Mo-Pwr! | MorePower!

TECHNICAL

Under the Hood: How Turbos work and why they matter

By: Gearhead George

This is a focused technical examination of the turbo: its applications, mechanical design, evolution through generations / various forms and its overall pros and cons.

"A turbo is like a vacuum cleaner for exhaust gases, but instead of sucking up dirt, it uses the energy from those gases to force more air into the engine. More air means more fuel, which means more power!"

Maybe a ToC here?

Architecture and layout

All naturally aspirated engines reach a point where they cannot produce more power. No. It is not because the fuel has reached its limit, it is because it lacks air. An engine is essentially an air pump. It takes in air, mixes it with fuel, ignites the mixture and expels the exhaust gases. To produce more power, you add more fuel, but to burn more fuel, you need more air. Thus the more air you can get into the engine the more fuel you can burn and the more power you can produce. Here comes forced induction to the rescue. If you cannot move fast enough to suck in more air, you can pump it in. This is what a turbo does.

Design

This is a turbo

Lots of text explaining how it actually works here

Pros

Air: Lots of air

Low cost: No belt power driven supercharger or weird battery powered motors needed

Great variety: many different varitations exist, there is always a turbo setup suited for your exact problem

Cons

Yes, the unfortunately they have cons too:

Turbo lag: Turbos work in specific RPM ranges. Outside of that they do nothing and when entering the range the added power can make the engine feel .. ehm .. Temperamental
Lubrication: Without proper oil they break. So they are a complication for engine design
Space: they take up space. Nothing huge, but still if you are packing a tight package they might be difficult to fit

What kinds of turbos exist

Short answer: 1 - the awesome one

Long answer: Several

Single: The snail as we know it
Sequential: One attached to another
Twin: More is more

There are many more varitations, but these are the main ones. Each of them can again be applied in various forms e.g. the size of the turbo, targeted RPM range, the addition of electric assist motors and so on.

Alternatives

Well there is the option of going back to naturally aspirated or going with a supercharger. Both of these have their pros and cons as well.

The Turbo