Supercharger vs Turbocharger

The supercharger versus the turbocharger, this can easily be one of the most discussed & heated topics in the automotive world. Ironically enough, they are in technically the same exact thing. They serve the same purpose, and that is to force more air into the engine, hence more power. These are called systems of forced induction. The difference between the turbo and the super lies in the process in which they force that air into the engine.

The turbo is consisted of two turbines (fans). The first turbine spins according to how fast the exhaust air is coming out. So basically, the more exhaust air that is coming out of your tailpipe, the faster your first turbine will be spinning. The second turbine on the other hand, is directly connected to the first turbine via an axle, so whenever the first turbine spins because of the exhaust flow, the second turbine constantly spins with it. Now this second turbine is connected to an air intake, so while the exhaust is pushing the first turbine, the second turbine is sucking the equivalent amount of air back into the engine. 

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The supercharger on the other hand is just a turbine that is connected to the engine on one of its many pulleys via a belt. So as the engine creates the rotational motion, it is causing the superchargers turbine to constantly push more air.

Superchargers and turbo chargers can be modified in terms of how much "boost" you want. Setting the boost to the desired pressure is not difficult, and it is usually determined by atmospheric pressure. Our atmospheric pressure is 14-15psi (pressure per square inch), so theoretically speaking, you should double your horsepower with every additional 14psi of boost you make your super/turbo push out. That is only in theory though, in the real world, hp increase will more likely be 60-70% as opposed to 100% given that there are countless real world variables that we cannot control. 

Both the supercharger and turbocharger have pros and cons. The main problem with the turbocharger is turbo lag. There is nothing in the whole world of cars that people hate more than turbo lag.. Turbo lag is basically the lag time it takes for your turbocharger to build up momentum and start giving back air. Because the turbos rotational energy comes from the exhaust, it can only work at full potential once there is enough exhaust flow. So in other words, you can put your pedal to the metal but the turbo won't fully kick in until your engine is working itself (usually somewhere between 3,000-4,000 rpm), only then will there be enough exhaust flow for the turbo to give you that full additional power. There are hundreds of ways to decrease turbo lag, but the general rule of thumb is: The bigger the turbo, the bigger the power, the bigger the turbo lag. Turboed cars are usually seen to have sudden and abrupt power since torque is not even throughout the rev range. 

Superchargers on the other hand do not have any lag, because they are constantly spinning as the engine is spinning. So the supercharger works as fast as the engine is working, creating quite an impressive torque range. Now at this point, everyone is probably thinking its clear now that a supercharger is much better than a turbocharger. That's not true. Even though the supercharger never lags, and has instant power readily available, it is because of that reason that makes it also weaker in a sense. You see, if anyone can recall newtons third law of motion, every action has an equal and opposite reaction. The engine is excerting energy in order for the supercharger to spin, and that is power robbed from making the car go faster, only so the supercharger can spin. Now the supercharger still gives more power than it takes, but a turbo charger robs NO power from the engine, because it is using a source of energy (exhaust flow) that was going to end up leaving the car either way. So where as a supercharger at 14 psi can give you 100 hp, a turbo of that same size at that same psi might give you 120 hp. 

So the point I'm trying to make is that one isn't really better than the other. It really depends more on the car than the system of forced induction itself. Nowadays Turbos are used much more than superchargers are. In fact, in less than the last decade alone, the whole automotive industry became saturated with turbo charged cars from the factory. Those cars that have turbos aren't meant to go fast, but to get better mileage. To make this easier to understand, you can have a 5 liter v8 @ 400 hp, or you can have a turbocharger 3.0 liter v6 @ 400 hp, the v6 will still have better mileage, even though it has v8 performance. 

If we're just talking about speed and power, turbocharged applications are more for smaller engine cars such as 4 cylinder Japanese sports cars. Twin turbos are sometimes used for the bigger block american muscle, but i would generally rather have a supercharger because the massive engines can deal with the slight power loss from a supercharger, and torque will be virtually instant.

All in all, both systems are great. If you're looking to buy one or the other, be prepared to dish out $5,000+ in add-ons and installation costs in order for these systems of forced induction to work fine.