Installing A Blower System On a Corvette - Force-Feeding A C6
Stenod Performance Installs A&A Corvette's Intercooled Blower Kit-And Gives A Hungry LS2 All It Can Eat
From the March, 2010 issue of Vette
By Barry Kluczyk
Photography by Barry Kluczyk
THERE'S AN UNDENIABLE allure to a supercharger. The debate over whether to go normally aspirated or forced induction in building power is a worthy one, but the academic reasons often fall to the simple fact that a blower is cool.
The A&A Corvette supercharger...
The A&A Corvette supercharger kit for C6s includes a Vortech V-2 SQ compressor, an adjustable bypass valve, and A&A's unique bracket/pulley design, which offers excellent belt wrap (the amount of the blower pulley that is in contact with the drive belt) to all but eliminate the chance for slippage. Not seen in this photo is the large heat exchanger for the air-to-air charge cooling system.
Blowers look cool, and they certainly sound cool, and with the benefits of modern tuning-and the fact that modern Corvettes have never been better equipped to handle them-they're relatively efficient tools for making big horsepower in an otherwise stock vehicle.
The kit comes with a 3.8-inch...
The kit comes with a 3.8-inch supercharger drive pulley that enables about 10 pounds of boost. That's great for street-driven vehicles that will be tuned for pump gas. The company also offers smaller- and larger-diameter pulleys that alter the maximum boost; smaller pulleys increase boost, but sometimes at the cost of pump-gas driveability.
We've seen plenty of Roots-type blower systems on C5 and C6 Corvettes, most of them versions of MagnaCharger kits, but comparatively few centrifugal blowers. So when we had the opportunity to follow the installation of a Vortech-based, intercooled system from Oxnard, California's A&A Corvette, we loaded up our camera gear and camped out at Detroit-area tuning shop Stenod Performance for the wrench-turning session.
"We were impressed with the kit," says Stenod's Joe Borschke. "From our experience installing and tuning it, it seems like a good value for our customers."
To facilitate the task of...
To facilitate the task of "pinning the crankshaft," the steering rack must also be removed. A&A Corvette also recommends removing the factory power-steering cooler in order to make room for the supercharger kit's plumbing. See the main text for more information on the pinning process.
Although Vortech offers a specific, intercooled kit for the C6, A&A's system is priced approximately $1,800 lower. Differences between the two include things like fuel injectors and A&A's inclusion of a Kenne Bell Boost-A-Pump for the fuel system, but the biggest differentiator is tuning software. Vortech's C6 kit includes a plug-in programmer, while the A&A kit does not.
"We don't believe in a pre-programmed tune," says A&A's Steve Padfield. "Each project is unique, so we believe it's best to have a custom tune performed at the time of installation."
In order to mount the intercooler...
In order to mount the intercooler and its related plumbing, as well as other components of the supercharger kit, the Corvette's front fascia must be removed. It involves carefully pulling out a number of delicate plastic push pins, as well as the removal of the front wheels.
Of course, that presupposes a qualified tuner is available in a customer's area. But assuming one is, it's definitely the method that ensures optimal performance. In the case of our project, additional engine modifications necessitated a custom tune that would have rendered a pre-programmed calibration unusable anyway.
The test vehicle for this story was an '05 automatic with a mere 4,000 miles on the odometer. Like all '05 models, it features a 6.0L LS2 rated at 400 hp and 400 lb-ft of torque.
There are two major things...
There are two major things to note in this photo. First, at the 5 o'clock position on the crankshaft hub, the pin to lock together the crank and balancer/pulley is installed. Second, at the bottom right of the balancer/pulley, threaded into a drilled-and-tapped hole in the front of the oil pan, is the required oil-return port that links to the supercharger head unit.
As with any intercooled system for a late-model Corvette, the installation involved removing the front bumper cover to provide room for the heat exchanger and related plumbing. Generally speaking, the kit was well engineered and used first-class materials. Kevin Gluski, the installer at Stenod Performance, found some of the instructions in the downloadable assembly manual to be a bit vague, but the overall impression on the fit and finish was one of admirable quality.
That's not to say the project wasn't without its difficulties. Regardless of whose kit is used, stuffing an intercooled supercharger system into the tight confines of a Corvette's nose isn't easy. Care must be taken to ensure adequate clearance for a variety of hoses, tubes, electrical lines, and more. There are a few other details worth mentioning:
When drilling and tapping...
When drilling and tapping the oil pan, white lithium grease should be used on the end of the bit to hold shards released during the drilling process. Keeping this debris out of the oil pan is vitally important. Some installers even drill the initial hole in the pan prior to draining the oil, allowing material to flow out with the old oil.
Like all late-model, LS-engine vehicles, the precaution of "pinning" the crankshaft is necessary, because the balancer is press-fitted to the crank hub. Pinning the crank involves drilling a hole or two between the balancer and crank, and inserting a dowel-type pin to provide a simple lock between them. This prevents unwanted slippage that could occur under the greater load imposed by the supercharger.
Pinning the crankshaft requires the removal of the steering rack, which includes holding the steering wheel in place to ensure it aligns perfectly when the rack is re-installed. Otherwise, driveability will suffer, and the rack will likely need to be removed again to correct the problem. Reinstallation of the steering rack automatically means a trip to the alignment shop, too.
With the oil pan drilled and...
With the oil pan drilled and tapped, the oil-return line is connected to it and held out of the way until the supercharger itself is mounted to the engine.
Finally, the routing of the plumbing between the blower, the intercooler, and the engine requires the permanent removal of the factory power-steering cooler. A&A Corvette says only hard-core road racers in hot climates should notice a difference in performance, and that the average street enthusiasts shouldn't have a problem.
A lift and the tools typically found in a house-sized Snap-on chest make the job easier, but after watching Stenod Performance work on the car for a couple of days, it seems like a job best left to professionals.
Next, the rear portion of...
Next, the rear portion of the supercharger bracket is installed in place of the factory belt tensioner. That's fine, because the A&A kit includes its own tensioner to be mounted on the bracket.
Of course, there's more to the installation than just the blower's head unit, the intercooler's heat exchanger, and the hoses that connect them to the engine. The fuel system is upgraded, too, with higher-capacity fuel injectors and the electronically controlled fuel-pump "amplifier" in the Boost-A-Pump from Kenne Bell. It maximizes the output of the factory fuel pump without the need to drop the tank and replace it with a higher-volume unit. Also, the kit's intercooler is a simple, air-to-air design, rather than a liquid-to-air air design that requires a dedicated coolant supply, an electric water pump, and complementing wiring upgrades.
With the front part of the...
With the front part of the bracket attached to the supercharger head unit, the assembly is mated with the rear bracket. Trimming a bit of material from the factory water pump is necessary to ensure adequate clearance for the water pump.
Before we divulge the chassis-dyno results of the project, we should address a couple of points: First, as we mentioned early in the story, this Corvette received additional engine mods that included a blower-spec camshaft (also from A&A Corvette), a set of L92 cylinder heads and an LS3 intake manifold, Dynatech long-tube headers, and a Corsa exhaust system. So the engine was already set up for deeper breathing capabilities than in its stock configuration. The mods were smart additions, however, as they better exploited the pressurized air that would be crammed through the throttle body.
When the supercharger is securely...
When the supercharger is securely in place, the oil feed and return lines are installed. Shown here is the return line being installed. Not shown is the feed line that runs from a port in the cylinder block to the head unit. Proper attachment of both with Teflon tape on the fittings' threads is imperative to prevent leaks. Because the Vortech blower uses engine oil circulated through it, its lubrication is refreshed every time the engine oil is changed.
Stenod Performance took care of the specific tuning calibration for the combination; it was designed for pump gas and the system's approximately 10-pound boost level. The other thing to note is that it's always difficult to get a good, accurate chassis dyno reading with an automatic-transmission car, as the electronically controlled lock-up design of GM's modern automatics doesn't allow for full run-outs on the rollers. That said, the newly blown Vette put down 508 hp and 439 lb-ft to the tires, or roughly 600 hp/520 lb-ft at the crank. The numbers represent a power increase of more than 50 percent, along with nearly 33 percent more torque over the baseline test.
The heads, cam, and exhaust system definitely contribute to the performance gain, with the heads and intake essentially bringing the engine to LS3 specs and enabling a greater rev range. Nevertheless, we were surprised by the dyno results. They were terrific for a combination using all bolt-on or off-the-shelf components.
Subtracting the cam-and-heads part of the job, the blower, installation labor, and dyno tuning cost the Corvette's owner, Mike Lucas, about $7,700. That's about average in our experience and represents good value in a performance-to-dollar evaluation. The accompanying photos provide an overview of the major steps involved in the installation process.
To paraphrase a popular advertising line: Supercharger kit: $5,200. Installation labor and tuning: $2,500. The sound of a fully wound supercharger as you leave a trail of F1 Supercar residue on the pavement: Priceless.
| DYNO COMPARISON (Peak numbers in bold)
Some trimming of factory components...
Some trimming of factory components was necessary in our case in order to mount the intake and discharge plumbing for the blower and intercooler. It included trimming the tabs at the top of the radiator. The aluminum material is easy to cut-almost too easy, so care must be taken to be precise with a cutter and/or grinder.
Another component to be trimmed...
Another component to be trimmed is the passenger-side lower apron, near the factory brake cooling duct. A larger hole must be cut into it to provide routing room for plumbing from the blower to the heat exchanger.
Next, the large heat exchanger...
Next, the large heat exchanger for the air-to-air-style intercooler is hoisted into place in front of the radiator. The air-to-air design speeds the kit's installation, as it doesn't require a separate cooling circuit that goes with the typical liquid-to-air intercooler design.
Here, a 90-degree silicone...
Here, a 90-degree silicone hose is shown feeding into the side of the heat exchanger. It's the discharged routing from the supercharger, which blows through the intercooler to reduce air temperatures and provide a more powerful, denser air charge at the engine. The denser charge also minimizes the chance for detonation in the Vette's relatively high-compression LS2. Note, too, the location of the bypass valve, which bleeds off excess boost when the throttle closes.
After all the intake and discharge...
After all the intake and discharge hoses are plumbed under the hood, the rest of the engine work involves adding new, colder-range NGK TR-6 spark plugs and replacing the fuel injectors with the 60-lb/hr units that come with the blower kit. An engine with higher-capacity fuel injectors shouldn't be started until the ECM has been updated to reflect their presence, or big problems can occur.
Rather than replacing the...
Rather than replacing the factory in-tank fuel pump, the A&A Corvette kit comes with a Kenne Bell Boost-A-Pump system that increases the voltage to the factory pump and effectively "supercharges" its output. It mounts in the driver-side rear fenderwell. The inner fender liner is removed and re-installed over the system, for a hidden, well-protected installation.
Here's the completed installation...
Here's the completed installation of the supercharger kit. The close-out plate, with its OEM-looking black finish, looks great under the hood and is wholly appropriate for the premium feel of the Corvette. Stuffing all of the kit's plumbing into the nose of the Corvette wasn't exactly a cakewalk, but no major problems developed, and the general fit and finish of were excellent.
A custom calibration for the...
A custom calibration for the engine controller was performed by Stenod Performance upon the completion of the kit's installation. Stenod's techs tuned it not only for the supercharger, but for the additional engine modifications as well. These included L92 heads, a "blower" camshaft, an LS3 intake manifold, headers, and more. Then, it was onto Stenod's Mustang dyno to evaluate the shop's many hours of labor.
On the rollers, the supercharged...
On the rollers, the supercharged LS2 delivered a stunning 508 hp at the rear wheels and 439 lb-ft of torque. And remember, this was through an automatic transmission and on a conservative-reading Mustang dyno. Peak numbers aside, that's a whopping 170hp/110-lb-ft jump over the baseline 338hp/329-lb-ft numbers. Talk about bang for the buck!