Written by Miles Cook
Photography courtesy of Holley Performance
We love Corvettes of all generations from the first 1953-1962 solid-axle cars to the timeless Mid-Year era from 1963-1967. Shark-body Vettes followed in 1968 and lasted all the way until 1982. From there, the C4, C5, and C6 generations proudly flew the crossed flags during 1984-2013. And while the current-generation 2014-2019 C7 is a high-tech smorgasbord to be sure, in all honesty, the 2005-2013 C6s are among our favorites in terms of their appearance. They’re not exactly ox-carts either with their LS2 and LS3 engines, the latter of which makes 430 horsepower in stock trim.
But what if the stock LS3 isn’t enough for your C6 street or track Corvette? That’s where Holley and STS Turbo come in. The latter brand is now a part of the Holley family and it offers C6 Corvette rear-mounted turbo systems. And for good measure, 1997-2004 LS1- and LS6- powered C5s are covered as well, so much of what we’re discussing here also applies to those cars too.
Last year, Holley announced that STS Turbo Systems, a pioneer in rear-mounted turbocharger technology, also added a 2010-13 C6 Corvette Grand Sport application to round out a bolt-on twin-turbo solution that spools quickly while increasing power and torque across a broad rpm curve. The patented rear-of-the-car design (U.S. Patent Number 6,745,568) allows keeping the stock intake and throttle body, without the need for headers or mufflers.
Relocating the turbos to the rear of the car eliminates extreme under-hood temperatures and keeps the engine compartment free from clutter. It also simplifies repairs as there’s no need to remove the turbos or tubing to work on the rest of the engine with the STS system in place. Being exposed to ambient air rather than hot underhood air is said to improve cooling and provide denser exhaust gasses that drive the turbine wheel more efficiently. Rear-mounted STS Turbo systems also provide better weight balance as opposed to cars with the turbos installed in the front.
The systems come complete with all the components needed for an OEM-quality installation, including the turbos, a wastegate, a blow-off valve, an intercooler, tubing, fasteners, and a detailed instruction manual that covers the entire installation process.
Turbo temperatures approximately 500-degree are said to eliminate the need for a turbo-timer, which makes the engine to run after the ignition switch or key is turned to the off position in order to cool down the turbo and prevent oil and bearing damage. The turbos are also exposed to ambient air rather than under-hood air which allows for better cooling of the turbo components. Denser exhaust gasses also drive the turbine wheel more efficiently.
“If you’ve seen under the hood of a C6 Corvette, you know it’s a tight fit,” Rick Squires of STS Turbo told us. “The installation process is so much easier with the rear-mount design. Putting them where there’s room is clearly the way to go. The turbos themselves are also actually great mufflers. The car’s stock mufflers are removed and are replaced with the turbos so it’s a win-win all the way around. Temperatures coming out of the intercooler are thus close to ambient after coming to the intercooler from the turbos at the back of the car.”
Each of these is also available as a standard kit with no injectors or tuner or as a tuner kit with fuel injectors and a DiabloSport handheld tuner. The result is a total of eight variations of the system for 2005-2013 C6 Corvettes.
- 2005-2007 LS2
- 2008 LS3
- 2009-2013 LS3
- 2010-2013 LS3 Grand Sport