Let's get something straight: There's no such thing as a turbo toaster, turbo stapler, or turbo hair dryer. Even though marketers have usurped the term to mean "mega" or "ultra powerful" or "cool," turbo actually means something...and not just to the punk down the street with the Mitsubishi terrorizing the neighborhood by pretending he's in The Fast & The Furious.
A turbocharger is a specific component you'll find on a growing number of modern automobiles. It is not a new invention. The turbo was patented in 1905 and began appearing on trains, aircraft, cars and trucks in the 1920s.
Turbos are still around because they boost engine power. Need a huge-horsepower engine for a sports or luxury car? Add a turbo (or four, as on the 1001-horsepower Bugatti Veyron). Have a small car that can't be fitted with a larger engine but it needs more power? Turbos can be packaged to fit in almost any engine compartment. Any readers remember the 1986 Dodge Omni GLH-S, an economy car with muscle-car-humbling acceleration? The legendary Carroll Shelby added a turbo to the little hatchback's 2.2-liter engine and created a giant killer.
Geek 101: How Turbos Work
A turbocharger can be best understood by looking at its two main components: the turbine and compressor wheels. Each comprises about half of a turbo, and although physically separated, they are connected by an axle so when one turns the other does too.The turbine is spun up to speed (as high as 250,000 revolutions per minute) by exhaust exiting the engine's combustion chamber. The exhaust has some velocity of its own, but most of the energy comes from the expanding, super-hot gasses created during the combustion event. Passages within the turbocharger's housing channel these gasses past the turbine so it spins like pinwheel in a hurricane. Because the turbine is spun by otherwise useless exhaust gasses, engineers think of turbos as delivering “free” power.
Made from special temperature resistant metals (nickel-based alloys) or ceramics, the spinning turbine turns an axle (technically the impeller shaft) connected to the compressor wheel. When the engine is under load -- meaning the driver wants power -- engine electronics direct the turbo to force more air into the intake at higher than ambient pressure. The greater concentration of air (and the combustible oxygen in the air) sets the stage for more explosive combustion.
Turbochargers work in one of harshest environments imaginable. Exhaust temperatures exceed 1800 F. Due to these temperatures and the speeds the assembly spins, absolute precision is required in production and assembly or the turbo won't last long.
Turbochargers and supercharges are both intake compressors, true. But, the compressors in a supercharger are gear- or belt-driven by the engine's crankshaft. Unlike turbochargers that don't sap power from the engine to add power, superchargers do have a parasitic effect that is must be over come by a large factor for the device to be effective. Engineers from General Motor's note that the supercharger on the mighty Chevrolet Corvette ZR1's 6.2-liter engine requires 70 horsepower just to operate the device. This fact matters little given the engine's incredible 638 hp output.
Over the last 100 years the technology has enjoyed spikes of popularity. Engineers turn to turbos when fuel prices increase because the technology endows smaller, more efficient engines with power equal to larger engines that require more fuel.
Following the most recent surge of high-boost status in the 1980s, turbos nearly vanished from mainstream cars. Problems with long-term durability, high replacement costs, overall drivability (turbo lag), and cheap fuel caused the vacuum in popularity. Because of the Obama Administration's recently passed higher fuel economy standards, turbos are making a comeback.
Your next new car or truck could have one under the hood. For example, Ford Motor Company estimates that their turbocharged EcoBoost family of engines -- introduced in four 2010 models -- will be available in 70-percent of their vehicles by 2013. This ended Ford's dry spell of no turbocharged gasoline-fueled vehicles since the 1992 Probe.
What's a Turbo?
In simplest terms, an automotive turbocharger is an intake air-charge compressor that gets driven by an engine's hot and expanding exhaust gasses. Boring! But stick with us for just a little and you'll be the expert on turbos, blowers and huffers at your next cocktail party or BBQ.
Technically speaking, engineers say that engines are nothing but big air pumps. The more air that moves through them, the more power they make. Turbos improve volumetric efficiency: how much air the engine can move into the intake and out through the exhaust pipes. By compressing the engine's intake charge (how much air goes into the combustion chamber), turbos make engines more powerful and significantly more efficient (meaning fuel economy goes up).
Now you get why turbos are so cool.
Trending Toward Turbos
Turbos enable manufacturers to make engines smaller without compromising power. Examples include the optional 1.4-liter turbo in the new 2011 Chevrolet Cruze. It produces 136-horsepower, exactly the same as the 1.8-liter non-turbo engine that is standard, but will give significantly better fuel economy, up to 40 mpg highway in the optimized Cruze Eco model.
Chevrolet's new application adds to the growing number of “forced-induction” engines that include long-term pressure cookers such as the Subaru WRX, MazdaSpeed3, Mitsubishi EVO, and Audi TT. For 2011, Ford is adding the 2.0-liter engine to its lineup of available EcoBoost engines. In the 2011 Explorer, for example, the 2.0-liter EcoBoost delivers more power than the V-6 in the 2010 Explorer and 30-percent better fuel economy.So know you know that turbos are coming, but more importantly, you know that putting a Turbo sticker on a car does not a turbo car make.