What is the difference between a supercharger and a turbocharger in a vehicle’s engine?


Turbocharged engines seem to be much more popular in recent years, especially on smaller engines. How does a turbocharger “turbo”, and what is a supercharger?

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Turbochargers use exhaust gasses to spin the compressor, superchargers use a belt run off of the engine to spin the compressor. Both use a compressor to increase the density of the air being sent to the engine which in simple terms, creates more powah.

A turbocharger is a fan powered by engine exhaust that compresses extra air into an engine intake. A super charger is not powered by exhaust, but by the engine itself or even electrically powered. Turbochargers have an inherent lag while superchargers are a bit faster. Turbochargers are more fuel efficient, while superchargers are faster with generally higher performance.

Both devices compress the air going into the engine which makes it more explosive. A turbocharger uses the engine’s exhaust gasses to drive the rotation of the impeller and a super charger uses a belt driven by the engine’s crankshaft.

Turbochargers use the exhaust gas to spin a high-speed turbine, which compressed air before it enters the combustion chambers. Superchargers do the same thing but are powered directly from the engine. Superchargers therefore give the benefit of compressing the incoming air whenever the engine is turning; turbochargers lag behind a little as they need a reasonable flow of exhaust gas to start working.

A turbo charger is an impeller which takes cold air and “packs” it into your air intake, increasing the air pressure in your cylinders. More air = more kaboom = more vroom. The turbo’s impeller is driven by exhaust gas in a feedback loop, so there’s a little bit of a lag behind when you step on the gas and when the turbo kicks in, because the cylinders have to exhaust the increased output to drive the turbo to boost the air intake to drive more cylinder combustion.

A super charger does the same thing: packs more air into your combustion cylinders – but its not driven by exhaust gasses, its driven by the same rotating mechanical bits that the pistons in your cylinders drive. The feedback is more immediate, there’s no turbo “lag”, but it comes with a more severe parasitic drain on your engine’s output. Say 10%. But its giving your engine a 20% boost, so you have net 10% more power coming out of your engine.

Meanwhile turbo penalties are less, like 5% but they maybe don’t contribute as much performance gain maybe only 10-15% percent, so you’re net 5-10% performance boost overall.

There are pros and cons for each, and you can even use a turbo and a super charger together.

Both devices are designed to increase power and performance of an engine by increasing the air that enters said engine’s combustion chamber and the main difference between the two is how they’re driven:

-a supercharger is engine-driven, meaning that it operates by way of a belt or chain on the engine that drives the supercharger to increase airflow.

-a turbocharger is exhaust-driven, meaning that it’s driven by the exhaust gasses exiting the engine to inject pressurized air into the engine.

Turbochargers and Superchargers both exist to increase the pressure of the charge, i.e. the gulp of air a cylinder takes which fuel is combined with to burn. They’re both air compressors that compress the intake air to the engine.

The more air, the more fuel can be burned, the more powerful the resultant explosion, and the more power the engine makes.

The difference between the two his how this compressor is powered. With a supercharger it’s powered by a belt directly off the engine. With a turbocharger it’s powered from a turbine that sits in the exhaust gas flow.

All engines ultimately boil down to the fire triangle that most of us learned about in school. The three points are air, fuel and an ignition source.

In a car that’s air, gas, and a spark. If you want an engine to make more power you can increase the air (and the fuel) and it will make a bigger bang.

Both Turbos and superchargers increase the air that gets taken into the engine, they just do so in different ways.

Turbos and superchargers are really both fans. Those fans suck in air and push the air into the engine, this is known as boost. It means more air gets into the cylinder and when combined with extra fuel it makes the car have more power.

Now, in order for a fan to suck air into an engine, the fan needs to be spinning. In order for the fan to spin it needs to get that that power from somewhere. You could use electricity but that’s actually pretty inefficient on an internal combustion engine.

So other than an electric fan, there’s 2 main methods. There’s a power take off, meaning the engine itself spins the fan. This is the same system that runs the coolant pump, AC, or car electrical system. The engine has a belt, and in addition to making the wheels turn the engine makes the belt go around (using a pully). Then a bunch of accessories attach to that belt and the belt powers them all. In most cars this belt is right at the front of the engine and can be easily seen if you look down in the front of the engine compartment.

A supercharger is a device that also runs off that belt. Basically this is the engine powering it’s own fan and generating even more power. This has plusses and minuses, mainly it’s easier to add big power this way but it’s not super efficient. It’s like taking away 10 units of power in order to add 20 units. It’s a net gain of 10 but the engine is burning more than 10 units of fuel in order to get there.

Turbo chargers are a little more smart. A turbo uses the engine’s own exhaust to make the fan spin. Think of a water wheel on a river. The river is the exhaust being pushed out of the car, the turbo is the water wheel. the exhaust is going to be moving out of the engine with or without the turbo, so the turbo just takes some of that energy and uses it to spin the fans. Therefore there’s no extra load on the engine.

The problem with turbos is heat. Exhaust gases are REALLY hot when they leave the engine. That heat is bad for everything, but mostly it’s bad for anything that has moving parts. Like a turbo. So a turbo has a lot of stress on it because it’s dealing with super hot engine exhaust. So while turbos are more efficient than superchargers, they are less reliable because of all the problems that heat causes.

So both methods make the car go faster by adding extra air into the combustion. They just do so differently and both have their advantages and disadvantages. It’s more common to see a turbo in a car than it is to see a supercharger but that’s more about meeting fuel efficiency standards than it is about turbos being inherently better or worse.