Superchargers are distinct from turbos in they are mechanically driven units, whereas turbos get their boosting powers from exhaust gasses. The supercharger can be belt, gear, or chain driven like other automotive accessories including the alternator and the power steering. While this allows for instant power availability, nearly 1/3 of the engines efficiency is eaten up by the unit, leading to the supercharger being labeled parasitic. However, if efficiency is a secondary concern and response and power are paramount, then the supercharger rules.
A turbocharger, on the other hand, runs off of exhaust gasses produced by the car already, leading proponents to say that the turbo is actually more eco-friendly. In a 4-stroke internal combustion engine, the final stroke is exhaust. The hot gas that would normally travel down the tailpipe to mingle in the atmosphere is instead sent into a turbo where it spins a turbine which powers a compressor that will send pressurized air into the combustion chamber to achieve a more efficient burn.
This sounds like it should be the hands down favorite, but it takes a while for the heated exhaust gases to build enough momentum to start the effective spinning of the turbine, giving poor performance at lower RPM’s. This is normally referred to as turbo lag or boost lag. The supercharger does give the driver immediate access to power, but the engine load it creates makes it a more cumbersome unit, even though at higher revolutions it will usually out perform a turbo-
The best set up according to Gale Banks in an interview he did with Jay Leno is to use two smaller turbos each injecting air into its own cylinder bank. While you still have the same draw backs as a single turbo, the lag is less significant and the power delivered is greater. But, superchargers won’t be left to the wayside in the attempt to deliver maximum horses with minimal draw. The future of supercharging is in electrically driven units. Controlled Power Technologies has a developed an electrical supercharger that provides 40% more torque at lower speeds as well as making available 90% of the units torque in less than 1 second, while also lowering emissions.
Like all great debates through time, the battle between supercharging and turbocharging may never be settled. As innovation drives science forward to create better, more efficient ways to achieve maximum power, the pros and cons will continually shift. All that will remain constant is our love affair with the spooling of the turbo, the whine of the supercharger, and a need for speed.
Source : automoblog.net
