Now more than ever, it's an exciting time to be a plutocrat. The stock market has largely recovered, tax rates on hedge funds remain low for the nonce, and, thanks to the efforts of talented tuners everywhere, it's become a relatively simple matter to infuse a C6 street car with a truly unwell amount of horsepower.
Shall we build your new Z06 Carbon with 1,000 horsepower, sir, or would a figure of 1,500 be better suited to a man of your stature? Assuming your pockets are deep enough, the choice is yours to make.
As for the rest of us, the more pertinent question centers around whether it's still possible to noticeably improve the performance and exhaust tone of a late-model Vette without spending a cubic crapload of money. This month, we'll endeavor to find out by installing a couple of basic, affordable bolt-on parts on an '05 C6.
Our Airaid CAI kit came complete...
Our Airaid CAI kit came complete with filter, air bridge, installation brackets, bellows, seals, and hardware. At a price of just under $250, it’s one of the more affordable C6 systems on the market.
Bearing in mind the old saw about an engine being nothing more than an air pump, we selected as our first upgrade a cold-air induction system from Airaid. Part number 250-218 ($245.95) comes with a large, open-element filter; a low-restriction intake tube/air bridge; and all the hardware required for installation on an '05-'07 LS2 Corvette. (Z06 and LS3 systems are also available.) We specified a traditional oiled filter element for our Vette, but Airaid's SynthaMax oil-free filter is also available with the kit.
To back up our freshly decongested LS2, we chose a rear-section exhaust system from Stainless Works (PN C6CBSQUAD, $1,050). The kit comes with a pair of polished, 2.5-inch "S-Turbo" mufflers; matching over-axle pipes; a full complement of hardware; and a quartet of serious-looking double-wall tips. Although SW offers a full line of long-tube headers and complete, converter-back exhausts, we decided to limit the scope of this project to a simple axle-back replacement to keep costs down and minimize installation headaches. We also thought it would be interesting to find out just how restrictive the factory C6 (non-NPP) mufflers alone really are.
The work took place at Source Interlink's East Coast HQ in Tampa, a locale that afforded us the opportunity to dyno-test the car beforehand, as well as immediately after each phase of the installation. Follow along now as we cover the highlights of the job.
Stainless Works’ C6 axle-back...
Stainless Works’ C6 axle-back kit features a pair of low-restriction turbo-style mufflers in a positively smashing mirror- polished finish. At an MSRP of $1,050, it’s hardly cheap, but the looks and assembly quality far exceed that of the “budget” brands.
Prior to the installation,...
Prior to the installation, we spun our ’05 coupe tester on the rollers to establish baseline output figures. The car cranked out a healthy 362.64 horses and 363.89 lb-ft of torque at the rear wheels, which is a bit higher than we’d expect for a stock manual C6. The disparity is likely attributable to a reduction in drivetrain friction, achieved through the use of micro-polished rear gears (“More Grip, Less Slip,” Feb. ’11) and super-slippery synthetic fluids.
Our perfunctorily trained...
Our perfunctorily trained tech assistants begin the job by raising the car on a lift and removing the factory mid-pipe. A shot or two of rust-penetrating spray may be required to break loose the bolts.
With the mid-pipe gone, the...
With the mid-pipe gone, the stock mufflers and inlet pipes can be gently maneuvered out over the axle.
The hangers and rubber isolators...
The hangers and rubber isolators are then removed from the stock mufflers and reinstalled on the SW units.
The new SW mid-pipes are lifted...
The new SW mid-pipes are lifted into place and secured, followed by the mufflers (shown). Note the reflective quality of the 304 stainless and the tight welds at the outlets.
The last step in the exhaust...
The last step in the exhaust installation is to install and tighten the 3.5-inch slash-cut tips. If you’re performing this job yourself, ask a helper to eyeball the rear of the car from a distance while you line things up. There’s nothing worse than a great-looking new exhaust system with misaligned tips.
A shot of the completed exhaust...
A shot of the completed exhaust from below reveals the show-quality appearance of the SW setup. Too bad you can’t park upside down.
We weren’t expecting to see...
We weren’t expecting to see much of an increase in output from a simple axle-back installation (after all, bypassing the mufflers altogether only yields 6 hp on the ’08-up NPP system), so the improvements of 1.53 hp and 1.42 lb-ft were a pleasant surprise. More important, the insipid blat of the stock system has been replaced with a deep, baritone rumble that gradually transitions to a menacing ursine growl under power. Nice.
Having lowered the car, our...
Having lowered the car, our techs were ready to get to work on the CAI install. (The lines attached to the coil wires are for the dyno’s rpm readout.)
After disconnecting the various...
After disconnecting the various tubes and wires, the stock air bridge and filter housing may be removed as one piece.
With the intake tract off,...
With the intake tract off, we decided to make a quick dyno pull to see how the LS2 would perform with no inlet restriction aside from the MAF screen.
Perhaps not surprisingly,...
Perhaps not surprisingly, power and torque both plummeted in this configuration, as the engine computer scrambled to adjust spark and fuel timing to match the incoming rush of turbulent air. When it comes to late-model Corvette engines, it’s clear there’s much more to improving intake performance than simply eliminating restriction.
Our experiment concluded,...
Our experiment concluded, the job continued with the transferral of the stock MAF onto the Airaid intake bellows.
With that done, the bellows...
With that done, the bellows and MAF install directly onto the factory throttle body.
The air bridge and filter...
The air bridge and filter may then be installed and secured with the included clamps. The final step involves attaching the two rubber isolator flaps along the top edges of the mounting bracket. With the air-injection tube and MAF-sensor lines reattached, the end result should look like this.
We should point out that the...
We should point out that the Airaid kit does call for two holes to be drilled in the radiator shroud (one on either side) to serve as attaching points for the mounting- bracket bolts. Having determined that the intake was secure enough without these bolts, our car owner elected to skip this step.
Our final dyno pull of the...
Our final dyno pull of the evening showed the car to be making 373.16 rwhp and 366.15 rwtq—up 8.99 horses and 0.84 lb-ft, respectively, over our previous exhaust-only tally. Given the minimal investment and effort involved, this mod seems like a no-brainer.
In all, our ’05 coupe picked...
In all, our ’05 coupe picked up 10.52 hp and 2.26 lb-ft over its baseline readings—all without custom PCM programming to take full advantage of the changes. It also sounds more like a Corvette now, and less like an electric carpet-cleaning implement. We may not be big players on the international stock market, but we still know sound investments when see them. vette