The 5.7 HEMI Supercharger Vs Stock: A 100-HP Power Gain Breakdown

The 5.7-liter HEMI V8 has been a cornerstone of Chrysler performance since its reintroduction in 2003. Found in everything from the Dodge Charger and Challenger to Ram trucks and Durango SUVs, this engine delivers a satisfying blend of torque and reliability straight from the factory. For many owners, however, the stock output of roughly 360 horsepower and 390 lb-ft of torque leaves room for more thrills. Adding a supercharger is one of the most effective ways to unlock that potential, often yielding a gain of approximately 100 horsepower at the wheels. This article breaks down exactly what changes when you go from a naturally aspirated 5.7 HEMI to a supercharged setup, covering performance numbers, driving dynamics, costs, and key considerations.

Stock 5.7 HEMI: A Solid Foundation

Before diving into forced induction, it's important to understand what the stock engine offers. The 5.7 HEMI features a hemispherical combustion chamber design that promotes efficient airflow and a high compression ratio of 10.5:1. In standard trim—depending on the vehicle and year—it produces between 360 and 395 horsepower and 390 to 410 lb-ft of torque. The engine uses a multi-displacement system (MDS) that deactivates four cylinders under light load to improve fuel economy, though this system is often deleted or disabled in performance builds.

The stock engine is paired with either a TorqueFlite eight-speed automatic or a six-speed manual in some Challengers. It delivers a 0-60 mph time of about 6.5 seconds and a quarter-mile in the low 14-second range for a full-size sedan. While these numbers are respectable, they leave significant headroom for forced induction—the bottom end, connecting rods, and pistons are shared with higher-output HEMI variants and can handle moderate boost levels without immediate failure.

Types of Superchargers for the 5.7 HEMI

Choosing the right supercharger depends on your goals, budget, and preferred driving feel. The three main types used on the 5.7 HEMI are Roots, twin-screw, and centrifugal superchargers.

Roots Supercharger

Roots-type blowers are the classic choice for muscle cars. They sit directly on top of the intake manifold and use two rotating lobes to push air into the engine. Design examples include the Whipple 2.9L or 3.0L kits. Roots superchargers produce immediate, low-end torque because air density builds quickly with throttle opening. The downside is that they generate more heat under sustained boost, often requiring an intercooler or water-methanol injection. Power delivery is linear and aggressive from idle to redline.

Twin-Screw Supercharger

Twin-screw designs (like the Kenne Bell 2.8L) are mechanically similar to Roots but compress air internally before it enters the manifold, leading to higher efficiency and lower discharge temperatures. They still produce strong low-end torque but maintain better power throughout the rev range. Twin-screw kits often come with an integrated air-to-water intercooler to manage intake air temperatures.

Centrifugal Supercharger

Centrifugal superchargers (such as the ProCharger D-1SC or Paxton Novi 2200) behave more like a turbocharger. They are mounted away from the engine and driven by a belt, spinning a compressor wheel to force air into the engine. These produce max boost near the top of the rev range, so power builds gradually. Centrifugal kits are usually easier to install, run cooler, and place less stress on the drivetrain at low RPM. For a daily driver that also sees track time, a centrifugal supercharger often provides the best balance of power and reliability.

Power Gain Breakdown: From 360 to 460 HP

The headline number for most bolt-on supercharger kits targeting the 5.7 HEMI is a 100-horsepower increase at the wheels. Here is a typical dyno chart comparison (engine horsepower and torque):

  • Stock: 360 hp @ 5,200 rpm / 390 lb-ft @ 4,200 rpm
  • Supercharged (6-8 psi): 460 hp @ 5,800 rpm / 480 lb-ft @ 4,000 rpm
  • Peak Gain: +100 hp / +90 lb-ft

However, the real-world improvement is greater than the peak numbers suggest. The supercharger flattens the torque curve, delivering over 400 lb-ft from 3,000 rpm to redline. This means second-gear pull on the highway feels dramatically stronger than stock. With a good tune (often required for the installation), the engine can safely run on 91-93 octane fuel. Some kits offer intercoolers that allow boost levels up to 10 psi, pushing output past 500 horsepower at the crank—but that moves beyond the "100-hp gain" scope and requires supporting upgrades like forged pistons.

Torque Improvements

Torque is where supercharging really transforms the 5.7. The stock engine’s torque peak of 390 lb-ft occurs around 4,200 rpm and drops off quickly above 5,000 rpm. With a supercharger, torque comes on hard from low RPM and stays elevated. A typical supercharged 5.7 will produce 430-460 lb-ft at 3,000 rpm, peaking near 480 lb-ft around 4,200 rpm before gently tapering. This broad torque band makes the car feel immensely quicker in everyday driving—merging, passing, and climbing hills require much less throttle.

Performance Comparisons: Stock vs. Supercharged

To quantify the difference, here are measured performance figures for a 2019 Dodge Charger 5.7L with a Centrifugal supercharger at 7 psi (data from independent tests):

  • 0-60 mph: Stock 6.5 seconds → Supercharged 4.5 seconds
  • Quarter-Mile: Stock 14.1 sec @ 98 mph → Supercharged 12.0 sec @ 115 mph
  • 100-0 mph Braking: Not directly affected, but heavier front weight from supercharger may increase stopping distance slightly (softer pads recommended).
  • Top Speed: Stock limited to 155 mph (electronically). Supercharged versions can exceed 170 mph with appropriate drivetrain and tires, but most kits leave the stock limiter.

These numbers show not just a drop of two seconds in the quarter-mile but a massive increase in trap speed—going from 98 mph to 115 mph indicates the car is making significantly more power at high speed. A supercharged 5.7 HEMI in a Challenger weighs about 4,200 lbs, so a 12.0-second quarter-mile at 115 mph is genuinely quick, putting it in the same league as stock 392 Scat Packs or even some Hellcats at lower boost levels.

Driving Experience

Behind the wheel, the difference is immediate. A stock 5.7 feels responsive but moderate; with a supercharger, the engine pulls hard from any speed. The throttle becomes sensitive—blips in second gear result in strong acceleration. However, the added power does require careful modulation, especially in the rain or on cold tires. Many drivers note that the car feels like a different vehicle, losing its "dual-purpose" character and becoming a pure performance machine.

Installation and Supporting Modifications

Adding a supercharger is not just a bolt-on; it requires several supporting upgrades to ensure reliability and longevity.

Fuel System

The stock fuel pump and injectors are adequate for about 460-470 wheel horsepower. Above that, you will need a fuel pump voltage booster, larger injectors (e.g., 60 lb/hr), and possibly a higher-flow fuel pump. Most supercharger kits include injectors and a tune to compensate.

Cooling

Forced induction increases heat load. An intercooler is essential for any supercharger type other than some low-boost centrifugal kits that use water-methanol injection. Many owners upgrade the radiator, thermostat, and cooling fans to prevent heat soak. An oil cooler is also recommended, especially for track use.

Exhaust

The stock exhaust is restrictive and can limit power gains. Installing long-tube headers, a high-flow mid-pipe, and a cat-back system can add another 15-20 horsepower and reduce exhaust gas temperatures. However, the supercharger itself masks some exhaust note; many find the sound more aggressive with a full exhaust.

Drivetrain

The eight-speed automatic ZF 8HP transmission in most 5.7 HEMI vehicles is robust and can handle 500 lb-ft of torque without failure, but a torque converter upgrade or transmission cooler is a wise investment. Manual transmissions (TR-6060) can handle more, but clutch wear accelerates. Rear axles on some older models may need upgrade to 3.92 gears or a limited-slip differential with higher torque capacity.

Cost Breakdown

A typical supercharger kit for a 5.7 HEMI ranges from $5,000 to $7,500 for the main components, including the supercharger, intercooler, brackets, tune, and installation kit. Professional installation adds $1,500-$3,000. Supporting modifications (fuel system, cooling, exhaust) can add another $2,000-$4,000. Total investment: roughly $8,500 to $15,000 for a reliable 460-500 hp build.

Compared to buying a factory supercharged car (like a used Hellcat at $40k+), this is a more affordable way to achieve comparable thrill in an existing 5.7 vehicle. However, resale value may be affected; a supercharged car will appeal to enthusiasts but might be harder to sell to a general buyer.

Reliability and Longevity

The 5.7 HEMI engine is robust, but adding boost shortens component life if you beat on it constantly. With proper tuning and respect for detonation limits, a supercharged 5.7 can last 100,000+ miles without major failure. Common weak points include rod bolts and ring lands if boost exceeds 10 psi or if the engine detonates. Using high-octane fuel, monitoring knock with a good tune, and avoiding prolonged full-throttle operation will extend engine life.

One key note: MDS (cylinder deactivation) is not recommended with forced induction because the active fuel management system can cause surging and detonation. Most tuners disable MDS in the calibration.

Alternatives to Supercharging

If a supercharger is outside your budget or not suited to your driving style, you have other options to reach the 100-hp gain mark:

  • Nitrous Oxide: A 100-shot wet nitrous kit costs under $1,000 and offers similar peak gains, but only when the bottle is open. Not consistent for daily driving.
  • Turbocharging: More complex to package on a HEMI, but a twin-turbo kit can produce 500+ hp with better efficiency. Cost and complexity are higher.
  • Camshaft Swap + Supporting Mods: A performance cam, headers, intake, and tune can yield ~400-420 horsepower naturally aspirated—a 40-60 hp gain. Combined with lighter weight, this can be satisfying but not the same torque as a supercharger.

Final Thoughts

Adding a supercharger to a 5.7 HEMI is one of the most transformative modifications you can make. The jump from 360 to 460 horsepower (and the associated torque gains) reshapes the car’s personality, delivering thrilling acceleration that rivals much more expensive vehicles. However, it requires a thoughtful approach to supporting upgrades, a capable tuner, and an acceptance of reduced fuel economy and increased maintenance. For those who want to wring every bit of excitement from their Dodge or Ram, a supercharger is a proven path to the 100-hp gain that makes the HEMI legend truly sing.

For more information, check out Whipple Superchargers and ProCharger for comparison kits. Also, forums like Charger Forums offer detailed owner experiences.