Project Update for August 6th, 2013: My last two posts in this thread were not specific to our 2011 or 2013 GT builds, but needed to be covered: the Torque Arm discussion followed by the EPAS warning. I will get back to our project cars in this post, I promise. Where were we....well back in June we hit several events. After we got back from the NASA weekend at Hallett in the TT3 Mustang, it was time for another Five Star Ford track day at ECR. In preparation for this event, we developed and installed our 14" Brembo BBK as well as a new Vorshlag brake ducting kit for the 2013 GT and performed our typical race prep on the 2011 GT and tweaked a few other things. The 2013 GT is now for sale as well (see
this link or the details at the end of this post).
Three Track Tests in the 2013 GT
If you have been reading this thread for a while you know that I had purchased a 2013 Mustang GT last September for use in SCCA autocross use, for a dedicated ESP build. Long story but that plan was scrapped, so we decided to keep the car long enough to develop some new parts and move it to make room for an all new 2015 Mustang (that's still happening). We tracked it twice before and planned one more track event with this car, and each time out on track was a test. Each time I drove the car, at ECR, on the same set of 295/35/18 Nitto NT05 tires, to try to keep the variables minimized.
Test 1: NASA at ECR, Oct 6th, 2012 - This was when the car had 500 miles on it, stock brake pads, the base GT's smaller 13.2" front brakes, even stock brake fluid. The car had our lightweight 18x10" wheels, the 200 treadwear 295 Nittos (that were purchased to run at the Optima Challenge in July 2012), a big Eibach front sway bar, and Vorshlag camber plates. I ran it in NASA TTB class (got killed, of course) and ran it for two sessions on October 6th. Even with stock suspension, power, and brakes, I managed a best lap of a 2:07.315, a solid
9 seconds slower than TTB winner KenO, but we stuck it in TTB just for testing purposes. I was only able to take about 3 hot laps, as the brakes would go to the floor on my 2nd hot lap, and it took several cool down laps to get them under control. During my 2nd session the front pads melted, fell apart, and it went to the backing plates. No brakes. The car was a big floaty mess and pushed like mad, but it could still boil the 295mm rear tires on any corner exit, easily.
The ambient temps were in the 50°F range and the weather was clear. I drove two cars that weekend: our '13 GT and the '11 GT in TTS class, turning a 1:56.343 in the red '11 Mustang on Sunday - my new personal best lap at this track. Driving the '13 Mustang GT was a big hot mess, and braking with the small stock brakes was downright scary. The fluid got so hot that we melted some seals in the master cylinder (took us a while to figure that one out). I will never... EVER do another track event on OEM brake fluid or pads. Never.
Test 2: Toy Run at ECR, Dec 8, 2012 - Now we had installed about $5000 worth of suspension upgrades and the handling on the 2013 GT was a LOT better. The suspension mods included a lowered ride height via AST double adjustable coilovers with remote reservoirs, 400#/200# spring rates (still relatively soft, but stiffer than lowering springs), and the same camber plates, wheels, tires and front sway bar.
We also upgraded the brakes to Carbotech pads and Motul 600 fluid + Vorshlag SS brake lines. Massive improvement in stopping, but it would still only do about 1-2 laps and didn't stop much, if any harder. It kept the fluid from boiling, but the pedal was still mush (we hadn't found the master cylinder seal issue yet). The ambient temps were again 50°F and clear - almost exactly matching the NASA event two months prior. My best lap was a 2:03.7, so we dropped 4 seconds with coilovers and brake pads. That's a solid lap time that most S197 owners would kill for, and yet we had bone stock rear suspension parts, bone stock power, and still were on the small diameter brakes.
I drove a staggering four cars that day (2013 GT, ChumpCar, BRZ, and 2011 GT) so my slate was very full. Needless to say I didn't get in a lot of testing/tweaking. With some more time and testing we might have found a little more time, but the brakes were still a limiting factor - they still had almost no endurance, and the mushy pedal did not instill confidence. I could take one hot lap followed by a cool down, rinse and repeat. Two hot laps in a row wasn't possible, due to the brakes overheating.
Test 3: Five Star Ford at ECR, June 29, 2013 - So our third and final track test with this 2013 GT was the ECR event in June. I will go over the test results, then I'll back up and show the work. Same tires, and suspension, just one improvement to the car. However, this event was brutally hot and we saw ambient temperature creep up to 99°F by day's end - when I ran my best laps in the 2013 GT. People and bodies were overheating, and brakes were a nightmare on this day for most (see my event write-up below for more), but not this car.
This event was a lot more crowded than either of the previous two tests, and since we were sharing the AIM Solo (GPS lap timer) between our two Mustangs, I ran in intermediate while Amy ran the 2011 GT in Advanced. This made getting a clear lap utterly impossible for me in the 2013 GT. I ran four sessions in the 2013 GT, one session in the 2011 GT, and another session in a friend's GTS3 BMW, for a total of six sessions. I caught cars on almost every single lap. At the end of the day I finally took the 2013 GT out in the Red group and got one - count em -
one clear lap. I finally ran a 2:03.3 lap with clear track, in the hottest part of the day. It was MUCH easier to drive to that time on that lap than back in December, when it was almost 60 degrees cooler, too. And for reference, the best Amy or I could get in the 2011 GT was a 2:00 flat lap on this hot June day, nearly 4 seconds off that car's pace from October or December. So this brake upgrade did much more than the ~1/2 second improvement in lap times show.
Making the 14" Brembo "Vorshlag" Brake Upgrade and Brake Cooling Kits
The brakes are
all we changed on the 2013 GT for this June track test. The brake system improvements made the car both faster and EASIER to drive. I could also push the car hard, lap after lap, without losing stopping power. Huge, massive,
immense improvement.
The upgrades included jumping up from the 13.2" OEM rotors to 14" Centric rotors, and from the 2 piston sliding calipers to the fixed Brembo 4 piston calipers. We went with Carbotech XP20 pads up front and XP12 rears, and had front brake ducting as well. The car could stop at 10/10ths every lap for 5-6 laps in a row (that was usually the length of the session). I was abusing the brakes as hard as I could and they just didn't care. We also had replaced the old Master Cylinder, so the pedal was finally rock solid.
The
Vorshlag S197 14" Brembo brake upgrade kit we came up with is based on the OEM 14" front brakes used on the GT500, Boss302, and 2011-14 "Brembo" GT's and Track Pack cars. We get the new calipers from Ford, the rotors from Centric, the pads from Carbotech, Vorshlag stainless braided lines (BrakeQuip), and it comes with all of the Brembo hardware. We make the kit option-able with any of the Carbotech pads, with or w/o the Vorshlag lines, and even w/o the brake backing plate dust shields - if you want to upgrade to a brake ducting kit. The prices are very competitive and we've already sold a few of these to track drivers in 2005-2013 Mustangs that came with the smaller front brakes. It is immensely more affordable than an aftermarket BBK, as it uses $99 replacement rotors and a common brake pad profile.
Continued below