Gains across the board! That’s...
Gains across the board! That’s what we like to see when we do projects like this. We gave our power-improved Snake a severe workout on AMP’s Dynojet chassis dyno, and the numbers were incredible. You’ll notice the distortion in the 6,700-rpm area of each curve—a telltale sign of belt slippage, which came about consistently just as boost reached 17-20 psi. Unfortunately, limited time prevented us from experimenting with idler pulleys that we think would have helped our cause. But as the graphs show, the addition of hot camshafts and the big supercharger definitely puts the Cobra’s power and torque output on the next level.
Dyno testing after changes is always the most-anticipated phase of projects like this ’03-’04 Cobra cam/big-blower upgrade, and we certainly didn’t waste any time getting Miguel’s freshly modified ’03 Terminator loaded onto the Dynojet chassis dyno at AMP Performance. With our goal being to see how far a switch to hotter camshafts and a much-larger supercharger takes horsepower and torque, we evaluated the new setup using blower pulleys measuring 4.25, 4.00, and 3.75 inches. Our sights were on seeing 700-or-better horse-power from the new combination.
For this experiment, the numbers tell it all. With PCM calibration accomplished using DiabloSport’s Chipmaster Revolution tuning software and through a Predator handheld flash device, our cams/twin-screw combination (with the big 4.25-inch pulley) immediately came within 40 hp of our ultimate goal of 700. Belt slippage limited this and the two other configurations (4.00- and 3.75-inch) from showing the setup’s true hand, which we believe ultimately could approach 800 horses at the feet. (An unofficial pull with the 4.00-inch pulley netted 735 hp.) For the money you’ll invest in parts and labor, the package is a beast!
We’re firmly entrenched in a time when 600 horses is the expected norm for street-driven Mustangs, as bolt-on power adders have made reaching the once-unfathomable mark quite doable. To have a completely driveable ’Stang that puts nearly 800 horses on the ground is truly above-board, especially for Terminators with stock–bottom-end 4.6s as opposed to Shelby GT500s with fully built supercharged 5.4s.
It indeed is refreshing that despite all the forward progress the aftermarket is making for the latest Mustangs, new technology for ’03-’04 Cobras is still being developed, and in some ways, performs even better than similar hardware for later models.
This 4.00-inch pulley proved...
This 4.00-inch pulley proved the best of the rest during our dyno session. However, when the slipping situation with the 3.75-inch wheel is corrected, we’re sure Miguel’s ’03 Cobra will approach the magical 800-rwhp mark.