If you're at all interested in the performance of your engine, you've likely heard the phrase "turbocharged" before. Nearly every model on the market offers a choice between turbo and non-turbo engines, yet some drivers might assume that this is simply marketing speak. In reality a turbocharged engine has a significant change compared to a regular one, and it's important that drivers understand the advantages and disadvantages.
The best way to understand engine powers is to first learn the basics. Essentially, engines need both air and fuel to function. The way that engines achieve more power is by fitting more air and fuel into the engine. Typically, this is done through adding larger cylinders, or more cylinders. This is why a V8 outperforms a V6 - it can handle more fuel, so it results in more energy.
However, automakers can't simply just make engines larger, as this adds significant weight to a vehicle, which kills fuel economy and also means that the car requires more power to run properly. This is why nearly all SUVs and pickup trucks come with V6s or V8s.
The theory behind a turbocharger is simply to compress the air that goes into an engine. The thinking is that by packing the same amount of air into a smaller amount of space, more fuel can be added and drivers can get more power. Normal atmospheric pressure is 14.7 pounds per square inch (psi), and a turbocharger adds around 7 psi. It's not completely efficient, so that means that drivers tend to see a 30 to 40 percent increase in power with a turbocharged engine.
A turbocharger comes with some disadvantages as well. The prefix "turbo" comes from turbine, which is essentially what's used to compress the air. The turbine spins in the charger in order to work. However, this essentially adds an extra step to the process. When the driver presses the gas in a non-turbocharged car, they add fuel and feel the boost immediately. But turbocharged cars suffer from "turbo lag," which is what refers to the time of the turbine powering up.
This means the driver will step on the gas, but the car won't go considerably faster until the turbine gets up to speed, then rocketing the car forward. It takes some getting used to for drivers of non-turbo cars, and may result in a jerkiness that some drivers don't like. There are a few ways to combat this as well, but it starts to get expensive. Smaller turbochargers have less turbo lag at lower speeds, and its also possible to use things like ceramic turbine blades to reduce the feeling considerably.
Another side effect of installing a turbocharger is something called "knocking." When air is compressed, the temperature rises. This means that it's possible for the air to ignite the fuel before the spark plug actually fires, which is bad for the engine and the performance. Most cars with turbochargers require a higher octane fuel to prevent this, which is another cost for the driver to shoulder.
Turbo lag and knocking are less of an issue for drivers who are buying a car designed to have a turbocharger, such as from the manufacturer. However, it's something that drivers who are considering adding a turbocharger to their current vehicle need to consider. Essentially, moderation is the key here - if drivers go with a turbocharger that brings "too much boost" to the car, then it can create serious problems for the engine. It's also likely that the fuel injection system will need to be recalibrated to take advantage of an aftermarket turbocharger.