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Kenne Bell 2011 Mustang Supercharger Test - Mammoth Gains
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Because we prodded Kenne Bell into letting us take an early look at its Coyote kit, this article reflects early low-boost information. So, despite how Jim Bell opened our interview, we'll be back for more boost and tuning tips, including some huge power numbers. Given the airflow-happy Coyote engine, and what looks like an average of about 20 hp per pound of boost at this point, it's going to be a wildly fun ride. Driving Impression
Jim Bell was kind enough to turn us loose in his red '11 GT automatic test mule. Fitted with the standard kit pullied to 8 pounds of boost and tuned enough to start, run at wide open throttle, and that's about it, our goal was simply to sample the Coyote/Kenne Bell combination as a preliminary check. It's fast. No joke-pulling out onto the street and rolling swiftly into the throttle had us talking out-loud to ourselves, "This is how a blown V-8 is supposed to feel!" There's a big, grin-inducing torque hit anywhere on the tach, followed by excellent pull to the fuel shut-off. Heavy as the Kenne Bell blower kit is, it seems to magically take hundreds of pounds off the car when you have your foot in it. We didn't have time to evaluate the car in turns, but the extra weight up high must be noticeable to the sensitive driver. Romp the throttle from a standing start and be prepared for generous tire spin; she lights 'em up right now thanks to all that instant torque. The same easy power is a great match for the automatic transmission. Hit the gas and it downshifts one gear, then gets out of Dodge. With a manual, there's less need to shift due to the torque, and there's absolutely no need for steep rear-axle gearing. Stock 3.31s are fine. Noise is not a factor. If you know what you're listening for, you might pick up the faintest gear grrrr during idle or maybe cruising, but for any practical purpose, the KB is silent. While making boost there is a slight scream, but the long intake tube muffles that to the-people-next-door status. Exhaust noise gets amped up with boost-which is all part of the fun with stock mufflers-and rowdy with aftermarket mufflers, so you might want to take that into consideration if you're trying for stealth status.  The 2.8-liter, liquid-cooled...  The 2.8-liter, liquid-cooled Twin Screw is the backbone of Kenne Bell's '11 Mustang GT offerings. Here it is mounted to its adapter plate under the blower and Mammoth cast-aluminum air intake. The bypass valve and its vacuum motor are on the far side of the intake. Because of the 5.0-liter Coyote's prodigious airflow capacity, KB isn't bothering with its older "standard" inlet; all '11 GT kits include the giant Mammoth intake.  From the rear, the drainpipe...  From the rear, the drainpipe dimensions of the Mammoth air intake are even more apparent. Low-restriction airflow is vital to the inlet side of the supercharger because this portion of the system is naturally aspirated. At around 1,800-cfm capacity and with gentle bends, the Mammoth supports all the power anyone is going to make with this kit.  Turn the blower upside down...  Turn the blower upside down and its discharge port is visible. KB offers its 2.8-liter blower in standard or high-pressure (2.8H) configurations. The difference is the high-pressure blower has a higher internal compression ratio and is more efficient at higher boost levels, starting at 15 psi. From 8 to 12 pounds of boost, the standard 2.8 is definitely the better choice; up in the 18-psi range, the 2.8H could free up an additional 50 hp or so.  Another Kenne Bell option...  Another Kenne Bell option is liquid cooling, denoted by the pair of hose nipples on the blower's front face. These admit charge-cooling water to the front of the blower, cooling (actually evening) supercharger temperatures front to rear. This maintains better rotor clearances at higher boost levels and is a help as boost reaches well into the teens.  Low air-charge temperatures...  Low air-charge temperatures are a screw-blower advantage over Roots designs, but an efficient charge-cooling system is still a must. In front is the heat exchanger from all recent Kenne Bell Ford kits. In back is the new, approximately 25-percent-larger intercooler used in the 5.0 kit. Both taller and longer, it's the largest cooler KB could package, and a major reason 5.0 discharge temps are nominally a chill 110-120 degrees. The extra cooling is a big help with the Coyote's 11.1 static compression ratio, which is higher than ideal for a blower motor.  A two-piece aluminum casting,...  A two-piece aluminum casting, the Kenne Bell intake manifold assembly is essentially a relatively thin "adapter plate" for the blower, combined with a big breadbox housing for the charge cooler. (The blower sits on top and blows air down through the charge cooler; the air turns upward, then downward into the cylinder-head ports).  There is no runner length...  There is no runner length because the twin-screw makes too much torque; any runner length would only stifle high-rpm airflow. The irregular relief in the side of the charge cooler housing is for knock-sensor clearance. KB says it had to raise the knock sensor's sensitivity cylinder-by-cylinder in the 5.0 kit.  Kenne Bell uses a relatively...  Kenne Bell uses a relatively large heat exchanger radiator mounted behind the front bumper. A Bosch electric pump-everybody in the blower business seems to use this pump-circulates the coolant. Hefty steel brackets provide mounting-KB kits would benefit from a weight reduction program, but nothing ever falls off!  From a plumbing standpoint,...  From a plumbing standpoint, all there is to the liquid-cooled blowers is the hose kit shown here with the standard intercooler system. The LC fittings plumb into the two large holes facing the camera in the rotomolded tank, while the hoses run to the front of the supercharger.  Jim Bell fiddles with his...  Jim Bell fiddles with his hot-rodded flow bench while demonstrating the 5.0 air inlet to us. After turning up the voltage to the bench's motor, he can pull over 2,300 cfm of air through it-along with birds, small aircraft, and so on. In the foreground is the 5.0's oversized 2,000-cfm air filter (also used on KB's GT500 kit) hanging from the 4.5-inch-diameter, polished inlet tube. It's hanging from a stock throttle body, Mammoth intake, and the flow bench's tall funnel adapter. The noise this bench generates is incredible.  Hiding behind the big throttle...  Hiding behind the big throttle body's adapter plate are the stock 80mm Ford throttle body and Kenne Bell's 168mm billet piece. KB says the stock throttle body flows 976 cfm and is good up to about 650 rwhp-anything burning pump gas, in other words. The Kenne Bell unit flows 2,150 cfm and is good up to the kit's 1,400hp maximum.  KB's standard 5.0 fuel injectors...  KB's standard 5.0 fuel injectors are these 39-lb/hr '03 Mustang Cobra units. These are tall injectors compared to the '11 Mustang's short style, but they plug right into the stock fuel rails (which KB mounts backwards on the engine). If necessary, Kenne Bell steps up to 60- and 80-lb/hr injectors on the 5.0. All KB injectors are the same length, so they easily interchange.  Because the KB kit reuses...  Because the KB kit reuses the stock fuel rail, but mounted 180 degrees from its stock position, it is necessary to add a fuel line to make up the longer run to the relocated fuel rail. This is done with a single length of braided hose; we're using two hoses here to simultaneously show both ends. One end has the appropriate OEM pop-on fitting; the other uses an AN fitting plus an adapter to a standard fuel line.  There isn't much wiring involved...  There isn't much wiring involved in the KB 5.0 kit, and a plug-and-play wiring harness is provided in each case. Most folks will only install two jumper harnesses; a third is required with the big KB billet throttle body.  Kenne Bell doesn't need a...  Kenne Bell doesn't need a blower bracket, but an idler pulley bracket is required at the passenger-side front of the engine. It's shown here with the three idler pulleys and associated hardware that attach to the bracket.  Looking at the idler pulley...  Looking at the idler pulley bracket edge-on shows the six press-in spacers used by the mounting bolts. KB says they've gone to anodized-black for the plate finish because the previous polished-aluminum plates are worked so hard by the polishers, they dig divots into the plate, leading to cockeyed idler pulleys and thrown belts. The three bolt holes at the top of the bracket in this photo are for idler pulley adjustment with varying blower pulley diameters.  This low-profile billet-aluminum...  This low-profile billet-aluminum breather is a good example of Kenne Bell's bulletproof but heavy way of doing business. The billet piece is necessary to provide clearance for the intake air tube running over the engine's valve cover; the Ford plastic unit it replaces is too tall to work  More clearance is gained by...  More clearance is gained by relocating the evaporative emission canister purge valves to the inner fender. The valves are unchanged, only a new mounting is provided.  Hastily installed for testing,...  Hastily installed for testing, the red box in the corner of the trunk is a Boost-a-Pump module. It increases fuel flow by bumping up the fuel pump voltage, something that shouldn't be necessary on cars burning pump gas (under 600 hp), so the BAP remains an option for the high-power crowd. Ford made several changes to the '11 fuel system-which is obviously sized for forced induction as the pump, lines, and so on, are large enough to support 900 hp, according to KB. Stock fuel pressure is 58 psi, with a pop-off valve inside the fuel tank right next to the pump. That means no easy way to increase fuel pressure, but flow can be augmented with the BAP. That's how Ford does it-the engine management computer commanding 8 volts to the pump at idle and low speeds; then battery voltage at higher-power settings.
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