Turbochargers use the waste-energy in the hot exhaust gas to drive an air-compressor that pushes more, denser air into the cylinders at some range of RPM and throttle position. Superchargers use energy from the crankshaft to drive an air-compresor that does the same thing, but pumps air whenever the engine turns, not just at some RPM and throttle positions. Turbos are more theromdynamically efficient; superchargers tend to give much better performance at lower engine speeds. Turbos are pretty simple - typically with just one moving part, superchargers are typically bigger, heavier and more complicated with several moving parts.

There are several different types of each. Both operate by driving a compressor to push pressurised air into the cylinders. Pushing pressurised air in means that more air is being taken into the cylinder than a naturally aspirated engine. That means more fuel can be injected, and the resulting bang is bigger. Simple result: much more power out of the engine. Superchargers are usually comprised of a centrifugal compressor, or some form of helical (screw type) compressor. A centrifugal compressor is the same as the compressor on a turbo: it is a specially shaped disc with angled vanes on it that, as it rotates, it draws in air and pumps it out at higher pressure. The helical type is usually a pair of long, angled gears that mesh together, and as the air moves through them the space between them gets smaller, which compresses the air. Turbochargers are all centrifugal. I haven't seen one that is not. Turbos and Superchargers are very different in their operation, and their application. Superchargers are usually much larger, and operate efficiently at lower RPM. Because of their size and design, they don't operate too well at high RPM. Turbos are smaller, and the turbo itself operates at far higher RPM than a supercharger. Some turbos spin at up to 100,000rpm under full boost. Turbos use exhaust gas driving a turbine to power the compressor, so at low engine RPM where there is not much exhaust pressure, it doesn't work very efficiently. Depending on the size of the turbo, they come into their efficient range anywhere from 2,500 RPM upwards. Superchargers are powered directly off the engine's rotation - so either through gears or a belt. Superchargers typically give good bottom end and midrange torque increases, while turbos are more suited to high mid to top end power. ------ As for differences in the engines, there isn't really much physically. They still operate the same. The main variations have to do with how much pressure (boost) is being pushed into the engine. The first modification for any forced induction engine is lowering the compression ratio. Most naturally aspirated engines run between 9:1 and 11:1 compression. The higher the compression, the better quality fuel you need. Anything over 10:1 or 10.5:1 requires premium (higher than 95RON) Most turbo or supercharged engines run around 8:1 compression. Big boost turbos often get the compression dropped down to 7:1 or so. More air means more fuel - once you start getting into big boost, the fuel injectors need to be replaced with higher capacity ones. If you're building a high boost engine, then you'll want to consider better quality engine internals - pistons, rings and rods. Forced induction engines also use different camshaft profiles, and will vary between turbo and supercharger. Depending on the design of the camshaft, it can either increase torque or power, and create these increases at different points in the rev range. A supercharged engine will have the hardware to drive the supercharger, whilst a turbo engine will have different exhaust and intake plumbing to connect to the turbo.

Well, one major difference is price. Superchargers can start at $1500, while turbos can be only a few hundred. The second major difference is the way in which they work. Turbochargers are attached to both the intake and exhaust systems, and consist of two turbines. The exhaust that comes out of the engine under pressure spins the exhaust turbine, which in turn spins the intake turbine. This forces more air into the engine (specifically the cylinder), allowing more fuel to be added, and therefore more bang for every explosion in the cyliner. It does not rob the engine of any power and is common on big diesel engines to add power. Superchargers are belt-driven. This means that they are connected directly to the engine and driven by the belt that connects to the crankshaft, A/C, alternator, etc. on the front of the engine. They sit directly on top of the engine. The 'blower' as they're called, forces air directly into the intake manifold under more pressure than a turbo. This results in more air being forced into the cylinder, more fuel being added, and subsequently even more bang per explosion. This is referred to as 'boost' for both chargers. Hope this helps, Good luck

geek860 has covered it fairly well, so I'll just add a couple of notes. Supercharged engines do not experience the pressure lag (called turbo lag) common with turboed engines, and provide a fairly high constant boost. A supercharger also will typically draw (depending on the specific make of blower) 15-25HP from the engine, while the turbo uses waste energy. Detroit Diesel series 53, 71, and 92 (all 2-cycle diesel) engines are supercharged from the factory.

Hi could you tell me turbo charger and a super charger that would be good on a 2.4D HILUX?.. lol I know you might say its not worth it but I love that car and want to fix it up. Also is possible to have both done? - I mean turbo and super - also I am going to get it changed into a diesel-GAS mix because its supposed to boost the power by heaps... Ok thanks. My e_mail is nicky_hansard@hotmail.com