Should you have a car that adds forced induction through a turbocharger or a supercharger? This is becoming more of a common question in the automotive industry.
In the past, more power for an engine came from larger displacement and more cylinders. Despite this antiquated but proven method of producing more power, most automakers are looking for other ways to provide drivers with more power, and in some cases, better efficiency. When talking about real-world performance, you could look to horsepower, torque, speed figures, and efficiency as reasons to choose either a turbocharger or supercharger when you want more out of your engine.
How do these systems add more power?
In order to produce more power in an internal combustion engine, more of some thing needs to be present in the combustion chamber. The most effective way of producing more power is to add more air into the system. Fuel requires air to combust, which means the maximum power of any engine depends on how much air is present when burning fuel.
The desire to force more air into the chamber led automakers to figure out how to force air into the system. When either forced-induction system is present, more air is fed into the chamber, which allows the engine to burn more fuel and produce more power. Turbochargers and superchargers both compress air, forcing more into the system, but they do so in extremely different ways.
What’s the difference between a turbocharger and a supercharger?
Turbochargers use exhaust gases to spin the turbine that drives a compressor. This compressor sends more air back into the engine to increase power output. This means a turbocharger requires exhaust gases to move at a specified rate to spin the turbine and begin sending air back into the system. If you’ve ever heard of the dreaded “turbo lag,” that’s the time it takes for the exhaust gases to build up enough pressure to get the turbo going.
Superchargers also have compressors that spin and send air back into the engine, but the pump is driven by the engine via a belt that runs off the crankshaft or an electric motor. This means a supercharger doesn’t require air to help it create more airflow to the engine, it uses the engine power. When engines rev at higher rpms, superchargers send more power into the system immediately, Engines that use superchargers don’t suffer from “turbo lag.”
Pros and Cons of Turbochargers
Pros
- Significant increase in horsepower
- Power allows for smaller engines to produce much more power relative to their size
- Better fuel economy
- Higher efficiency – turbochargers run off energy that is typically lost in naturally aspirated and supercharged engines. The recovery of this energy improves the overall efficiency of the engine.
Cons
- Turbo lag – turbochargers, especially large turbochargers, take time to spool up and provide boost
- Boost threshold – for traditional turbochargers, they are often sized for a certain RPM range where the exhaust gas flow is adequate to provide additional boost for the engine
- Power surge – in some turbocharger applications, especially with larger turbos, reaching the boost threshold can provide an almost instantaneous surge in power, which could compromise tire traction or cause some instability of the car
- Oil requirement – turbochargers get very hot and often tap into the engine’s oil supply. This calls for additional plumbing and is more demanding on the engine oil
Pros and Cons of Superchargers
Pros
- Increased horsepower – adding a supercharger to any engine is a quick solution to boosting power
- A supercharger’s biggest advantage over a turbocharger is that it does not have any lag. Power delivery is immediate because the supercharger is driven by the engine
- Boosted power at low RPM
Cons
- Less efficient than turbochargers – the biggest disadvantage of superchargers is that they suck engine power simply to produce engine power. They’re run off an engine belt connected to the crankshaft, so you’re essentially powering an air pump with another air pump. Because of this, superchargers are significantly less efficient than turbochargers.
- Reliability – with all forced induction systems (including turbochargers), the engine internals will be exposed to higher pressures and temperatures, which will, of course, affect the longevity of the engine. It’s best to build the engine from the bottom up to handle these pressures, rather than relying on stock internals
Should you have a turbocharger or supercharger under your hood?
If you want maximum power and speed, with no regard for fuel efficiency, a supercharged engine is the best choice for you. This system gives you the biggest boost using forced induction. On the other hand, if efficiency is a factor, you’ll want to choose a turbocharged engine to give you real-world performance and the added benefit of improved fuel economy.
