Car Tech 101: Turbos vs. Superchargers. Video
Car Tech 101: Turbos vs. Superchargers. Video Transcript
Both Turbos and Superchargers are air pumps. They run more air into the intake portion of the engine and when more air goes in that means the engine can combine more fuel with it to get what's called a bigger charge. That's the air and fuel before it's ignited. I have been putting more air into the intake portion of the engine that also means its other components will combine more fuel with that air. You've got to do that to maintain the charge. That may sound piggy like. So what? More gas, more power. What's the magic about that? But because you're doing it under pressure and using modern valve timing, ignition timing, and fuel metering in a high tech fuel injection system, you increase what's called volumetric and thermal efficiency. That means you can scale the power of the engine more efficiently than you scale its fuel consumption. How those 2 pumps do that though? It's different and very interesting. First of, let's meet the Turbochargers. That's this apparatus sitting right here. Let's see how it works. This is the exhaust manifold. The exhaust gases are coming off and still under here, which would normally go out to your tail pipe. The turbo sits here and intercepts those gases. It blows by this. This is called the impeller. Spins that thing really fast. On the other end of its shaft is this little part. That's the compressor. Cold air comes in here. This compresses it and sends it up the plumbing to the intake to run more into the engine. The beauty of this system is that it's using otherwise wasted energy. Exhaust that otherwise just goes out into the air. It's getting something out of that. The downside is turbo lag because those exhaust gases are created at the late part of each cylinder cycle. It takes this kind of system a moment or two to spool up as they say. That's where you get turbo lag. You step on the gas now, a moment or two later, this thing really spins up to the demand you want. Now, the Supercharger is a whole different animal. Here's one on top of a Mustang engine. It's in this big apparatus you see right here. Note the difference of the Supercharger. It's not driven by exhaust gases. It's driven by mechanical connection to the engine. In this case, a belt that's running off other pulleys and the crank so that pulley turns these gears, those operate these impeller blades here that turn, compress the air and then ram it down into the intake here. Therefore, it is always turning and always on a fuel, gear to engine RPM. Unlike a turbo that has all those lag issues so that's a bonus here. On the downside, this guy has got parasitic losses. That's another big, old rotating accessory that is hung off the engine. So this tend to be used more to create additional brute horsepower than to create efficiency or really high MPG in everyday cars. Okay, the last part of the turbo and supercharger story is intercooling. Here's the thing. When you compress air in either those technologies, it gets hot, the molecules want to expand, fewer oxygen molecules in a given space. The engine doesn't like that. It wants the most oxygen molecules in a given cubic inch if you will as they go on to the cylinder. That way combines more efficiently with fuel like we were talking about earlier. To do that, you cool the air, intercooling. Look down here. In this engine for example, that's basically a radiator. It's kind of hard to see the structure, but this is-- it's a chiller if you will. The compressed air goes through here first. That's make it more dense. More oxygen molecules in a given space as the temperature drops and then you can combine it more efficiently with fuel. Both turbos and superchargers typically used one of this. Okay, bottomline, as you go shopping for a car, you're pretty unlikely to find many that have superchargers. They tend to be rarified and extremely high performance. So let's talk turbos how to shop for one. Take the car out for a test drive and notice the turbo lag. That's the delay between stepping on the gas and feeling that whoosh of power from the turbo that we talked about. Secondly, notice the additional torque. Turbocharge engines didn't have a lot of torque compared to the amount of horsepower they have and torque is the fun stuff. It's what really gets you off the line and gets you going. And third, notice the price. Turbocharge engine options tend to cost more. Take that price factored against any fuel efficiency gains and comp with a rough amortization schedule if you will, or if there's not a big gain, comp with a personal feeling of how much more fun it's gonna be to have a turbo with all this additional torque times the cost you got to pay to get it.
Learn the difference between a turbo and a supercharger as they are taking center stage in new cars, get a look at the most interesting cars from the New York auto show, and find out what's on Cooley's list of Top 5 car tech flops.
Fitness tech is an emerging trend, and we're facing off the Nike+ FuelBand and Fitbit Ultra. Is Nike's branding power alone too much for the Fitbit? Let's get it on!
Hit the track with Cooley to see - and hear - IndyCar tech, learn why turbos are like a magic trick and get the list of Top 5 car technologies you can blow off.
Feature-hungry music fans will find their appetites whetted by this supercharged, high-capacity portable music machine.
Learn how to split your Netflix account between different users using profiles.
John Falcone explains the difference between the two high-definition connections.
CNET's Brian Cooley explains the differences in hybrid technologies and how they efficiently manage fuel consumption and power.
Get a jump on your taxes with these TurboTax-powered mobile apps.
Twin turbos will launch you into tomorrow; that's good, because much of the cabin tech is yesterday's.
A Matrix for the less tech savvy.