Turbo Paper

As you are making your way home, you come to a gentle stop at a rural stop sign. Suddenly, some deviant young teen pulls up next to you in his shiny sports car. He revs his engine a few times, and then speeds off down the road in a cloud of horrible-smelling rubber smoke. As you slowly continue your trip home, you wonder to yourself. How was this reckless teenager able to accelerate so quickly down the road? You know that your old Buick would never be able to perform like that. There is, of course, an explanation. The teenager had something in his car that greatly improved the engine’s output. This device is known as the turbo.

The turbo was invented in 1905 , first intended to be employed in airplanes to allow them to fly at greater altitudes. It was later developed for large diesel engines, such as in dump trucks and heavy machinery. These types of engines were able to use turbos because they consumed a large amount of air, which drives the turbo, and little fuel. Also, the high cost of such large engines could blanket the cost of the addition of a turbo.

Throughout the 1950’s, turbos were only used in dump trucks and other heavy-duty diesel engines. But, in 1975, Buick developed a 3.8 liter V8 engine that employed the turbocharger (it was actually a V6 - Ed.). The turbo began to gain popularity in Europe and Japan, through companies such as Sweden-based Saab Automobile AG, which has made many pioneering developments with turbos, and is still breaking new ground today. As more companies began using the turbo, more developments were made.

One problem that has plagued the turbo industry is turbo lag. This is a phenomenon seen when one steps on the gas pedal of a turbocharged car. If the car suffers from significant turbo lag, there will be a delay of a few seconds before the full amount of turbo boost begins to power the engine. This can be explained easily by first describing how a turbo works. Before engine exhaust is put through the catalytic convertor and expelled out the tailpipe, it is first passed through a small turbine, like in a jet engine. This is the main portion of the turbocharger. The turbine spins at very high speeds, (up to 180,000 RPM) and in turn powers a compressor that pushes the fuel and air going into the engine, increasing efficiency and power output. For the turbine to begin spinning fast enough, there first must be a certain amount of exhaust coming out of the engine. At idle speeds, the turbo does not spin, and exhaust simply passes through it and out the muffler. When one steps on the gas, the engine begins getting more gas, which prompts it to speed up. However, the turbo was previously inactive, so it has to speed up. This will usually take a few seconds, since the engine has to spin up a little before enough exhaust is being expelled to spin the turbine. As the engine speeds up, now being helped by the turbo, it is able to make the turbo spin even faster, thus creating more boost, making the engine more powerful.

If there were no safety systems, this would keep happening until the turbo was creating so much boost pressure that the compressor itself actually blew up. Of course, engineers didn’t want this to happen, so they created the wastegate. A wastegate is a valve located on the compressor that opens when the turbo reaches high pressure. To prevent an explosion, the pressure is regulated at a safe level by the wastegate, which is essentially a hole in the assembly that lets air out to relieve pressure. If you drive a car which has a turbo, you can identify when the wastegate is activated by a slight decrease in acceleration.

Many things have been developed to tackle turbo lag. Engineers have tried electric motors that keep the turbo spinning at idle speeds so that when gas is applied, the turbo doesn’t need as much time to spin up. They have tried hybrids between turbos and superchargers, which are like turbos, but are belt-driven instead of using exhaust. A hybrid turbo would use a belt attached to the engine to keep it spinning, and then when sufficient exhaust was present to drive the turbo, the belt would spin freely. A lot of these ideas have not had much success. What most automotive companies do is to simply use smaller turbos, sometimes employing two of them. Recently, the use of ceramics in the making of the actual turbine has helped reduce turbo lag by making the whole thing lighter and thus easier to spin up. Some cars that use the twin-turbo concept are the Mitsubishi 3000GT and the Nissan Skyline VSpec.

Everyday use of the turbo is present in some car companies, but not others. In America, car companies tend to avoid the turbocharger, opting instead simply for bigger displacement engines. In the past, this has had a negative effect on fuel consumption, causing some American cars of old to be considered “Gas Guzzlers.” Saab Automobile AG of Sweden prefers to use smaller, turbocharged engines. They employ turbos in many of their cars, and have been doing so since the late ‘70’s. Mitsubishi motors of Japan and America uses turbo technology avidly, in many of its models, chiefly the 3000GT and the eclipse. The 3000GT VR-4 uses a 3.0 liter engine, which, without a turbo, as in the SL and base models, produces about 222 horsepower. With the twin-turbo configuration, like in the VR-4 models, the engine can be modified with a new boost controller and new exhaust assembly to produce over 400hp. The Nissan Skyline, made only in Japan, has been known to be modified to produce over 1000hp, in a relatively small engine, and twin turbos.

Another problem known to exist with turbos is the extreme temperatures. Inside the turbine, exhaust smoke can reach temperatures over 1,800°F. This is sufficiently hot to melt metals such as aluminum. The industry’s remedy for this problem has been the intercooler. A device that acts like a radiator, the intercooler is situated between the turbo and the engine, and cools the compressed air as it passes through it. This has been another one of the ground-breaking developments in turbo technology, because as well as prolonging the life of the turbo, it also can create more horsepower and prevent engine knocking.

As you can see, the turbo has played a major role in automotive technology. It is used under the hoods of some of the fastest cars in the world. It has come a long way since its creation. Although turbos these days have become very advanced, mostly controlled by computers, and very efficient, they still have a long way to go.