Dyno test after dyno test have proven that Two-Valve modulars are extremely efficient motors with few gains (compared to their predecessors) to be had with simple bolt-ons. But whether you choose to go with a naturally aspirated, juiced, or super-charged combo, you'd better make sure you have all the basics covered first. Otherwise, a choked intake or bottlenecked exhaust system will hold you back from the gains you were expecting from your next big investment.
To kick things off, the MRT...
To kick things off, the MRT H-pipe was unbolted from the stock manifolds as well as from the rusty stock after-cat. The tailpipes were cut to ease removal. Hopefully, tech Jack Swift was up to date on his tetanus shot.
With only a few bolt-ons under its belt, Gangsta Stang, our '99 GT, needed some help before we move forward. As it sat, the car had a ported upper plenum, a Professional Products lower intake, an MRT H-pipe, and a K&N air filter. The next obvious step was to ditch the factory rubber intake tube, heat-soaked factory exhaust manifolds, and choked rear pipes and mufflers.
BBK Performance was kind enough to quench Gangsta's thirst for a fresh supply of cold air via its cold-air induction system (PN 1718), which would place a washable air filter in the fenderwell and away from the hot engine. The hand-polished and chrome-plated aluminum tubing adds a touch of class and is quite an improvement over the crinkled rubber supplied by the factory.
Despite the 2.5-inch stainless pipes and high-flow cats in the MRT H-pipe, the exhaust was still corked by the factory after-cat and manifolds. By using MRT's MaxThunder 409 stainless steel exhaust (PN 92b002), one of those problems was easily amended. Ideally, we would've liked to keep the MRT H-pipe for its deep growl, but switching to long tubes made that impossible without driving out to the company's Michigan shop. Instead, we had long-time Mustang drag racer Craig Radovich of Radical Racing bolt up the MRT after-cat to a catted x pipe system (PN 6012) and 1 5/8-inch stainless steel long tubes (PN 5998S) from Kooks Custom Headers. The 2½-inch velocity spiked collectors and x pipe system were designed specifically for Two-Valves making up to 500 hp, which for this Pony meant we'd probably never have to buy another set of headers. To make sure the headers didn't lean out the mixture too much, and to ditch the lazy 87-octane tune, we had DiabloSport send over one of its Predator handheld tuners (PN U7146).
In order to install long-tube...
In order to install long-tube headers on an SN-95, the Radical crew found that it is easiest to just drop the K-member. To accomplish this task, the tie rods, brakes, sway bar, steering rack, and shaft must all be unbolted.
Just after arriving at Radical Racing in Atco, New Jersey, conveniently located just down the street from Atco Raceway, Gangsta's air silencer and stock paper filter were stuffed back into the airbox before the baseline dyno test on Radical's in-house Dynojet. Due to the combination of stock gears and speed limiter, all pulls had to be done in Third gear in order to let the 4.6 rev to its 6,000-rpm redline. Following the dyno test, we headed back to Englishtown to improve on Gangsta's pitiful 14.0 showing from the last time we were there. The road-race suspension, along with the heavy 18s, lack of gear, and lack of top end have really been holding it back. It's about time we got this thing respectable again. Thank-fully, we upped the ante and busted off a new best of 13.6 at 101 mph. While this may seem a bit slow for the mods, remember we have a heavy wheel and tire package, big front brakes, and a suspension that's set up for road racing. Additionally, we have the stock gears back there, but that will change in short fashion. With a few more ponies, Gangsta should be prancing into the 12s.