Twin-Screw Blower Boosts 2007 Shelby GT500 To Nearly 1,000 RWHP

Regular readers know that Whipple Superchargers revamped its product line with a pair of new superchargers last year. The first new entry to its lineup was a third-generation version of its vaunted 2.9-liter twin-screw unit, which features a number of improvements including a high-flow case, a more efficient rotor pack, and other detail improvements that combine for a more potent upgrade.

If you have the supporting mods you can double your stock horsepower on a 5.4 with the Whipple 2.9-liter. — BJ McCarty, Venomous Consulting

“The Gen 3 2.9-liter supercharger features a new rotor profile and housing, allowing for increased airflow, lower temps, reduced drag, and more power than previous models. It fits perfect for daily driver as well as modified engines as it has enough capacity to significantly outflow the stock superchargers on the GT500,” Dustin Whipple, Vice President of Whipple Superchargers, told us. “The 5.4-liter engine’s supercharger is extremely inefficient, therefore our 2.9-liter drastically improves performance on all levels. The 5.8-liter had an upgraded 2.3-liter, which was a large improvement, therefore our 2.9-liter is best fit for guys asking for more airflow as the stock unit begins to hit a wall, along with issues with getting a belt system on it to spin the RPM levels needed to try and make power the larger superchargers can.”

BJ McCarty’s 2007 Shelby GT500 is known as Christine, as she can be a difficult gal. In his quest to push her into the 9-second zone, he opted to install the latest Whipple 2.9-liter supercharger, which he dyno tested at Mastiff Performance in Debary, Florida. “The Gen 3 twin-screw takes less power to drive, produces lower boost temps, and has a higher airflow capacity,” Dustin Whipple said. “It’s a better fit for the 5.4- and 5.8-liter engines as it is in a more ideal, usable RPM range.” (Photo Credit: BJ McCarty/Venomous Consulting)

A person with a car suited to putting this upgrade to the test is BJ McCarty, who recently started his own consultancy business. Among other things, his new operation offers custom-designed performance packages for factory boosted Shelbys like his 2007 Shelby GT500, which goes by ‘Christine.’ Yeah, she is named after the Stephen King character.

Bigger Blower

“When I launched Venomous Consulting, LLC one of my primary goals was to broaden my knowledge of available options for GT500s beyond those with which I’ve been intimately involved for a number of years,” BJ explained. “When I was presented with the opportunity to work with Dustin Whipple and Jared Rosen, of Lethal Performance, on an upgrade for Ms. Christine, I was excited to see the benefits of their latest third-generation rotor pack in the time-tested 2.9-liter supercharger.”

The 2.9-liter is a perfect fit for the 1,000-rear-wheel-horsepower daily driver. — Dustin Whipple, Whipple Superchargers

Having experience with a variety of power adder upgrades, BJ wanted to expand his experience level with a broader range of parts. That way he could pass that experience on to his clients.

BJ was impressed with the Whipple system, from the packaging to the completeness of the kit. Because the GT500 comes with a factory blower, the Whipple Gen 3 is a direct bolt-on and the kit comes with all the hardware you need to install it.

“The Whipple 2.9-liter has been an extremely popular upgrade for GT500s for years, both as a head unit upgrade and in full Whipple and Ford Performance kits. It’s always made great power and is a proven street and track performer,” BJ said. “That said, I knew I could make more power with the larger blower, but what I didn’t know was just how strong the bottom end would be. So, that level of torque makes it an awesome choice for dusting off the pesky car next to you on the third honk. It also makes enough power to make it a real performer at the track.”

Of course, before you get that power, you have to order the kit and bolt it on. From unboxing to thumbing through the expansive directions, BJ knew he was off to the right start with this upgrade.

Total Package

“The quality of the kits is simply outstanding. From the moment it landed on my doorstep, I was really blown away at the level of quality in everything from packaging to included hardware to the finish of the supercharger itself. It looks and feels like the custom build that it is,” BJ said. “The average GT500 owner will find the installation doable and the results will speak for themselves. Looking to add a couple of hundred horsepower? Piece of cake. If you have the supporting mods you can double your stock horsepower on a 5.4 with the Whipple 2.9-liter. If you want to double the power of the 5.8, I think Whipple has an answer for that, too.”

On a stock car the installation is pretty straight forward. The only real challenge is reaching the bolt under the inlet. Using a long, 10mm ratcheting boxed-end wrench is the secret to tightening this one. As you might expect with a car named Christine, BJ’s aftermarket fuel system and K-member necessitated some re-working of the fuel lines. The K sets the engine back, so BJ replaced the crossover line with a flex line and new fittings. He also shielded the line from the EGR tube by installing a Nomex sleeve.

Of course, if your car’s moniker is Christine, you expect there might be a couple of challenges. Were it not for some other mods on BJ’s GT500, the install would have been dead simple. However, with its return-style fuel system and the engine-setback of its Maximum Motorsports K-member, this one had a couple of extra hurdles.

“I honestly didn’t know what to expect. Nothing has ever been simple on Christine, so I was prepared for surprises!” BJ confessed “There were two: The need to revise my fuel system routing to accommodate the huge Whipple inlet and the fact that I found the limits of my fuel system on E85 due to the increased power potential of the Whipple 2.9-liter. At the end of the day, Christine gets an awesome upgrade and I have hands-on experience to share with my clients.”

2007 Shelby GT500 Mods

• 5.4-liter iron block honed, line-honed, balanced, and assembled by Central Florida Machine

• AEM wideband oxygen sensor

• AFCO dual-fan, dual-pass heat exchanger

ARP fasteners

• ATI 15-percent-overdriven crank damper

• Billet Pro Shop fuel rails

• Bogart Bolted GT wheels, 17×4.5-inch front and 15×10-inch rear

• Cobra Jet dual-key crankshaft

• Dynatech long-tube headers w/ 1 7/8-inch primaries, high-flow X-pipe and Ford Performance SVT1 mufflers

• Ford 8.8-inch rearend w/ 9-inch bearing ends, Moser 33-spline axles, Ford Performance 3.73 gears, and a Strange spool

• Ford Performance M-5300L lowering springs

• Ford Performance timing assembly

• Hoosier bias-ply front runners, 27×5-inch

• Injector Dynamics ID1300 fuel injectors

• JLT Performance 148mm cold air intake

• JLT Performance 3.0 oil separators

• King bearings

• L&M Racing Engines no-spring-required camshafts

• Lund Racing custom calibration

• Manley H-beam rods 2/ ARP 2000 hardware•

• Manley flat-top pistons w/ 9.7:1 compression

• Maximum Motorsports K-member

• Mechman 240-amp alternator

Mickey Thompson ET Drag rear tires, 28×10.5×15-inch

• MGW shifter

• PST 3.5-inch aluminum driveshaft

• Return-style fuel system w/ Fore dual-pump fuel hat, and two Walbro 465-lph pumps

• RPM chrome-moly roll bar w/ swing-out door bars

• Stock Four-Valve cylinder heads

• Strange Engineering single-adjustable front struts

• Tremec TR-6060 transmission prepped by Astro Transmission

• Triangle Speed Shop crank and oil pump gears

UPR Products upper and lower control arms

• Viking double-adjustable rear shocks

• Whipple 2.9-liter Gen 3 supercharger w/ 3-inch pulley

• Whipple elliptical throttle body

From Bolt-Ons To Built

Obviously, BJ’s Shelby features a wide array of upgrades, but you could add this kit to a stock or bolt-on GT500 for a nice gain. If you want to make the kind of power this car did, however, the proper complementary mods are required. Tuning is also key, so he turned to the experts at Lund Racing for a custom calibration to maximize the new combo.

“Supporting hardware will depend on your goals,” BJ counseled. “A basic installation for an ’07-’12 GT500 would require at least a set of ’13-’14 Ford injectors and I’d recommend a fuel pump booster. I would also suggest a 123mm intake like a JLT. I use a 148mm JLT, but that’s not necessary until you’re at 775-800 rear-wheel horsepower.”

Positive-displacement superchargers abhor inlet restrictions, so BJ opted to run the optional 140mm elliptical, single-blade throttle body fed by JLT Performamce’s massive 148mm cold air intake. This combo helped deliver the kind of airflow needed to create four-digit horsepower.

“In my case, my power goal was 950-1,000 SAE-corrected, rear-wheel horsepower. I built the engine about 5,000 miles ago in preparation for a larger blower, so I knew it was strong enough to let it eat,” he added. “What I didn’t anticipate was running out of fuel at that level. Running both C85 and pump-grade E85, I was seeing the dual Walbro 465 pumps struggling to keep up and taxing even ID1300s. I replaced both pumps and mesh filter for some final tuning and it either needs a third pump or I will be using C16.”

However, as it stands the results were quite impressive. The car put down over 991 horsepower and over 890 lb-ft of torque at the rear wheels, and there is likely more to be had with additional fuel flow.

Clad with a 3-inch pulley, the Whipple Gen 3 twin-screw supercharger looks right at home atop Christine’s budget-built 5.4-liter engine. Cranking out 21 pounds of boost, the blower imbued this Shelby with 9-second potential.

Four On The Floor

“First of all, I was truly surprised at the torque delivery. As would be assumed, the Whipple delivered a 60 rear-wheel increase over the 2.3-liter TVS at lower boost (21 versus 23 psi) and less timing (21 versus 24 degrees). Downstream temps averaged 7-10 degrees below what Christine has seen previously at full boil,” BJ explained. “At peak power, in spite of two new pumps, it was clearly at the point where a third would be necessary or a switch to C16 was in order. A trip back to the dyno someday soon will see that 1,000-rear-wheel-horsepower mark, but it will take a fuel change to make it happen. Whether it is a couple of degrees of timing or a step down on the pulley, it’s ready to go. I have a funny feeling that she is about to see her first 9-second time slip.”

With the Whipple Gen 3 delivering 23 pounds of boost to the built 5.4 and a custom Lund Racing custom calibration in the PCM, Christine put down 991 horsepower and 890 lb-ft of torque at the wheels on a muggy Florida day. In cooler weather this is a legit four-digit machine. While the power is impressive, it was the fat slab of torque delivered by the latest Whipple rotor pack that impressed BJ the most. It also led to a bit of tire slip on the dyno rollers at 6,200 RPM. With a bit more fuel flow and RPM this one will crank out four digits even in the heat.

And that is definitely the goal BJ has his sights set on, but even if you aren’t a drag-strip demon, the latest Whipple delivers impressive results that you can enjoy on the highway as well.

“I am very happy with the results, power was right where we expected it,” Dustin added. “The 2.9-liter is a perfect fit for the 1,000-rear-wheel-horsepower daily driver.”

It is definitely the era of the four-digit daily, and it’s nice to see one of the more experienced Shelbys getting in on the action courtesy of the Whipple Gen 3.


Article Sources

About the author

Steve Turner

Steve Turner brings decades of passion and knowledge in the world of Ford performance, having covered it for over 20 years. From the swan song of the Fox Mustang to the birth of the Coyote, Steve had a front-row seat.
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