The term and name turbo is synonymous with going faster. Some of you might remember old PC systems with a “Turbo” button that can increase its clock speeds. However, the turbo in such computer systems is nothing like the turbo used in automobiles. For one, you cannot just push a button to activate the turbo, and the performance boost that a turbo provides does not come instantaneously. To understand why, it is necessary to look at how a turbo setup is like and how it works.
Simply put, a turbo is really just a device that has a turbine that is spun by exhaust gases. Since this turbine is connected
to the compressor, as the turbine spins, so does the compressor, which forces more and more air into the intake of the engine. The turbine in a turbo can spin as high as 150,000rpm. And because they are driven by exhaust gases which would have otherwise been wasted, turbos are commonly said to increase an engine’s efficiency.
However, because a turbo is driven by exhaust gases and spins so fast, it also generates a lot of heat. Heat decreases the density of the charged air and reduces the potential performance gains that can be had. To rectify this, a turbo setup also includes something called an intercooler. An intercooler can be thought of as a radiator that helps cool down the mass of charged and compressed air that is entering the engine.
Another downside to the turbo is lag or more commonly known as “turbo lag”. Remember that the turbo is driven by exhaust gases? For a turbo to start being useful, the engine first needs to get up to speed to generate enough exhaust gases to spin the turbo, only then can it effectively generate “boost” and force air into the engine. This is always why the power and torque graphs of a turbocharged car often have a very steep and sudden increase.
The time that it takes for the turbo to spin and generate optimal boost is therefore referred to as “turbo lag” and this is generally undesirable especially for track driving as it makes the car somewhat unpredictable, especially when cornering. On the other hand, turbo lag makes driving turbo cars exciting, which is very true for cars with huge turbos since drivers often wait in anticipation for the boost to kick in; the car then experiences a dramatic surge in power and torque.