Teal I have to chime in here.. with more hp you accelerate faster. Faster acceleration means you're more likely to be goiing too fast for a turn when you get there because of the way most people drive. They romp on it and stop at the last second. It's not that you require bigger brakes with more HP it's just common sense to add more capacity as you add power.

I've had the following experiences on my 03GT. These are all from runs over 1 hard driving mountain road that I've been over like 950 times so the results are pretty well normalized. the first 4 are with OEM type pads:

stock front/GT rear = MASSIVE fade under hard driving. So much so that after one particular trip over my favorite mountain road at speed, I had to slam on the brakes to avoid a horse in the road and the front end lifted after about 5 seconds because the brakes overheated. That required an emergency maneuver I don't want to have to do again. They took forever to cool back down and it just felt wrong for a V8 car to stop that slow. A car that lethargic in slowing down makes me nervous.

stock front/cobra rear = no real change in stopping distance or reliability but ebrake slides were easier. Car was a tad unbalanced in uphill right cornering braking.

Cobra front/GT rear = Wicked stopping. Minor fade under extreme braking but they cooled quickly and returned to normal. Tires were the limiting factor on my stopping distances. Rears would smoke after a trip over the hill.

Cobra Front/Cobra rear = Same basic stopping as the Cobra front/GT rear except that I got a little lockup on the rears now and then. Very much a confidence inspiring feeling to be yanked to a halt that fast.

Cobra front/cobra rear w/ EBC green pads = A serious workout of the ABS system. bites hard and never lets go. No fade that I could induce. Increased rotor wear. tires are still the limiting factor.

So, to break it down. For a v6 the stock brakes are adequate for most driving. For a V8, there's just too little rotor mass and area to let you stop hard more than once without fade. The cobra kit stops about as well as I can stand and there's plenty left over for a second sudden stop.

As for drag cars... most of the guys that I know that drag race use pretty small brakes for the power they make. They also use parachutes so I can't see that being really a valid basis for comparison.

 

yea look back to my first post i said that one of the reasons to upgrade brakes were for auto-x etc (because of brake fade) but your adverage highway/city driver wont need it imo.

I believe the "more likely" argument is null because that is up to the individual, some people have a lead foot, some dont. odds are having more horsepower isnt going to change your diving habits.


Good writeup though, good info for someone looking to upgrade.

 

no, I read that. But that road wasn't autoX. it was my commute for 4.5 years.

I drive like most stangers, hard and fast all the time and I need all the brakes I can get anyway. The hell of it is, everyone around here drives like madmen all the time... the freeway is 80-0-80 without fail so fast repeatable stops are imporatant.

Don't get me wrong, I agree with you as far as the typical american driver goes, just not the typical American Mustang driver... we're a lively breed and as far as I'm concerned, if you're gunna drive it fast you better be able to stop just as fast.

If you're super calm or just knocked out on oxycontin all day, then stock brakes are fine but if you like to gitty-up when you know there's a turn coming, upgrade.

The best combination for balance and average performance with a 4wheel cobra kit is OEM type pads in front and Hawk HPS or EBC Green in back. It's a very firm and well balanced arrangement. Aggressive pads up front are not usually worth the extra money on the street.

 

i have a bullit n they suposed to have cobra brakes

 

they're supposed to and they do... unless it was molested prior to your ownership. they're a great brake setup. Should have come stock on all v8 cars.

 

I would agree for most people with a daily driver the 13" upgrade really just isn't going to be needed. If you drive hard and use the brakes allot then fad will be a problem. I too had a scary experience when i was racing and i came from 130-0 then about 1 minute later we raced again too 120ish and when i stepped on the pedal there was nothing there hardly at all. It was damn scary feeling to say the least. Thats the only time i felt like the stock brakes weren't gonna cut it.

Now i never do that ever i mean thats happened once since i owned the car. But i must say that was an eye opener when i pulled over finally and the rotors were glowing red and i had no stopping power with a **** for a good 10 mins of driving.

 

I am drooling over some "big brakes" for the 03 GT I just got, but have been terrified at the prices....... Where did you get the "$360-$450 new for front kits" I've been seeing prices closer to $800-$900 for 4 piston upgrades. And the only $350 cobra upgrade I saw was the from older cobras (wanna say 98). I would love to find brakes that cheap.... Also, is going from one 2 piston setup to another really that beneficial.

 

So just to clarify..... The add in the Summit I just looked at to "upgrade your GT to Cobra stopping power" that includes 13" rotors and 2 piston calipers "used on the 94-98 Cobra", plus lines pads and brackets from ford motorsports is worth the $394. Or do you know a better way?

 

No kidding I did my Bullitt brake swap (w/ stainless line) 2 weekends ago anyone who says they're not worth it hasn't done the swap. Big time difference. For the better. Now I'm just going to get the D/S Baer Eradispeed+ rotors for looks...

 

Just to chime in here... Bigger brakes aren't really going to change the braking distance greatly... The big thing about larger rotors, venting and slottinh is the fade resistance.

If you want harder stops, by some good pads with good strong initial bite. If you're never going to see track time, save your money. It's not like you're going to almost get in a wreck 10 times in a row one after the other like on a track.

One more thing, I think it was said before. Tires make the biggest difference in stopping distance anyway. I can't even get my ABS to kick in with my 275/40 Kumho VictoRacers (treadwear rating of 50...) on the car... I can brake from 130mph down to 45mph or so without the ABS kicking at all. Get my 245/40 Bridgestone Potenza's back on and it's an ABS nightmare.

Just some useless food for thought...

-B

 

Car and driver tested that the BULLITT was the shortest braking mustang made since the '95 R. That car is a monster at the track (as long as it has a bit more breath... Long tubes and free exhaust usually does the trick)... I should know, I had one lol.

 

upgraded my '04 gt to bullitt brakes. on the front used frpp calipers and severe duty rotors and hoses, used the stock gt brackets. on the rear also used frpp calipers and install kit. differance in bracking performance very noticable and reasuring. driving in sf bay area is less scary now than before. even for otherwise stock gt this is a advantagous change. just my 2cents

 

I know this is an old thread but I was just wondering if there was anything you could do with the stock rims.....
AM brake kits all say you need 17" rims... i dont want 17's

 

then you'll have to suck it. Try more aggressive pads... EBC yellow have a pretty strong bite and they don't fade easily.

 

would getting the cross-drilled rotors from AM help any?
i do alot of mtn driving

 

nope... do more harm than good probably. You can get slotted rotors if you like but I'd stay with plain faced.

 

You don't HAVE to have 17" rims, but they have to be ATLEAST 17" in diameter, that is to make sure the wheel clears the brake assembly.

 

so, with my biggest enemy being fade, is it better (dont realllllyyyy want to spend 1K) to just bite the bullet and get bigger rims and the 13" rotors and such or just get better pads and rotors (are there any better ones for stock size?)
ive read r3dn3ck post on the top of this page and seems like there really is no way to stop fade with stock rotors....
is this true?
Thanks guys!

 

fade is based on your rotors ability to move heat and your pads ability to generate heat. If you're running it like a race car for half hour endurance breaking events then yeah.. bite said bullet and get cobra or even 4 piston brembo's. As you increase the capacity of your braking system with bigger rotors and more powerful calipers then you can decrease the aggressiveness of the pads to yeild about the same heat carrying capacity.

If you have trouble with fade with EBC yellow pads on stock rotors then you're pretty well screwed and you'll need to upgrade to cobra 2 piston or brembo 4 piston. Of course then you get to deal with finding the right pad and rotor combo for that setup.

I'd say try the EBC's first.

 

I agree with ICEMAN, the pads are more important than anything else!
I tracked my Bullitt at watkins glen with the stock setup, the brakes never faded within 8 25 min. runs with about an hour and a half in between runs, but the pads were gone (no material left) after the 8 runs. The stock cobra (PBR) front pads are awsome for the street,but won't last under heavy use. I put Hawk Blue Race pads on for the next event and loved them, more bite and very little rotor wear, I got 3 track events out of that one set. I now have a set of street pads and rotors and a set of track pads and rotors. My point is, you just need to match you brakes to your needs. A good set of street pads won't be a bad thing.

 

Old

 

I've been thinking of upgrading the front brakes on my 2000 GT for some time. Can anyone tell me if the Cobra set will work with the stock 17" wheels or do I need to replace those first? The ones I have are the standard silver 5 stars'.

 

If they are 17" stock rims they will work.

 

bigger brakes = more surface area & lower rotational speed at the caliper, the smaller your brakes are the faster they will be spinning. I can't remember all of the formula's and it's too confusing looking at it now that I've been out of school for several years BUT we can assume that if the diameter of your tires/wheels is 26" and your brakes are 13" and you are travelling at 60mph that your brakes are probably rotating somewhere near 120mph, if you have the same set up but with smaller brakes say 10" they will be rotating at 156mph at the caliper.. now lets say you, for whatever reason decide to put honda civic brakes on your car.. the brakes are rotating 165mph at the caliper (remember the car itself is only moving 60mph)

now lets say you're at the race track going uhh... 160mph. The 13" rotors are going 320mph. the 10" rotors are going 416mph and the honda civic 240mm(9.45") are going 440mph.

factor in momentum, friction vs ground, friction vs calipers, friction vs rotor and the 10" brakes start looking very scary for panic situation

bigger brakes
= lower rotational speed at the caliper
= more surface area
= shorter/faster stops (so you don't hit anything/one)
= less wear/tear (so your pads dont need to be replaced as often)


if you DONT go to the track and you DRIVE the speed limit you probably dont need better than stock brakes, otherwise go upgrade!

my .02
if you don't like my numbers feel free to crunch them yourself, but I'm pretty sure they are accurate

 

You're partially incorrect: it's actually a higher rotor speed if you're measuring linear velocity. If you're measuring angular velocity it's exactly the same.

The larger surface area and higher linear velocity of the larger diameter rotor creates greater friction across a friction pad of similar area using a caliper of similar clamping force capacity by exposing a greater surface area to the friction pad in the same amount of time at a given wheel speed than a 10.8" GT brake setup. In short, bigger rotor is better pretty much regardless. And I 100% do not agree with them as a race item. There are 4 and 6 pot calipers for 14" rotors for real racing. The cobra brake kit is what I'd call a minimum for reliable stopping of as powerful a machine as ford puts into the hands of total motards.

Pads and rotors are slightly more expensive but stopping that extra 30ft sooner sometimes is important. It's like carrying a pistol or a pocket knife or a hanky, you're better to have it and not need it than to need it and not have it.