KJ Jones
November 22, 2013
Photos By: KJ Jones

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.

Ricardo Topete of GTR High Performance in Rancho Cucamonga, California, puts final adjustments on Granatelli Motor Sports’ ’05-’10 cold-air-induction system—the blingy showpiece in our collection of simple performance bolt-ons for Three-Valve 4.6-liter Mustangs.
While finding ’79-’93 Mustangs with bone-stock pushrod 5.0 engines is a bit of a challenge these days, S197 ponies with virgin Three-Valve bullets are readily available. This is the stocker in Candy Barrientos’ ’06 GT. The engine performed as we expected it would during the baseline dyno session; the Granatelli Motor Sports hop-up gear we installed really woke it up.
A twin-blade, 62mm throttle body is also on the short list of affordable, direct-replacement pieces that are highly recommended for a basic Three-Valve hop-up. Granatelli Motor Sports’ modified Shelby GT500 ‘body (PN GM-TB0007; $475) bolts right up to the factory intake manifold thanks to a slick, CNC-machined spacer plate that syncs the intake’s holes with the fastener bores on the throttle body. It’s important to note that a cold-air-intake system and PCM calibration are required when using this piece.
A twin-blade, 62mm throttle body is also on the short list of affordable, direct-replacement pieces that are highly recommended for a basic Three-Valve hop-up. Granatelli Motor Sports’ modified Shelby GT500 ‘body (PN GM-TB0007; $475) bolts right up to the factory intake manifold thanks to a slick, CNC-machined spacer plate that syncs the intake’s holes with the fastener bores on the throttle body. It’s important to note that a cold-air-intake system and PCM calibration are required when using this piece.
A twin-blade, 62mm throttle body is also on the short list of affordable, direct-replacement pieces that are highly recommended for a basic Three-Valve hop-up. Granatelli Motor Sports’ modified Shelby GT500 ‘body (PN GM-TB0007; $475) bolts right up to the factory intake manifold thanks to a slick, CNC-machined spacer plate that syncs the intake’s holes with the fastener bores on the throttle body. It’s important to note that a cold-air-intake system and PCM calibration are required when using this piece.
Where the big cold-air tube enhances incoming airflow to the engine, Granatelli’s 3-inch stainless-steel exhaust system (PN GM-ES0530; $712) ensures burnt gasses exit in a most-efficient manner. The exhaust set directly replaces the entire OEM exhaust system from the manifolds back, and includes all of the hardware required.
With PCM calibration required for two of the bolt-ons we’re working with (GMS’s cold-air and exhaust systems), we’re using DiabloSport’s all-new InTune OBD-II hand-held programmer (PN i-1000; $389) and custom tuning by Bob Kurgan of Kurgan Motorsports (www.kurganmotorsports.com) to get things right. The i-1000 unit is the much-smaller successor of DiabloSport’s long-popular Predator unit. It features all of the same tuning and diagnostic functionality, and can be used with multiple vehicles provided the original car’s stock calibration is reloaded from the InTune unit before moving on to another vehicle.
Coil replacement is an easy swap that takes Ricardo only about 30 minutes to accomplish using basic tools. Granatelli’s Hot Street coil packs don’t require anything extraordinary when bolting them in place other than care not to over tighten their fasteners, which could cause the ears on the coils to break.
Coil replacement is an easy swap that takes Ricardo only about 30 minutes to accomplish using basic tools. Granatelli’s Hot Street coil packs don’t require anything extraordinary when bolting them in place other than care not to over tighten their fasteners, which could cause the ears on the coils to break.
Here’s the stock airbox that severely restricts the Three-Valve engine’s airflow. This piece’s design really is sort of purpose defeating, as the engine’s cylinder heads feature an additional intake valve (per each cylinder) that is supposed to allow more air to enter the cylinders. Improving this area with a smoother-flowing, larger-diameter intake tube should show us a solid horsepower gain.
One of the cool things about basic efforts like this is that parts—like the OEM airbox—are removed and installed with simple handtools, and the procedures don’t take much time to complete.
In this side-by-side comparative photo, the diameter difference between mass-air housings on the GMS CAI (left) and the factory airbox is night and day. Granatelli’s tube measures 3.420 inches (compared to the OEM’s 3.185 inches), and obviously does not have the same restrictive interior contents as the stock piece.
With the airbox removed, Ricardo then pulls the throttle body; it’s a quick procedure that involves unplugging the wiring and removing four fasteners.
A twin-blade, 62mm throttle body is also on the short list of affordable, direct-replacement pieces that are highly recommended for a basic Three-Valve hop-up. Granatelli Motor Sports’ modified Shelby GT500 ‘body (PN GM-TB0007; $475) bolts right up to the factory intake manifold thanks to a slick, CNC-machined spacer plate that syncs the intake’s holes with the fastener bores on the throttle body. It’s important to note that a cold-air-intake system and PCM calibration are required when using this piece.
The throttle body bolts in place using the aforementioned billet spacer. One of the cool things about this piece is it does not require anything beyond the supplied hardware for installation (OEM throttle-body studs are removed), and is ready-to-use as soon as the electronic-throttle wiring harness is connected.
As we mentioned earlier in this report, Granatelli’s CAI and throttle-body upgrades require reflashing the ‘Stang’s ECU to make corrections to account for the increase in intake air. GTR High Performance works closely with Bob Kurgan for this segment of a mod-motor performance upgrade in a unique-but-effective remote manner that involves transferring data and calibration files via the Internet. Once Bob has modified the tables accordingly, Ricardo uses the DiabloSport InTune to transfer updates into the GT’s computer.
Our exhaust upgrade is highlighted by the big 3-inch Granatelli Motor Sports off-road system, which eliminates these catalytic converters from Candy’s Pony. Despite removing the cats, the new pipes bolt directly to the stock exhaust manifolds with no problem.
The S197’s stock exhaust tubes and converters come down without any sort of significant fight, and can be discarded or held onto for use come inspection time.
GMS manufacturers its big-tube exhaust system using 304 stainless-steel, and mandrel-bends the entire works for more efficient transfer of exhaust gas. Note the difference between the OEM tube (left) and our new exhaust pipe, which is much smoother.
A twin-blade, 62mm throttle body is also on the short list of affordable, direct-replacement pieces that are highly recommended for a basic Three-Valve hop-up. Granatelli Motor Sports’ modified Shelby GT500 ‘body (PN GM-TB0007; $475) bolts right up to the factory intake manifold thanks to a slick, CNC-machined spacer plate that syncs the intake’s holes with the fastener bores on the throttle body. It’s important to note that a cold-air-intake system and PCM calibration are required when using this piece.
The new system reuses the factory hangers and can be completely installed (by two people) in about an hour and a half.
Each piece in the GMS exhaust system fits well, and does not require any major modification or revamp other than slightly opening the ends of a few of the slip-fit pieces (like the X-shaped crossover). Additional PCM updating is required with the free-flowing exhaust.
It’s not often that we get to work with a car that’s owned and operated by a female ‘Stangbanger and painted with one of the coolest colors Ford has sprayed on a Pony’s flanks. Thanks to Candy Barrientos for letting us use her Grabber Blue ’06 GT for this effort. We’re sure the upgraded Three-Valve ‘Stang will be a hit with fellow members of her Street Stangz family. 5.0

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.

We installed the Granatelli bolt-ons and made several runs on GTR’s Dynojet chassis dyno to determine the efficacy of each part, individually and as a complete package. One of the cool things about installing these pieces on a stock 4.6-liter Three-Valve engine is that every change clearly yielded more and more rear-wheel horsepower, to the tune of an overall 23 hp and 19 lb-ft of torque gain by the time we completed our test.