While some can only dream of owning a $70,000 supercar such as the LS7-powered Corvette Z06, some followed their purchase with envy of the new ZR1's output and the means to do something about it. Thankfully the Australian company Air Power Systems (APS) makes a twin-turbo kit with OEM-quality fit and finish that will transform the already potent 427-cube Gen IV into a fire-breathing dragon, and satisfy even the most hard-to-please Corvette owner. With their recent release to the U.S. market and a limited amount of U.S. retailers and distributors, we had only seen a few installed kits on GTOs and F-bodies. All seemed to look and perform marvelously, though, with one of the most complete, well thought out, and high-quality designs out there. When we happened to get wind of an upcoming install at APS retailer and installer Redline Motorsports in Schenectady, NY, I jumped at the chance to get this exciting new product onto the pages of GMHTP and Editor Jensen was happy to comply.
Like all of its late model GM kits, the APS C6 Z06 Twin Turbo Kit comes with two cutting edge Garrett water-cooled turbos, heavy-duty cast manifolds, high efficiency bar and plate air-to-air intercoolers, hot and cold plumbing, a higher capacity MAF housing, twin APS blow-off valves, and TiAl wastegates. For the hungry 427 LS7, APS supplies Garrett GT3582R ball bearing turbos with Inconel turbine wheels that efficiently produce up to 1200 horses at only 18psi knowing that with a few modifications-such as forged pistons-these engines can certainly handle it. Big turbos, though, need big wastegates, so cleverly packaged TiAl 44mm units are tucked under the floor pan. This particular kit also comes with a larger oil cooler (to replace the smaller factory piece), a stainless steel after-cat exhaust, and the necessary fuel system upgrades including high flow fuel rails, injectors, and dual in-tank pumps.
Our '06 test car is Redline's official guinea pig, which owner Howard Tanner had previously had a set of Kooks long-tube headers, B&B exhaust, and a centrifugal blower enhancing the stock motor. He had planned to use the APS kit to eventually make up to 1,000 rear wheel horsepower, so the first order of business was to replace the stock LS7 with a low compression 427 using Diamond forged pistons, as well as a heavy-duty set of rods and a crank, and a re-sleeved block from Race Engine Development. He even decided to have West Coast Cylinder Heads port a set of LS7 heads and put in a larger boost cam. That being said, we expected that even at 6psi dyno pulls would be healthier than a boosted stock LS7. (APS claims 625 horses at the wheels in that configuration.) The added benefit of having the fortified motor is that Howard had no problem cranking up the boost to 9psi on pump gas to give us an idea of what this kit was really capable of, where the stock hypereutectic pistons and lightweight titanium rods might have called it quits.