Gadgetory

now both turbos and superchargers are air pumps they ran 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 by putting more air into the intake portion of the engine that also means it's 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 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 it's fuel consumption how those two pumps do that though is different and very interesting first off let's meet the turbocharger that's this apparatus sitting right here let's see how it works this is the exhaust manifold the exhaust gases are coming off a cylinder here which would normally go out to your tailpipe the turbo sits here and intercepts those gases that 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 ram more into the engine the beauty of this system is 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 and because those exhaust gases are created at the late part of each cylinders 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 supercharged is a whole different animal there's one on top of a Mustang engine it's this big apparatus you see right here note the difference with a supercharger it's not driven by exhaust gases it's driven by a mechanical connection to the engine in this case a bill that's running off other pulleys and the crank so that pulley turns these gears those operate these impeller blades hear the turn compress the air and then Ram it down into the intake here therefore it is always turning and always on if you will geared to engine rpm unlike a turbo that has all those lag issues so that's a bonus here on the downside this guy's got parasitic losses it's another big old rotating accessory that is hung off the engine so these 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 of 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 into the cylinder that way it combines more efficiently with fuel like we were talking about earlier to do that you cool the air and your cooling 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 a chiller if you will the compressed air goes through here first that makes 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 use one of these okay bottom line is you go shopping for a car you're pretty unlikely to find many that have super chargers and they tend to be rarefied 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 turbocharged engines tend to have a lot of torque compared to the amount of horsepower they have and torques the fun stuff it's what really gets you off the line and get you going and third notice the price turbocharged engine options tend to cost more take that price factor it against any fuel efficiency gains and couple the rough amortization schedule if you will or if there's not a big game come up 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