The Corvette ZR1 looks and...
The Corvette ZR1 looks and performs on par with the world's finest exotics, but did Chevrolet limit its output by fitting it with a restrictive exhaust system? To find out, we're going to introduce the factory cans to the nearest dumpster and replace them with the Corsa RSC Track Exhaust System.
If you're looking for the ultimate in factory performance, nothing comes close to the Corvette ZR1. With its supercharged LS9 engine (churning out a factory-rated 638 hp), carbon-fiber-body good looks, and see-through-to-the-supercharger Plexiglas hood insert, the ZR1 is America's most popular dream car.
For those lucky few who own a ZR1, however, one of the common observations is that the factory exhaust doesn't supply the looks and sound characteristics the car deserves. In their minds, the ZR1 should have a set of pipes as awe inspiring as the rest of the vehicle.
Luckily, Corsa Performance Exhausts of Berea, Ohio, now offers a ZR1 version of its RSC Track Exhaust System (PN 14164), which features guaranteed horsepower gains, the company's patented Reflective Sound Cancellation (RSC) technology, and stainless-steel construction for long-lasting great looks. (The system also fits Z06 models.)
Our first step is to strap...
Our first step is to strap the ZR1 onto Backstreet Performance's mobile Dynojet dynamometer and ask company co-owners Rich and Erik Johnson to put it through three successive, no-holds-barred pulls. The best yields readings of 517.01 hp and 500.36 lb-ft of torque.
"Although the ZR1 is a superb vehicle and the flagship of domestic performance, its OEM mufflers lack sound from start-up and through the revs," Paul Santiago, Corsa's Sales Manager, explains. "Corsa provides a uniquely tailored exhaust note that could be best described as a blend of exotic supercar and muscle car all in one. At initial start-up, it already sounds like the supercar it is. [And] Corsa's promise of a no-drone internal cabin sound means that all 600-plus horsepower can be enjoyed at any level of speed without the fatigue experienced when the OEM muffler valve is manually left open during cruise."
According to Corsa, RSC technology reflects sound-pressure waves within the muffler case to produce the same 180-degree, out-of-phase, wave-cancellation effect found in electronic noise-suppression mufflers, without added complexity or flow restriction. As a result, Corsa is able to design a free-flowing, straight-through exhaust with awesome sound at full throttle and idle, while at the same time canceling low-frequency cabin resonance.
There's also a major difference in construction and materials between the ZR1's factory exhaust and Corsa's after-cat system. The ZR1 ships from GM with aluminized pipes and muffler casings, which are prone to deteriorate over time. Corsa, in contrast, "offers exceptional build quality and superb craftsmanship that make our exhaust systems almost jewelry-like. [They're] crafted of 321 military-grade stainless steel, the best in the industry for this vehicle," Santiago says.
Take a good look at the ZR1's...
Take a good look at the ZR1's stock exhaust tips and mufflers before we retire them for good. We'll show you a photo of the new Corsa tips and mufflers installed later in the story and let you decide which is the better-looking system.
We've featured Corsa exhaust systems in the past, and they've always provided a righteous rumble coupled with a drone-free cabin sound, along with stellar, stain-less steel looks any Corvette owner would be pleased to add to his or her car.
But what about horsepower? Did Chevrolet significantly limit the ZR1's output through its choice of pipes and mufflers, unwittingly giving Corsa and other aftermarket exhaust companies an easy way to uncork big power gains? There was only one way to find out-tear out a ZR1's factory exhaust, replace it with a Corsa RSC system, and dyno test the car to determine the power and torque differences.
We conducted our testing at Corsa's headquarters, which houses a professionally staffed R&D department where new exhaust systems are designed, tested, and installed before being released to the public. Backstreet Performance, "Ohio's Portable Dyno Specialist," provided the mobile Dynojet dynamometer required to objectively administer our tests. Company co-owner Erik Johnson made a trio of pulls with our ZR1 in stock trim, then repeated the routine immediately after the installation of the Corsa system.
We'll share the results of our test at the end of the story. Meanwhile, follow along as Corsa Lead R&D Technician Mark Bockwich shows how easy it is for you to install the Corsa RSC Track Exhaust System in one afternoon in your home garage or even in your driveway.
Now it's time to extract the...
Now it's time to extract the factory after-cat system. Corsa Lead R&D Technician Mark Bockwich uses a 15mm socket to loosen both of the factory
crossover-pipe clamps from the axle pipes (one on each side of the transmission).
Staying with the 15mm socket,...
Staying with the 15mm socket, Bockwich removes the two bolts and nuts connecting the factory crossover pipe to the converter pipes. (On the ZR1 or Z06, the lower two fasteners are bolts, and the upper two are nuts. On a standard C6, all four fasteners are nuts.)
The crossover-pipe assembly...
The crossover-pipe assembly is attached to the factory spring hangers by two nuts. He removes them with a 13mm socket, freeing the crossover-pipe assembly from its remaining mounting points underneath the Corvette.