I thought my fronts looked bad. Yuck! those were horrible. I laughed out loud when I saw the pic.

 

LOL...isn't there a thread somewhere about how stock brakes don't suck???
Try upgrading your brakes to handle the application. That's why they're made. It's not "marketing hype", and it's definately "cool" when you can out-brake another driver into a corner. Mustangs don't seem to like trail braking, so getting all your slowing done before the turn is ideal and with the weight of these cars, if you're going to track your car more than once or twice, you need better brakes. It just kind of makes sense, dosen't it? Why push something beyond it's design limit, just to prove a point or save a few dollars? 13" four piston Wilwoods are more than adequate for all but full competition, and the entire kit is available for about 1700.00. Oh, and FIND a way to cool those brakes. That's almost mandatory if they're going to live.

Edited to add, and eat, a little crow. I was mistaken about the stock brakes...My bad...sorry for that, but there's still a point to my post, in that you're still dealing with a factory one piece cast rotor. I would have not recommended the GT500 brakes as an upgrade for that reason alone, plus the cost. They're veryheavy for what you pay for, and the rotor has little heat dissipation or separation as with a two piece. All you really get is an upgrade in diameter, and the Brembo caiper which really dosen't improve brake performance much. IMO the biggest advantage of the aftermarket brakes IS the 2 piece rotor, and without that, it's of little benefit. Remember that with the bigger diameter, you get added mechanical advantage, yes, but the surface speed of the rotor is higher, and they'll generate more heat faster, so unless you;re really taking advantage of the bigger rotor, there's no advantage there, just more weight. 14" rotors IMO are overkill for these cars. I have a few friends that run Time Attacks, and run very hard...they run the 13" Will's with no issues.

 

This sounds a lot like improper pad transfer, usually due to improper bedding of the pads. Here is a good Stoptech article:

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

Unfortunately there doesn't seem to be a good solution other than to have the rotors resurfaced or to get a very abrasive set of track brake pads.

 

Really? Care to elaborate on the trail braking issue? Please do it quietly, though, since my Mustang doesn't seem to understand this and responds quite well to trail braking.

Oh, and better make sure you tell some of the AI racers to upgrade their brakes, since some of them are using the stockcalipers quite successfully in their S197's. Even more are using the Cobra twin-pistons brakes.[sm=smiley2.gif]

 

F1Fan

Thanks for the reponse.

houstonnw

Here is a quote from the article you mentioned and as Figure 4 looks like my front rotors, http://public.fotki.com/colinjohn/mustang-gt-brakes/
, this seems to confirm that they are hard spotted.

"Regardless of pad composition, if both disc and pad are not properly broken in, material transfer between the two materials can take place in a random fashion - resulting is uneven deposits and vibration under braking. Similarly, even if the brakes are properly broken, if, when they are very hot or following a single long stop from high speed, the brakes are kept applied after the vehicle comes to a complete stop it is possible to leave a telltale deposit behind that looks like the outline of a pad. This kind of deposit is called pad imprinting and looks like the pad was inked for printing like a stamp and then set on the disc face. It is possible to see the perfect outline of the pad on the disc. (FIGURE 5)
It gets worse. Cast iron is an alloy of iron and silicon in solution interspersed with particles of carbon. At elevated temperatures, inclusions of carbides begin to form in the matrix. In the case of the brake disk, any uneven deposits - standing proud of the disc surface - become hotter than the surrounding metal. Every time that the leading edge of one of the deposits rotates into contact with the pad, the local temperature increases. When this local temperature reaches around 1200 or 1300 degrees F. the cast iron under the deposit begins to transform into cementite (an iron carbide in which three atoms of iron combine with one atom of carbon). Cementite is very hard, very abrasive and is a poor heat sink. If severe use continues the system will enter a self-defeating spiral - the amount and depth of the cementite increases with increasing temperature and so does the brake roughness. Drat!"

As the budget won't allow anything elseright now I'm going to order some Centric replacement GT500 rotors and make sure they are properly bedded in beforethe next track day - June 25 at the Mosport GP circuit.

 

Sleeper,
Before your next event try and figure out a way to get the brake duct hose routed. That will go a long way in taking care of your rotor heat issues. Is it a tire width/offset issue preventing the ducting from being mounted?

I've attached a picture of how mine are routed--so far, no issues with 275's up front.

[IMG]local://upfiles/96090/B1E586443CE045BE8C6E0F0B74CD5D1C.jpg[/IMG]

 

Import_Slaya

Thanks for the pics.

I'll get some more hose and give it another try.