Innovation and change drive product development, and when it comes to the C6, that means increased performance for the Corvette enthusiast. Case in point: Sensing a largely untapped niche in the C6 aftermarket, Air-Charger president Carlos Allen decided recently to develop a cold-air kit for the car that worked in conjunction with the factory airbox to provide a quality source of fresh air for the engine. Although much improved over the stock C5 airbox design, the C6 setup allows intake air to be heated as it passes through the grille and around the radiator before being drawn into the airbox assembly. Even worse, on the Z06, the oil-cooler assembly adds an additional heat source, further increasing intake-air temperatures.
Since the airbox assembly on the C6 was changed to flow better from the factory, Carlos reasoned, why not focus on creating a cold-air source for the existing box? Using air from the high-pressure area in the grille and routing it to the factory airbox would also allow him to offer a ram-air system for a reasonable amount of money.
The Air-Charger system differs in other ways, too. Rather than putting the requisite airscoop at the forwardmost edge of the grille opening, as is common with C5 units, Carlos decided to take a different route. "Scoops in the lowest levels of the grilles on the C6 are not in the highest-air-pressure area and can be quite dangerous to those enthusiasts who use their C6 or Z06 in inclement weather. By patenting the industry's first 'acute upstream airscoop' in the high-pressure area behind the grille, not only does the engine get cooler, denser, pressurized air, but the chances of ingesting water are virtually zero under normal driving conditions. Many designs were tested over a six-month period until [our] patented 'Gen 1' system was released."
[Edtor's note: It should be noted that we've never heard of a case in which an aftermarket ram-air kit caused water-related engine damage under normal driving conditions. Typically, such damage occurs only when the nose of the car is completely submerged, as might happen in a flooded parking lot. Nevertheless, locating the scoop higher in the grille is likely to provide a greater sense of security for C6 owners who dwell in wetter climes.]
According to John Page, owner of Carrollton, Texas-based tuner Twenty First Century Muscle Cars, "Carlos contacted us about providing him with test facilities and feedback on construction, quality, and ease of installation as he developed his prototype hardware. After numerous revisions to the initial design, we were convinced by the test data that the system was effective. The system installs in under an hour and . . . typically we see average gains in the 6-to-8-rear-wheel-horsepower range with equal or better torque improvements and [peak] gains of 9 to 10. Gains on modified cars are often less at the peaks, but depending on camshaft selection, midrange torque can be significantly improved. Since a cold-air kit-and especially a ram-air system-is most effective under road conditions, any gains seen on a dyno should easily be surpassed on the road."
Our subject Z06 is owned by Sanjay Mehta, a radiation oncologist from Houston, Texas. The Z had already been modified by Horsepower Engineering (HPE) in Houston, and it boasted a custom-ground camshaft, a set of Kooks stainless steel headers, a high-flow catted intermediate pipe, a Halltech air filter, and a custom tune generated using LS7 Edit. In stock form the Z06 put down 465 rear-wheel horsepower; the HPE upgrades nudged that figure to 515 rwhp. Follow along as Twenty First Century Muscle Cars technician Jonathan Verhovshek installs the Air-Charger, and tuner Patrick Sparks tweaks on LS7 Edit to refine the tune to work best with the new intake.
ResultsAfter the dyno rollers stopped spinning, and the noise of the ravenous LS7 dissipated, the test results were analyzed. Although the Air-Charger coaxed out only an additional 2 peak horsepower, peak torque jumped by 12 lb-ft. Even better, there was as much as a 20hp and 46-lb-ft gain at 2,100 rpm. Below 3,100 rpm the average gains were just over 10 hp and 24 lb-ft. Overall, the average gains were 7 hp and 15 lb-ft.
Peak-horsepower gains are the most commonly cited metric in dyno testing, but average gains in the usable power band will definitely translate into better performance on the track and, especially, on the street. And because the Air-Charger system can't benefit from the ram-air effect on a stationary dyno, additional gains should be seen in the real world.
Says car owner Sanjay Mehta, "The Air-Charger performs very well, especially . .. from 4,000 rpm to redline. The car pulls harder, and I am confident that the additional airflow will allow me to trap higher speeds at the dragstrip plus eclipse [my] personal best of a 184.5-mph Texas Mile, done in my Lingenfelter ZR-1 a couple of years back."
According to John Page, "From a peak horsepower and torque standpoint, this was the lowest-gaining Z06 we have installed the system on. Since [this car] was modified with a more aggressive camshaft, it leads me to believe that the addition of more air at the lower rpm definitely helped fill the cylinders and attributed to the outstanding average power gains. On my personal Z06, I saw peak gains of 7 hp and 7 lb-ft, while Carlos Allen's car gained 7 hp and 9 lb-ft."
From start to finish, the installation took approximately one hour. For C6 and Z06 owners looking to cram more air into the cylinders, the Air-Charger provides a stealthy, cost-effective option. Look for the company to release a complementary high-flow air filter in the near future.