Turbo engines explained.

Dear Car Talk

Dear Car Talk | Dec 01, 1993

Dear Tom and Ray:

You guys are really funny! I enjoy your column. Can you explain to me how a turbo engine works?

RAY: Sure, Andy. Here's the basic idea: An engine needs air in order to run. And on a normal engine, air just flows in as it's needed. But if you could FORCE extra air into the engine, then you could increase the engine's power. And that's exactly what a turbo does.

TOM: A turbo-charged car engine uses two turbines, like you'd see in a jet engine. And those two turbines are connected to each other.

RAY: One of the turbines is driven by the exhaust gas, which comes out of the cylinders at very high pressure. That exhaust pressure gets the turbine spinning at thousands and thousands of revolutions per minute (that's even faster than my brother moves when he sees an un-spoken-for cheese danish!).

TOM: And the first turbine turns the second turbine, which sucks fresh air into the engine, and forces it--at very high pressure--into the combustion chambers. The result of that extra air is more powerful explosions in the cylinders, and therefore, more power for the car.

RAY: So that's how the turbo operates for approximately the first 75,000 miles. After that, the owner of the car goes to the dealer, hands him $1,000, and the turbo works that way again for the next 75,000 miles.

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