Understanding the 6.4 Hemi Engine and Its Supercharger Potential

The 6.4-liter Hemi V8, often called the 392 Hemi (cubic inches), is one of the most popular modern Mopar engines. Factory ratings sit around 485 horsepower and 475 lb-ft of torque in the Charger, but the engine’s forged crank, robust block, and decent connecting rods make it a natural candidate for forced induction. Adding an Edelbrock supercharger kit is a proven path to reach the 500–550 horsepower sweet spot—enough to transform a daily driver into a street terror without sacrificing reliability.

Before diving into the build, it’s critical to understand the engine’s constraints. The 6.4 Hemi uses a high compression ratio of 10.9:1. Adding boost raises cylinder pressures dramatically, so careful fueling and tuning become non-negotiable. The Edelbrock E-Force supercharger kit is designed specifically for the 6.4 Hemi, offering a twin-screw rotors setup that provides ample airflow with minimal heat soak—a major advantage over centri-style blowers.

For those new to forced induction, the target range of 500–550 wheel horsepower (approximately 575–630 at the crank) is a well-documented reliability ceiling on pump gas (93 octane). Pushing beyond often requires fuel system upgrades, lower compression pistons, or E85 conversion. This guide focuses on a clean, 500–550 whp build using the Edelbrock system.

Essential Components for the Build

A proper supercharger installation is more than just bolting on a blower. You need supporting modifications to ensure the engine breathes, fuels, and cools correctly. Below is a complete list of required parts.

Core Supercharger System

  • Edelbrock E-Force Supercharger Kit (Part #1535 or similar for the 6.4 Charger) – Includes the blower unit, intake manifold, intercooler, discharge tube, and all necessary gaskets and fasteners.
  • Fuel Injectors – 6.4 Hemis with the Edelbrock kit typically require 72–80 lb/hr injectors (high-impedance) to supply adequate fuel under boost.
  • Boost-Referenced Fuel Pressure Regulator (if using return-style system) – Maintains correct fuel pressure as boost rises.

Supporting Power Mods

  • Cold Air Intake – Many Edelbrock kits include a high-flow intake, but upgrading to a larger MAF housing or aftermarket design (e.g., K&N or AEM) can reduce inlet restriction.
  • Fuel Pump Upgrade – A Walbro 525 or similar high-flow in-tank pump is often needed to feed the larger injectors, especially if you plan to run E85 later.
  • Spark Plugs – Iridium plugs one step colder (e.g., NGK 6510) help prevent pre-ignition under boost.
  • Thermostat – A 180°F or 160°F thermostat lowers coolant temps, mitigating heat soak from the supercharger.

Exhaust System

  • Headers – Long-tube headers (e.g., American Racing Headers or Kooks) significantly reduce backpressure and improve top-end power.
  • Cat-Back Exhaust – A 3-inch system with free-flowing mufflers (Borla, Corsa, etc.) completes the exhaust flow.

Tuning Hardware

  • ECU Flashing Tool – A HP Tuners MPVI2 or HPTuners Pro Feature set is essential for reading and writing the 6.4’s PCM. Many tuners prefer the Pro version for wideband logging.
  • Wideband O2 Sensor – Adding a dedicated wideband (e.g., AEM X-Series) gives the tuner real-time air-fuel ratio data, critical for safe tuning.

Step-by-Step Installation Process

Preparation and patience are key. The following steps assume you have mechanical experience and access to a lift or jack stands.

Step 1: Prepare the Engine Bay

Disconnect the battery and drain the cooling system. Remove the factory air box, intake tube, and engine covers. Check for any coolant or oil leaks; fix them now. Drain the engine oil and replace it with a quality 5W-30 synthetic (preferably one with high zinc content like Brad Penn or Valvoline VR1). This is also a good time to check spark plug condition and gap—install the colder plugs now.

Step 2: Remove Stock Intake Manifold and Throttle Body

Label all vacuum lines and wiring harness connectors. Remove the throttle body (four bolts) and set aside. Remove the intake manifold bolts in a criss-cross pattern to avoid warping the manifold. Lift the manifold carefully—the 6.4 uses a two-piece intake with integrated runners. Remove the fuel rail (beware of residual pressure) and set aside the injectors (they will be replaced).

Step 3: Install Edelbrock Supercharger Base and Intercooler

The Edelbrock kit replaces the entire upper intake with the supercharger unit. Begin by installing the lower intercooler brick and gasket set. Torque all bolts to factory spec (usually 18–22 ft-lbs). Next, position the supercharger assembly over the intercooler. Use new O-rings on the water jacket passages. Install the supercharger’s throttle body adapter and bolt on a compatible throttle body (the kit may use a 92mm or 100mm unit). Tighten the blower mounting bolts in a spiral pattern to spec (typically 20–25 ft-lbs).

Note: The Edelbrock kit for the 6.4 Charger requires clearancing the factory hood liner or even the hood itself. Measure clearance before final assembly; many owners swap to a thinner hood liner or upgrade to a functional Ram Air hood.

Step 4: Upgrade the Fuel System

Remove the factory fuel injectors and install the new high-flow units (recommended: 72lb/hr injectors from ID or FIC). Reinstall the fuel rail. If you are retaining the factory fuel system, you may need to modify the fuel return line to maintain pressure. Many builders install a boost-referenced regulator in the engine bay (e.g., Aeromotive 13109). Connect the vacuum line to the supercharger’s boost reference port. Install the high-flow fuel pump in the tank—this involves dropping the tank or using an access hole. Wire the pump to a relay that activates at ignition-on, using a 10-gauge power wire.

Step 5: Cold Air Intake and Boost Tubes

Mount the cold air intake tube that comes with the Edelbrock kit. It routes air from the front bumper area to the supercharger’s inlet. Ensure no sharp bends are pinching the filter. Connect the discharge tube from the blower to the throttle body, using supplied silicone couplers and T-bolt clamps. Pay attention to the MAF sensor placement—if the kit relocates the MAF, you must ensure no vacuum leaks before the sensor. Use a small amount of RTV on coupler joints to prevent blow-offs.

Step 6: Install Headers and Exhaust

Long-tube headers are optional for the 500 hp target, but strongly recommended. They can add 15–20 hp alone. Install the headers with new gaskets and ARP header bolts. Connect the mid-pipes and high-flow catalytic converters (if street legal). The cat-back system installs by sliding over the muffler y-pipes. Use band clamps instead of U-bolts for a leak-free fit.

Step 7: ECU Tuning and Calibration

This is the most critical step. Never run a supercharger on a stock tune. Load the base calibration provided by Edelbrock (usually delivered via HP Tuners) or work with a reputable remote tuner (e.g., Hemifever or The Tuning School). The base tune will be safe for 93 octane and the supplied injectors, but a custom dyno tune will maximize power and drivability.

Before starting the engine, double-check all fluids: engine oil, coolant, supercharger oil (if separate), and power steering fluid (if any lines were moved). Prime the fuel system by cycling the key three times. Start the engine and let it idle for 10 minutes, scanning for leaks and monitoring coolant temp.

Testing and Fine-Tuning on the Dyno

Take the car to a chassis dyno (Dynojet or Mustang). Run a baseline pull with the base tune, then let the tuner adjust timing and fuel tables. Typical numbers for this setup: 480–510 whp on a Dynojet (equivalent to 550–600 crank hp). If you want to hit 550 whp, you may need 2-3 more psi of boost (via a smaller pulley), meth injection, or higher octane fuel. Most can achieve 520–540 whp on 93 octane with headers and good intercooling.

During tuning, monitor short-term fuel trims, knock retard (should stay at 0), and wideband lambda (target 0.78–0.80 under boost). Dial in the idle for a consistent 750–800 rpm. Test part-throttle transitions—many Edelbrock kits have excellent drivability, but the tune is where the magic happens.

Common Dyno Results for Edelbrock E-Force on 6.4 Charger

ConfigurationHorsepower (whp)Torque (wtq)
Supercharger + stock exhaust470–490480–500
Supercharger + headers + cat-back510–530510–540
Above + smaller pulley (3.8”)550–570560–580

Note: All figures on 93 octane, with safe tune (13-14° peak timing).

Maintenance and Reliability Considerations

Building a 500+ hp daily driver requires more frequent maintenance. Change engine oil every 3,000–4,000 miles. Inspect supercharger oil levels (Edelbrock units have a separate oil fill) and replace annually. Check intercooler coolant level and ensure no air pockets. Spark plugs should be replaced every 15,000 miles; the gap should stay around 0.030–0.035 inches. Fuel filter changes every 10,000 miles are wise.

Watch for heat soak on hot days. The intercooler heat exchanger may benefit from a larger aftermarket unit if you drive aggressively. Many owners add a low-temperature thermostat and electric fans that run after the car is turned off to combat heat soak.

If you plan to regularly track the car or run high ambient temperatures, consider a water-methanol injection kit (e.g., Snow Performance) to cool intake temps and reduce knock risk.

Frequently Asked Questions

Yes, Edelbrock E-Force kits for the 2015+ Charger with the 6.4L are CARB EO# D-257-74, making them 50-state legal. Keep the included tune and air filter for smog compliance.

Can I run the 500 horsepower safely on a stock 6.4 bottom end?

Absolutely. The stock 6.4 bottom end (forged crank, powder-metal rods) is safe to around 600 whp with proper tuning and fuel. Beyond that, rod bolts become the weak link. For your 500–550 target, the engine is reliable.

Do I need to upgrade the transmission?

The ZF 8HP70 8-speed in the 6.4 Charger is stout. It can handle up to 700 lb-ft with tuning. However, a torque converter upgrade (2800–3200 stall) will improve off-the-line performance and reduce slip at high RPM. A transmission tune is recommended.

What if I want more than 550 whp later?

To go beyond, you will need: forged rods and pistons, a larger fuel system (return-style, boost-a-pump), a larger intercooler, and likely a camshaft swap. Many owners just bolt on the supercharger and stop at 500–550 because it’s a sweet spot for street use.

Final Thoughts

The Edelbrock E-Force supercharger kit for the 6.4 Hemi Charger is one of the most well-engineered forced induction systems available. It fits like OEM, preserves cold starts, and delivers the power right where you want it. By following the steps above—prepping the engine, installing the blower with supporting mods, and tuning properly—you can build a clean, powerful, and daily-drivable car that humbles most of the cars on the road.

Remember that power is addictive. Once you feel 500 whp, you might start thinking about the next level. But if you build it right the first time, this setup will give you years of trouble-free smiles.