How much HP will a supercharger add to a 5.7 Hemi?
A typical supercharger on a 5.7-liter Hemi adds about 180–250 horsepower at the crank on common street setups, with more aggressive builds pushing toward 300–450 HP if the engine and supporting systems are upgraded and tuned. The exact number depends on boost, tune, fuel, cooling, and the rest of the drivetrain.
The following explains how a supercharger changes power in the 5.7 Hemi, what kind of gains to expect in practical terms, and the considerations a buyer should weigh before committing to a boost install.
How a supercharger affects the 5.7 Hemi
Superchargers compress intake air, enabling more fuel to be burned and producing more horsepower across the rev range. On a modern 5.7 Hemi, power gains come from higher airflow at higher manifold pressure, with the most noticeable impact coming in the mid-to-high RPM range. Gains are typically quoted at the crank, while wheel horsepower will be lower after drivetrain losses.
Typical horsepower gains by kit type
These are ballpark ranges for common street-oriented kits and setups. Actual results vary with engine condition, fuel, tuning, and installation quality.
- Entry-level/compact boost (roughly 6–8 psi with standard intercooling): about 180–230 HP increase at the crank; wheel HP will be lower due to drivetrain losses.
- Mid-range boost (8–10 psi with intercooler and upgraded fuel system): roughly 230–300 HP increase at the crank; wheel HP typically in the 200–260 HP range above stock, depending on the car.
- High-boost or internally upgraded builds (exceeding 10 psi and/or forged components): roughly 300–450+ HP increase at the crank; wheel HP can approach 260–380+ HP higher than stock with proper tuning and cooling.
Note that these figures are indicative and depend on the vehicle (Ram 1500, Challenger, Charger, or other 5.7 Hemi applications), year, fuel octane, and the reliability of the tune and supporting hardware.
Key factors that influence the final results
Several variables determine the actual horsepower gain you’ll see on a 5.7 Hemi after boosting with a supercharger.
- Boost pressure and compressor efficiency — higher, well-controlled boost yields more air and more power, but requires corresponding fuel and cooling upgrades.
- Intercooling effectiveness — cooler intake air improves density and knock resistance, enabling safer, more aggressive tuning.
- Fuel system capacity — injectors, fuel pump, and lines must support the added fuel demand at higher boost and possibly ethanol blends.
- Tuning and ECU calibration — a proper tune optimizes timing, fueling, and air/fuel ratio to maximize power without compromising reliability.
- Exhaust and intake flow — upstream and downstream flow characteristics affect how much additional air the system can move.
- Cooling system and heat management — more air in equals more heat; adequate intercooling and radiator/airflow are essential for sustained performance.
- Drivetrain losses and drivetrain setup — wheel horsepower gains will be lower than crank gains; automatic vs manual transmissions and rear-end gearing influence the real-world feel.
- Engine health and internals — stock internals are usually fine for moderate boost, but extreme setups may require forged rods/pistons and stronger components.
Even with well-mmatched components, real-world results hinge on how carefully the system is designed, installed, and tuned for the specific vehicle and fuel environment.
Kit selection and installation considerations
Choosing a kit and planning the installation are as important as the boost itself. A careful approach helps protect reliability and performance gains over time.
Kit selection criteria
Key points to consider when selecting a kit and planning install:
- Compatibility with your engine family (5.7 Hemi) and integration with intercooling, fuel system, and ECU tuning.
- Quality of components (intercooler, piping, brackets, belt drive, and pulleys) and the design’s thermal management.
- Availability of a proven tune and dyno support for your exact model and year.
- Warranty coverage and the potential impact on factory warranties or vehicle insurance.
- Installer experience and access to reliable dyno tuning.
Conclusion: A reputable kit paired with professional installation and tuning is critical to achieving the expected horsepower gains while maintaining reliability.
Cost and maintenance considerations
Budgeting for a supercharger upgrade involves more than the price of the kit. Here are the typical budget components to plan for.
- Kit price: commonly around $3,000–$8,000, depending on brand, features (intercooler, fuel system upgrades), and completeness.
- Labor and installation: typically $1,000–$2,500, influenced by vehicle model and whether additional fabrication is required.
- Supporting upgrades: upgraded fuel pump/injectors, potential ethanol-compatible tuning, intercooler upgrades, and exhaust changes.
- Tuning and dyno: about $600–$1,200 for a professional dyno tune and verification.
- Ongoing maintenance and monitoring: more frequent inspections, cooler maintenance, and ensuring consistent octane fuel for optimal performance.
Conclusion: A boost project is an ecosystem investment — the power gains depend on the full package, not just the blower itself.
Summary
For a 5.7 Hemi, a supercharger typically adds roughly 180–250 horsepower at the crank in common street configurations, with potential gains toward 300–450 HP in more aggressive builds that include intercooling, upgraded fueling, and internal hardware. Real-world results depend on boost level, tuning, fuel quality, cooling, and the overall reliability plan. When pursuing these gains, prioritize a reputable kit, professional installation, and a dyno-tuned calibration to maximize power while safeguarding engine health.
