How much hp does a supercharger usually add?
On most modern engines, a bolt-on supercharger typically adds about 50 to 150 horsepower at the crank. Smaller four-cylinder setups tend to land on the lower end of this range, while larger V8 applications with higher boost and proper tuning can approach or exceed the higher end—though real-world gains depend on boost, fueling, intercooling, and the overall build.
What a supercharger does
A supercharger compresses intake air so more oxygen can be packed into each combustion chamber. With more air paired with additional fuel, the engine makes more power. The exact horsepower gain depends on the engine’s size, the blower type, the amount of boost, how well the system is cooled, and how the engine is tuned.
Blower types and how they differ
There are three main configurations used in street and performance applications. The following list outlines the common options:
- Roots blower (positive-displacement)
- Twin-screw (positive-displacement)
- Centrifugal (dynamic)
These configurations influence when the boost comes in, how much boost is needed for a given power target, and how efficiently the system runs under different RPMs. The right choice depends on the driving character you want and the engine’s build.
Roots blower
Roots blowers deliver immediate boost from low RPM and are known for strong mid-range torque. They tend to run hotter and can be less efficient at high boost, but they respond quickly and are popular for street-driven setups. Typical gains on a small 2.0–2.5 L engine might run in the 40–90 hp range, while a well-tuned larger V8 kit at moderate boost often lands roughly in the 100–150 hp range.
Twin-screw
Twin-screw superchargers are similar to Roots in that they provide positive displacement, but they seal more tightly and generally run with better efficiency and cooler intake air. This can yield more consistent boost and slightly higher effective gains for the same boost level. Expect roughly similar ranges to Roots for many street applications, with some kits pushing into the 100–180 hp territory on larger engines when paired with strong supporting upgrades.
Centrifugal
Centrifugal superchargers use an impeller that boosts air pressure progressively with RPM, meaning most of the boost arrives at higher engine speeds. They often require less parasitic loss at idle and can scale to very high horsepower targets with bigger pulleys, boost, and intercooling. Real-world gains vary widely, typically around 60–120 hp on small to mid-size engines at moderate boost, and 150–200+ hp on larger V8s with high boost and robust fueling/tuning.
How much HP by engine size and boost level
To give a practical sense of what’s achievable, here are broad expectations based on common street setups. Note that actual results depend on the complete package, including fuel system, intercooling, exhaust, ignition timing, and engine internals.
- Small four-cylinders (roughly 2.0–2.5 L): typically 40–90 hp gain with a properly matched Roots or centrifugal kit.
- Inline-six/mid-size engines (roughly 3.0–3.5 L): commonly 70–150 hp gain, depending on boost and tuning.
- Big V8s (roughly 5.0–6.2 L): often 100–180+ hp gain when paired with appropriate fuel, cooling, and a tuned calibration; some high-boost applications exceed this range.
These figures assume a street-oriented setup with reliable intercooling, adequate fuel supply, and a professional dyno tune. Gains can be smaller if boost is limited to protect the engine or if supporting systems aren’t upgraded.
What else affects the horsepower gain
Several factors can swing the actual horsepower numbers up or down. Boost pressure, air-to-fuel ratio, intercooling efficiency, engine compression, cam timing, exhaust flow, and the quality of the tune all play crucial roles. More air and fuel must be matched with stronger cooling and robust fueling; otherwise, the engine may detonate or run lean, which can limit gains or cause damage.
Bottom line
For most buyers, a supercharger is a straightforward way to substantially increase power, with typical gains ranging from about 50 to 150 horsepower at the crank, depending on engine size and blower type. Larger engines and higher boost levels can push gains toward 200 hp or more, but achieving that requires careful engineering, supporting upgrades, and a professional tune. The intended driving style—instant torque at low RPMs versus high-end peak power—will also influence the best choice of blower configuration.
Summary
In short, a supercharger usually adds tens to hundreds of horsepower, with a broad spectrum driven by engine displacement, blower type, boost, and tuning. Roots and twin-screw blowers deliver immediate, broad torque with modest to strong gains, while centrifugal units offer scalable power that climbs with RPM. For reliable results, plan a complete upgrade package including fuel delivery, cooling, exhaust, and a dyno tune, aligned with your performance goals.
