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ProCharger boost and custom tuning unleashes nearly 200 HP

Posted By: Evan J. Smith
ProCharger boost and custom tuning unleashes nearly 200 HP
 
Written by Steve Baur
Photography courtesy of Indiana Muscle Car
 
Moving the legendary Corvette to a mid-or- rear-engine platform was in the wind for years, if not decades, and when Chevrolet finally made the move with the 2020 C8 Corvette, any complaints were largely hushed by the overwhelming acceptance of the new machine. The automotive performance aftermarket jumped right on it as well, and ProCharger wasted no time in creating a supercharger system to boost the LT2 engine well beyond its 495 horsepower.
 
Before offering its supercharger systems to the public, ProCharger performed extensive drag strip, dyno, and road testing ensuring the supercharger system delivers the expected results reliably. The company even put one of its test vehicles on the road visiting dealers while logging over 2,000 miles of highway driving.
 
Supercharger Options
 
ProCharger offers several options when it comes to supercharging the C8 Corvette, beginning with its HO system that utilizes a mere 5 psi of intercooled boost pressure to improve engine horsepower to around 665. The company’s Stage II system ups the boost pressure to 7.5 psi for additional gains, and from there you get into the HO and Stage II Tuner kits that require ECU calibration, but also offer the option to skip over the P-1SC head unit and move up to the D-1SC or the P-1X, which is the unit chosen for this installation. And yes, you read that right—PCM calibration is finally available for the “unbreakable” C8 Corvette engine ECU!
 
Additional upgrades for these kits include a black powdercoat or polished finish for the supercharger and bracket, a helical gearset for reduced noise, a sheetmetal aluminum intake manifold with port-injector bungs and fuel rails for those going for big power, powdercoating for the intake manifold and cover, and carbon fiber upgrades for the intake manifold cover and trunk panel.
 
System Installation
 
During a conversation with NMCA True Street competitor Justin May, he informed us that he already performed one ProCharger installation and with another C8 Corvette coming into his shop, Indiana Muscle Car in Leesburg, Indiana, future so we followed along with the installation and dyno testing.
 
Located just northwest of Fort Wayne, Indiana Muscle Car specializes in upgrading late-model and LSX-powered vehicles. On the weekends, IMC proprietor Justin May regularly competes in True Street and drag-and-drive events with his turbocharged and LSX-equipped, Third-Gen Firebird that clocks 7-second quarter-mile times. During the week, he and his staff are busy upgrading customer cars, with the shop offering engine builds, component installation, custom tuning, and dyno testing.
 
ProCharger’s C8 Corvette supercharger system, like many of the company’s other offerings, can be installed by the average automotive enthusiast with a bit of hands-on technical ability. It is also, at the time of this writing, the only forced-induction system for a C8 that can be shipped to a customer and installed DIY or at a shop of their choosing. Even better, ProCharger engineered the system to require no permanent changes to the vehicle — currently the only supercharger kit on the market to offer that.
 
While there is quite the parts list to install, the installation is pretty straightforward. If you’re not a hands-on type of enthusiast, or just don’t have the time, then ProCharger dealers and install shops such as Indiana Muscle Car can get the job done for you.
 
“Installation is more challenging than a C7, but no body panels need to be removed. Once the trunk panel is removed, access is relatively open to the engine. The most challenging part of some of the work is best done while sitting in the trunk,” May explained. “It’s a two-day install plus dyno time, more or less, maybe a little quicker since we have done a couple now.” Perhaps another bonus is that the supercharger kit requires no additional fuel system upgrades, either.
 
As part of Indiana Muscle Car’s C8 Corvette ProCharger installation, the company also adds some addition upgrades to the engine to support the supercharger system.
 
“With our C8 package, we upgrade the rocker arms and pushrods with Manton products,” May told us. “With the supercharger installation, we have increased pressure on the valvetrain and our testing shows there is more horsepower to the wheels when we bump up the size of the push rod and add an upgraded rocker arm.”
 
Cracking The Custom Tune
 
What was perhaps the most intriguing aspect of this installation is the C8 computer is now fully tunable which allows for greater control and performance from ProCharger’s C8 Corvette supercharger system.
 
“This particular Corvette is fully tuned,” May explained to us. “ProCharger has been able to develop not only world class hardware, but also robust software calibration for this system.  They have offered a kit that has auxiliary timing retard boxes and they work ok, but it’s really the Holy Grail to be able to fully tune it so you can optimize the calibration.”
 
The subject car pictured here is a 2021 C8 Corvette Z51 in the vibrant Rapid Blue—perhaps even more fitting now that this particular Stingray will benefit from additional horsepower. With the details on the supercharger system covered, it’s time to show you what’s involved regarding the installation. And if you’d rather just check out the dyno results, feel free to skip forward to the chassis dyno sheet.
 


 

ProCharger offers a few different supercharger systems for the C8 Corvette depending on your needs and wants. “It’s quite a departure from the C7 kit,” said Justin May of Indiana Muscle Car. “There’s lots of engineering to drive the ProCharger because the engine is in the rear of the car.”
 

Step one of the installation involves the removal of the factory intake manifold, as well as the air boxes and rear trunk trim panel. This is followed by the installation of the jackshaft assembly that connects the front-mounted accessory drive system to the rear-mounted cog pulley and idler that will drive the supercharger. “This kit is full of billet artillery awesomeness,” May said. “The beefy brackets and driveshaft look killer and would equally be at home on an M1 Abrams tank or Bradley Assault vehicle.”
 

To expose room for the new intake manifold, the oil fill is relocated to the passenger side.
 

ProCharger utilizes a cog belt to drive the supercharger off of the jackshaft. While removing any belt slip from this end of the drive system, the cog drive does create a noteworthy whine, which many enthusiasts prefer. “When you hear the cog drive out the back of the car, it sounds really exotic, just incredible,” May noted.
 

For this build, May chose the P-1X head unit, which is capable of producing over 875 horsepower. Here you can see the cog drive pulley has been installed, and the supercharger comes pre-clocked and ready for installation into the C8 Corvette engine bay. “We changed the ratio of the cog pulleys since we are able to tune it. It brings the boost in sooner and there is more peak boost,” May explained. “The first kit we did made 6.5 to 7 psi while this one makes a little over 9 psi.”
 

ProCharger created its own intake manifold for the C8 application, and it includes an integrated air-to-water intercooler. It comes in two pieces and must be fastened together. ProCharger offers the intake manifold in several different finishes and has a carbon fiber appearance option to personalize the engine bay. Indiana Muscle Car offers its own finishing touches, with this manifold featuring the black powdercoat with red trim. “The custom-fabricated air-to-water C8 manifold is cool and a huge visual statement,” May said. “The AN lines, brackets, and heat exchanger are top-notch. Thermal control with the air-to-water intake is excellent. We are only seeing 15 degrees F of temperature rise from 0-100mph and very fast recovery after that.”
 

Next, the supercharger mounting bracket is installed onto the TREMEC transaxle using included hardware. Then, it’s time to slide the P-1X head unit into the bracket and the cog belt on the opposite side.
 

With the supercharger now mounted to the drive unit, Taylor Easterling of Indiana Muscle Car can now install the intake manifold fitted with the factory throttle body. Easterling actually sits in the trunk while he sets the intake manifold down onto the engine. “With this package, we’re tuning the ECU, so we are using an intake temp sensor in the manifold past the intercooler,” May explained. “ProCharger has used a software change to adapt the use of the in-intake air-temp sensor just like the Cadillac Blackwing.”
 

“GM left us an open duct behind the door on the driver’s side, so ProCharger designed its heat exchanger to mount directly inside,” explained May.
 

The intake manifold is fastened to the LT2 engine and here you can see that the coolant lines have been connected to the integrated air-to-water intercooler as well. These connect to the heat exchanger mounted in the driver’s side air duct.
 

A few short elbows later and the induction side of this ProCharger installation is buttoned up. The factory mass airflow sensor is utilized and installed into the provided cold air tubing. 
 

As part of the kit, ProCharger includes a new trunk trim panel, which you can see in place here, that accommodates the supercharger and accompanying hardware. The company also offers this piece in carbon fiber, and according to May, you can still fit a golf bag in the trunk, but May recommends bypassing the golf course and heading directly to the track!
 

All tucked into the engine bay and on display for people to look at, the ProCharger intake manifold incorporates design cues from the Corvette’s exterior.
 

As previously mentioned, the C8’s engine management computer is now tunable thanks to the efforts of ProCharger engineering. You or your installation facility will need to remove the ECU and send it to them to be unlocked, and then it will be flashable for custom tuning. “We have full tuning control of the E99 ECU, and the custom tuning allows for quicker, yet smoother shifts to protect the C8 clutch from the added torque.”
 

Once tuned and strapped to Indiana Muscle Car’s Dynojet chassis dyno, this C8 Corvette ripped the rollers and increased power output from 441 to 639. Torque was up over 120 lb-ft as well. “It’s an insane gain for that kind of psi,” May said of the 9psi of boost pressure delivered by ProCharger’s P-1X blower. “The sound of the non-helical ProCharger in tandem with the cog drive sounds like Marty McFly’s DeLorean at 88 mph. It’s freaking unreal!”


Sources
Indiana Muscle Car
(574) 527-1663
IndianaMusclecar.com
 
ProCharger
(913) 338-2886
ProCharger.com
 
 

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