---
15-17 S550 PP makes same power as 11-14. But, I do see your point, and it is logical. Thanks!

 

I was thinking the same thing. The camaro came out with 15" brakes and all the magazine comparisons and reviews pointed out the difference in brake size. It didn't take too long for Ford to move up to the 15" 6 piston brakes.

 

Another observation on larger rotors. I have upgraded my rear brakes to the 13.8" set up from the 2013 Shelby GT 500. I did it mostly for looks, since I didn't like how small the rear rotors were compared to the front. I have noticed rear brake temps are typically 20-25 degrees cooler with the big rotors after track sessions.

Also, I have seen several S550's and Camaro's with the 15" 6 piston brakes that have completely smoked their brakes at the track using stock brake pads. You will still need upgraded brake pads for track use with the larger brakes. Cooling ducts are also highly recommended with either size rotors. The larger rotors take a little longer to heat up, but like 5.Monster said earlier, they will still heat up and fade with stock pads, it just takes a little longer. If I had stock (non-Brembo) brakes and was upgrading I would have to weigh out the cost/benefit of upgrading to the 4 pot or 6 pot set up. Since my car came with the 4 pot Brembos from the factory I do not see enough benefit of upgrading to the 6 pot set up to out weigh the cost for my intended use. We all have different goals where are Mustangs are concerned. Some are performance oriented and others purely cosmetic. That is what is fun about these cars, you can make it uniquely yours.

 

One thing I failed to mention...my friend owns and tracks an Alpha 4C. Tiny, light car. His brake caliper is equivalent in size to my 11GT Brembo - almost 1000lbs difference. Food for thought there. Honestly, in 2011, the 4-pot Brembos were great, and kind of special for a Mustang - at the time they came out. I do like mine, street and track. But, you can't stop progress. They are small in comparison by today's standard. Even the S550 GT regular 4-pots are huge. On the 2-mile track near me my brakes are solid, all day. On the 3.5-mile track near me, not so much. That's why I'm looking down this road.

 

---
I, too, have the 13.8" rears, my OEMs were getting fried at the track (I have a very long and detailed thread on TMS about this). No issues with the rears since the switch to 13.8", all good there. Yes, I am considering switching pads, based on comments here. That's why I like getting input on the forum. Thanks!

 

I ran my first 2 track weekends using Hawk HPS 5.0 pads. My stock Ferodo pads were already gone from street driving. They did okay for my first couple outings. I added cooling ducts to try and prolong the use of my high performance street pads, since I didn't want to deal with the squeal of track pads on the street and there was plenty of life left in my Hawks. I ran a couple more weekends with this setup and was getting quite a bit of fade as my speeds increased. I switched to stickier tires and GLoc pads for track use before my first event this season. I couldn't believe how much of a difference these changes made. I could push the pedal has hard as I wanted with the Hawks and not engage the abs. At times the car didn't feel like it was going to stop. I am using much less pressure on the brake pedal with the GLocs and can engage the abs anytime with a little extra pressure. The grip and improved braking has really improved my driving on track. The 14" Brembo set up is adequate for our cars on the track with proper pads, good fluid and cooling ducts. I too have a 2011 GT premium, but with the 401A interior. I agree, these cars are heavy, but my current setup is more than capable of slowing it on track.

 

---
I am looking at G-Loc pads, as well, thanks.

 

I think there are several manufacturers that make good pads for the track, it is just choosing what works for your tires and car. I went with the GLocs because the dust is not supposed to be corrosive. The dust from my Hawks had eaten the finish off of my wheels over time.

 

---
Yikes, good to know, thanks.

 

So I got to thinking about the physics around all this, 'cause that's what I do, I can't help it . . .

For the brakes, conservation of energy is the main principle -- the engine converts gas to kinetic energy moving the car forward, and the brakes convert that to heat to slow the car down. Theoretically, in a straight line, the weight of the car does not matter; the Velocity will be higher for a lighter weight car for the same kinetic energy with the same engine horsepower.

Weight (mass) of the car matters for cornering -- the heavier the car, the more friction needed between the tires and the pavement to make it turn. So that does affect braking a bit also, because you have to slow the heavier car down more to get it around the corner.

 

Kinetic energy = 0.5 x mass x velocity squared, so mass does matter.

 

yes but -- where does that energy come from?

the more I think about this, it is very much like archery ;-)

 

The energy came from burning gasoline. Velocity is a much larger component in the energy equation, but you can't ignore the mass.

 

Understood, the Mass is definitely needed to do the math . . . what I am trying to say is, the higher engine horsepower will put more kinetic energy into the car that the brakes have to turn into heat, the mass of the car does not matter for that. The higher mass car won't be going as fast so the kinetic energy is the same; the lower mass car will be going faster and have the same kinetic energy.

So the brakes need to be sized to handle the horsepower of the engine, not the weight (mass) of the car. In other words if you took a Miata engine and put it in a Mustang, the Miata brakes would be just as adequate as they were on the Miatta. Conversely if you took the Mustang engine and put it in the Miata, you would need the same brakes as you needed in the Mustang.

So there really is some physical logic to the newer, higher horsepower cars "needing" the bigger brakes.

And we are talking about use on road track here, for the street we really don't "need" those bigger brakes at all (because we are not using the full acceleration and braking potential on the street)

I told you before, I can't help it ;-)

 

 

I feel like F=ma is more applicable here.

 

Okay, so here is my update. Based on all of the great feedback from TMS forum members, I have decided to give new pads and fluid a chance, keeping my 4-pot set-up. So, I'm going with DBA XP650 pads in front, PowerStop PST1465 in the rear (I can't find DBA's that fit the rear, bummer), Motul RBF600 fluid (will do a full flush out for old and full bleed for new). Next track events are Sept/Oct, and I'm hoping I'll feel the improvement. Wish me luck!

 

Let us know how it works for you. My Motul 600 with GLoc R10 front R8 rears held up well at CMP a couple of weeks ago. No fade and I never boiled the fluid.

 

---
Sounds good. I really wanted to try the DBAs first, before GLoc. Fingers crossed. I won't post results until the next track days for me, in the Fall. I did see, for the first time, a Motul 660, with slightly higher dry boiling point, but it was $7 more per bottle, and I bought four bottles of the 600 (full flush and bleed). I wonder if the 660 is that much better.

 

You should be fine with RBF 600. I ran it for 3 years with no issues at all, and just this year switched to Castrol SRF. Hope the pads work out, they should be better than stock and in line with R8 pads, though the fade temp is still a bit low for hard use. The R12 is ~1100C by comparison.

Good luck and I hope you see fade free braking later this season!