For owners of Mercedes-AMG vehicles powered by the M177 engine—found in models like the C63 S, E63 S, and GLC63—the pursuit of more power is a common passion. While the factory twin-turbocharged V8 is formidable, many enthusiasts look to forced induction upgrades to unlock the engine’s full potential. The HPE700 supercharger kit, developed by Hennessey Performance Engineering, offers a comprehensive solution that transforms the M177 into a high-horsepower monster. This article provides an in-depth look at the costs, performance gains, installation process, and supporting modifications needed for the HPE700 supercharger, helping you make an informed decision about this dramatic upgrade.

Understanding the HPE700 Supercharger

The HPE700 is not a standalone supercharger unit but a complete forced induction system engineered specifically for the M177 4.0L V8 engine. Unlike turbochargers that rely on exhaust gas to spin a turbine, a supercharger is mechanically driven by the engine’s crankshaft via a belt. This eliminates turbo lag entirely, providing instant throttle response and linear power delivery. The HPE700 system replaces the factory twin-turbo setup with a single, large positive-displacement supercharger (typically a Whipple or Eaton TVS unit) mounted atop the engine. It includes a high-flow intercooler system, upgraded fuel injectors, a high-pressure fuel pump, a forged crankshaft pulley, and a custom ECU calibration. The result is a guaranteed 700 horsepower at the crank (hence the name) with the potential for more with additional modifications. The system is CARB-exempt (for 50-state legality) and comes with a limited warranty, reflecting Hennessey’s commitment to quality and reliability.

Complete Cost Breakdown

Investing in the HPE700 supercharger requires a significant financial commitment. Below is a detailed breakdown of the expenses you should expect. Prices are in USD and may vary based on your location, chosen installer, and specific vehicle model.

1. Supercharger Kit Cost

The base HPE700 supercharger kit from Hennessey is priced between $7,000 and $10,000. This includes the supercharger assembly, intercooler, injectors, fuel pump, belt, pulleys, and the tuning hardware/software. The exact price depends on whether you purchase directly from Hennessey or through an authorized dealer, as well as any current promotions. Some kits come with a stage 1 calibration, while others include a dynamic tuning module for future upgrades. Shipping and handling can add another $200–$500.

2. Professional Installation Labor

While a skilled DIY mechanic could attempt the installation, it is strongly recommended to have a certified shop perform the work. The M177 engine bay is tight, and the supercharger installation requires precise alignment and torque specifications. Labor costs typically range from $1,500 to $3,500, depending on the shop’s hourly rate ($125–$200/hour) and the complexity of your specific vehicle. Expect 10–15 labor hours for experienced installers. Some shops offer a discounted rate if you also purchase the kit through them.

3. Tuning and Calibration

After the hardware is installed, the engine must be tuned to optimize air-fuel ratios, ignition timing, and boost levels. Hennessey provides a base calibration with the kit, but many owners opt for a custom dyno tune to maximize power and safety. Custom tuning adds $500 to $1,500. Expect multiple pulls on a chassis dynamometer to fine-tune parameters. If you choose a remote tuning option (e.g., via email), the cost is lower but requires data logging equipment.

4. Supporting Modifications

To handle the increased power safely, several supporting components may need upgrading. These are not always included in the HPE700 kit and can increase the overall cost by $1,000–$3,000 or more.

  • Fuel System Upgrades: The M177’s direct injection system can reach its limits at higher horsepower levels. Upgraded low-pressure fuel pump, larger injectors, or a port injection kit may be required. Expect $500–$1,500.
  • Intercooler and Heat Exchanger: The HPE700 kit includes an intercooler, but for sustained track use, a larger heat exchanger or an auxiliary cooling system might be beneficial. Cost: $200–$800.
  • Clutch or Torque Converter: The 700+ horsepower will stress the factory automatic transmission or clutch. A stronger torque converter (for 9-speed auto) or upgraded clutch pack can cost $1,500–$3,000.
  • Exhaust System: To unlock full power, a less restrictive exhaust (downpipes, cat-back) is recommended. Budget $1,000–$2,500.
  • Drivetrain Components: Upgraded half-shafts, differential cooling, or a limited-slip differential may be needed for consistent launches. Add $500–$2,000.

Total estimated cost for a complete installation: $11,000–$20,000, depending on options and labor.

Performance Boosts: Real Gains and Driving Experience

The HPE700 supercharger dramatically transforms the M177 engine. Here are the quantifiable and qualitative improvements you can expect.

Horsepower and Torque Gains

On a chassis dynamometer, a properly tuned HPE700-equipped M177 consistently produces 520–560 wheel horsepower (whp) and 580–620 lb-ft of wheel torque. This translates to approximately 650–700 crank horsepower after accounting for drivetrain loss. Compared to the stock output of roughly 500 HP (C63 S) or 600 HP (E63 S), the gain is substantial. For example, a stock C63 S might dyno at 440 whp; after the HPE700, it jumps to 520+ whp—a gain of nearly 80 wheel horsepower. With additional modifications like downpipes and E85 fuel, some owners have reported 600+ whp (750+ crank HP).

Throttle Response and Power Delivery

The supercharger’s immediate boost eliminates the slight lag inherent in the factory twin-turbos. At 2,000 RPM, the engine pulls with authority, and by 3,500 RPM, full boost is available. The power curve is linear and builds all the way to the 7,000 RPM redline, without the drop-off typical of smaller turbochargers. This makes the car feel significantly faster in everyday driving—merging onto highways or overtaking requires a feather touch on the pedal. The sense of urgency is addictive.

Acceleration and Quarter-Mile Times

Real-world performance numbers are impressive. A C63 S with the HPE700 can sprint from 0–60 mph in the low 3-second range (mid to high 2s with sticky tires and a prepped surface). The quarter-mile time drops from factory 12.0–12.3 seconds at 118 mph to approximately 11.0–11.2 seconds at 125–128 mph. In an E63 S, the extra weight slightly reduces gains but still yields consistent 11.0–11.3 quarter miles. Trap speeds of 125+ mph indicate a car capable of high 10-second runs with traction optimization.

Reliability Under Boost

Despite the power increase, the M177 engine is robust. The HPE700 system is designed to operate within the engine’s safe limits, using conservative timing and air-fuel ratios. With proper cooling and fuel delivery, many owners have logged tens of thousands of miles without issues. However, like any modified high-performance engine, regular maintenance (frequent oil changes, spark plugs at shorter intervals) is critical. The supercharger itself requires little maintenance—just periodic belt inspections and intercooler cleaning.

Installation Process: What to Expect

The installation of the HPE700 supercharger is a complex process best left to professionals. However, understanding the steps helps you appreciate the work involved and prepare your vehicle. Below is an outline of the typical procedure.

Preparation and Tools

The shop will need a full set of metric sockets, torque wrenches, specialized intake removal tools, and a vacuum pump for the fuel system. The vehicle should be on a lift for easier access. The kit comes with a detailed instruction manual. Expect the installation to take one to two days.

Step 1: Removal of Factory Components

Start by disconnecting the battery and draining the coolant. Remove the intake air boxes, intercooler coolant reservoir, and the entire intake manifold. The factory twin-turbochargers and their associated piping, wastegates, and oil lines must be removed. This is the most time-consuming part, as the turbos are nestled in the V-bank of the engine. The oil drain lines must be plugged to prevent leaks. The exhaust manifolds can remain if they are not being upgraded.

Step 2: Fuel System Preparation

If the kit includes upgraded injectors and a high-pressure fuel pump (HPFP), these must be installed. The HPFP is located on the left cylinder bank and requires careful removal of the old pump and installation of the new one, ensuring proper lubrication. The injectors are replaced while the intake manifold is off — apply new seals and torque to spec. Additionally, low-pressure fuel pump wiring may need modification if a second pump is added.

Step 3: Supercharger Mounting

A custom mounting bracket (included) bolts to the engine block. The supercharger is then positioned on top of the intake valley, aligning the drive pulley with the crankshaft. The intercooler assembly (air-to-water) is pre-installed between the supercharger and the intake manifold. All bolts are torqued to Hennessey’s specifications. The belt is routed around the supercharger, alternator, and tensioner. The new intercooler pump and heat exchanger are mounted in the front bumper area, with coolant hoses run to the air-to-water core.

Step 4: Reassembly and Wiring

Reinstall the intake manifold (with adapter if needed), throttle body, and all air intake ducts. Connect the intercooler hoses and electrical connections (fuel pump relay, MAP sensor, etc.). Fill the coolant for the intercooler system and the engine. Check for leaks by pressurizing the system. Reconnect the battery.

Step 5: Tuning and Validation

Load the base calibration into the ECU using a handheld programmer (e.g., HP Tuners device). Start the engine and check for idle stability, fuel pressure, and boost leaks. A test drive under varying load conditions is performed. Data logs are reviewed and adjustments are made to the tune for optimal air/fuel ratios and knock control. A final dyno run verifies the horsepower numbers.

Supporting Upgrades for Maximum Reliability

To fully exploit the HPE700 and ensure long-term durability, consider these additional modifications:

  • Transmission Tune: The 9-speed automatic in M177 cars can handle the extra torque, but shift firmness and torque converter lock-up should be refined. A transmission tune ($500–$1,000) improves shift logic and prevents slippage under full throttle.
  • Cooling System Overhaul: Upgraded radiator, oil cooler, and transmission cooler are recommended for track use. The extra heat from sustained high-speed driving can stress standard cooling.
  • Brake Upgrade: With more speed comes the need for greater stopping power. Consider larger brake rotors, upgraded pads, and high-temperature brake fluid.
  • Suspension and Tires: Lowering springs or coilovers improve handling, while sticky summer tires (e.g., Michelin Pilot Sport 4S or Cup 2) provide the grip needed to put power down.

Common Questions and Concerns

Yes, the HPE700 supercharger kit is CARB EO (Executive Order) approved for 50-state legality. This means it passes emissions inspections in California and other states with strict regulations, provided all components are correctly installed and the tune does not delete emissions equipment.

How does it affect fuel economy?

Under normal driving conditions, fuel economy remains similar to stock—around 15–18 MPG combined. However, when the supercharger is in boost, fuel consumption increases dramatically. Expect single-digit MPG during aggressive driving. The upgraded fuel injectors also allow the engine to run safely at higher horsepower levels.

Can I run the HPE700 on pump gas?

Yes, the base kit is calibrated for 93 octane pump gas. For maximum power, some tuners recommend a blend of 93 and E85 (85% ethanol). E85 offers higher octane and charge cooling, allowing more aggressive timing and boost. However, it requires a flex-fuel sensor and larger injectors, which are often added in a stage 2 package.

External Resources and Further Reading

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Conclusion

The HPE700 supercharger installation on the M177 engine is a major modification that delivers transformative performance. With careful planning, a realistic budget, and the support of a skilled installer, you can turn your AMG into a true supercar slayer. The immediate throttle response, wave of torque, and high horsepower numbers make every drive exhilarating. While the initial investment is substantial, the resulting driving experience and potential for further upgrades ensure that the HPE700 remains one of the most rewarding forced induction kits for the M177 platform. If you are ready to unlock the full potential of your AMG, the HPE700 is a proven path to automotive bliss.