With a mile long wait list reported by GM as up to a full year for some models of the C7 Stingray, the demand for these vehicles far outweighs their supply. When Chevy designed the C7, their intentions were to evolve the C6 into a vehicle that had performance capabilities that far exceeded the cost of the car. For those who are fortunate enough to take delivery of a C7 this year, the question becomes whether to mod the vehicle or not. While some owners are going to cherish their 455 hp C7’s in the picturesque stock form, what if you are someone that wants to get the most performance out of your vehicle? What direction do you turn if you want to maximize your power gains for your investment?
One of the biggest differences between the 6.2L LT1 featured in the C7 and prior generation LS-series motors is that the new generation of Chevy small block motors feature direct injection as opposed to port injection. When we asked Ryne what impact this has on the performance of the kit, he responded: “A port injection fires the fuel into the port, and you are firing into an area where it’s going to hit the port walls, it can sit on the valve and then it will sometimes wait for the valve to open and then draw in the fuel. With direct injection, it comes right out of the TDC on compression and then fires it so the fueling it gets is exact.”
“If you run it too rich, you will run the fuel into the exhaust cycle, it will misfire, and will soot it up. So you have to be careful not to run it too rich or it could get the rich knocks. Direct injection is just more exact. Everyone worries about DI being too lean but in actuality there is not much difference to a port injected car, it’s just more exact. As for timing, the timing is about the same as a similarly boosted LS3. On the same fuel at peak boost, an LS3 car with the same boost would be right around 11.3:1 air.fuel ratio with 13 degrees of timing as opposed to 12.4:1 air/fuel ratio and 14 degrees timing for the LT1.”
For many car enthusiasts, forced induction has and will be the go-to when it comes to getting the most amount of power in relation to the amount of money invested in their project. Although forced induction has been around for decades, technology has come a long way and the newer systems have had to evolve with the changing times of automotive production. Thanks to new federal and state laws requiring lower emissions combined with higher efficiency, the automotive industry has had to adapt in order to meet these requirements and in turn have created products jam-packed with more technology than ever.
ProCharger has done a great job meeting these challenges head-on by creating a great turn key system. The goal for this project was to take a stock 2014 Corvette Z51 equipped with an automatic transmission, install a supercharger, and see how much power would actually be gained. In their stock form, Corvette’s have had a reputation for being extremely great at being both a dependable daily driver but also a car you can take to the track on the weekend to have some fun with. With this in mind, an additional goal of this install was to see how much drivability and reliability was able to be retained. This is something that is extremely important because most people that purchase a C7 are going to want to be able to comfortably drive it at more places than just a racetrack.
In order to compare the performance improvements of the ProCharger system, we had to establish a baseline with our C7. In stock form, the Z51 equipped C7 produced 407.3 hp and 399.9 lb-ft of torque at the wheels on our dyno. From there, we wanted to take it to the good ole’ quarter-mile to see what she was made of. On a hot April morning, we took the C7 to the Auto Club Dragway in Fontana, CA. Straight off the showroom floor, we were able to run 12.34 at 113.04 mph which are impressive figures when you consider this is a vehicle targeted at people who can easily daily-drive it. The C7 had excellent road-manners that did not disappoint on the highway or at the track. With our baseline established, we moved forward with our build.
ProCharger blower, bracket, crank pulley, and assorted hardware/hoses.
Being one of the first C7 Corvette Stingray systems on the market, we were eager to get our hands on the ProCharger kit to install it in our C7. Not only does the kit offer strong power gains, but it does so using only 7 psi of boost and high quality pump gas (91 octane or greater). Discussing the kit with Erik Radzins, Calibration Technician at ProCharger, he mentioned, “The install is so simple you can do it in your garage and you are not modifying any factory parts. One customer bought the kit on Wednesday and was showing it off on Friday night after two nights of wrenching after work.”
ProCharger’s vertically-mounted intercooler with only four pieces of molded piping.
With this kit being available for both manual and automatic transmission applications, ProCharger has tested the one piece billet bracket system up to 1300+ hp to ensure it will be strong enough for any application. ProCharger doesn’t force everyone to get the same system, but instead give owners options like: two air inlet options – OEM interface inlet or Stage 2 race air inlet, vertical or horizontal mounting options for the intercooler, three different color options, and a handheld tuner option that yields significant gains over stock. No matter what options your C7 has, ProCharger has a kit with options that will meet your needs.
Installing the ProCharger Supercharger Kit
With an install time estimated at four to five hours, Erik added, “Unlike our competitors, customers installing the ProCharger won’t have to modify the ABS module and no factory fluids need to be touched.” For weekend warriors with no lift looking to install this kit themselves, additional time should be allotted as we used one for this install for ease of access and photography purposes. To install the kit, we summoned the help of Ryne Cunningham of Cunningham Motorsports who is no stranger to performance tuning.
To start, we placed the vehicle on the lift, fully engaged the parking brake, disconnected the battery, and removed the plastic coil covers. The Chevrolet engineers did a great job designing the C7 with tons of room to work under the hood and an easy to access battery compartment located in the rear of the vehicle.
From here, we gained more space to work by removing both from wheels and although this is not outlined in the instruction manual, it most definitely helped create more room to work for later steps. In addition, we prepared the front bumper for removal by removing all fascia shroud screws and the various splash guards located in and around the front bumper.
Once all of the clips, bolts, and pins are removed, the front bumper easily comes off which greatly simplified the installation of the intercooler in later steps. With the hood open and bumper removed, Ryne's shop removed the entire factory air inlet system, PCV hose, MAF harness, wheel liners, and brake cooling duct bolts in preparation to lower the radiator.
The fan was removed to gain access to the radiator. As part of the installation, the various radiator bolts and their corresponding plastic shroud bolts need to be removed while keeping the radiator in the car. The radiator is attached using zip ties so that it can be moved around inside the engine bay without needing to remove it and drain the cooling system. Once the radiator was free, they shifted their focus underneath the vehicle. In order to gain access to the crankshaft balancer bolt, the bolts holding the ABS bracket, K-member, sway bar, and steering rack need to be removed so that a pry bar can be used to separate the K-member from the frame. While separated, a one inch spacer is inserted on both sides of the vehicle.
The steering rack is pushed up to gain access to the crankshaft balancer bolt. Using a 24 mm socket and an impact gun, Mike was able to remove the balancer bolt. On some vehicles an impact gun may not be enough and with the vehicle in a high gear and the brakes firmly pressed, ProCharger suggests using a torch to heat the crank balancer bolt combined with an extended breaker bar.
From there, Ryne’s team prepared the supplied 8.125-inch crank pulley and cam lock assembly by affixing it to the the factory balancer. After care was taken to ensure proper spacing and filament, the new crankshaft bolt was installed and tightened.
The bracket that comes from ProCharger requires special attention to detail when installing to ensure that the three different length standoffs are installed in the right order. With the longest spacer mounted on the bottom, the entire bracket was test fitted to the pre-existing tapped holes located on the engine block and water pump.
With the supercharger and corresponding mounting brackets affixed to the motor, their attention shifted to the intercooler. ProCharger gives you the option of mounting the intercooler either vertically or horizontally but for this build, it was mounted vertically. According to Radzins at ProCharger, “In order to ensure proper cooling, the kit comes with a massive intercooler that is actually one of the biggest we have ever put on any kit. If you are an all out drag racing guy, our vertical kit is hands out the best kit out there. If you’re a road car guy, you can mount it horizontally inside the easy-to-remove C7 bumper.”
Once the intercooler was secured to the mounting brackets, the intercooler surge tube was reinstalled along with the ambient air temperature sensor.
The fan was then reinstalled along with the corresponding driver’s side intercooler tubing.
After reinstalling the front bumper, wheel well splash guards, headlights, side markers, wheels and tires, and various covers, the physical work of the installation is complete.
Under the hood of the completed installation. When asked about the difficulty of the install, Cunningham said, “The installation is very easy. If left alone, an average guy could install the kit in around five, maybe six hours.” Pictured here is the stock air box that was later replaced with the aftermarket intake that, “did make a noticeable difference” according to Cunningham.
With the ProCharger installed, we turned our focus to tuning the system. In our case, Cunningham didn’t use the supplied inTune DiabloSport to generate a custom tune for our application. Cunningham’s explanation was that “There is nothing wrong with the ProCharger tune, it’s just I wanted to make a tune dialed in for this particular vehicle rather than use a blanket tune for every C7 with a ProCharger. It was very simple and only took about an hour.” For those that choose not to do a custom tune, ProCharger has you covered. Simply upload your stock tune from the ECM, upload it to your computer, and then email the stock tune to ProCharger who within 24 hours will send back a vehicle specific tune to be uploaded to the vehicle.
Dyno and Driving Impressions
The MustangDyne shows rear-wheel horsepower and torque figures for both the stock baseline and the ProCharger equipped dyno run.
With the ProCharger system fully installed, it was time to test the results of all the hard work. A simple press of the push button start fired the motor right up and it idled with ease. The subtle whine of the ProCharger was auditory excellence and with much eagerness, the C7 was quickly moved to the MustangDyne to test the results of all the hard work. With the simple bolt-on of the ProCharger kit, the C7 picked up an additional 134.3 hp and 81.6 lb-ft of torque on 91 octane pump gas bringing the new power figures to 541.6 hp and 481.6 lb-ft of torque– at the wheels. What’s more impressive is that these figures were attained with only seven pounds of boost, which is a conservative figure done deliberately at the owners request. With more boost and additional tuning, there is even more potential in this power packed system.
Driving the C7 with all of its new found power is extremely noticeable, but only when you want it to be.
You would not know it had a mod until you floored it. -Ryne Cunningham
Around town under normal driving conditions, the C7 handles much like it did in its stock, naturally aspirated, form with solid road manners and a daily-driver friendly demeanor. However, with a more aggressive push of the throttle, the C7 roars to life with its newfound 134.3 hp extra over stock. To this point, Cunningham added, “You would not know it had a mod until you floored it, it’s a lot stronger than before, but it drives just like a stock vehicle” and later added, “That car is fast!” The power delivery is very controllable and as you can see on the dyno results, there is still a linear power curve just like the baseline, there is just a lot more of it. The ProCharger kit greatly increases power from 5,000 rpm all the way up to its peak power around the 6,300 rpm mark.
One of the options available for the ProCharger kit is the choice of two different intake options– either stock or Stage 2. We wanted to compare the two intake kits back to back so that we could get the full effect they have on the system. Due to timing, we had to run the comparison on a separate day than the original dyno runs, which unfortunately was hotter. Due to the heat, the ProCharger equipped C7 baseline produced 524.9 hp and 476.5 lb-ft with the stock intake compared to the 541.6 hp and 481.6 lb-ft measured previously on the cooler day. After bolting on the Stage 2 intake kit and taking another round on the dyno, the C7 was able to produce 538.7 hp and 483.0 lb-ft of torque– a gain of 13.8 hp and 6.5 lb-ft of torque. Considering the heat which resulted in the lower power figures to begin with, these numbers are very respectable for a simple bolt on change to the kit. We are confident that had we had similar weather to the previous test day, the results would have been even more pronounced.
The Quarter Mile
With a two week gap between the stock baseline run and the ProCharger equipped run, the two weeks felt like an eternity as we were more eager than ever to test it out. Originally, with the C7 in stock form, we headed to the Auto Club Dragway in Pomona, CA to see what it was capable of. With weather hovering around the mid 80s and the tires set to 27 psi, we were able to log a 12.34 second, 113.04 mph quarter-mile time with a 1.880 60 foot time – not bad for a box stock vehicle. Upon returning two weeks later to mid 90s weather, we hit the strip one more time to test the difference the ProCharger would make. We were able to log a 11.20 second quarter-mile pass at 125.44 mph with a 1.708 60 foot time. Considering the conservative tune we put on the system and only seven pounds of boost, we were able to pick up an impressive 12.4 mph and drop 1.14 seconds off the quarter-mile time just by bolting on the ProCharger.
All in all, we could not be happier with how the 2014 C7 Corvette handled when equipped with the ProCharger system. While we were initially worried about drivability prior to the install, we were happy to see that the vehicle can still be driven exactly like it was in stock form with excellent road manners. What we were even more happy to see (and feel), were the great power gains accomplished by the ProCharger kit that provides power on demand. With 541.6 rwhp, the ProCharger kit gives you more than enough power to have a blast on the weekend and easily drive it to work come Monday.