For quite some time, the only way that engine designers knew how to make power was by adding displacement. The bigger the engine, the more power it could make. While this type of design was acceptable in the 50s and 60s, as technology moved on and fuel became more expensive, it became clear that smaller motors could be made to develop healthy power too.



There are plenty of imports out there with 4-cylinder motors in the 2 liter range. If you have one of these engines, then you know that while it might be fun to drive it in the higher rpm range, it does not have a lot of grunt down low, and it tends to run out breath pretty quickly in top gear. You might have seen some sporty-looking compacts zoom by you on the highway and heard a distinctive "pssh pssh" sound when they shifted gears. That is the sound of a turbos blow-off valve. A what?

A turbocharger is a device that crams more air into your engine by compressing it as much as possible. A quick lesson on how engines make power: they take air and fuel, combine them together, and then ignite that mixture to create an explosion that turns your cars crankshaft. This generates horsepower. Now, if you can figure out a way to get more oxygen into that mixture before the spark plug fires, then you can add an extra amount of gasoline and create an even more powerful explosion. Thats what a turbocharger does, through compressing air so that it contains more oxygen per cubic foot than the air around us in the atmosphere.

In order to do all of this compressing, a turbo has to spin pretty fast actually, really fast. Most turbos spin above 20,000 rpm, and this allows the blades inside the device to compress air incredibly quickly. Turbochargers are really efficient devices, as they are driven by the exhaust gases of the engine itself. These gases exit the engine at great speed, and this speed is translated into the high rpms of the turbo itself.

However, this design is also the source of one of a turbochargers greatest downsides turbo lag. Since an engine running at a low speed does not produce a significant amount of exhaust, when you mash the gas, it takes a little while for the turbo to spin up to maximum power. The time it takes between the pedal being depressed and full power being available is known as lag. This can be a frustrating experience when running the stoplight grand prix, as some turbo cars are a bit slower off the line than their more torquey opponents. Once that turbo kicks in, though, all is forgiven.

A turbo can be a great way to add some real punch to your imports engine, but its important that you take the time to install everything properly, and make sure that your fuel delivery system is up to the demands of all that extra air rushing in. Turbochargers add extra pressure to many engine components, and its far better set things up well at the beginning than it is to have to call a tow truck to take your baby back to the garage.