Corvette ZL435 PerformancePac - Power Switch

Having recently dissected a variety of C6 forced-induction systems, we decided to take a slightly different tack with our latest sixth-gen upgrade project. Two criteria were set: First, we wanted to noticeably increase the car's horsepower and performance using only bolt-on parts; second, we wanted to be able to install the entire package in four hours or less. After a little Internet research, we determined that the SLP ZL435 PerformancePac would likely allow us to accomplish both of these goals.

With a package selected, we asked SLP Director of Engineering Hank Daniecki for a more in-depth description of the ZL435's selling points. "The ZL435 Pac is a great entry-level performance package for any C6 enthusiast," he said. "All included parts are easy bolt-on items that add a significant gain in horsepower and torque. Best of all, most DIY'ers should be able to handle the installation in their driveway."

The ZL435 PerformancePac comes with a choice of three exhaust systems, each designed to provide a unique sound. Our system came with SLP's Loud Mouth mufflers, the most aggressive of the bunch. The other options include the slightly quieter Loud Mouth II (package price: $1,689) and the comparatively demure PowerFlo (package price: $1,739). Despite their divergent sonic characteristics, all three systems are said to make virtually identical power on the dyno.

Our SLP ZL435 package retailed for $1,639 and included the following:

* Blackwing Cold-Air Induction
* Loud Mouth Exhaust System
* DiabloSport II C6 Programmer with SLP Custom Tuning
* 160-degree Thermostat
* ZL435 Fender Badges (pair)

Follow along as we install and test the SLP ZL435 PerformancePac on an '07 C6 convertible.

The Blackwing CAI is the first item in the ZL435 upgrade. Said to outflow the restrictive factory airbox by as much as 90 percent, the Blackwing uses a washable, high-flow filter media; a built-in flow indicator; and a carbon-fiber-look, high-volume air bridge. It includes all the pieces and mounting hardware shown here.

The Loud Mouth exhaust system includes after-cat downturns; 211/42-inch pipes; polished resonators; polished, 3.5-inch tips; and all necessary mounting brackets and hardware. The entire system is built from stainless steel and can be installed without welding.

The included 160-degree thermostat reduces operating temperatures, improving thermal efficiency, and, presumably, engine performance.