The last items we ordered...
The last items we ordered before heading out to the dragstrip were a set of wheels from Summit and tires from Mickey Thompson. The Summit Fast Five wheels measure 15x7 up front, and 15x10 out back. They're wrapped in 26x10x15 Mickey Thompson Sportsman radials for the fronts, and 275/60-15 ET Street radials for the back. Yes, the fronts are awfully large, but the idea was to retain some streetability, since cruising around town with 4-inch-wide skinnies isn't any fun.
During the second pass, we got a bit more aggressive with the launch, loading the converter up to 2,500 rpm. The big-block promptly blazed the tires, and the e.t. took an embarrassing hit, as the car posted an 11.45 at 134 mph. Despite the pathetic result, one important lesson we learned firsthand is that unlike a bias-ply slick, once a drag radial starts spinning it will never recover unless you lift off of the throttle. To make sure our first pass wasn't a fluke, we lined up Project Fox just before midnight for one final run. Leaving the line at just above idle and babying the gas, the Mustang ran another 10.54-at-138-mph pass on a slightly improved 1.72-second 60-foot time. Although the car was more than a half-second away from our 9-second goal, we were quite pleased with our maiden voyage to the track considering that we didn't touch the suspension, air pressure, or engine tune the entire night.
For the initial burnout on...
For the initial burnout on a fresh set of tires, Mickey Thompson recommends a slightly longer than usual burnout. Otherwise, the burnout procedure on drag radials isn't much different from slicks. Spinning them until you see a nice puff of smoke billowing from the wheelwells is all that's needed. Prolonged burnouts merely overheat the tires and accelerate wear.
Following the better-than-expected first round of testing, we returned to the track the following afternoon for some eighth-mile bracket racing. With the ambient air temperature pegged at 100 degrees, the track temperature conceivably much higher, and density altitude registering in at an asthmatic 4,000 feet, we prepared for greasy starting line conditions. The plan was to fiddle around with the timing curve with our programmable MSD 6AL-2 ignition box. This trick little gizmo allows dialing in a custom ignition advance curve with a laptop to account for varying track conditions. To get started, we pulled 12 degrees of advance at idle, and progressively ramped it back in by 5,000 rpm. The results were simply amazing. With no other changes from the night before, the 60-foot time dropped to 1.50 seconds and Project Fox ripped a 6.50 pass at 107.09 mph. Compared to the night before, where the car posted a best eighth-mile time of 6.94 at 107.53 mph, Project Fox picked up nearly half a second. You read right, a few simple keystrokes on the laptop to the MSD program netted nearly a half-second improvement in the eighth-mile. This is literally Pro Stock technology for the street, and the proof is in the timeslips. For a drag radial car like ours, the programmable MSD box is the most powerful tuning tool you can ask for.
While 1.50-second 60-foot...
While 1.50-second 60-foot times look extremely mediocre on paper, they're actually enough to pull the front tires just a hair. A staple of any properly dialed-in drag car chassis is a rear suspension that separates from the body at launch. Thanks to Bill Buck, Project Fox does just that.
Depending on whom you ask, for a car that pulls the second half of the track as hard as Project Fox, a 6.50-second eighth-mile e.t. is awfully close to a 9-second quarter-mile pass. The problem was that we entered the car in a 7.00 index class, so we actually had to slow the car down. Nonetheless, it still gave us an opportunity to work on the 60-foot times, and Project Fox posted consistent short times in the 1.50 to 1.57 range all day long. Through some skillful sandbagging, we managed to make it to the finals, eventually finishing as the runner-up and taking home $200. That's not bad for a day's work.