before swapping in the DS2500's and new OE spec rotors that the seals were starting to get a little wet around the edges... I guess it is time to upgrade, yet again. The rears SEEM to be okay, (not leaking) but being that I was on the stock pads in the rear, the rotors/pads are toast. The Essex kit should be looked at as more then a performance upgrade, it is also a reliability upgrade if you drive your car hard on track. I think I need a set...

Hmmmm...I'm really surprised by the seal failure. It doesn't sound like you had much track time on your OEM calipers! Give us a call if you want a kit...they're starting to ship today, and there only a handful left out of the first batch.

would you go as far as saying if there is a stock replacement thats even worth considering- ie, is taking a set of centric blanks rotors to the track smarter than stock-given the reports of cracking? I too planed to live with fast wearing rotors and ds2500s for a hot minute while I save up bbk money. is it worth twic ethe price for a 'cryo treated powerslot', knowing its made from a centric blank and will be piss after a dozen track days no matter what?

I need to look at BBK options I suppose but it really wasnt in my budget right away, but after what I am reading here, seems I need to move it up on my timeline...

I wouldn't spend any extra for cryo treated discs. The Centric/Powerslot discs are good replacements for stock. The main point is that they won't give you any additional thermal mass, and unless they have a directional vane design (I'm not sure on their latest version), they won't flow any more air than stock. You will still be limited by their overall dimensions and fundamentally similar design to the stock pieces.

The AP Racing discs are giving you a much larger heat sink, and they are far more efficient at moving air and dissipating the heat they absorb. Also, the friction puck on the pads in our kit are 50% thicker than stock...giving you a much thicker thermal barrier between the pads and the seals/pistons. The seals in our calipers are high temperature racing seals, designed specifically for the track. Finally, the pistons in our system are stainless steel, and don't transfer heat to the fluid as rapidly as the OEM ones. All of these points add up to a setup that is far more suited to track temps.

IMO, if you need to save up for a bbk, you'd be better off with brake ducting than fancy OEM replacment discs as a short-term solution. Proper ducting will bring more cooling air to the discs (by proper, I mean positioned precisely so the air is flowing into the center of the disc...not just blowing in the general direction of the brake assembly). Even ducts may not do the trick though, because there's nowhere for the air to go! The air gap on the OEM discs (below) is so narrow and tight, it's sort of like trying to blow a gust of wind through a drinking straw.


Here's one of my favorite pics again...the air gap on the AP disc is twice as wide and optimized for flow. This is the Sprint disc...the Endurance disc is even bigger!

[Dave-ROR]

Originally Posted by OrbitalEllipses

Dave, are you running XP8 all around or XP10 at the front and XP8 at the rear? It's typical with Imprezas to run a higher cF rear compound for better bias. If you guys are overheating the front while the rears aren't getting hot...perhaps try a higher cF rear pad and report back?

I'm running XP10F and XP8R. I will be running AP C300 on track F&R in November.

[Dave-ROR]

Originally Posted by JRitt

Hmmmm...I'm really surprised by the seal failure. It doesn't sound like you had much track time on your OEM calipers! Give us a call if you want a kit...they're starting to ship today, and there only a handful left out of the first batch.

Stopped reading after this, but that's the best news I've heard all day!

[OrbitalEllipses]

Originally Posted by Dave-ROR

I'm running XP10F and XP8R. I will be running AP C300 on track F&R in November.

Interesting. I recall people arguing about pad compound front to rear in another thread, not sure why higher cF rear pads didn't come up. If the rear brakes aren't working as hard as the fronts...give them a more aggressive pad. I undertand it can make ABS funky, but I've never experienced that. Only better braking.

[Dave-ROR]

Originally Posted by OrbitalEllipses

Interesting. I recall people arguing about pad compound front to rear in another thread, not sure why higher cF rear pads didn't come up. If the rear brakes aren't working as hard as the fronts...give them a more aggressive pad. I undertand it can make ABS funky, but I've never experienced that. Only better braking.

I've noticed the back get light in the BRZ, which to me points to the rear not doing enough work (at least I've fixed it before with more aggressive rear pads).

So I'll see what happens once I'm running equal pads F&R.

[JRitt]

Interesting. I recall people arguing about pad compound front to rear in another thread, not sure why higher cF rear pads didn't come up. If the rear brakes aren't working as hard as the fronts...give them a more aggressive pad. I undertand it can make ABS funky, but I've never experienced that. Only better braking.

Our recommended starting point with our kits is to run the same pad compound front and rear. Then you can adjust to taste. Each platform is going to be a little different, as will each driver. I've had some top time attack customers running higher mu rear vs. the fronts on their STI's, etc. It just depends on what you like. Again though, our recommended starting point is same cF front and rear.

[gmookher]

yeah..while I wait till I can afford BBK, where the heck are those ds2500 rears? what are you all making do with in the interim? my rears are still oe
the XP8R will be okay with my 2500 fronts? or should I just wait?

didnt realize there was a AP C300 avail in OE rear sizing?

[JRitt]

yeah..while I wait till I can afford BBK, where the heck are those ds2500 rears? what are you all making do with in the interim? my rears are still oe
the XP8R will be okay with my 2500 fronts? or should I just wait?

didnt realize there was a AP C300 avail in OE rear sizing?

My latest updates from both Ferodo and AP Racing is that we should have the rear pads the week of Nov. 11th. Yes, the AP Racing C300 will be available for the OEM rear as well...just don't have them yet.

I have never personally run the XP8 rears with the DS2500 up front. My hunch is that you'd probably be fine, but I just don't know how the mu stacks up on those too (real world mu across a temperature range, not claimed mu on paper based on different dyno's). Conceptually, those two compounds are designed for the same thing...light track duty, autoX, etc.

One other note...We have front (OEM front and for our CP8350 calipers) and rear Endless compounds coming in about 3 weeks as well. We have their MX72 and ME22 incoming.

[Dave-ROR]

Ok So I'll be running C300 front and rear after November, Sebring event is Nov 11th December = Road Atlanta race, but maybe AMP Dec 2nd.

[Calum]

Originally Posted by Dave-ROR

Ok So I'll be running C300 front and rear after November, Sebring event is Nov 11th December = Road Atlanta race, but maybe AMP Dec 2nd.

Where is this AMP you speak of? I doubt it would be Atlantic Motorsport park, but I thought I'd ask.

[Dave-ROR]

Originally Posted by Calum

Where is this AMP you speak of? I doubt it would be Atlantic Motorsport park, but I thought I'd ask.

Had to google Atlantic Motorsports Park. Their website has a virus, but thanks to Wiki.. no I'm not going to Nova Scotia

Atlanta Motorsports Park: http://www.atlantamotorsportspark.com/

They are doing a Toys for Tots drive on 12/2 which I want to do if it's not full.. $85 + 2 toys..

[gmookher]

jritt

soon as you get the rear Ferrodos let me know, can paypal or give credit card as soon as u can ship
thanks!

[mike2100]

Originally Posted by Dave-ROR

Good job on getting that much out of the pads.. stock fluid?

I had air in the calipers which caused my fade after a few laps at Mid Ohio. Not sure if it was a bad factory bleed or if I boiled it.. hard to believe I boiled it in 3 laps though.

I left the stock fluid in for the first day. I wanted to see how it would fair. I boiled the shit out of it, but it only took about 750mL of Super Blue to replace it and get the gas bubbles out.
After the second day I had the pads all the way down, but they wore very unevenly (inner/outer wear was similar, but on the same pad I had a hell of a wedge going).
This was on VIR South, a roughly 1.5 minute course with 4 braking zones per lap. And this was with VSC in sport mode both days!
They probably lasted that long because I was still on stock tires, but I'm not yet convinced of the necessity for an expensive total brake system upgrade.
Wishful thinking perhaps...

[Surok]

Do you think your sprint brake kit and endless mx72 front and rear will be a good combination or should I have a more/less aggressive rear pad?