Mods for Coyote Mods, Part 2 - The Perfect 10

The Controls Pack included ECU and wiring harness, MAF, air intake system, factory airbox, OBD-II diagnostic port, and a complete calibration. The Controls Pack even included a drive-by-wire throttle pedal. Owners of the Ford Racing crate motor and Controls Pack can drive with confidence knowing that their 5.0L was the product of literally millions of dollars of research and development.

In Part 1, we were successful in installing the 5.0L crate motor on the engine dyno and running a few simple performance tests. The Coyote was runs sans accessories (equipped only with a Meziere electric water pump). We started the adventure by running the killer Coyote in stock trim from the stock airbox right through the stock exhaust manifolds. The 5.0L belted out 448 hp and 405 lb-ft of torque, proving that though it certainly made peak power higher than its original namesake, it also offered an abundance of torque.

We were happy with the results, but couldn't help wanting the ability to properly tune the combination. We know from experience additional power was available by dialing in the ignition timing, cam timing and air/fuel mixture to say nothing of replacing the factory airbox.

Our original intention was to combine an air intake upgrade from JLT Performance and tuning from SCT with a quartet of performance cam profiles from Comp Cams, but we decided to delay that test until next month to make room for boost. Actually, we wanted to run boost on the bone-stock motor before adding performance cams. While cams are a popular upgrade, many 5.0L enthusiasts will install forced induction on their otherwise-stock motor, and we can always run more boost on the modified motor at a later date. Plus, we already have two cam tests in this issue.

So, the Comp Cams, SCT PowerFlash, and JLT air intake were put on hold as we installed (albeit temporarily) a 2.8L twin-screw supercharger from Kenne Bell. Rather than run an all-out, high-boost combination, we decided to illustrate the power gains offered by the basic kit. Along the way, we also ran a few additional tests to demonstrate the importance of minimizing inlet restrictions. Obviously, we couldn't help but increase the boost pressure somewhat along the way. (We're only human!)

What we found was that not only was the new 5.0L motor plenty powerful in normally aspirated trim, but the killer Coyote just loved boost! Given the Camaro/Mustang rivalry, it seems only natural to compare the 6.2L LS3 to the 5.0L Coyote. The Coyote more than holds it own against the much larger rival, but it's important to note that the Ford engine offered this level of performance with 1.2 liters less displacement.

The Kenne Bell kit for the current Mustang included a 2.8L, twin-screw supercharger, air-to-water intercooler, and Mammoth air intake. While we had the motor on the dyno, we took the liberty of comparing a couple of different air intakes, three different pulley sizes, and a pair of throttle bodies. Naturally, the kit included larger 47-lb/hr injectors, a Boost-a-Pump, and all plumbing required to install the complete kit in an '11 Mustang. Some of these components (heat exchanger, mounting brackets and Boost-a-Pump) were not employed on the engine dyno, but none had any effect on the ultimate power output of our supercharged crate motor.

Having run the Coyote previously in normally aspirated trim, we removed the factory intake manifold and throttle body to make room for the supercharger. It was necessary to swap over the factory rubber O-rings from the stock intake to the blower manifold, but installation of the Kenne Bell was quick and easy thanks to Mike Decourcey from Kenne Bell. After the lower intake was in place, on went the supercharger and Mammoth intake assembly, the injectors, and stock throttle body. The Mammoth intake was a critical element, as positive-displacement supercharged motors are ultra sensitive to inlet restrictions.

According to the gang at Kenne Bell, every effort was made to minimize restrictions and maximize airflow into the blower. The basic philosophy for the blower is the same as any air pump--the more airflow in--the more power (or boost) that comes out. As our testing would illustrate, the factory air intake system, including the 80mm throttle body would prove to be quite restrictive. While an 80mm throttle body might seem sizable (especially for those of us who cut our teeth on the original 5.0L), it was certainly restrictive on this supercharged application.

Initially the 5.0 was not happy running on the engine dyno due to a lack of input shaft speed. Basically, the motor was spinning, but the ECU didn't see any vehicle speed. Because of the confusion, the drive-by-wire throttle body refused to go to wide-open and instead limited torque output to 100 lb-ft. A few magic key strokes and flash tunes by the wizard had us up and running and ready to test. Run with the stock air intake system, the supercharged 5.0L produced 588 hp at 6,800 rpm and 493 lb-ft of torque at 4,500 rpm. The combination produced a peak boost reading of 6.5 psi at 4,600 rpm, but the boost fell slightly to 6.0 psi at 6,800 rpm.

Our next test involved removal of the lower portion of the factory airbox and the installation of a K&N panel filter. The rectangular opening in the factory airbox was certainly restrictive, as removal of the lower portion of the box resulted in a jump in peak power to 610 hp and 501 lb-ft of torque. The peak boost was up slightly to 6.6 psi, but the air intake upgrade increased the boost pressure at the top of the rev range by nearly 0.5 psi.

Next up was the dedicated air intake system offered by Kenne Bell. Measuring a whopping 4.5 inches in diameter, the air intake offered not only unrestricted airflow, but also a dedicated cold-air source (when installed on a 2011 Mustang) for the supercharger. After swapping the MAF electronics from the factory airbox, we were rewarded with 622 hp and 513 lb-ft of torque. Thus far, removal of the inlet restrictions improved the output of the supercharged motor by 34 hp and raised the boost pressure by 1 full psi.

Though we knew the factory 80mm throttle body was now the single biggest inlet restriction in the system, we decided to increase the boost slightly by replacing the 4.125-inch blower pulley with a smaller 4.0-inch pulley. Pulley swaps were a snap and this one was worth an easy 20 hp, as the peak numbers now checked in at 642 hp and 527 lb-ft of torque. Peak boost pressure was up to a steady 7.6 psi.

Now it was time to upgrade the throttle body. Using an adapter plate, Kenne Bell designed the Mammoth intake to accept a variety of different throttle bodies, including its 168mm, single-blade unit. The oval throttle body offered more than twice the airflow of the factory 80mm throttle body, and the supercharged Coyote put that extra flow to good use. The throttle-body upgrade increased the peak power numbers to 681 hp and 536 lb-ft of torque.

It is important to note that the gains offered by the throttle body (or any inlet upgade) will vary with boost and power output. Tested on a stock 400hp motor, the gains will be less than on an 800hp supercharged motor. We have seen this throttle body upgrade net as much as 60 hp at higher hp/power levels.

Being so close to 700 horsepower forced us to install one final blower pulley. Replacing the 4.0-inch pulley with a 3.875-inch pulley pushed the peak power numbers over the 700hp mark, to a high of 704 hp and 549 lb-ft of torque. The peak boost reading registered 9.9 psi, but was closer to 9 psi through most of the curve. We were impressed with this for a number of reasons, not the least of which was the fact that it was now pumping out over 700 hp at less than 10 psi of boost.

According to Kenne Bell, this combination will run on 93-octane pump gas (not the 91-octane junk we have here in California) thanks to a combination of efficient intercooling, a dedicated cold-air intake, and proper tuning. Combining the Ford Racing Performance Parts Coyote crate motor with the intercooled Kenne Bell twin-screw makes the combination nothing less than a perfect 10.

Ford Racing crate motor-NA vs Kenne Bell (9.9 psi)

We know every reader will jump right to the 700hp peak number, and for good reason. Any 5.0L that thumps out 700 hp is an impressive piece, but every bit as important was the fact that the Kenne Bell twin-screw supercharger offered sizable torque gains through the entire rev range. Step on the gas and you are immediately rewarded with a surge of power. Peak power doesn't win races--average power does. Low speed power is often more fun on a street car, as how often do you get to wind the Coyote out past 7,000 rpm without feat of losing your license. Boost makes this high-winding small motor feel like a high-winding BIG motor!