How much HP will a supercharger add to a 5.7 Hemi?

On a stock 5.7 Hemi, a quality intercooled supercharger kit running about 6–8 psi on 91–93 octane typically adds roughly 100–200 horsepower at the wheels (about 520–620 hp at the crank). With E85 fuel and supporting upgrades, gains of 220–300 whp are possible, though reliability margins narrow and costs rise. Below is a detailed look at what determines the final number, what common kits deliver, and how to plan a safe, effective setup.

Why the answer varies: platform, boost, fuel, and tune

The 5.7 Hemi spans multiple vehicles and years, with baseline output and drivetrain losses that differ widely. A 2015–2023 Charger/Challenger 5.7 is rated around 370 hp at the crank, while many Ram 1500s show lower wheel horsepower due to heavier drivetrains and 4×4 losses. Supercharger type (centrifugal vs. roots/twin-screw), boost level, intercooling, fuel octane, altitude, and tune quality all move the needle—sometimes dramatically.

Typical horsepower gains you can expect

These ranges reflect commonly reported dyno results for otherwise stock 5.7 Hemis with reputable kits, conservative boost, and a safe calibration. Wheel horsepower (whp) figures account for drivetrain losses; crank horsepower (chp) is the engine’s output before those losses.

• Conservative, pump gas (91–93), intercooled, ~6–8 psi: +100 to +150 whp (roughly 450–500 whp total; ~520–600 chp)
• More aggressive pump gas, 8–10 psi, headers/intake, optimized tune: +170 to +220 whp (about 500–550+ whp; ~600–650+ chp)
• E85 or flex-fuel, higher boost with proper fuel system and cooling: +220 to +300 whp (roughly 550–650+ whp; ~650–750+ chp)
• Truck applications (Ram 1500) often read lower whp than cars due to drivetrain/weight but see similar crank gains

These brackets are broad by design: identical hardware can produce different outcomes depending on density altitude, dyno type, and even tire/wheel choices. They are realistic targets for street-driven builds on stock internals.

What major kits typically deliver

Manufacturers tune their offerings for reliability and emissions where applicable. The figures below summarize commonly reported results for stock-motor setups; individual outcomes vary with calibration, fuel, elevation, and drivetrain.

• Centrifugal (ProCharger, Vortech, TorqStorm): Often +150–200+ whp at ~7–8 psi on 93 octane in cars; slightly lower in trucks; strong top-end power
• Roots/Twin-screw (Magnuson TVS, Whipple, Edelbrock): Frequently +120–180 whp at ~6–8 psi on pump gas; strong low-mid torque, linear feel
• CARB-legal street kits (Magnuson/Edelbrock variants): Typically on the conservative side of those ranges to meet emissions and durability targets

When comparing kits, look beyond headline numbers. Intercooler efficiency, pulley options, compressor headroom, and the vendor’s calibration approach often matter more than peak gains on a marketing sheet.

How to estimate your own gains

If you want a quick estimate for your vehicle, you can combine a baseline dyno with a simple boost-based projection to set realistic expectations before you buy parts.

1. Establish a baseline: Dyno your car/truck stock to get whp; if you can’t, assume ~320–340 whp for a healthy 370-chp Hemi car, typically less for heavier 4×4 trucks.
2. Apply a boost factor: Crank hp roughly scales by (1 + boost psi/14.7) multiplied by a real-world efficiency factor (about 0.75–0.90 for intercooled street setups).
3. Convert back to wheels: Subtract 12–18% for driveline losses in cars; 18–25% for trucks/AWD.
4. Adjust for fuel and tune: Higher octane or E85 with proper injectors/pumps and a careful calibration can safely support more timing/boost—and more power.

This method won’t replace a dyno session, but it keeps expectations grounded and helps you size fuel system and cooling upgrades appropriately.

Key factors that influence the result

Beyond the supercharger itself, these variables often make or break the final dyno sheet—and, more importantly, long-term reliability.

• Fuel quality: 93 octane outperforms 91; E85 meaningfully expands knock margin and power potential
• Intercooling: Efficient air-to-air or liquid-to-air systems lower intake temps, allowing safer timing/boost
• Tuning strategy: Conservative timing and rich mixtures trade a little peak power for piston/ringland safety
• Drivetrain loss: Heavier trucks and 4×4 systems show lower whp than lighter RWD cars at the same crank power
• Altitude and weather: Hot, thin air cuts power; cool, dense air helps—plan for worst-case conditions
• Engine year/spec: 2009+ Eagle 5.7s breathe better; condition (compression, oil control) matters

Most street builds are limited by fuel, heat, and knock control—not the blower’s peak flow. Address those first if your goal is consistent, repeatable gains.

Safe targets on stock internals

The 5.7’s stock bottom end is stout for moderate boost, but it is not indestructible. Many tuners consider the following ranges pragmatic for long-lived street use.

• Pump gas, intercooled, conservative tune: ~450–525 whp is commonly achieved and daily-drivable
• E85, strong cooling, careful calibration: ~525–600+ whp is attainable; risk rises with cylinder pressure
• Above ~600–650 whp: Consider forged pistons/rods, better ring gaps, and meticulous knock control

No dyno number justifies a risky tune. Keep intake air temps in check, monitor knock, and don’t tune to the edge for a street car, especially in hot climates.

Supporting upgrades you’ll likely need

Even “complete” kits often assume certain baseline capabilities. Budget for these components to hit your target safely.

• Fuel system: Larger injectors, upgraded pump/boost-a-pump; full E85 setups may require lines and flex sensor
• Cooling and air management: Efficient intercooler, heat exchanger, larger radiator (if towing/track days)
• Exhaust flow: High-flow cats and cat-back; long-tube headers can add power and reduce heat
• Engine management: Quality calibration on a chassis dyno; data logging for knock/temps
• Drivetrain and brakes: Fresh plugs (colder range), transmission service or upgrades for high-torque applications, better pads/tires

A reliable forced-induction build is a system, not just a blower. The best horsepower is the kind you can use every day without drama.

Legal and warranty notes

As of 2025, many new Stellantis models are moving away from the Hemi V8, but millions of 5.7s remain on the road. Some supercharger kits carry a CARB EO for 50‑state emissions compliance; others are “for off-road use only.” Dealer warranties generally do not cover powertrain failures linked to aftermarket forced induction—confirm coverage before you modify.

Bottom line

A supercharger on a 5.7 Hemi typically nets about +100–200 whp on pump gas at modest boost, landing most street builds in the 450–550 whp range depending on platform. With E85 and supporting hardware, +220–300 whp isn’t unusual, though careful tuning and component choices are essential for durability. Aim for balanced, cool-running power rather than chasing a peak number.

Summary

Expect roughly +100–200 whp from a well-spec’d 6–8 psi, intercooled supercharger on a stock 5.7 Hemi (about 520–620 hp at the crank). Aggressive E85 setups can add +220–300 whp with the right fuel, cooling, and tune, but reliability margins shrink beyond ~600 whp on stock internals. Choose a proven kit, prioritize intercooling and fuel system upgrades, and work with an experienced tuner to match your goals and driving conditions.

How much boost can a stock 5.7 Hemi handle?

A stock 5.7L HEMI can typically handle around 6-8 PSI of boost pressure reliably, but it depends heavily on the quality of the tune, the type of fuel used (with E85 being more forgiving), and whether the piston ring gaps have been modified. Exceeding these levels increases stress on the engine, with the risk of detonation and broken piston ring lands, especially on the piston’s thin ring lands. 
Factors that influence how much boost a stock 5.7L can handle:

• Tune and Fuel: A conservative tune and high-quality fuel, like E85, are crucial for reliability. A good tune will keep timing low and mixture rich to prevent detonation. 
• Piston Ring Gaps: The stock ring gaps on the 5.7L are tight, and for significant boost, they often need to be opened up to prevent piston damage under pressure. 
• Mileage and Engine Condition: Older, high-mileage engines or those that are not well-maintained may have reduced reliability and should be considered more cautiously. 
• Boost vs. Horsepower: Boost is a pressure measurement, but actual power output is more critical for assessing engine stress. A well-engineered system with adequate airflow can achieve higher power figures safely. 
• Internal Components: The 5.7L HEMI’s piston design with thin ring lands is a weak point when it comes to boosted applications. 

Risks of Exceeding the Limit: 

• Detonation: Opens in new tabOverboosting can lead to detonation, where the fuel ignites prematurely, causing significant stress and potentially leading to catastrophic engine failure.
• Piston Damage: Opens in new tabThe thin ring lands on the stock pistons are prone to breaking when under excessive pressure from boost, leading to engine issues like oil burning and misfires.

What is the maximum HP for a 5.7 Hemi?

A 5.7L Hemi’s stock internals can safely handle around 500-550 horsepower, with some sources indicating limits closer to 500-600 hp, but the piston’s thin ring lands are particularly vulnerable to failure from detonation, especially with boosted setups. Beyond this, significant upgrades to the rotating assembly (pistons, rods, and crankshaft), along with the transmission, are necessary to reliably handle more power. 
Stock vs. Upgraded Internals

• Stock Internals (Crankshaft, Pistons, Rods):
  • The stock rotating assembly is not forged and is the weak point. 
  • It can handle around 500-550 hp before components like piston ring lands fail. 
  • More than this, especially with boost, carries a significant risk of catastrophic failure. 
• Aftermarket Internals:
  • The Gen 3 Hemi block is strong and can handle much more power (1000+ hp) with the right aftermarket internals. 
  • Upgrades typically include forged pistons and rods. 

Forced Induction (Superchargers & Turbochargers) 

• Boost Levels: A stock 5.7 Hemi is generally limited to around 6-8 pounds of boost. 
• Fuel: Higher horsepower with forced induction will often require higher octane fuel or ethanol to prevent detonation, which can damage the pistons. 
• Tune: A good tuner is essential to manage power safely. 
• Fueling & Transmission: You’ll also need upgraded fuel injectors and a transmission capable of handling the increased torque and power. 

Beyond the Engine

• Transmission: Stock transmissions have a comfortable range, but 450 wheel horsepower will rapidly approach the limit for the stock NAG1 or ZF8, requiring upgrades like a high-stall torque converter and cooler. 
• Drivetrain: Upgrades to the driveshaft and differential are also necessary for reliability at higher power levels. 

Key Takeaway
While you can achieve more than 500-550 hp on a 5.7 Hemi with forced induction, it becomes a high-risk endeavor that quickly necessitates a full engine build with forged internals to prevent component failure.

How to add 100 hp to a 5.7 hemi?

To add 100 horsepower to a 5.7 Hemi, the most reliable and significant power gains come from adding forced induction, such as a supercharger or turbocharger kit. This often requires reinforcing the engine with forged pistons and connecting rods, along with upgrading the fuel system with higher-capacity fuel pumps and injectors. For a budget-friendly approach or to complement a forced induction system, consider a camshaft and cylinder head upgrade, long tube headers and exhaust, and a custom engine tune to integrate the modifications and optimize performance.
 
This video demonstrates how to add 100 HP to a 5.7 Hemi with a cam and header upgrade: 1mPrecision Diagnostics IncYouTube · Jan 24, 2024
Forced Induction (Most Effective for 100+ HP)
This method provides the largest and most consistent horsepower gains, but also involves higher costs and more significant engine modifications. 

• Supercharger or Turbocharger: Opens in new tabInstall a complete forced induction kit. 
• Internal Engine Reinforcement: Opens in new tabUpgrade to forged pistons and connecting rods to withstand the increased pressure from boost. 
• Fuel System Upgrades: Opens in new tabInstall a high-capacity fuel pump and larger fuel injectors to deliver enough fuel for the boosted engine. 
• Engine & Transmission Tuning: Opens in new tabA custom tune is essential to synchronize all the new components. An unlocked Powertrain Control Module (PCM) is often required for newer vehicles before tuning. 

Naturally Aspirated Upgrades (For Significant Gains, Less than 100 HP)
While naturally aspirated modifications can provide impressive gains, reaching a 100 HP increase without forced induction is challenging and might require a more aggressive combination of parts. 

• Camshaft Upgrade: Opens in new tabA performance camshaft and improved valve springs can provide significant horsepower and torque increases, though gains will be less than 100 HP on their own.
• Improved Cylinder Heads: Opens in new tabUpgrading to high-flow heads, potentially from a 6.1L Hemi, can improve airflow.
• Intake & Exhaust: Opens in new tabReplace the restrictive intake and exhaust manifolds with long-tube headers and a high-flow exhaust system.
• Throttle Body: Opens in new tabA larger, ported, or bored throttle body can increase airflow into the engine.
• Engine Tune: Opens in new tabAn E85-compatible tune with upgraded injectors is recommended to maximize gains from these modifications.

How much horsepower does a supercharger add to a Ram 1500?

As tested on our Dyno Dynamics Dynamometer the factory V6 Ram makes a measly 260 horsepower at the wheels. After installing the supercharger power output is raised to *442HP & 410ft/lbs of torque at the rear wheels!