Project Update for May 1, 2012 - Part 1: The day after the MW ProSolo we got to work on the Mustang prepping it for the NASA Time Trial event at TWS the following weekend. In this two part update I'll show some new mods done to the car for better track worthiness (Part 1) as well as talk about the TWS event (Part 2).
Front Brake Cooling
For a while now there has been one item we've been meaning to design and fabricate for the car, which is the front brake ducting. It is something I highly recommend to all S197 Mustang owners who track their cars. Now Ford Motorsport (FRPP) has a kit that they sell for the 2010-2012 Mustang GTs that is made to work with the optional CS lower fascia we have (pulls air in from the lower foglight holes). The problem with that kit is that the backing plates included have a tubing diameter that is too large to fit inside the common 3" high-temp brake duct hose. Users end up having to hack the hoses to pieces to make them fit. It also requires modification to the inner fender liners to route the hoses they include, which is not legal for STX.
For the longest time we held off making our own front brake ducting because of the STX rule limitation, but I decided - to Hell with it. We change rotors and pads and now rear aero/trunk configurations between autocross and track events. How much harder is it (if necessary) to pull the brake ducting off? So Ryan and AJ built the brake cooling set-up above using some steel tubing we had (in a diameter slightly
bigger than the brake hose), welded them to the OEM backing plates, then routed the ducting to the CS lower fascia foglight openings and through the fender liners - without cutting them. We found a gap between two liners we could use legally in ESP and routed them there. We zip-tied them to the swaybar - which moves up and down with the wheel, pointing the ducting to the back of the rotor. We checked it at ride height at full lock with the 18x11's on the front and it just barely cleared.
And man, did that help! Running at TWS you do get some extra brake heat after coming off the banking and bombing into Turn 1 then stabbing the brakes, in excess of 140mph. The brakes felt GREAT and I was very happy with the extra cooling added. If someone sees something here that is
not SP compliant, please speak up - but it looks legal to me. And its not like we need brake cooling in an autocross, so we can take it off if need be. We've made similar one-off brake cooling solutions before, so this was fairly easy for us.
High Speed Aero
The rear spoiler (shown above, now painted black and weighing 9.3 lbs) we made for ESP class autocross use really has no business on a proper road course and was only made to be used at sub-70 mph speeds seen in autocross. It was also made to meet the somewhat arcane rules of SCCA Street Prepared. The
Wright Brothers had more advanced aerodynamics in 1903 than the SCCA allows in many classes in 2012, but hey - the rules are what they are. So that 10" tall rear spoiler is basically a big parachute that does provide some downforce at low speeds, but at the expense of drag. This style spoiler is not at all efficient above those parking lot speeds. I know they use similar parts in NASCAR... see my comments above about antiquated rule sets.
I had this "3D" APR wing (GTC-300), a 67.5" wide carbon fiber monstrosity that we purchased a while ago (we've been an APR dealer for many years). I think I got it for the E46 TTD car, but we re-did our TTD class points with the current tire size (285mm Hoosier R6) and realized we didn't have enough points to do any aero. Then I talked about sticking it on the E30, then decided that putting a $1200 wing on a $2000 car was nuts. So it was just sitting here.
The 3D wing shape is really made for use with coupes and sedans to sit lower than the roof height, where the greenhouse adds an aero blockage in the middle of the car and the airflow is compromised behind the rear window. So this style wing kicks up in the middle, behind the greenhouse, to try to capture air flow coming off the roof. Mounted 2 to 12 inches off the trunk floor (under the roof height) it is ideal for this type of situation.
When we looked at using it on the Mustang this year, we checked the rules for classes where other S197 Mustangs play - NASA TTS and NASA American Iron (as well as SCCA Street Modified). We noticed that in each of these classed we can stick the rear wing well
above the roofline (8" above in AI/TT, 6" in SMOD!) and a 3D wing isn't necessary if you can mount it up that high. But we had this wing on hand, so we made uprights to fit it to the car anyway. This would allow us to see how it would work and to verify the upright design that we had been tinkering with. We have since found out that we can get a flat style CF wing from APR for a good price and will likely go to that style wing at a later date. This 3D wing will be used in the future on another car where it will be mounted below roof height.
continued below