The Dodge Charger, especially in its SRT and Hellcat trims, represents a pinnacle of American muscle car engineering. For enthusiasts who have tasted the stock power and crave more, a supercharger upgrade is the most direct path to the 700-horsepower milestone. However, selecting the right supercharger size for a reliable, daily-drivable 700+ HP build requires more than just picking the biggest unit off the shelf. This guide gives you the complete picture—matching supercharger type, displacement, and supporting mods to your specific Charger engine and driving goals.

Understanding Supercharger Types and Their Behavior on the Charger

Superchargers mechanically force more air into the engine, but they do so with different torque curves and heat characteristics. The three main designs each have distinct advantages for the Charger platform.

Roots Superchargers

Roots superchargers are the classic muscle car blower. They sit on top of the engine in a "hat" configuration and deliver immediate, low-RPM boost and massive torque. For a heavy sedan like the Charger, a Roots blower transforms the driving experience from a stoplight—the car surges forward the instant you step on the gas. However, they generate more heat at high RPM and are less efficient than twin-screw units. Popular aftermarket Roots options for the Charger include Whipple and Magnuson kits. A 2.3L to 2.9L Roots unit will comfortably support 700+ HP on a 6.4L or a built 5.7L engine.

Twin-Screw Superchargers

Twin-screw superchargers are essentially an evolution of the Roots design with an internal compression chamber. They are more efficient, produce less heat at the same boost level, and deliver excellent low-end torque with a flatter power curve. Kenne Bell is the most recognized name in twin-screw superchargers for the Charger. A 3.0L to 4.0L twin-screw unit is ideal for a 700+ HP street build, as it requires less boost to achieve the same power, reducing stress on the engine and intercooler. Expect immediate throttle response similar to a Roots, but with better top-end pull and lower intake air temperatures.

Centrifugal Superchargers

Centrifugal superchargers behave like a belt-driven turbocharger. They produce boost that builds with engine RPM, resulting in a linear, progressively harder pull at higher revs. This design is less intrusive (often mounted on the front of the engine) and easier to intercool, making it popular for those who mainly drive at highway speeds or on road courses. ProCharger and Vortech are the market leaders. For 700+ HP, a centrifugal unit like a ProCharger D-1X or F-1A will easily get there, often with lower heat soak than a positive-displacement blower. However, you lose the instant low-end torque that makes a heavy Charger feel truly fast around town.

Critical Factors for Choosing Your Supercharger Size

Size matters, but it’s only one part of the equation. Here’s what you need to evaluate before writing a check.

Engine Platform and Displacement

The Charger comes with three main Hemi variants, each with different supercharger requirements for 700+ HP.

  • 5.7L Hemi: A relatively low-compression (9.6:1) iron-block engine. To reach 700+ HP, you need a lot of boost (12-15 psi) and internal upgrades (forged pistons, rods). A 2.9L Roots or 3.0L twin-screw at moderate boost may work, but a larger 4.0L unit running lower boost is safer. Expect to spend heavily on the short block.
  • 6.4L Hemi (392): The popular choice. With forged pistons from the factory and 10.9:1 compression, it can handle up to about 700-750 wheel horsepower with a good tune. A 2.3-2.9L Roots or 3.0-3.2L twin-screw at 10-12 psi is perfect. Many off-the-shelf kits (Whipple 2.9, Kenne Bell 3.0) hit 700+ HP on pump gas with supporting mods.
  • 6.2L Hellcat / Redeye: Already supercharged from the factory (2.4L IHI unit). Upgrading to a larger blower (3.0L+ twin-screw or a centrifugal) with a smaller pulley and higher boost can crack 700 WHP easily. But the Hellcat engine is already built for it; the limitation becomes the fuel system and drivetrain.

Boost Levels and Fuel Octane

For 700+ HP on a 6.4L, expect about 10-13 psi of boost. On a 5.7L, you may need 14-18 psi, which significantly stresses the engine. Boost is not the goal—airflow and efficiency are. A larger supercharger moving more air at lower boost produces less heat and is safer. Always plan for 93-octane pump gas as your baseline. E85 can unlock another 50-100 HP with the same boost level, but requires a full fuel system upgrade (injectors, pump, lines, controller).

Supporting Modifications: The Non-Negotiables

A supercharger is just an air pump. To safely handle 700+ HP, your Charger needs:

  • Fuel System: Upgraded fuel injectors (85-130 lb/hr for 93 octane; 130-160 lb/hr for E85), a dual-pump setup, and a boost-referenced fuel pressure regulator. The stock fuel system on a 392 will go lean above 550 HP.
  • Cooling: A larger intercooler (air-to-air or air-to-water) is essential. Positive-displacement blowers especially need an efficient heat exchanger to prevent heat soak after a few pulls. Consider a killer chiller or ice tank for track days.
  • Transmission: The ZF 8-speed is strong, but above 700 wheel torque, the torque converter and clutches can fail. A billet torque converter, upgraded valve body, and a strong transmission tune are highly recommended.
  • Drivetrain: The stock driveshaft and CV axles can handle 700 HP for street driving but may break at the track. Upgrade to a one-piece aluminum or carbon fiber driveshaft and stronger half shafts.
  • Exhaust: A free-flowing exhaust (long-tube headers, 3-inch system) reduces backpressure and allows the supercharger to breathe. Expect a gain of 20-30 HP.

Choosing the Right Supercharger Displacement for 700+ HP

Here is a practical sizing guide based on your engine and supercharger type.

For the 6.4L Hemi (392)

Roots/Twin-Screw: A 2.9L Whipple, 3.0L Kenne Bell, or 2.8L Magnuson will put you right at 700-750 wheel horsepower with 93 octane and a safe tune. A 3.2L or larger unit (4.0L) is overkill unless you plan to run E85 and shoot for 850+ HP, but it will work at lower boost.

Centrifugal: A ProCharger D-1X or P-1X with a 3.5-inch pulley will produce 700-750 WHP. The power curve is smooth and builds from 3500 RPM to redline. It is easier on the drivetrain and runs cooler than a positive-displacement blower.

For the 5.7L Hemi

This engine needs more displacement to reach 700 HP reliably. A 4.0L twin-screw (Kenne Bell 4.0) at 12-14 psi is the sweet spot. Alternatively, a large centrifugal unit like the ProCharger F-1A-94 will make 700+ HP but requires a built bottom end with forged rods and pistons (compression dropped to 9.0:1).

For the Hellcat (6.2L)

Upgrading the factory 2.4L blower: you can pulley down and add a larger throttle body and inlet to hit 700 WHP. However, a 3.0L or larger aftermarket blower (a direct replacement) with a smaller pulley will push 750+ WHP with ease. The motor is already built for it; focus on fuel and cooling.

Always verify the supercharger's maximum airflow rating. A Roots 2.3L may peak around 1,400 CFM, enough for 700 HP on a 6.4L, but you'll be near its ceiling. Moving to a 2.9L or 3.0L gives headroom and lower IATs.

Installation and Tuning Considerations

Installing a supercharger on a modern Charger is not a weekend job for the faint of heart. The process involves removing the intake manifold, fuel rails, and often the radiator for access. Professional installation is strongly recommended unless you have extensive experience with late-model Hemi engines.

Fuel System Upgrades During Install

While the supercharger is off, it’s the perfect time to install larger fuel injectors, a fuel pump booster (for positive-displacement blowers that raise fuel pressure), and a return-style fuel system if you plan on E85. Many kits come with injectors, but confirm they match your power goal. Do not skip a boost-referenced fuel pressure regulator—the stock system cannot maintain pressure under high boost.

Intercooling and Heat Management

Whipple and Kenne Bell kits include intercoolers, but the stock heat exchangers are often undersized for 700+ HP. Upgrade to a dual-pass radiator, a larger heat exchanger, and electric fans. Also consider a coolant expansion tank with a higher pressure cap. On a centrifugal setup, an air-to-air intercooler is simple and effective; just ensure it flows well without creating a pressure drop.

Tuning: The Make-or-Break Step

You cannot drive a supercharged Charger without a custom tune. The stock ECU (NG11 on 392 cars, NG17 on Hellcats) must be flashed. For 700+ HP, you need a competent tuner who understands the 8HP70/90 transmission logic. A bad tune will destroy pistons or melt spark plugs in seconds. Plan to visit a dyno after installation—don't rely on an off-the-shelf mail-order calibration for this power level. Expect to pay $500-$1,000 for a proper dyno tune.

Belt and Pulley Slippage

At 700+ HP, belt slip is a common enemy. Use a quality 8-rib or 10-rib belt setup, and ensure the tensioner is heavy-duty. Some tuners recommend a cog belt (like a Gilmer) for absolute grip, but it adds noise and maintenance.

Performance Expectations and Reliability

After the build, a properly set up 700+ HP Charger is a monster. Zero to 60 mph in the low 3-second range, quarter-mile in the mid-10s at 130+ mph, and the ability to light the tires at 50 mph. But reliability depends on the quality of the parts and the tune.

Street-driven cars with a 2.9-3.0L twin-screw on 93 octane and a conservative tune can last 50,000+ miles with proper maintenance. Track cars pushing 750+ HP with a centrifugal blower and E85 require shorter oil change intervals (3,000 miles), spark plug changes every 15,000 miles, and regular belt inspections. The transmission will need fluid changes every 30,000 miles.

For more detailed build examples and community experience, check out the build threads on Charger Forums or the technical guides from Modern Muscle Xtreme. If you are considering the Hellcat route, the MotorTrend Hellcat swap guide is a valuable resource for understanding differences.

Conclusion

Choosing the right supercharger size for a 700+ HP Dodge Charger comes down to your engine, your driving style, and your budget for supporting modifications. For a street-driven 6.4L Charger, a 2.9-3.0L positive-displacement blower from Whipple or Kenne Bell is the gold standard—instant torque that matches the car's heavy chassis. If you prefer highway pulls or track days, a centrifugal ProCharger provides cooler, higher-RPM power with less drivetrain stress. Whatever you choose, remember that a supercharger is only one component in a system. Invest equally in the fuel system, cooling, transmission, and a professional tune. Do that, and 700+ HP will not only be achievable but reliable enough to enjoy every day.