D Walker

iTrader: (1)

Brakes can only be as good as the contact patch your stopping, otherwise its wasted weight and money.

gkmccready

The AWR kit is just 2pc stock sized rotors and better pads.

What you're really looking at with a BBK is:

• rotors
  • more mass = more heat capacity
  • slightly better leverage if the rotors have a bigger diameter
  • better iron composition
• caliper
  • pad cost
  • pad availability + available compounds
  • pad thickness/size = more heat capacity
  • ease of pad changes
  • caliper rebuild cost
  • heat resistant pistons (stainless steel, titanium inserts, thermolocks, etc)
  • caliper stiffness
  • reduce pad taper (asymmetric piston sizes?)

I both agree and disagree with D Walker... your ultimate braking force is certain controlled by your tires available grip -- but they're lots of other benefits to a brake upgrade than just more clamping force...

D Walker

iTrader: (1)

Well I was being a bit simplistic

With adequate calipers, pads, and cooling there is little need for "bigger" brakes as most people think of them. What I look for in a better brake setup is:
A> more heat capacity through more material or improved cooling etc.
B> more mechanical advantage through greater torque arm effect, swept area, etc.
C> the least amount of weight possible to do the job. Sprung/unsprung arguements aside, there is no legitimate reason to carry 100lbs worth of rotors/calipers when you can carry 80lbs and get the same job done.

gkmccready

Exactly.

My biggest concern with brakes is always heat capacity as there really is only so much cooling you can route to the brakes in a useful fashion. It's a bonus when you can get thicker, cheap pads at the same time...

2Fierce

iTrader: (7)

Well, thanks for the info. I have 255's up front.

NOW! can anyone answer my question, in theory will the BBK kits made for the FD FIT an FC ??

RockLobster

iTrader: (7)

The is another reason to run big brakes in racing. Longevity.

We run larger brakes than we probably need but, the upside? We use a set of brake pads, per year. Yes, we are getting roughly 24 track hours on the pads. And rotors should last even longer. I'll let you know how long the first time we change em.

With stock pads and rotors on FDs and FCs me and friends had tracked we were using a set of pads a weekend. In my buddy's case on his FD he would use a set of pads in a day and a set of rotors in a weekend.

MUCHO more cost effective to have oversized brakes for when you are on a budget...and who isnt?

wrankin

Stock pads?!! At the track?!! Forget the weekend - I'd completely cook them the first session out and then they'd be all glazed up and useless after that.

I really cannot see that as a valid data point - a set of hawk blues(f)/blacks(r) and stock rotors on my 2400# NA FC has lasted me a dozen HPDEs.

Heavier car and faster braking speeds - I could see that. Was he running sticky rubber and stock pads? (Very bad combination, IMNSHO.)

I don't buy it - I can get a whole lot of rotors and pads for the cost of a brake upgrade kit. As long as I have enough brake to stop (which I do) and am not cooking the pads (not yet) the expense is just not justified especially since I am on a budget.

Best recent investment for brakes was installing a proper proportioning valve. Probably the next major effort will involve getting some actual on-track rotor and caliper temps and see if I need to put some ducting in.

Certainly different cars have different requirements for brake systems. But brake performance is the result of a lot of different factors and trying to fix it by going bigger/better/shinier (big brake kit) without first looking at the other components (pads, ducting) is really not going to be the most economical approach.

RockLobster

iTrader: (7)

By stock pads i mean stock size pads, in an HT-10 or DTC-60 compound.

The pads im running on the racecar now are WAY larger than stock, and a whole lot thicker.

My ducting is as good as it gets and was when i was using stock rotors and calipers. Still blew them up constantly. For me it is far more cost effective to spend 1500 on brake upgrades front and rear and race a whole season on pads and multiple seasons on rotors, vs a set of pads in a weekend minimum, and rotors lasting only a couple weekends.

TrentO

Brakes are all good to talk about what you can get away with, until they fail. Mine failed at 100 mph heading into a turn surrounded by concrete. Luckily, the felt a little spongy before so I started braking early and the pedal just hit the floor. After four pumps it grabbed a bit, but at that point I had already thrown the car into a spin to scrub off speed.
My current willwood setup was around $2500 CAD and includes the 6 piston calipers, 1.25"x 13" GT vented rotors and 3 pedal master cylinder setup with full recirculation. If I were to do it again, the only thing I would change is using an integrated recirculation system as opposed to the two one-way valves I an currently using (too many fittings and possible spots for leaks)

Overdo it on the brakes, you are much less likely to die.
-Trent

jrx13

iTrader: (3)

Anybody data log? My 87 N/A FC highest decel g was .97 (so accel g = -0.97). Guess I'm not braking hard enough because my stock rotors and Hawk Blues seem to last quite a while. Of course I'm not racing, just open tracking and my car only makes 140rwhp.

RockLobster

iTrader: (7)

Decel Gs are 98% tire and 2% brake...

Don49

iTrader: (3)

I run SCCA Nationals in EP. I'm running the stock brakes with Hawke Blue front, Hawke Black rear with a Wilwood proportioning valve. Ducting the fronts through the bumper with 3" duct. My pads last 6-8 races and will overpower the tires (23x9.5x15 Hoosier slicks) at will. The car weighs 2400#+. I know a number of guys who have tried to improve on what's there with no discernible improvements given the limitation we have on tire size. I regularly outbrake other cars in the class and see no need to change anything at this point. YMMV





2010 SCCA Sunoco EP Hard Charger

RockLobster

iTrader: (7)

It's definitely all dependent on weight and power. I think the stock brakes are fine on a non-turbo, lighter car that is sub 2600lbs race weight or even less... And yeah in SCCA the tire/wheel limitations certainly make it a no brainier.

But i still defend a well designed larger brake system as being more cost effective in the long run. Even in that case...

You try to run the stock brakes on a turbo and/or 3-rotor or a V8 car at anything north of 2600lbs and you will annihilate the stock brake pads in a matter of minutes, regardless of if they can lock the tires up. It's all pad and rotor volume and mass...

Then of course, if you want to try some of the longer endurance races in NASA you had better have larger pads just from the standpoint of them lasting a whole race...

TrentO

My stock brakes on my turbo FC worked until the brake ducting folded up on one side. At 2300 lbs, 400+ rwhp and 10" wide slicks in an hour race, the stock rotors just don't have the heat absorption required. I have built stainless backing plates to put behind the carbotech Xp12 pads and the heat still managed to boil the 550+ degree racing brake fluid.
I built my Willwood system to ensure brakes would never be a concern even as I went to bigger slicks and more power. The recirculating setup is the best thing ever invented as the pedal is always the same, lap after lap.

I'd advise overbuilding the brakes if you can. For an N/A Car, you don't need to bother, as the TII setup is pretty strong. When you cross 350 rwhp and serious grip, you need to upgrade.

-Trent

gkmccready

Waking this thread up again. My T2 front calipers are shot. I just ordered some Raybestos reman's from RockAuto ($150) because Mazdaspeed wanted close to $1k for them. Are there other sources for the 4-pot calipers if the RockAuto ones don't work out? Or just go Wilwood? http://store.revolutionbrake.com/marx7genii5l.html

aeowner

rotora makes a bbk for the fc around 2 grand

gkmccready

http://www.rotorabrakes.com/catalog/...oducts_id=6800 -- I don't see anything in that kit that makes it worth twice the price of the Revolution Brakes Wilwood kit. The 2pc rotors may be nicer, but I'm sure you could get HRP to build a 2pc to match the Revolution set up.

Miata_mx5

Try Worldpac if you have access to it.

j9fd3s

iTrader: (3)

out brakes started lasting longer when we put stickier tires on the car! the pads in the car now did something like half the 2009 25 hour, and all of this season, and there is still 4-5mm left.

so PFC pads + sticky tires = long pad life.

actually right now the rotors are looking pretty bad, we're going have have to change them because of cracking/metal fatigue.

wrankin

I assume that this is b/c you have higher corner entry speeds and so you don't have to brake/slow as much?

Definitely change them out - I've seen several instances of rotor failure (not on RX7s, just in general) and I really would not like to have been behind the wheel when it happened.

Speaking of which, I need to go look at mine now...

-b

j9fd3s

iTrader: (3)

exactly. power stayed the same, so straightaway speed is the same, but we can carry more thru the corners = less braking.

a few years ago we borrowed a Vtek engine, and the brakes weren't up to that, even though those lap times were about the same as we are running now.

doing the sticky tires AND vtek is tempting!