A supercharged car uses a belt-driven air pump to force more air into the engine than it could pull in on its own. More air means more fuel can be burned per cycle, which means more power. Most supercharger systems add 30 to 50 percent more horsepower over the engine’s stock output, translating to roughly 50 to 100 additional horsepower depending on the setup.
How a Supercharger Works
Every engine is essentially an air pump. It sucks in air, mixes it with fuel, ignites the mixture, and pushes out exhaust. A naturally aspirated engine can only pull in as much air as atmospheric pressure allows. A supercharger changes that equation by compressing air before it enters the engine, cramming in a denser charge than the engine could inhale on its own.
The key detail is how it gets its power: a supercharger is mechanically connected to the engine’s crankshaft, usually by a belt. When the engine spins, the supercharger spins. This direct connection is what gives supercharged cars their signature feel: instant throttle response with no delay. Press the gas and the power increase is immediate, rising in direct proportion to how far you push the pedal.
That mechanical connection is also the supercharger’s biggest trade-off. Because it takes engine power to compress the air, the supercharger creates what engineers call parasitic drag. The engine has to spend some of its own energy driving the compressor. This is why supercharged cars tend to use more fuel, and why superchargers pair best with larger engines that can absorb that extra load without feeling strained.
Three Types of Superchargers
Not all superchargers work the same way. The three main designs each deliver power differently, and the type determines how the car feels to drive.
Roots Type
The oldest and most recognizable design. A Roots supercharger sits on top of the engine and uses a pair of spinning rotors to push a high volume of air downward into the intake manifold. It doesn’t actually compress the air inside the unit itself. Instead, it acts more like an air pump, shoving air into the engine where it gets compressed in the cylinders. This design delivers strong low-end torque almost instantly, which is why it’s popular in drag racing and trucks that need pulling power for towing. The downside is heat: sitting directly on top of the engine, Roots blowers are prone to heat soaking, and the hot compressed air they produce often needs a cooler to maintain performance. They’re also heavy and can create hood clearance problems.
Twin-Screw
Twin-screw superchargers look similar to Roots units and also mount on top of the engine, but they work differently inside. Two interlocking helical rotors actually compress the air within the supercharger housing before it enters the engine. This makes them more thermally efficient than Roots blowers while still providing strong immediate boost. They’re a common choice for factory supercharged performance cars, including the Cadillac CT5-V Blackwing and its 668-horsepower V8.
Centrifugal
These look and operate much like a turbocharger, using a high-speed impeller inside a rounded shell to compress air. But instead of being powered by exhaust gases, the impeller is driven by a belt or gear from the crankshaft. Centrifugal superchargers are compact, mount to the side or front of the engine rather than on top, and generate less heat because they’re not in direct contact with the engine block. The trade-off is that they compress more air the faster they spin, so they don’t provide much boost at low RPM. Power delivery builds progressively with engine speed, making them feel closer to a turbocharged car than a Roots-blown one. For everyday driving, they offer a smooth, all-around power improvement with the biggest gains at higher revs.
Supercharger vs. Turbocharger
Both superchargers and turbochargers force extra air into the engine, but they get their energy from different sources. A turbocharger captures exhaust gas that would otherwise exit the tailpipe and uses it to spin a turbine that compresses incoming air. Since it runs on waste energy rather than stealing power directly from the crankshaft, a turbocharger is more efficient. This is why automakers leaned heavily into turbocharging for fuel economy: a small turbocharged engine can cruise efficiently at low loads and deliver big-engine power only when you ask for it.
The most obvious difference from the driver’s seat is response time. Turbochargers need a moment to “spool up” after you press the gas because it takes time for exhaust heat and pressure to build. That brief hesitation is called turbo lag. A supercharger has zero lag. Its power boost arrives the instant you touch the throttle because the compressor is always spinning with the engine.
Fuel economy tilts clearly in the turbocharger’s favor. A supercharger adds load to the engine all the time, which typically shows up as lower MPG. Turbochargers are today’s default solution when automakers want more power without sacrificing gas mileage, which is why turbocharged cars vastly outnumber supercharged ones on dealer lots.
Why Compressed Air Gets Hot
Compressing air heats it up significantly. In one dyno test of a twin-screw supercharger on a Mustang, air entering the supercharger at about 29°C (84°F) exited at roughly 198°C (388°F) before any cooling. That’s hot enough to reduce the density of the air charge and hurt performance, which is the opposite of the goal.
This is why nearly all modern supercharger systems include an intercooler. The intercooler sits between the supercharger and the engine, passing compressed air over a heat exchanger (cooled by either outside air or a separate water circuit) to bring temperatures back down. In that same Mustang test, intercooling dropped the air temperature from 198°C down to about 66°C (151°F) before it reached the cylinders. That’s a massive reduction, and it’s essential for making reliable, consistent power. Higher boost levels generate more heat, so intercooler performance becomes even more critical on high-output builds.
Factory Supercharged Cars Today
Supercharged cars from the factory have become rare. Among passenger cars currently sold in the United States, only a handful still use the technology. The Cadillac CT5-V Blackwing pairs a 6.2-liter V8 with a traditional supercharger to produce 668 horsepower and 659 pound-feet of torque. The Genesis G90 and Volvo S90 take a different approach, using electric superchargers (small electrically driven compressors) paired with turbochargers to eliminate lag while keeping efficiency high.
The broader trend is clear: turbocharging and electrification have taken over. Superchargers remain more common in trucks, SUVs, and specialty performance vehicles, but even there the numbers are shrinking. For most buyers, the supercharger is something they’ll encounter in the aftermarket rather than on a window sticker.
Aftermarket Supercharger Costs
Adding a supercharger to a car that didn’t come with one is a serious investment. Aftermarket supercharger kits typically range from $6,000 to $20,000 for the hardware alone, depending on the vehicle and the brand. Installation adds another $1,000 to $4,000 in labor, and most builds also require professional engine tuning and supporting modifications like upgraded fuel injectors or a better cooling system.
For a rough sense of pricing: a kit for a BMW M3 or M4 runs about $6,000 to $8,000 plus $1,000 to $1,500 for installation. A Porsche 911 kit lands between $8,000 and $12,000 with $1,000 to $2,000 in labor. Exotic car kits from brands like Novitec or Hennessey can push past $20,000 before anyone turns a wrench. These aren’t weekend projects for most people. A quality installation involves ensuring the engine management system is retuned to handle the extra air and fuel, and that cooling, exhaust, and drivetrain components can handle the added stress. Done properly, a supercharger kit can transform a car’s character. Done cheaply, it can shorten an engine’s life dramatically.