The Science Behind Supercharged and Turbocharged Engines
The high-performance category instantly conjures the excitement and thrill of the racetrack. Growling motors whizz around tight turns, fans jump to their feet, jumpsuit-clad racers pose atop the winner’s podium post-race.
And when it comes to discussing engines under the hood of race-ready models, there’s two terms that tumble around the high-performance realm pretty freely: supercharged and turbocharged.
You may be wondering how these two engine exemplifiers work and which one is faster.You’re about to find out! Let’s take a closer look at the science behind supercharged and turbocharged engines.
An Introduction to Forced Induction
Both superchargers and turbochargers are considered types of forced induction systems. Forced induction refers to the way in which air that flows into the engine is compressed upon entry. When air takes up less space within the motor, there’s room for more air to come into each cylinder and more fuel to be added to the mixture. This is what produces greater power in each tiny explosion.
But the way that each engine setup goes about forced induction is where things start to differ.
Superchargers Charge from Within
Superchargers make forced induction happen through a belt that’s rigged up directly to the engine’s crankshaft. When the engine starts its cycle, the supercharger’s belt activates a pulley that’s connected to a drive gear that triggers a compressor gear. And voila! This speedy chain reaction achieves superpacked engine air in an instant.
The Turbocharged Approach
Turbochargers, on the other hand, don’t exactly rely on an internal component to activate elevated air compression within the engine. In turbocharged models, the vehicle’s exhaust gases create pressure that spins a turbine that activates an air pump that feeds extra air (and fuel) into the engine for more power. Because the exhaust gasses take a little bit of time to build up, there can be a gap between when turbo power kicks in.
Pros and Cons: Superchargers vs. Turbochargers
Superchargers and turbochargers each offer significant increases in horsepower, but how do they fair in other areas?
Efficiency: Turbo wins. By using a by-product of engine operation (exhaust) that would otherwise go unused, turbochargers can boost both speed and efficiency. Superchargers actually impact efficiency in the opposite way. Because they’re entangled in the engine’s internal functions, superchargers rely on engine power to boost engine power, which brings down overall efficiency.
Power Delivery: Superchargers win. Activated by the engine’s crankshaft, superchargers can deliver an instantaneous power boost without the lag time that turbochargers often require in order to provide a noticeable lift.
What’s the Tradeoff?
Superchargers may be better for certain applications, while turbochargers are more readily used for others. In instances where you can’t spare lag time, superchargers are the popular pick. But when efficiency is a priority, it’s more likely that you’ll find a turbocharger under the hood working its magic.
There’s no wrong or right system, and high-performance techs and researchers are working to improve the limitations of superchargers and turbochargers every day. Students enrolled in ATC’s Hi-Performance and Automotive Technology program learn the ins and outs of supercharged and turbocharged engines working with exciting modern vehicle technology that’s alive and well on today’s international raceways.
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