AP Racing "Sprint" BBK long term update
 

We've had the BBK on for around 29k miles of mixed street and track driving. We've also gone through 2.5 sets of tires on them, but keep in mind that most of the driving on the BRZ was in spurts of 1-2 hot laps at a time for data collection rather than full sessions, and spirited canyon runs, so it's a LOT of heat cycles.

In terms of brake pad, we went through around a 1/2 set of AP Racing C300 C300 (~7mm), a full set of Carbotech XP12 (15mm), and 1/2 set of Project Mu Racing 999 (~7mm). Additionally, we went through about 1mm of street pad (Carbotech 1521). Also, we ran NO ducting, which is testement to the sheer capability of this setup.

The microfractures on the inner edges have been there a while, and we've been keeping an eye on them, but they haven't propagated past the vanes. Essentially, they LOOK bad, but have zero effect on braking or brake pedal feel for street and track driving.

FYI, the inner edges of the rotors also have J-hooks. We just wore completely THROUGH them.


We're currently running a special on this setup, please PM @CounterSpace Garage for pricing, details, wheel fitment, and application questions. If you need pad recommendations, feel free to PM either myself or @CounterSpace Garage.

Now, on to the pictures.

Inner side of the rotors; you can see the cracks, and the J-hooks are completely worn off. You can also see heat checking/microfractures if you look closely.
https://fbcdn-sphotos-g-a.akamaihd.n...84248977_o.jpg

Compare the thicknesses of the inner and outer edges...

https://scontent-b.xx.fbcdn.net/hpho...25894437_n.jpg

The front J-hooks are nearly worn down. The heat checking is much more visible on this side.

https://scontent-a.xx.fbcdn.net/hpho...22406789_n.jpg

Front and back of the rotors

https://fbcdn-sphotos-b-a.akamaihd.n...90478661_o.jpg

Wow such amaze! Much brake! Doge want.

http://i3.kym-cdn.com/entries/icons/...t0ZfPEZ_1_.gif

@CSG Mike

What would your take be on the uneven wear? as in why it happened and prevention?

It has to do with physics.

ww

Wow, really. And here I thought it was astrology.... It's monday where you live isn't it?

My first guess is the uneven wear is caused by, IIRC, the lack of piston seals in this kit. I'm sure we'd all like to hear what Mike or David have to say about it though.

I'd suspect the inner side is hotter since there's less heat sinking (the hat) and less airflow than the outer edge.

Ducting will likely mitigate most, if not all of this.

We're watching @ImperiousRex's car for this, as he has the same setup, but with ducts.

We run a similar setup on our S2k, and we're keeping an eye on that as well.

Thanks for the reply, people have had ducting worries of uneven wear of cooling only inner side.

If this checks out, it may be that the ducting will actually reduce the uneven wear.

Oh you.



trollface.jpg

I have the APR inner ducting with AP spring kit both order from CSG. I will see mine after long term test.

Other than stopping power, didn't someone talk about the benefits of cheaper pads/rotors and longer lasting pads/rotors before? (can't remember which thread).

Can you elaborate on this?

Currently running OEM setup with the TF Brake Cooling kit; front pads are lasting around 6 total track days ($180 a set) and OEM-based rotors are lasting around 6 days as well ($90 a set). Looks like I'll get about a years worth of events with the rear pads. I'm fine with the braking capabilities of my setup, just curious of long term costs vs. BBK initial cost and long term expense.

you guys murdered those brakes... lol

Two front rotors for $90? That seems unbelievably cheap, even for a basic Centric rotor. It's pretty scientific with regard to the consumables cost: the pads are thicker, so there's more to use with less often time to replace.

Have you read @JRitt's technical posts about the Essex kits?

Yep, $90 for two front Centric blanks, after two days I noticed a little bit less heat checking than I got with the OEM rotors, so I'm thinking they might last even longer than the stock ones. And in terms of actual wear (thickness), I measured 0.948" new, and after 2 days at Sebring, I measured the exact same thickness.

Nope, haven't read any of his technical posts.

I have only really looked into the Wilwood SL6 front kit, and found the replacement rotors to be about $170 each, which even if they last twice or 3 times as long, it still isn't worth it. And looking at the pads for the Wilwood SL6, they are only $40 to $50 cheaper than the OEM based pads.

Even if you're not interested in the kit, I highly recommend reading the technical posts. Some of it's marketing for sure, but there's a lot of great brake information that you will find useful even if only retained in your repository of knowledge.

We're on track to average around 8-15 days per set of pads (depends on the track... Laguna Seca and Auto Club Speedway are murderous on brakes), which is roughly 2.5x longer than pads on the stock calipers. However, the pads themselves, on average, cost about 5-25% more. OEM size pads typically last 2-4 days, depending on the track.

OEM rotors or replacements average about $200/pair (ballpark) for the fronts, and typically last 1 set of pads (for us) when they're on the verge of fully cracking.

The increased life is a function of a larger pad(50% thicker, ~85% more pad material), larger (thicker) rotor, increased cooling area (more vanes, more surface area), and increased heat sinking with larger components.

Keep in mind that less experienced drivers will probably have reduced wear rates, but the increase in brake life will still be consistent.

The numbers:
2-4x pad life for 1.2x the cost.
3-4x rotor life for 1.5x the cost.

Additionally, if you do decide to sell the BBK at a later point, you'll recoup a lot of the initial investment in purchasing the BBK to begin with.

While absolute braking performance isn't increased, the BBK will allow for much finer control when you're modulating the brakes, whether its threshold braking, trail braking, or left foot braking, and give you massively increased heat capacity. There is a minor performance gain from having less unsprung and less rotational mass.

Anyone who is tracking more than a few times a year will save money with a BBK.



@ImperiousRex is at about 15 track days on his current set of pads, and has around 2/3 of the pad remaining.

@D1cker is at about 5 track days on his current pads, and has over 75% remaining.

Yeah, I am seeing the rotors last about the life of pads, but dang, $200? you buying OEM from Subaru?

15 days is incredible on a set of pads. I'm getting about 4-6 days out of mine, depending on what pad combo, but mostly at Sebring, which is very hard on brakes.

Hey @Dave-ROR, what are you seeing at Sebring with your AP kit?

http://www.knsbrakes.com/c/car-serie...-+Single+Rotor

Not the rotor I'd go with...but I see it is possible to get cheapo blanks.

I've cracked 3 c-teks in 2 sessions before... :D

I stick to Brembo blanks on my own car, with Centric Premium as a backup when I can't get Brembos (I usually buy a stack at a time...)

Agreed. Brembo blanks are fucking pricey though.

Only about $55 for my s2k :D

But they're still not as cost effective as a BBK. Nowhere near. Problem is, clearing a BBK on the S2k is really, really difficult.

Good thing we have no such design limitation! The Brembo blanks in STI size were hideously expensive if I recall...but I had no qualms about running a DBA rotor in that application.

I agree. Clearing a BBK on the FRS/BRZ is just a minor consideration when selecting wheels... and you can always get higher offsets and run spacers/extended studs, so options are nearly limitless.

My wheels need a 20mm spacer to clear the Sprint kit on the S2k... which would mean I need a widebody or at least wide fenders. My fenders are already rolled and pulled...

This is a CSG customer's car... you can see how tight the clearance is. He's running track camber (the car is tracked regularly).

https://scontent-a.xx.fbcdn.net/hpho...91795446_n.jpg

Showing all the little things considered when this car was designed.

Das hawt.

He rolls on Ohlins TTX36. :bow:

I don't think he's ever swapped pads either...

that's even a bit too cheap for my taste, lol.

I went with the Centric "premiums":
http://www.knsbrakes.com/c/car-serie...-+Single+Rotor

They're fairing better than the OEM rotors did on my first 2 days out with them on track, even with a more aggressive pad setup than I had with the OEM rotors (more front bias on my XR2/XR4 combo now than my DTC-60 square setup that I ran on the original rotors).

Premiums are decent rotors, but no directional vanes or any fancy stuff like that...which ultimately is going to help your braking performance at the track.

More importantly, non-direction vanes promote cracking in deep heat cycling scenarios. The cracks almost always form along a vane. On the other hand, directional vanes add to the structure, and prevent the crack from propagating, as with our rotors, because it has to crack THROUGH the vane in order to continue.

I didn't get the mention in my notifications.. but.. I actually have paid less in general for my pads than I did for stock size, but.. I might have a slight hookup there ;)

I cracked one AP rotor before getting as much use out of them as CSG did, however, I was being VERY abusive on the brakes to see if I could actually get fade/failure (I never did - at least I don't consider a crack to be failure. I did however get some serious heat in the calipers and rotors). Pads.. I haven't even used a set up yet.

how many days total do you have on the setup?

12 I think? I think I had 8 or 9 on the rotor that cracked but that's wasn't normal.

Wow, that's great. Might have to look into a kit.

And still no issues with the stick rear set up?

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The Sprint kit is designed to be used with the stock rear brakes. We haven't had any issues :thumbsup:

I know the bias is good, just interesting that you still run out of thermal capacity at the front before the rears fade.

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One day, we'll find out... when we're running stickier tires and/or more horsepower. As it sits, there's no way we can ever overwhelm the brakes.

Garbage engine :mad0259:

http://www.s2ki.com/s2000/public/sty...t/banghead.gif

But the brakes are awesome. And the chassis. And the steering.

Agreed, but I drove @thejevans 20 year old Miata with a dead clutch last night...more fun than you can have with a BRZ on the street.