There are few things that bring as much excitement to the heart of a performance enthusiast as the roar from a great sounding exhaust system. A mellow rumbling at idle, followed by a fierce snarl from the tail pipes as a finely tuned V8 screams towards redline is truly music to a car guy’s ears. But, at the same time, there are few things more annoying than the booming resonance and interior drone at cruising speeds that many performance exhausts can create. That 4-inch straight-pipe system might be fun for a few days, but just wait until the first time you have to drive anywhere on the highway. We may love the added power, but an irritating, droning exhaust can quickly turn your performance car from “barrels of fun” to “barely fun.”
‘RSC’ stands for ‘Reflective Sound Cancellation’ and this muffler design pioneered by our company actually tunes out the unwanted low frequencies that cause drone at cruising speeds. – Lauren Bolmeyer, Corsa
This is one of the biggest issues that performance exhaust companies face when designing a system for any car that will actually be driven on the street; how to balance the exhaust tone between loud and mean when the driver wants it to be, and mild and smooth during part throttle cruising, all while providing considerable power gains. Luckily for all of you performance junkies that want the best of both worlds, our friends at Corsa Performance Exhausts
have the answer in their RSC exhaust systems, and we have an exclusive inside look at how these systems are produced.
Lauren Bolmeyer, the Marketing Director at Corsa, gave us the low-down on Corsa’s exhaust system design and manufacturing techniques. “Corsa exhaust systems are unique because of our patented RSC technology, which allows Corsa’s engineers to specifically tune the mufflers for each application to produce the best sound possible, as well as produce the most horse power and torque. ‘RSC’ stands for ‘Reflective Sound Cancellation’ and this muffler design pioneered by our company actually tunes out the unwanted low frequencies that cause drone at cruising speeds, while still keeping your performance car sounding like it should.”
Bolmeyer tells us that the sound frequencies are tuned by adjusting the size of the “360 degree air gap” and the length of the “pulse channels” within the muffler. The 360 degree air gap is an internal void, typically placed towards the inlet of the muffler, where sound waves are separated from the exhaust gasses. The exhaust gasses continue to follow the path of least resistance, unrestricted through the muffler, while the sound waves are captured within the air gap.
In the RSC design, exhaust flow is unhindered, while the sound energy is redirected through a series of channels.
Reduction through Reflection
“Once the sound waves enter the air gap they are guided into the pulse channels located along the sides of the straight-through piping inside the muffler. This is where all the Corsa sound tuning magic really happens. The pulse channels are literally a maze of strategically placed ‘walls’ that the sound waves bounce off of until they find their way back out to the 360 degree air gap,” says Bolmeyer. “At this point, it’s necessary for us to explain a little bit of acoustic science. Since sound is just a mechanical wave that travels through the air, like all waves it has a series of troughs (bottom) and crests (top). When two waves have the same frequency are combined 180 degrees out of phase (when the bottom of one wave matches up with the top of another) they will completely cancel one another out. This is called ‘Destructive Interference.’”
So, when the undesirable low frequency sound waves that cause drone meet back up in the 360 degree air gap, they are now 180 degrees out of phase thanks to the strategically placed pulse channels, and will completely cancel one another out. Essentially Corsa’s pulse channels use all of the drone’s evil power against itself, and all the good sounds that we do still want to hear move on to the tailpipes for our ears to enjoy.
“By moving pulse channels around, and changing the size of the 360 degree air gap, we can acoustically engineer the perfect exhaust note for any engine, just as if we were tuning a musical instrument,” Bolmeyer explains.
This cutaway reveals the internal construction of a Corsa RSC muffler.
Quality Baked Right In
Now that we know how RSC technology works, let’s get into a little bit about how these exhaust systems are manufactured. Corsa has been producing premium exhaust systems for performance cars since 1998, when they began fabricating systems for Corvettes. Now over 14 years later Corsa runs their entire operation out of their 58,000 foot facility located in Berea, Ohio. Bolmeyer says, “From this one location we do all of our research, system design, and prototyping, as well as all the final welding of the parts. We even handle all of the final packaging and shipping to customers ourselves from here.”
While automated welding is appropriate in some cases, there are certain tasks that are better accomplished by skilled workers.
Bolmeyer tells us, “A Corsa exhaust system starts out as a CAD 3D model, which our engineers use to run tests and simulations of the specific exhaust system they are designing. They are even able digitally test fit each system on computerized versions of the car to ensure that the dimensions of the production system will allow for a perfect fit.” Anyone who has ever spent several hours under their car trying to force an exhaust system to fit should really appreciate this level of detail.
- Straight-through design to improve horsepower and torque
- Patented RSC technology to cancel “problem” frequencies and eliminate drone
- 304L Stainless Steel construction
- Limited lifetime warranty
- Handcrafted in the USA
From Virtual to Reality
Once the final layout of the muffler pulse channels and the external dimensions of the piping are determined, Corsa’s production shop makes the computer models a reality. Corsa’s fabricators have access to state of the art laser cutting, TIG welding, and hydroforming equipment right in the convenience of their own shop.
Producing exhaust systems that fit properly means having the correct jig for each application.
“Regardless of what system is being manufactured, all of our exhaust systems are bent from premium 304L stainless steel by CNC operated mandrel benders,” says Bolmeyer. “Once the RSC mufflers and bent tubing are ready to go, the system is then welded up using a combination of computer controlled robot welding and welding done by our fabricators, depending on which is better for the particular part being welded. To put on the finishing touch, we have our own in-house laser etching machine for branding the Corsa logo on each one of our exhaust systems.” And best of all, each and every part produced by Corsa for your American Muscle car is 100% made in the USA, by a real live American… Well, with the exception of the welding robots, of course.
A combination of MIG, TIG, human, and robotic welding is required to put together a Corsa exhaust system.
Once a system is finally produced, Corsa’s testing and development doesn’t stop there. Corsa uses real-time Spectrum Analysis Equipment to test the sound produced by their exhaust systems at every level of operation. Bolmeyer explains, “The audio spectrum analyzer used is to measure the exhaust frequencies that translate into the cabin and the amplitude of those frequencies, recorded at varying engine conditions (idle, cruise, and acceleration). Out of those sample sets, the frequencies that cause interior resonance or drone are pinpointed through proprietary software that aids our engineers in acoustically tuning the exhaust system. The goal is to shape the sound to be distinctly Corsa; eliminating drone while enhancing the pure engine tone.”
Sound is Good; Power is Better
Since you’re reading this, it’s a safe bet that you don’t just buy exhaust systems just to make your car sound cool. You’re also looking for a little more kick-in-the-pants horsepower, right? Corsa’s RSC exhaust systems are a straight-through design for minimal back pressure that results in some respectable power gains. For example, their Corvette systems return an average of 17 to 19 additional horsepower; enough that you can feel a definite difference from the driver’s seat. The end product of all this research and testing is a technologically advanced exhaust system that produces great power and incredible sound, and most importantly, is easy to live with every day.