Turbocharging - Basics

Growing up, every car that had a turbo was immediately cool. Not only did turbo cars have obscene performance, they emitted a variety of whooshing noises - the sound of speed itself. If you've got a turbo under your bonnet already, or want become a hero at the pub with your knowledge on turbochargers this is the guide for you.

These days anything from a 660cc K-car, to a 1.8 litre diesel to a 800bhp Supra is equipped with a turbo. Even cars that did not come from the factory with a turbocharger are prowling the streets with some Garrett goodness tucked under the bonnet. Turbocharging your car can easily net a 40 percent increase in power as well as swelling the torque figure. That's right Honda owners - you too could have torque!

If you plan to add a turbo to a naturally aspirated car and have you mind set on big power, you'll need big engine mods to go with it. That said, whatever tuning method you choose, doubling the power will require substantial outlay.

So how does a turbo work?

All internal combustion engines work by igniting an air and fuel mixture. Typically more air and more fuel mean a bigger explosion providing more power. The exhaust gases produced by the combustion cycle exit through the manifold (just as with a naturally aspirated engine). With a tuirbo engine however, this gas flows into the turbocharger's turbine inlet. The flow of exhaust gases spin an impeller wheel called the turbine wheel.

The turbine wheel is connected by a shaft to a compressor wheel. The compresser wheel spins at around 180,000rpm, drawing air in at such a speed it becomes compressed. As the air is compressed it becomes very hot so the air then m through an intercooler, an air to air radiator, that cools the compressed air so that it is denser when it enters the combustion chamber.

In short: Adding more air and more fuel means more power. Turbos are great for this.

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