After a short period of ownership of your new Challenger, Charger, Ram, or an SRT version of the Durango, Grand Cherokee, or Wrangler, a decision was made that the horsepower the 5.7L or 6.4L Hemi was putting to the ground was no longer enough to satisfy the never-ending quest for more power. To increase the output of the Hemi, all options were considered, such as upgrading the heads and camshaft, adding nitrous, installing a turbocharger, or even mounting a supercharger. After carefully studying the benefits and drawbacks of each power adder, it was determined a centrifugal supercharger would provide greater performance than a head/cam swap, be available all the time unlike the constant bottle filling required for nitrous, would fit into the engine bay and look like a factory installation rather than an aftermarket add-on like a turbocharger, and the centrifugal supercharger would provide more effective output than a turbocharger when run on pump gasoline. A call was placed to ATI ProCharger for one of their High Output (HO) Intercooled System, which included an air-to-air intercooler. This supercharger kit was designed to work with stock compression pistons (which our 2018 Challenger has) and a fuel octane rating of 91 or higher.
Why did we select ProCharger? ProCharger was the only choice when it came to a 100 percent complete, bolt-on supercharger installation. They have been the leading aftermarket supercharger manufacturer for 25 years, and their products are some of the best engineered, reliable, and powerful on the market. The ProCharger line is USA engineered and built to provide excellent power/pound of boost for a multitude of applications, including not only late-model V-8s, but trucks, SUVs, compacts, motorcycles, and various marine applications. The ProCharger supercharger comes with an air-to-air intercooler that helps keep the charge air temperatures at a minimum for maximum power. Lastly, there’s a warranty with each supercharger system.
Before the installation of the ProCharger began, our stock 2018 Challenger with a 6.4L Hemi was strapped to a Mustang dyno to evaluate the rear-wheel horsepower and torque. With the engine and drivetrain up to operating temperature, a run from 3,100 to 6,200 rpm was performed. The numbers were impressive for a stock, off-the-showroom floor vehicle. We made several more baseline runs, and all the runs were very similar in performance output and consistency; the best run resulted in a peak of 426 rear-wheel horsepower at 6,200 rpm, and the torque peaked at 404 lb-ft at 4,300 rpm. Pleased with the results, we moved the Challenger to a four-post drive on vehicle lift, so the stock component removal could begin.
Prior to starting the removal process, we familiarized ourselves with the kit. With dozens of parts in the kit and a thick installation guide, it looked like a daunting undertaking, but with good planning and patience, the installation progressed smoothly. Following the steps of the installation guide, we ensured that no fuel pressure was in the fuel rails before they were removed by pulling the 20-amp fuse No. 6 or relay 46 (depending upon model year — both located in the trunk) to disable the voltage to the fuel pump, and the engine was turned over for 15 seconds to bleed off the fuel pressure. After the pressure was relieved, the negative battery cable was disconnected. We removed the engine covers, unclipped the wiring harnesses from each fuel injector, and pulled the injectors and rails from the intake manifold. Each injector was removed from its fuel rail and new injectors supplied with the kit were installed. The new injectors with the fuel rails were reinstalled into the intake manifold.
The manifold absolute pressure sensor (MAP) was removed from the intake manifold. A MAP adapter was threaded into the intake manifold, and a new supplied MAP sensor was installed on the MAP adapter. A fresh set of plugs (16) that were one step colder were gapped to .035 inch and torqued into each cylinder (two plugs per cylinder). The intake air temperature sensor (IAT) was removed from the engine. The positive crankcase valve (PCV) hose was freed from the airbox assembly, and with the unthreading of a bolt and the band clamp on the airbox housing, the airbox was pulled from the engine bay. While in the engine bay area, the radiator cavity covers (black airflow dams) were detached from the radiator support. If the vehicle had been equipped with a shaker hood, several additional steps would’ve been required to remove the airbox from the car.
The Challenger was raised so we could gain access to the under-chassis body cladding. There were three lower front fenderwell panel fasteners that were removed per side. The back cladding required unthreading of four fasteners to free it from the chassis. Following the removal of the back cladding, the removal of 11 additional fasteners released the front cladding from the Challenger. With everything that attached to the exterior of the fascia removed from the top and bottom sides, we had to dive deeper into the fenderwells and into the area around the air conditioning condenser to remove more clips, rivets, and fasteners to remove the fascia. While we were removing the various fasteners, we disconnected the wiring harness to the fascia, thus eliminating the need to unplug each turn signal and fog lamp separately. When we were sure we had every fastener removed, we taped the front edge of the fenders of the Challenger with several layers of 2-inch masking tape to protect the paint. Each side of the fascia was unsnapped, and the fascia was gently pulled straight forward off the Challenger. With the fascia placed on a pair of fender covers on the floor, we proceeded to remove plastic radiator shrouding and ducting from around the condenser and radiator. The serpentine belt and tensioner were removed, and lastly the horns were disconnected from the harness and removed. The horn brackets were set aside and wouldn’t be reused for the supercharger installation.
At this point, we moved to the cooling system of the Challenger. We removed the coolant reservoir cap, drained the coolant from the radiator, removed the coolant lines from the reservoir, and removed the reservoir from the engine bay. The reservoir wouldn’t be reused for the installation of the supercharger. Once the reservoir was removed, we removed the radiator bracket located on the driver side of the radiator. We still had more components to loosen or remove to get to the harmonic balancer. There was a radiator cradle, radiator trim, electric fan connectors, and several fasteners that had to be removed. The fan shroud was pushed up from below slightly, tilted to the rear of the Challenger, and then lowered out from the bottom of the engine bay. As the cradle and fasteners were removed, a jackstand was required to hold the radiator in its approximate location.
With just enough clearance between the harmonic balancer and the radiator, we backed off the factory harmonic balancer bolt and prepared the balancer for a dowel pin. We secured the supplied drill jig with a bolt and washer into the balancer bolt threads in the crankshaft, and we used a 90-degree drill with a drill bit in the jig to locate a small hole in the crankshaft and the balancer. A stainless steel dowel pin slipped into the drilled hole to engage the outer diameter of the crankshaft to the inner diameter of the balancer. The harmonic balancer bolt was reinstalled and torqued to specifications. Pinning the balancer was necessary because the factory doesn’t include a keyway and key, and the load on the belt and harmonic balancer pulley would be greatly increased by the supercharger, which could cause the pulley to slip on the crankshaft.
After the dowel pin was installed, the radiator fans were reinstalled and the support cradle was reattached along with all the mounting fasteners. A pair of aluminum intercooler brackets was installed onto the radiator support. Once the brackets were installed, the intercooler was guided behind the steel bumper of the chassis and in front of the condenser, where it was secured with several bolts to the intercooler brackets. Both horns were mounted on their new relocation support and attached to the passenger-side intercooler bracket. The harness was rerouted and connected to the horns.
In the engine bay, the four throttle body bolts were removed from the intake manifold as were the two idler bracket bolts and the two timing cover bolts just under the idler bracket. A standoff bracket was installed in the location, where the idler bracket had been. The factory tensioner with an idler pulley added to the assembly was installed in its normal position on the engine with the tensioner pointing downward. A sub bracket was installed, and the ribbed idler was reinstalled onto the sub bracket. The factory belt was routed as laid out in the instructions. After orienting all the brackets, spacers, and bolts, the main bracket was installed onto the engine. The ProCharger head unit (supercharger) was filled with the supplied bottles of supercharger oil via the fill plug/dipstick port, and the head unit was installed onto the main bracket. Two 8-rib idler pulleys were installed on to the main bracket, the supercharger belt was installed, and the belt was tensioned via a screw-jack belt tensioner attached to the main bracket and the tensioner assembly.
The task of routing all the ducting for the supercharger proceeded well. First, the throttle body was reinstalled onto the intake manifold. A 4-inch coupler was run from the intercooler to the air plenum and then from the plenum to the throttle body via a 45 degree 3.5-inch rubber elbow, which was all held together by clamps. The IAT was installed into the threaded bung in the air plenum. A series of silicone rubber elbows and tubes were plumbed from the bottom of the intercooler to the ProCharger supercharger. The Proflow surge system was installed between the intercooler and the supercharger. Just like the other tubes on the intercooler, the tubes and elbows were held together with clamps provided in the kit. To guarantee clean air entered the supercharger, a formed plastic ductwork was affixed to the supercharger, and at the other end, a conical-shaped air filter was installed. The PCV hose that was removed during disassembly was cut to length and slipped onto a barbed fitting, extending from the plastic ductwork.
The new coolant reservoir was installed on the opposite side of the Hemi from the stock location. One factory coolant fitting elbow was reversed (pointed toward the passenger side) in its factory hose, and the hoses were rerouted to the new location of the reservoir. The petcock in the radiator was returned to the closed position, and we filled the system and the reservoir to the full cold level designated on the new reservoir.
We were on the home stretch with our installation. Before the fascia went back on the Challenger, we had to attach the ambient air temp sensor to the intercooler bracket near the horns with zip ties, and two fascia deflectors had to be removed to allow the intercooler and the fascia to fit together properly. The fascia was carefully remounted, and the fasteners and clips were reinstalled. The electrical connection to the fascia was reattached, and both underside cladding panels were secured to the chassis. Lastly, the radiator cavity corners were snapped back into place.
We did a once-over of the installation to verify a component, fastener, trim panel, or anything else was not left loose or was out of place. Once we determined everything looked good, the negative cable was reattached to the battery, and the fuel pump fuse or relay was reinstalled (if it had not been previously). We started the 6.4L and listened for any abnormal noises or noticeable shaking from the engine. After a warm-up cycle, the engine was shut off, and after cooling, the fluid levels were all checked.
Regardless of which kit was purchased, the engine will require a new tune to be uploaded to the PCM before the engine can be run. We had a custom tune uploaded to the PCM (ProCharger will provide the custom tune on your PCM), and with that, we were ready for some additional dyno runs. With more than a quarter tank of 93-octane fuel in the tank, and a fuel pressure gauge connected to the fuel rail to verify the fuel pressure remained between 55 and 60 psi, we ran the Hemi from 3,100 to 6,400 rpm several times. Just like the baseline runs, the runs were consistent and repeatable, but unlike the baseline runs, the 7 psi of boost pushed the numbers up greatly. The engine torque increased to 502 lb-ft at 6,000 rpm, and the engine horsepower jumped to 601 hp at 6400 rpm. The engine horsepower was still increasing when the rev limiter was engaged at 6,400 rpm. The torque increased 98 lb-ft over stock, and even better, the torque with the ProCharger supercharger was higher at all points of the run than the peak torque of the baseline. The horsepower increase was an incredible 175 hp on pump gas at the rear wheels.
If you’re looking for triple-digit increases in torque and horsepower for your late-model Hemi, it’s time to step up to a ProCharger supercharger. The performance numbers provided are excellent, while maintaining decent fuel mileage and civilized street manners on 91 or greater octane fuel. If your engine is already modified or the horsepower gain of the HO Intercooled System doesn’t meet your needs, ProCharger offers an intercooled Stage II supercharger system that’ll elevate the performance numbers of your Hemi into rarefied air. For a boost in your Hemi’s output, give the reps a call about which ProCharger supercharger system will best fit your needs.
Are you looking for more power for your 2018 6.4L Hemi? Is 600-plus horsepower not enough satisfy you? ProCharger has increased the power levels with the Stage II Dedicated Drive System and tuner kit for the 6.4L (392) Hemi. The installation of the ProCharger Stage II supercharger can push the horsepower to 800, 900, 1,000, or even over 1,200. The ProCharger Stage II includes an eight-rib dedicated drive system to provide maximum belt wrap to control belt slippage and a race intercooler upgrade. The HO bracket system fits ProCharger head units up to the F-1A-94 without the need to modify your car. Just like the HO system, the Stage II system if a fully turn key complete system that includes a fuel system and the benefits of a handheld tuner. If your Challenger has a Shaker hood, don’t worry, ProCharger has a system for your needs; your Shaker hood will remain in place and will bring in the much-desired cool air. Contact ProCharger for more information about the 2018 Stage II offerings.
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