When asked what are the favorite cars we have driven, a certain Grabber Blue Mustang prepped by Ford Performance with a twin-screw blower always comes to mind, even more than a decade after driving it. Stock except for a stone-simple, non-charge-cooled supercharger pullied for a mere 5 pounds of boost, it doesn’t sound like much. However, augmented by a set of 4.10 rear gears and a short-throw shifter atop its manual transmission, it was a blast to drive.
Acceleration was instant and plenty strong. Sure, it didn’t have 700 horsepower at the tires, but given street rubber and some semblance of sanity you’d never notice. It was simply snap-eager, a daily driver that loved to party. And it was this combination of daily accessibility coupled with a nice power hit that won us over.
As such, when Ricardo Topete at GTR Performance said he had a customer wanting to put a Kenne Bell atop the Three-Valve 4.6-liter in a 2006 GT we were on it. This time the transmission is an automatic with stock 3.31 cogs out back, so the power delivery will roll in a little more than with a manual, but the whole idea is strikingly similar: a daily-friendly, real-world Mustang with fun power.
Even better, the charge-cooled, Kenne Bell twin-screw promised far more power than the aforementioned 5-psi kit could, so this one should be even more fun.
Of course, it’s worth a moment here to give thanks to the Three-Valve. If it weren’t for the Four-Valve Coyote, its Three-Valve modular cousin would get a lot more of the love it deserves. Overshadowed by the newer Coyote, RoadRunner and Voodoo Four-Valves, it surprises many to hear this 4.6-liter remains a best seller for many aftermarket parts manufacturers such as Kenne Bell. But it’s no surprise to us.
Available in huge numbers at fire sale prices the 2005-2010 Mustangs are still mainly clean, cars without excessive mileage so they don’t require a bumper-to-bumper restoration like their antiquated predecessors, love those Fox, SN-95, and New Edge cars as we may. Furthermore, their S197 chassis and powertrain potential is excellent as well. We doubt there is a more capable, available and affordable pool of project cars extant.
Our project 2006 GT stands out in two ways. For one, it’s exceptionally clean. Meticulously detailed at all times, it’s a fine representative of the breed and reflects well on its owner, Melissa Repreza. As Ricardo Topete, Wrench-In-Chief at GTR points out, “She’s more into her car than most of my male customers,” and considering this is her third Mustang and the attention she lavishes on it, we’re fully agreed.
Melissa enjoyed her GT as both her daily driver, and more lately, a weekend treat. Cruising and car shows have been her main activities, but she did confess a growing urge to take the car down the strip after eyeing Ricardo baseline her car at Auto Club Speedway. In such ways speed junkies are made!
With about 100,000 miles on the odometer—not that you’d ever guess from the beautiful paint and clean interior—Melissa’s ride remains mechanically sound and ready for a power adder. Almost to prove the point, as well as document our starting point, Ricardo saw 281 rear-wheel horsepower from the black GT on his Dynojet — a solid number from an automatic-trans car.
Ricardo also ran the car down the nearby Auto Club Speedway’s quarter mile in 13.895 seconds at 101.69 mph. For consistency he borrowed a set of big-and-little DOT drag rubber from Kenne Bell (GTR Performance and Kenne Bell are two different companies, but they just happen to be located within 300 yards of each other). Its eighth-mile posting was 9.050/80.34 mph.
When Melissa asked what she could do to step up her Mustang, Ricardo was quick to recommend Kenne Bell’s supercharger. The kits are complete with good instructions, says Ricardo, and the power increase is excellent. The Lysholm-screw design is inherently more efficient than its slightly less expensive roots blower competition and the polished blower option is showy, a big plus for Melissa who plans on attending plenty more car shows.
Ultimately a supercharger is a great choice for a fun driver where maximum utility and minimum maintenance are important. The blower is clearly a big financial step; the Kenne Bell Three-Valve kit Melissa selected features the Stage 2 130mm throttle body upgrade and clocks in at $6,299 plus another $500 for polishing, but nothing else provides such a punch coupled with no long-term hassles. Ricardo is also a Kenne Bell fan because he has an excellent working relationship with them — it’s possible to run almost next door for the odd part or engineering help — and he finds their customer service habits favorable.
2006 Mustang GT Baseline Testing
Ricardo gets more use out of his in-house Dynojet chassis dyno than just about anyone we know. Melissa’s Three-Valve GT baselined at 285 rear-wheel horsepower and 285 lb-ft of torque. At the drag strip it baseline with a 13.895 e.t. at 101.69 mph.
If holding costs in check is important for your street ride, think about forgoing the polishing and the larger Stage 2 throttle body. Each of those is $500; the polish is just for show and the bigger throttle body is worth 21 to 30 rear-wheel horsepower at street boost levels, so you might notice the $1,000 savings more.
There’s no way we can reproduce the 199-page Kenne Bell instruction manual here and in the photos, but let us say the manual is definitely a step-by-step guide with a photo or diagram for each step. Kenne Bell was one of the first in the industry to provide model-specific, truly detailed, easy-to-follow instruction manuals and they remain a highlight of the brand’s offerings.
And we always smile when watching Ricardo install a Kenne Bell; he’s probably installed 100 KB superchargers on Mustangs yet he still faithfully follows the instructions—more of a reminder these days — crossing off each step as he goes. The result is that he spends two full days on the job that steadily progresses with no backtracking or confusion. About the only item not included in the KB kits is spark plugs. “No supercharger kits have them,” Ricardo explained.
In overview, the Kenne Bell Three-Valve installation begins by stripping the top of the engine down to the valley, to be replaced by the Kenne Bell water crossover, intake manifold, and supercharger. Also on top of the engine new sparkplugs and fuel injectors are installed.
Little work is done to the front engine dress. The supercharger shares its drive belt with the rest of the engine accessories, so only a couple of idler pulleys and a longer serpentine belt must be added. The water pump, alternator, power steering pump, and A/C compressor remain unchanged. The coolant recovery tank and power steering reservoir are replaced for packaging reasons.
Because Melissa opted for the larger, 130mm Kenne Bell billet throttle body — good for at least an additional 21 horsepower — the electronic throttle body’s motor is moved from the stock throttle body to the Kenne Bell replacement. This throttle body upgrade makes the installation a Stage 2 in Kenne Bell parlance.
The front bumper cover is also removed so the charge cooler radiator can be hung behind the bumper along with its water pump. Back in the trunk, a Kenne Bell Boost-A-Pump is fitted to amp up the stock fuel pump. There’s no need to access the fuel pump as the BAP connections are made in the trunk.
Electrically Kenne Bell supplies all needed wiring extensions and interfaces with plug-and-play connectors that blend right in with the stock Ford connectors. The big throttle body, Boost-A-Pump, charge cooler and so on are also included at no extra charge.
As noted, an experienced pro such as Ricardo Topete can install this kit in two long days, and we’d say a senior enthusiast working at home might be able to equal that given a roomy, well-equipped shop, no interruptions and a willingness to power through the install. But we also see this more realistically as a week-long install for the enthusiast working after hours and weekends. In any case it’s all bolt-on and plug-in work with no fabricating required. As always, you’re ahead of the herd by simply reading ahead and following the detailed instructions. It’s amazing how many people don’t, then wonder why they went wrong.
In our next installment we’ll run the newly muscular combination over the dyno rollers and down the strip. Get ready to run at least 10 mph faster!
Stay tuned for our next installment when we hit the dyno rollers with the newly supercharged combo to see what this twin-screw Three-Valve can do.