BlackBob
06-27-2002, 03:22 PM
Turbo Basics
In Plain And Simple English
Don't you hate tech articles that confuse you more than help you understand the true concepts of things? Tell me if this sounds familiar: You see a tech article in a magazine. You're interested in learning about that topic. But before you're halfway through it, you get frustrated and move on to something else. It's as though the tech article is too technical. All the high-tech mumbo jumbo (which can be surprisingly inaccurate) doesn't help much, either. Well, here's my crack at turbo basics, in plain and simple English, for the everyday racer who is far from being an engineering graduate and a turbo techno guru.
Why Do People Turbocharge Their Cars?
Why do people drive well over 100 mph when a sign says the limit is 65? It’s simply for the thrill and the rush, for the love of speed and power, power that’s always there at the tip of your toes twenty-four hours a day, seven days a week. Turbocharging your car can easily net a 50 percent increase in horsepower--if not more.
I've seen Honda Civic coupes (that have 125 hp stock) double their horsepower output by turbocharging. But be forewarned that any plan to increase horsepower more than 50 percent of the stock power will need some bottom-end buildup and engine-management controls.
If you're planning to turbocharge your car, here's some advice: Take your time; do your homework; ask lots of questions (of qualified people); and do it the right way the first time around. Believe me, there's nothing like the power of a turbo, and the fun factor and driveability are beyond awesome.
How Does It Work?
Here’s a bare-bones rundown of how a turbocharger system works. The engine produces exhaust gases that exit via the exhaust ports of the cylinder head. These exhaust gases flow through the turbo manifold (just as they would through a header) into the turbocharger’s turbine inlet. As the exhaust gases enter the turbine housing, the movement of the gases begins to spool (spin) an impeller wheel called the turbine wheel.
As the turbine wheel begins to spin, it turns and drives a common shaft that's connected to another propeller-type wheel at the other end called the compressor wheel. As the compressor wheel begins to spool, the compressor stage of the turbo begins to draw in air. And as the compressor wheel spools faster and faster, the air becomes compressed and charged (it's like having a hair dryer in your engine bay). The faster the turbine and compressor wheels spin, the faster the shaft turns--thus the greater the pressure.
From the compressor stage of the turbine, the charged air exits at great velocity and makes its way to the intercooler. The intercooler is a huge heat exchanger (like a radiator, but for air) that cools the charged air. From the intercooler, the air travels through the throttle body and back into the motor. As more air is force-fed into the motor, an additional amount of fuel must be added. The amount of fuel must be proportional to the amount of air supplied to the motor.
Bottom line: Adding more air and more fuel means more power.
Turbo Boost!
A turbocharged engine revolves around one central idea, and that is boost. Boost is defined as the increase in manifold pressure above atmospheric pressure. So what the hell does that mean?
Basically, boost is a gauge of the amount of charged air pressure produced by the turbocharger. As boost increases, more charged air is being force-fed into the motor and more horsepower is being made. Boost levels are usually measured in pounds per square inch (psi).
In Plain And Simple English
Don't you hate tech articles that confuse you more than help you understand the true concepts of things? Tell me if this sounds familiar: You see a tech article in a magazine. You're interested in learning about that topic. But before you're halfway through it, you get frustrated and move on to something else. It's as though the tech article is too technical. All the high-tech mumbo jumbo (which can be surprisingly inaccurate) doesn't help much, either. Well, here's my crack at turbo basics, in plain and simple English, for the everyday racer who is far from being an engineering graduate and a turbo techno guru.
Why Do People Turbocharge Their Cars?
Why do people drive well over 100 mph when a sign says the limit is 65? It’s simply for the thrill and the rush, for the love of speed and power, power that’s always there at the tip of your toes twenty-four hours a day, seven days a week. Turbocharging your car can easily net a 50 percent increase in horsepower--if not more.
I've seen Honda Civic coupes (that have 125 hp stock) double their horsepower output by turbocharging. But be forewarned that any plan to increase horsepower more than 50 percent of the stock power will need some bottom-end buildup and engine-management controls.
If you're planning to turbocharge your car, here's some advice: Take your time; do your homework; ask lots of questions (of qualified people); and do it the right way the first time around. Believe me, there's nothing like the power of a turbo, and the fun factor and driveability are beyond awesome.
How Does It Work?
Here’s a bare-bones rundown of how a turbocharger system works. The engine produces exhaust gases that exit via the exhaust ports of the cylinder head. These exhaust gases flow through the turbo manifold (just as they would through a header) into the turbocharger’s turbine inlet. As the exhaust gases enter the turbine housing, the movement of the gases begins to spool (spin) an impeller wheel called the turbine wheel.
As the turbine wheel begins to spin, it turns and drives a common shaft that's connected to another propeller-type wheel at the other end called the compressor wheel. As the compressor wheel begins to spool, the compressor stage of the turbo begins to draw in air. And as the compressor wheel spools faster and faster, the air becomes compressed and charged (it's like having a hair dryer in your engine bay). The faster the turbine and compressor wheels spin, the faster the shaft turns--thus the greater the pressure.
From the compressor stage of the turbine, the charged air exits at great velocity and makes its way to the intercooler. The intercooler is a huge heat exchanger (like a radiator, but for air) that cools the charged air. From the intercooler, the air travels through the throttle body and back into the motor. As more air is force-fed into the motor, an additional amount of fuel must be added. The amount of fuel must be proportional to the amount of air supplied to the motor.
Bottom line: Adding more air and more fuel means more power.
Turbo Boost!
A turbocharged engine revolves around one central idea, and that is boost. Boost is defined as the increase in manifold pressure above atmospheric pressure. So what the hell does that mean?
Basically, boost is a gauge of the amount of charged air pressure produced by the turbocharger. As boost increases, more charged air is being force-fed into the motor and more horsepower is being made. Boost levels are usually measured in pounds per square inch (psi).