In the high-performance aftermarket, after-cat-system jungle, choosing the right package for your late-model Trans Am or Firebird Formula is oftentimes a challenging and risk-filled adventure. So many manufacturers claim to have the uncontested right to your hard-earned dollars, and if you sift through their marketing literature, you'll find a repetition of the same marketing words: great sound, guaranteed horsepower, unsurpassed quality, and so on.
Adding a new exhaust system to your Fourth-Generation Trans Am or Formula Firebird can be a fun and rewarding experience, as long as the system compensates you with power, sound, looks, quality, and proper fit with easy installation. Let's see if Corsa Performance's after-cat exhaust fits the bill.
When it comes down to it, many Pontiac hobbyists who modify their vehicles from stock agree that there are five things to expect from a great exhaust system-power, sound, looks, quality, and easy installation/proper fit. Though many will rank power as the most important of these five key points, they may find that sound is the one point that determines whether they stay with their new aftermarket exhaust for the long haul or kick it to the curb for a different brand.
Corsa Performance Exhaust of Berea, Ohio, is one of America's oldest and most-respected exhaust-system manufacturers. It has patented a design called Reflective Sound Cancellation (RSC) technology, which 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, but without electronic devices or flow restriction. As a result, Corsa is able to design a straight-through exhaust system that offers minimal resistance to the exhaust flow with awesome sound at full throttle and idle, while at the same time canceling low-frequency cabin resonance.
In layman's terms, Corsa promises no drone, a condition that pervades far too many muffler systems in the market today.
Corsa's kit features premium-quality complete 304L stainless-steel construction and mandrel-bent, 3-inch-diameter pipes. It's designed as a direct-fit, bolt-on option, which only takes 45 minutes to an hour for a professional shop to install. If you're the DIY type, Corsa includes a step-by-step instruction guide with photos with every kit, allowing you to install the system in your garage or driveway in nearly the same amount of time, depending upon your tools and skill level.
Corsa's after-cat systems for the '93-'02 Trans Am and Formula Firebird are not brand-new. In fact, they've been available for over 10 years. In that tenure, Corsa hasn't had to change its design once. That speaks solidly for the system's reputation, and you probably already know at least one fellow late-model Pontiac owner who has a Corsa exhaust installed on his or her car.
We wanted to learn more for ourselves, so we procured a system to install and test. Part number 14143, an after-cat system for the '98-'02 LS1, comes with dual 3.5-in Pro tips and costs approximately $1,200. To aid us, we brought in AntiVenom Performance, a late-model Trans Am and GTO speed shop located in Seffner, Florida. AntiVenom's Greg Lovell will turn the wrenches and perform the dyno-testing on the in-house Dynojet.
Follow along to see how Corsa's system fares when challenged to attain all five key points of a great after-cat system.
Conclusion
Let's review Corsa Performance's exhaust against the five key points we discussed earlier.
Now the T/A is ready for a leak check, a road test to ensure there is no interference between the exhaust and the body or suspension, and a follow-up dyno test. NOTE: Corsa suggests you check the clamp bolts again and retighten if necessary one week after driving with your new exhaust system installed.
Power: Greg reset the factory ECM, and then performed three more pulls on the dyno with the T/A, recording a best of 352.31 hp and 352.87 lb-ft of torque. That means the Corsa after-cat exhaust system added 9.98 hp and 17.36 lb-ft to the WS6 Trans Am, measured at the rear wheels. (Corsa recorded official gains of 18 hp and 10 lb-ft of torque when it tested the system on a stock LS1 with an aftermarket cold-air intake system, and stock exhaust manifolds and Y-pipe. Our testing was performed on an LS6-powered WS6 Trans Am with the factory Ram Air, and stock LS1 exhaust manifolds and Y-pipe.)
Sound: Our impression of the Corsa system's sound was positive. It gave the Trans Am a righteous rumble without compromising in-cabin quietness, regardless of the rpm or throttle pressure.
The federal government requires every exhaust manufacturer to perform standardized decibel tests before releasing exhaust kits to the aftermarket. "This exhaust system provides up to -2db in noise from inside the car over the stock exhaust when driving at cruise between 50 and 80 mph, and no drone at any speed. In addition, it provides a distinctly deep and aggressive growl, similar to the big-cube musclecars of yesteryear," says Corsa Sales Channel Manager Paul Santiago.
Looks: The Corsa system's clean, stainless-steel look is far more attention-getting than the factory's mass-produced, aluminized, rust-prone exhaust. It looks fantastic-not just at the tips, but underneath the car as well.
Quality: The Corsa mufflers feature fully welded cases and a limited-lifetime warranty to the original purchaser, something the factory mufflers cannot offer. In addition, Corsa's stainless steel is a lot more durable than the factory system.
Ease of Installation: As Corsa promised, Greg was able to remove the T/A's factory exhaust and bolt-in the Corsa upgrade in slightly less than one hour. "It's a fantastic system from an installer's vantage point," he told us. "Corsa's engineers designed an exhaust system that installs easily straight out of the box time and time again. I've installed dozens of them for customers, and I've never had to send a part back because it didn't fit perfectly."
When shopping for an exhaust, don't just look for power increases-think about how the system will perform in the other four key areas, too. When you do, you may just find yourself in love with the Corsa after-cat exhaust for your Trans Am or Formula Firebird-not just when you order it, but for years and years to come.
