Turbo 101

So let's talk about something cool - turbochargers and superchargers. Both are common terms but not usually well understood, and both are considered forced air systems. In essence they work by forcing more air into the engine. Since internal combustion engines - every car except a plug-in electric - work by burning fuel and air together, adding air either creates a fuel-lean environment. This means less of the fuel escapes unburned and the engine is more efficient and powerful. Engine builders use this in two ways - they can use a smaller engine and get better fuel economy or a larger engine and get significantly more power.

The most common type of forced-air system is a turbocharger (above). A turbocharger has two connected fans. Exhaust flows through one fan, forcing both to turn. The other fan compresses fresh clean air into the engine. Since compressing air increases its temperature, an intercooler (basically a second radiator) is used to cool the air before it hits the engine. One issue some turbos have is called lag - the time between the driver pressing the gas and the turbo spooling up to generate boost (compressed air). While modern technology has reduced lag on its own, the best solution is to use two small turbos instead of a single larger one. This is called a compound or twin turbo system.

The second type of forced-air setup is a supercharger. Unlike turbochargers, these use direct engine power from a belt to drive the compressor wheel. The two common types of supercharger are centrifugal (left) and rotary-screw (right). Since they don't rely on the exhaust to drive the compressor, superchargers are virtually lag-free. The trade-off is that the supercharger consumes some of the engine power as a parasitic loss.

So to wrap things up, I think we've safely busted the video-game  myth that you can turn a turbo on or off - those features more accurately represent nitrous (a topic for another day!). While it's obvious that forced-air systems provide a huge advantage, the value they provide was proved when their use was banned by Formula One and later NASCAR. In the drag racing world, however, few if any winning vehicles can be found naturally aspirated (non-forced air). Hopefully this post wasn't more confusing than helpful, but please feel free to leave questions below and they'll be answered as soon as possible. Thanks for reading, and as always, have a good one!

Luke