Horse Sense: History might show the '03 Cobra as the car that finally made the 5.0 Mustang obsolete. Its Four-Valve is the first modular engine to demonstrate the breathing and power beyond what the pushrod small-block is reasonably capable of.
Listen carefully to the buzz about what the '03 Cobra can do-that background noise you hear is the sound of tuners hard at work. Perhaps most animated of these is Jim Bell at Kenne Bell, thanks to the '03 Cobra's Eaton-built Roots-type supercharger. Jim has been eager to strut his stuff-all over the Eaton/Roots competition if at all possible-and what better vehicle for his agenda than the new Cobra? Obviously the car is factory-engineered for blower power, and all Jim has to do is take off the stock Roots-type blower and install his own supercharger along with the necessary supporting pieces. Luckily for everyone, after months of pleading on our parts, we were invited along for what proved to be a screaming dyno thrash-one of the highest-powered bolt-on tests we've ever experienced.
In the following pages is a huge but condensed mass of data on what the stock '03 Cobra is capable of and how the Kenne Bell supercharger was engineered onto it to form a 600hp rocket. Besides highlighting the impressive airflow capacities of the Kenne Bell supercharger, the story illustrates the Cobra's electronic sophistication and hints at the changing state of performance tuning in general.
To test an '03 Cobra, you have to have an '03 Cobra. Normally Kenne Bell simply buys the car or truck needed, but this time, Randy Kramer provided the all-important subject. He was willing to take his chances on the dyno in exchange for the latest in horsepower. The spanking-new yellow Cobra had all of 904 miles on the odometer when we started, and more than 950 when we ended. Imagine, almost 50 miles of supercharged, all-out acceleration. And if you're wondering how a guy could go without his new Cobra for so long, it's because Randy is a cruise-ship captain, and while he's out to sea, he can't drive his Cobra.
Only the temperature probes...
Only the temperature probes were nonstock when we started testing the '03 Cobra. With their fine wires, just the tubular metal ends of the probes show here.
All work was done on Kenne Bell's Dynojet. This is a favorite of ours, as Jim's dyno has more instrumentation on it than any other we know. In the cockpit, Kenne Bell technician Brent Morris had a Horiba air/fuel meter, a Fluke digital thermometer, a Toshiba laptop for datalogging, a STAR II tester, the dyno on/off control, a printer for the STAR tester (which was perched in the back seat), a power strip, enough wires and cables to start a phone company, and a clipboard with good, old paper and ink so the dyno and datalogging sheets could be notated and kept together in order. The data sheets were collected into a notebook as they were printed. In the end, more than 250 pages of data were obtained.
With the datalogging, horseback analysis, cooldown, and other requirements, each test took about 20 minutes to perform, although some had hours of downtime as a new chip was written or equipment fitted. In all, four long days of dyno time were expended. Though there were some false starts and deadends, there were never any failures. Yes, the test ran long, but given the complexity of instrumenting the test car-there's plenty of drilling and tapping involved in this-once the car was on the dyno, the impetus was to see the test through.
The engine was rigged with numerous probes, many of them for temperature. The stock Eaton blower and intake were removed and replaced so the intercooler/manifold could be drilled and tapped to accept the probes, which were hooked up either to the dyno or the laptop datalogger. This allowed us to see the ambient or blower inlet temperature, the blower outlet temperature, and the intercooler outlet temperature, along with boost and intercooler water temperature. When the Kenne Bell blower went on, it received the same treatment.
Datalogging was done with a Toshiba 325CDS computer running proprietary Kenne Bell software. This is non-user-friendly, DOS-based software designed by Ken Christley at Kenne Bell. He used to have his own company, and the software dates from those days.