When it comes down to it, the difference between a 9-second car and a 10-second car can be as much as a full second, or as little as a few measly hundredths. In terms of street cred, however, some goons feel that the difference between 10s and the single-digits is just as substantial as the gap that separate a 14-second slug from an 11-second screamer. Your author just happens to be one of those goons. So when our big-block-powered '93 Mustang project car laid down a string of 10.0-second passes, the experience was a bit bittersweet to say the least. Progress is progress, however, and we knocked off a solid three-tenths of a second since the first wave of testing began. Here's how it went down.
Back to the Track
Our last trip to the dragstrip with Project Fox ended prematurely due to a minor mechanical glitch. Tightening a few loose bolts got the car back on the road, and we headed out to Lonestar Motorsports Park in Sealy, Texas, on a warm October afternoon for a private test session. Located on the premises of Hennessey Performance (www.HennesseyPerformance.com), LMP is a hot rodder's wet dream come true. Owner John Hennessey was kind enough to lend us his facility for the day, and we weren't disappointed. Offsetting the less-than-ideal 35-mph headwind and 2,700-foot density altitude was a track surface that proved outstanding throughout the day.
One of the drawbacks of driving...
One of the drawbacks of driving a street/strip car around the block on supersticky drag radials is that they pick up a bunch of gunk all the time. Performing an extra long burnout before the first pass makes sure that the tires are nice and clean.
Due to the temperamental nature of our Mustang's 275/60-15 Mickey Thompson ET Street radials, we programmed the MSD 6AL-2 ignition box with a conservative timing curve that pulled 12 degrees of advance out of the hole and progressively ramped it back in by 5,000 rpm. Leaving off the footbrake at 2,000 rpm, Project Fox laid down a 10.53 at 134.81 mph. The underwhelming first pass of the day was two-tenths off of the car's previous best, and it was obvious that we set the ignition tune way too conservatively from the moment we hit the gas. The car dead-hooked and felt like a dog coming out of the gate, reflected in its painfully slow 1.79-second 60-foot time. A slight carb stumble didn't help matters, either.
For the next pass we hooked the laptop back up to the MSD box and ramped the timing in much more aggressively. Whereas the prior tune didn't reach full ignition advance until 5,000 rpm, we put all 28 degrees of total timing back in the motor by 3,500 rpm for the second pass. Just in case the drag radials decided to spin, the air pressure was lowered from 18 to 16 psi. The recipe was just what the big-block notchback ordered. Launching once again at 2,000 rpm, Project Fox busted out a 10.03-second pass at 137.70 mph. Our organic accelerometer registered a much more pleasing launch, reaffirmed by the car's 1.54-second 60-foot time. In addition to the Mustang's new all-time best quarter-mile e.t., it posted new bests in eigth-mile e.t. and mph (6.46 at 110).
On our second-to-last pass...
On our second-to-last pass at Lonestar Motorsports Park, Project Fox posted its best 60-foot time to date of 1.47 seconds. Likewise, the 110-mph trap speeds it achieved in the eighth-mile were 2-3 mph higher than usual, yet the car's 137.5 to 137.9 mph quarter-mile trap speeds were the same as in previous tests. This confirmed our suspicion that the windy conditions were slowing the car down on the top end.
Pleased with the gains from the prior run, we left the setup unchanged for the next pass. With an identical launch technique, Project Fox backed up its prior run with a 10.04 at 137.07 mph on a 1.51-second 60-foot time. Determined that a slightly harder launch would net a 9-second pass, we lined the car back up after 20 minutes of cooldown time with plans to stall the converter up even higher. Interestingly, the same torque converter that seemed too loose during shakedown testing felt too tight this time around. Maybe the cooler weather had something to do with it, but the highest we could load up the converter off the footbrake was 2,100 rpm. At anything beyond that, the tight converter combined with the stock drum brakes to spin up the tires, making the car creep through the staging beams. Nevertheless, on the next run Project Fox busted off a 10.01 at 137.89 mph on a 1.47-second 60-foot time.