Rear Brake Upgrade

[bullet6236]

I upgraded my non-pp GT to the PP rotors/calipers. Got me thinking, could the non-pp fronts be installed on the rears? Would this even provide increased braking performance?

I default to smarter people than me. :hail:

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[BmacIL]

I upgraded my non-pp GT to the PP rotors/calipers. Got me thinking, could the non-pp fronts be installed on the rears? Would this even provide increased braking performance?

I default to smarter people than me. :hail:

No, the caliper mounting points are different and there's not much, if any performance benefit to doing so. You need bigger/more powerful front brakes because the weight transfers to the front and requires far more brake torque to achieve lock-up/ABS activation than the rear. Unless you have enough grip where you cannot engage ABS, you do not need additional braking power. Tires are almost always the limiting factor.

 

[timd38]

Even if you made brackets to get it to fit, you still have a parking brake issue to deal with.

 

[daltron]

As others have mentioned, A) it will not mate up with the stock components and B) you will lose your parking break.

Your options are pretty much these two:

http://fulltiltboogieracing.com/2015_S550_Brake_parts.htm (scroll down to GT350R conversion brakes)

http://www.wilwood.com/BrakeKits/Br...016&make=Ford&model=Mustang&option=GT+Premium

I would go with the GT350R conversion parts.

 

[qtrracer]

Factory set the F/R brake bias to work with the selected calipers, rotor sizes, weight of the car, the tires, the front geometry strategy, etc. Just swapping to the PP front brakes probably messed with your F/R bias. Not certain the ABS has built-in learning to account for such changes. I know on the Fox cars working out optimal brake bias when swapping to SN95 components has been a crap shoot especially if one varies from the Ford package.

Brakes like most automotive parts are part of a system designed to work together with the car. Mess with the formula without some idea what doing so means to the system, generally doesn't result in "better".

Here, even if adapting the 6-pot Brembos to the rear was doable, the brake bias would be way off. Both ends would have the same caliper sizes, rotor sizes, swept area and brake torque on a car that is probably static weight biased 56/44 to the front. Add in weight transfer under braking and the rear would lock way before the fronts. Ever experience rear lock before front at speed? That is a pucker moment.

 

[bullet6236]

I had great braking performance at the last two hpde autocross events with the PP fronts.

 

[qtrracer]

Given that the 6-pot Brembo is a big brake with 15" rotors, it doesn't surprise me that it "feels" better. All Fox owners went down this same path when switching to the Cobra brakes, even when a drum was left on the back. But a true test is stopping distance. I actually tested the Fox after installing rear discs and found little to any difference in total stopping distance. However, I could repeat this more at the same distance than with the drum rear.

Remember, the tires stop the car; the brakes facilitate the stopping. The S550 is heavy in front as are most mustangs. Putting more brake on the front without biasing the rear to match will not shorten overall stopping distances. We know this - it is indisputable. The only exception is where the front brakes match the rears by accident. But it may feel better.

 

[Optimum Performance]

The rear brakes are the same on the GT Non-PP and PP GT so bias wise you have what is in the GT PP from the factory. The upgrade will allow you to run harder during a session just due to the mass of the front brakes. The mass allows more heat to be generated so you have a larger window to play in. The swept area is large allowing more friction surface. Everything being larger makes for a very robust system. Great upgrade to do. You have a solid brake system that really doesn't require much other than pads. The biggest thing is adding cooling, it allows you to really abuse them ;)

I was looking at doing a rear brake upgrade using front PP rotors but after seeing S550 race cars running stock rear brakes without issue I don't know if its needed. Again all depends how much tire you have in the front.

 

[wildcatgoal]

Having more rear break tends to help the car stay level during heavy breaking if you have the grip (otherwise you get squirrelly). Many BMW 3's are/were like this - you brake but you don't feel like the car is diving forward; it's almost like the car sinks backward. It's possible in that design of car because of a 50/50 weight distribution and lowslung design which keeps weight from tipping forward. On a Mustang... eh, not sure.

IMHO, the rear brake on a PP car (or non-PP car), especially with an upgraded pad, is going to be enough unless you are doing hardcore time trial, other type of advanced-level course work, etc.

If I upgraded, I would go with the Wilwood option. The GT350 setup changes wheel offsets, which I don't think Wilwood does (or as much). Unfortunately it's hard to spend $5K+ on brakes when I already have Brembos up front that seem to hold up to whatever I am capable of.

 

[bullet6236]

So then the next question...

When it comes time to replace pads (guessing 3-4 hpde events) for the first time, can I get away with replacing pads only and giving the rotors a light sanding to remove any glaze?

 

[wildcatgoal]

Assuming the rotors are within usable spec, yes. I have the rotors turned (or replace them if I can find them on sale) when installing new pads anyway.

 

[Optimum Performance]

So then the next question...

When it comes time to replace pads (guessing 3-4 hpde events) for the first time, can I get away with replacing pads only and giving the rotors a light sanding to remove any glaze?

60-80 grit hand sanded cleans off old pad residue. With the G-LOC's you can switch back and forth between compounds on the same rotors. This way you can throw on a track compound drive to the event, come home swap the front back to a street compound (GS-1) and DD it.

 

[F0J]

I'm pretty sure there are other options. Isn't there Brembo GT, Brembo GTR, Baer and AP Racing rear brake kits?

Depends how serious you are. I would definitely throw in an adjustable proportioning valve or whatever to make fine adjustments to the bias. But I think that's a little hardcore.

 

[wildcatgoal]

I'm pretty sure there are other options. Isn't there Brembo GT, Brembo GTR, Baer and AP Racing rear brake kits?

Depends how serious you are. I would definitely throw in an adjustable proportioning valve or whatever to make fine adjustments to the bias. But I think that's a little hardcore.

Not for the REAR in all cases listed above.

 

[timd38]

Not for the REAR in all cases listed above.

Ford is about to make a kit that will let you put the GT350 brakes on a normal and PP GT.

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