Horse Sense: From 2005 to 2008, Ford's Three-Valve, 4.6-liter V-8 Mustang GT engine was included in Ward's AutoWorld magazine's list of the 10 Best Engines available in the U.S. market. This isn't an easy list to make. Selected engines must be available in regular-production vehicles on sale in the U.S. no later than the first quarter of the year, and also must pass muster in a number of objective and subjective evaluation criteria that center around daily driving situations (horsepower, torque, NVH, technical relevance, and comparative numbers). That's quite an impressive run, when you consider the Three-Valve's successor, the vaunted Coyote and Roadrunner 5.0s, have only been named to the list one time each ('11 GT and '12 Boss 302)!
Does anyone remember the '05-'10 Mustang GT? You know, the Ponies that were powered by 4.6-liter V-8 engines that feature Three-Valve (two intake/one exhaust) cylinder heads and brought variable cam timing into the Mustang mainstream? While Three-Valve 'Stangs are the cars that actually started the S197 revolution, they definitely have been overshadowed by the Coyote in 2011. Despite the frequent exposure we give '11-'13 Mustangs, trust and believe that our commitment to earlier Mustangs is unwavering.
While Three-Valve-powered Mustangs' run only lasted five years, aftermarket high-performance companies fully embraced the engine and its support technologies during that short time. They created parts that enhanced the cars' much-improved handling characteristics, and, of course, increased the performance of their uniquely topped bullets.
With Coyote-powered Mustangs already into their fourth year at this point, acquiring a '05-'10 model is not too difficult. The cars really are affordable when compared to new 5.0s, and finding Three-Valve GTs in their original, stock trim nowadays is more the norm than it has been for most other Mustang models since '79.
The ample, affordable supply of these Ponies is one of the things that motivates us to continue to preserve their relevance, even if it means doing so by revisiting some tech concepts. With many new enthusiasts getting into the hobby by way of Three-Valve GTs these days, the time is perfect for showing off an affordable, Granatelli Motor Sports performance setup that features a few of our favorite first-mod components; everything necessary for improved intake- and exhaust-air efficiency, along with the latest in handheld programmer technology from DiabloSport.
At the end of the day, working with such basic engine bolt-ons is one of the best ways to introduce rookie 'Stangbangers to the addictive world of performance modifications. GTR High Performance in Rancho Cucamonga, California, is one of SoCal's nerve centers for enthusiasts who are just coming into the hobby, and Ricardo Topete and his team (Eddie Zapata and Jose Serrano) are experts at consulting novices on hardware that makes a difference.
GTR is where we focused our efforts on Candy Barrientos' '06 Mustang GT, a stock Three-Valve Pony. Its only mod thus far is a cool paint job (the Grabber Blue GT started life with a black finish), so we're excited about adding its first modifications in this magazine.
On The Dyno
When we strapped Candy Barrientos' '06 Mustang GT to the Dynojet chassis dyno at GTR High Performance, its baseline power-and-torque output left us hopeful that the Granatelli Motor Sports bolt-on collection would bring the Pony's performance more in line with its cool color.
We started the install/dyno-test sequences with GMS Hot Street coil packs and then installed air-induction pieces (throttle body/CAI), and completed the evaluation of basic Three-Valve 4.6-liter bolt-ons with Granatelli's 3-inch off-road exhaust set.
As you see in the dyno chart and graph, each part installed produced gains in rear-wheel power and torque. However, it's important to note that Granatelli recommends installing its throttle body and cold-air-induction tubing as a combination, not separately. Purely for the sake of experimentation, we tested the throttle body individually (with the factory airbox and no tuning), and still recorded a modest gain. However, the ‘body and CAI really are most-effective as a combined unit, which does require tuning. For support in this area, we sought assistance from Bob Kurgan of Kurgan Motorsports in Braselton, Georgia.
Using DiabloSport's Chipmaster Revolution tuning software and working via the Internet (the InTune i-1000 on our side is the device that ports calibrations into the Mustang's PCM via the OBD-II port), Bob developed a tune for the CAI and throttle body, modifying fuel (initially adding, then trimming back) until a safe WOT air/fuel ratio (12.9: to 13.0:1) was achieved.
Our final addition of a 3-inch exhaust system brought a great rumble from the Three-Valve, but it also altered the engine's air/fuel by making the mixture just a bit lean. Bob nosed fuel up once again to compensate, and also pulled a degree of timing to ensure there will be no detonation for Candy to worry about when she throws down on the throttle and puts the new bolt-ons to work.