Ford Shelby GT500 Modifications - Shelby Bolt-On Bonanza, Part 2 - Tech

The QA1s were set with four clicks or turns from the full loose position for the first run, and after heating up the hides in the left lane burnout box, Smitty rolled up to the starting line. Keeping everything the same as the first test, he left the starting line at 4,500 rpm and recorded a 1.673 60-foot time, the best short time for the Shelby as of yet. Making each of the three gear changes at 6,500 rpm with the throttle planted wide open, he piloted the Shelby to an 11.246 at 124.01.

"The car spun a bit on the first run, but it accelerated and actually felt very good because it never pulled the engine back, it just went," Smitty reported. In addition, there was no nonsense in the burnout. To combat the slight spin, Shaun Lacko of JDM wiggled underneath the rearend and changed the shock settings, adding two clicks, thus tightening the shocks. This was done to slow the action of the rear on launch, which would control the "hit" at the tires and the rebound effect that can cause spin. By changing the setting to 6, a stiffer setting, the rearend of the car would not squat as easily. With the harder setting, we were trying to get the rearend to plant and stay planted, instead of planting and rebounding. With the car cooled down and the shocks adjusted, it was time for a second attempt at the quarter-mile.

This time, the car hooked extremely hard, causing it to bog down the motor. This hurt the short time, as the Shelby mustered only a 1.718 60-foot clocking. At the stripe, the speed was up slightly to 124.25, but the elapsed time fell off a bit as the Shelby ran an 11.294. After another cooldown period, Smitty attempted to leave a bit more aggressively, but the traction had gone away on the starting line in the left lane. In an effort to try and get a decent third run, we let the car cool back down after three aborted launches (all of which were not better than 1.70) and subsequently moved over to the right lane. Our plans were foiled slightly, though. The traction in the right-hand lane was much better than any-thing we had experienced in the left throughout the day. The extra bite once again caused the car to hook hard and bog, resulting in the worst 60-foot time of the day, a 1.721. At the quarter-mile mark, the scoreboards lit up to read an 11.37/123 mph pass, our slowest of the day.

Ending on the Right Foot
While the Shelby progressively slowed down in elapsed time from our first run of the day to the last, the elapsed time and speed gains with the new bolt-ons were enormous. With tire pressure the same as the first test, as well as launch and shift rpm, the Shelby ripped off a best e.t. of 11.246 seconds and a best speed of 124.25 mph. Even more impressive were the gains from the previous modification and those seen overall with all of the bolt-ons from the baseline effort.

From the previous modification, the gears, MAF sensor and accompanying fresh-air kit, and adjustable shocks lowered the Shelby's best e.t. by a sizeable 0.539 second, while terminal velocity went up almost seven markers. With all of the bolt-ons we have installed combined, the performance gains seen over the numbers laid down by the car when it was in stock trim is astounding. Overall, the seven different bolt-ons that have made their way onto the Shelby have shown a drop of 1.134 seconds in elapsed time and an increase of 9 mph on the speed chart. That's not just impressive; it blew us away.

If we had more time to play, however, we would have changed the rear shock setting and practiced our launches. Like any drag car, the key to quick elapsed times is in the launch. In the Shelby's case, it's tricky moving the 2-ton weight off the line quickly and consistently. Also, keep in mind our tester still has the stock front wheels, tires, and the front antiroll bar installed.

So what's in store for Part 3? Our twisted, psychotic minds are working overtime with ideas. We wanted to try and change blower pulleys in this installment, but a few trial runs on the dyno showed us some things weren't up to snuff. "On the dyno, the engine went lean at 5,800 rpm," D'Amore says. "It needs more fuel, and that will only come with an upgraded and improved fuel system and more tuning-and that is coming next." While we aren't psychics, we can see headers, boost, more fuel, and a 10-second time slip in this Shelby's future.

Another Tale of the Times
Part 1 was good, but Part 2 was better. In addition to the bolt-ons we threw on in Part 1, we added a few more in the second installment. Once again, the numbers don't lie. This beast is getting out of control, which is how we want it. Note: Differences are from the baseline run first and previously performed modifications second. Additionally, we are including all of the previously printed numbers from Part 1.