From day one with D6C, I've been wholly unsatisfied with the car's sound. It has been in desperate need of an exhaust upgrade for months, and now it is finally getting one. Exhaust note is one of those things that can make or break a car. It doesn't matter how badass the car is if it sounds like a wheezing econo-box, the entire exercise is moot.
While most people stick with a simple converter-back exhaust system in the early rounds of modifications, I had to take a longer view. I chose to go with a Stainless Works 3-inch, Z06-style system, since a typical 2.5-inch system would likely become a restriction later on. This meant removing the stock H-pipe and, while I was at it, the exhaust manifolds. In their place went a pair of LG Pro Long Tube Headers and a 3-inch X-pipe.
LG Motorsports' Pro Long Tube Headers
Anyone who has closely followed sports-car racing over the past several decades will be familiar with the name Lou Gigliotti. Known as "LG" to fans and competitors alike, Gigliotti has also been a consistent force in the C5/C6 performance aftermarket. In fact, LG Motorsports has developed and marketed more race-specific and race-oriented Corvette components than any other company.
Perhaps LG's most ubiquitous component is the Pro Long Tube Header. First developed for the C5, the original LG Pros were hand-built at the firm's Wylie, Texas, race shop to satisfy customers looking for a race-quality header. "At the time, nothing more than a mid-length was on the market," recalls LG Motorsports' Anthony Forney. "After fabricating a couple sets, Lou and his son, Louis, started making different versions and doing dyno work with them. Once they settled on a final version, we began hand-building sets in-house for almost $3,000 each...and we couldn't build them fast enough!"
LG sold 80 pairs of the hand-built headers before Lou approached Borla with the intention of mass-producing them. "Working with our design, they updated the flanges slightly and made it a slip-fit like their exhaust products," explains Forney. The result? LG's Pro Long Tubes are arguably the most sought-after headers for both C5s and C6s. The reason? They fit perfectly and make power. I gave a great deal of consideration to some other manufacturers' units, but dyno testing has shown the LGs consistently make the most torque across the board.
This is attributable to their conservative 1.75-inch-diameter, 32-inch-long primary tubes. While mild steel flanges would have been more cost-effective, LG insisted that thick, 31/48-inch T-304 stainless flanges be incorporated to eliminate warping and complement the tubing and collectors, which are also T-304. The Pro Long Tubes also feature 3-inch merge-style collectors. The retail price is $1,595.
LG Motorsports 3-inch X pipe system
Like the Pro Long Tubes, this siamese x pipe system boasts T-304 construction and is built exclusively for LG Motorsports by Borla. Available with or without 3-inch high-flow catalytic converters, the x pipe system's slip-fit design works with stock or any aftermarket muffler system. I went with cats because I wanted to avoid smelling like a refinery every time I drove the car. The good news is that the cats are extremely efficient, absorbing only 3 rear-wheel horsepower.
I also selected LG's optional, 3-inch Z06 rear-pipe assembly for seamless integration with a 3-inch muffler system. The off-road x pipe system is included with the headers, but the high-flow cats will set you back an additional $300, while the 3-inch-exit option costs $229.
Stainless Works Converter-back Exhaust System
When it comes to the Corvette's exhaust note, GM just keeps dropping the ball. While the efficiency of the factory-installed converter-back system has improved significantly in the past several years, it still leaves a lot on the table when it comes to the oft-mentioned "musclecar sound." In fact, at anything less than WOT, the factory setup sounds, well, rather limp-wristed.
Another pet peeve? I hate quad exhaust tips. Yes, I understand they are meant to balance the appearance of the taillight quartet, and I'm sure some of GM's design-studio staffers are calling me an unsophisticated boob [They're not the only ones-Ed.], but my tastes veer towards simple and functional. Four exhaust tips just look stupid.
That said, one of my criteria for selecting D6C's exhaust system was the availability of a simple, two-tip tailpipe setup. I also wanted to go with a Z06-style 3-inch system to eliminate the need for another change later in the build. I've hinted that I have big plans for D6C, and the Stainless Works 3-inch system was selected for these reasons.
As the company name implies, the Stainless Works exhaust is built entirely from CNC mandrel-bent T-304 stainless tubing. It is also available in a standard 2.5-inch configuration for use with the OEM H-pipe or like-sized aftermarket systems. SW offers two muffler choices: a traditional turbo-style muffler for excellent sound control, and a straight-through muffler for maximum performance. I opted for the latter and, for now, the sound is just right to my ears. That said, I may have to switch to the turbo muffs when the wick gets turned up, as my gut tells me these guys may be a skosh loud when creeping back into the neighborhood after a day of fun.
And yes, SW offers some really handsome exhaust tips. I went with a pair of 4-inch, angle-cut, rolled-tip pieces that look perfectly aggressive. They've even got laser-cut SW emblems welded in place. This is a nice touch that really makes the SW exhaust stand out in a sea of etched, quad-tip systems. As optioned, my SW setup retails for a very reasonable $991.
We utilized LG Motorsports' huge facility in Texas for this install. The nice part about using a fully equipped shop is the ability to perform before-and-after dyno testing. While I would have preferred to dyno-test the exhaust system separately and prior to the header install, the move to a 3-inch converter-back would have made integration with the factory 2.5-inch H-pipe rather hokey.
Though gains will vary from car to car, replacing a factory converter-back system with a quality aftermarket piece will usually net you 7-10 rwhp. That's not as much gain as used to be possible, but it's nothing to shake a torque tube at. Either way, I submit that the most gratifying reason for bolting up an aftermarket exhaust is the drastic improvement in tone. Every system on the market has its own sound, so my advice is to listen to as many as you can before making your decision. To my ears, the SW system sounds great. It has a pleasing, low-frequency grumble that makes me smirk every time I roll into the throttle.
Okay, enough of the subjective crap. What about the power? Pre- and post-install dyno testing revealed a very healthy gain of 29 horsepower and 28 lb-ft of torque. As you can see on the dyno sheet, the gain was solid throughout the rpm range. This is the kind of power even an uncalibrated butt-o-meter will feel. Check out the accompanying photos for running commentary on the actual installs.