Shortly after lunch break, the car was fired up and sounded really good. The Two-Valve was throaty at idle, but not excessive. The Bassani mufflers aren't terribly loud during regular driving, and Miele has reported back that there isn't the dreaded drone at highway cruising speeds either. On the dyno, the car sounded so much better and healthier-as did the horsepower and torque results. There is no doubt that adding exhaust on a high-mileage Mustang is worth power, the exhaust flow from the high-flow cats versus the six factory units (which were probably half-clogged) is worth the swap alone. Radical Racing's DynoJet chassis dyno showed nice peak gains, 9 rwhp and an outstanding torque increase of 29 rwtq.
Our gains at peak horsepower might not be up to snuff for some, but you cannot deny that the additional peak torque is super-impressive. Increases in peaks are glamorous and great for bragging rights, but in our world of track testing, the average power is what makes cars run quicker. One look at the graphs tell us that on track, the Silver Stealth Stang should pick up considerably. As we pour over the data, the graph shows it picked up 22 rwhp in the mid-range and as much as 40 rwtq. Comparing the two graphs, the mid range gains are not just an up and down trend. The baseline and after-exhaust lines stay far apart from 3,000 rpm through nearly 5,000 rpm. Those kinds of gains are sure to show up on the dragstrip, which is precisely where we headed after the chassis dyno testing. Radical Racing is a mere one mile away from Atco Raceway, the site of our initial testing.
Earlier in this article, we mentioned that Miele had driven the car to a best of a 13.98 with a sick 2.00 60-foot. The unfortunate part of that heroic pass was that the weather was abnormal and Miele has yet to even get close to that short-time again. The car's engine was also iced down for the 13-second run. Our follow-up times for the exhaust upgrades were done on a warmer day, and the Predator showed a 210-degree water temperature, similar warm engine conditions to our baseline runs and post-intake upgrades. Stock, Miele ran 14.43 at 95 mph, and then followed it with a 14.31 at 96.8 mph. Miele delivered a new-best time of a 13.97 at 97 mph, with a 2.07 60-foot, with the new exhaust enhancements. It puts our overall gains at .46 seconds better than stock, and .31 seconds quicker than the parts from stage two of the build.