Whats a Turbocharger? Whats a Supercharger?
Published September 3, 2014
Over the years, automotive engineers have come up with a lot of different technologies in their search for more power from internal combustion engines. Today, two related technologies are commonly used: turbocharging and supercharging. This article will take a look at both of these techniques and their pros and cons.
Engineers know that the speed and power of a car engine is limited by a number of factors. One of them, and a critical one, is the rate and pressure that fresh air can be drawn into the combustion chambers. Standard engines “pull” outside air into their combustion chambers by means of pistons sliding down and sucking the air in. This works fine for standard engines but when higher power is desired, one way of achieving it is to “push” in more air, instead of pulling it. And that’s exactly what turbochargers and superchargers do, they push in more air.
Let’s start with turbochargers. A turbocharger is basically two fans connected together. On one end, it has a fan that is in the exhaust manifold. When the engine is running, hot exhaust gases hit the fan blades and make them spin very rapidly. On the other end is fan that sucks in the outside air and drives it down into the cylinders. Essentially what you have is a dual fan device that takes energy from the exhaust gases and uses it to drive more fresh air into the combustion chambers. Turbochargers have been around for years and work quite well. A potential negative is that it takes a second or so for a turbo to come up to speed when rapid acceleration is needed. This is called “Turbo Lag” and is simply the nature of the technology.
Superchargers are also devices that drive more air into combustion chambers to increase horsepower but they are physically driven by the engine. In otherwords, no exhaust gases are harnessed to drive the induction fan, it is driven by a gear or belt connected directly to the engine’s crankshaft. The advantage of this sort of arrangement is that there is less lag when power is needed, but superchargers tend to be larger than turbochargers so they take up more space under the hood.
It should be noted that turbo and superchargers are not purely performance enhancing devices for racing and sports use. They have been used for decades on the diesel engines that power many trucks, trains and construction equipment. Generally these large engines are supercharged with what is called a “roots blower” which is like a large, spinning screw-type induction fan.
If you are considering buying a vehicle with a turbocharger or supercharger, you can rest assured that you are buying technology that is mature and reliable. Note that besides just for higher horsepower, in many cases today, turbochargers are installed on cars for the purpose of increasing fuel mileage. The way this works is that manufacturers can install somewhat smaller engines in cars when they have turbochargers installed. During ordinary use this leads to thrifty operation yet can pour on the power when needed. The best of both worlds.