Project Lightning

The process of developing more horsepower from our project Ford Lightning is not simply a matter of bolting on various aftermarket parts. We wanted to take a theoretical approach in determining what areas of the truck's drivetrain could use some improvement and where some extra horsepower could be hiding. This approach meant taking several baseline dyno numbers on the truck and installing probes in key locations to gather data. To help us in this process, we sought the help of Kenne Bell, a company who already has a deep understanding of Ford products, developing many supercharger systems, upgrades, and performance intake systems for Mustangs.

We first took a serious look at the Lightning's intake system to determine how it makes horsepower. The Eaton supercharger on the 5.4L small-block is rated at 10 pounds of boost and uses an air to water intercooler. This is used to bring down the air intake temperature charge to create more available boost. Our baseline inertia dyno runs showed that the Lightning in stock form made 338.3 hp at 5,100 rpm to the rear wheels.

One of the horsepower theories we wanted to test was how cooler intake temperatures affect horsepower. But does this theory hold true with intercooled supercharged engines such as that in the Lightning? Jim Bell of Kenne Bell believes that through the many dyno tests the company has run, the numbers have shown that it is not the discharge temperature that creates more horsepower (air after the intercooler), but the inlet temperature that can generate more horsepower from this system. We had the quarter- mile numbers to back this up when we compared the runs on two separate occasions where the weather was dramatically different. It was almost a year ago at Los Angeles County Raceway when the Lightning ran a 13.78 quarter-mile time. That day, the temperature at the track was a chilly 12 degrees. Under warmer conditions at the same track a few months later, the 90-degree heat didn't allow the Lightning to muster anything faster than a 14.30.

The Lightning obviously ran faster when the temperature at the track was much cooler even though the Supercharger was producing the same amount of boost. According to Bell, a general rule of thumb is that for every 10 degrees of air temperature (cooler or hotter), there is a corresponding 1 percent of horsepower increase or decrease.

To test this theory, we opted to dyno the truck with an open element cone K&N air filter. The filter measures 4x6 inches; we removed the stock airbox and connected the cone filter to the end of the factory mass air meter. We ran the dyno with the hood open and closed. Open, the air inlet temperature measured 97.3 degrees Fahrenheit. When closed, the inlet temperature measured 99.5 degrees Fahrenheit. Although there was only a 2.2 degree of difference in the air temperature, the difference in performance was 9 hp. Some of this could also be attributed to the cone filter being less restrictive than the factory system, which gave us a start toward finding more horsepower on this truck.

The next step was to see if we could make up that difference using the factory air intake box. A recommendation from our friends at Ford SVT was that there was an additional 8 hp if we opened up the air inlet hole on the fender. This is the area where the air enters the gaps between the headlights and runs through the inner fender. The factory air intake system takes its cold outside air from this area, and we decided to open it to the same diameter as the rubber inlet tube that mates up against it. We used a Sawzall to open up the area and, after reinstalling the factory air-intake system, it netted 8 hp. To get the most horsepower during our testing, we opted to reinstall the 4x6 cone filter.

Following the air intake test, we wanted to see if there was any more power to be gained by optimizing the Lightning's computer programming. The staff at Kenne Bell tried several programming modifications that, when tested, ended up creating a new chip that made 19 extra horsepower over stock. The Kenne Bell Switch Chip also has a unique feature that enables the chip to be switched from its stock programming to the modified version with a flick of a small switch.

Another idea was to try to install the Cobra Mustang, high-flow throttle body. This throttle body has the same dimensions as the factory Lightning throttle body, however, it features a single blade rather than the factory's double barrel blade design. The only problem with the Cobra throttle body is that the TPS sensor and throttle linkage is reversed from that of the Lightning's. We tried it anyway, manually opening the throttle linkage throughout the dyno runs. The results of this test using the factory chip setting netted us another 14 hp. Flipping the chip to the performance setting, the combination of the chip, the free-flow air intake modification, and the Cobra throttle body achieved 30 extra horsepower.

The final step (for this session) in our quest for more horsepower was to test the factory exhaust system. This is done by inserting a pressure gauge that extends from behind the catalytic converters. During the dyno runs, the Lightning produced only 2-1/2 pounds of backpressure at 6,000 rpm. Considering that the exhaust is a dual system, which exits quickly out from the passenger side of the cab, we felt there wasn't any horsepower to be found here. Perhaps most of the backpressure was in front of the cats. We would have to test for this later. The one thing that we did notice was a bad vibration that sounded like a loose junction in the exhaust. We took the truck to our friends at Ace Muffler Shop in Santa Ana, California, where we discovered that the baffle inside the stock muffler (used to keep the right and left side exhaust pulses separate) had deteriorated. We replaced the muffler with two Flowmaster mufflers in parallel. The difference in the Lightning's tone was great but not obnoxious. We noticed that there wasn't any significant change to the horsepower levels we achieved at Kenne Bell.

Where do we go from here? How about trying a smaller supercharger pulley that should give us another 3 psi of boost? Another addition will be using the larger 90mm mass air sensor off of the new '01-model Lightning. Furthermore, we may be able to install the '01-model Lightning components, which include the intake, the supercharger, and the intercooler. We will also check on adding a set of headers to see if we could reduce some of the backpressure in front of the catalytic converters. We'll keep you posted.

Sources

Ace Muffler Shop
Dept. TR
401 E. 1st St.
Santa Ana, CA 92701
(714) 543-5992

Kenne Bell
Dept. TR
10743 Bell Ct.
Rancho Cucamonga, CA 91730
(909) 941-1375