How Does a Supercharger Work?
Using a supercharger is a functional method of enhancing mileage and boosting performance. Your don’t have to be a drag racer to have one, but it sure helps.
A supercharger is no longer a luxury item. Admittedly, the first image that pops into your mind when you hear the term is “drag racing”. They sound expensive and loud – and seem like a hassle to install. Yet in the day and ages of soaring fuel prices, making your engine fuel efficient is the best way to scrimp. Let’s break it down to the fundamentals.
The concept of forced induction is what created the supercharger. In regular cars, air at ambient temperature is suctioned without any assistance into the combustion chambers of the engine to combust. The problem lies in that at high rpms (revolutions per minute) there isn’t enough air getting into the combustion chamber. As a result, fuel is burned less efficiently and this causes excessive exhaust that has more carbon monoxide, black smoke and other harmful particulate matter. Forced induction basically means force feeding air into the engine to make it burn fuel more efficiently.
A supercharger does just that. Typically placed on top of your engine, a belt is connected from the supercharger to the crankshaft of engine. As the crankshaft rotates, this powers the impeller to channel air into the supercharger, then compress and pressurize it before forcing it into the cylinder. There are three main types of superchargers:
Section of a Centrifugal Supercharger
Just like a turbocharger, this supercharger uses centrifugal energy harnessed by the bearings, a gear and pulley connected to the crankshaft to impel air into a metal tubular housing that reduces in size and diameter to pressurize the air.
As the impeller is an external part, it is easy to change its size. The Centrifugal Supercharger is also easy to install and the various impeller sizes allow you to customize the power you need for your engine. It’s generally reliable and your exhaust temperatures are not significantly hotter than operation without one. A drawback is that at lower rpms, the lack of power supplied to the supercharger means it does not deliver a noticeable power boost.
Video: 3D animation of centrifugal supercharger
Roots Type Supercharger
Roots Type Supercharger with an exposed air intake
This is the original supercharger type with models dated to the 1880’s. Unlike centrifugal superchargers, the roots blower pumps air instead of compressing it. They typically have 2 or 3 lobes that interlock but never touch. These lobes can be straight or curved for more efficiency. The advantage of a roots supercharger is that is gives you power throughout your car’s RPM range. The power is immediate, with little lag even after idle.
They are a staple for any legitimate drag racer and are very intimidating to look at. Yet they have issues that affect performance. The first is a violent throttle response, the moment you put pedal to the metal, the car lurches forward violently and can often destabilize a car with a high center of gravity. This power does not increase proportionally to the rpm so higher rpm’s do not get much of a boost. They are a pain to install as the shear size and exposed parts mean protracted installation times. The exhaust temperature is also abnormally high.
Video: 3D animation of Roots type supercharger
Screw Type Supercharger
Video: 3D animation of a twin screw compressor
This roots type charger lookalike functions in the exact same way apart from the following. The twin lobes are replaced with twin screws that also do not touch. The air follows an axial flow between the threads of the screws to compression. This creates positive pressure and reduces heat in the supercharger.
This supercharger can be factory fit, has a seamless appearance and is very reliable. It’s ability to provide substantial power at a low RPM makes it an ideal option for towing or usage in heavy vehicles. The only few downsides are that installation takes a long time and the power doesn’t increase consistently and flatlines at high RPM’s.
Problems and Alternatives
The main issue with superchargers is that it saps power from the engine to operate. The gains from high efficiency are stunted by diverting some power from the engine to the device itself. The sound produced by a supercharger is whiny and can be off-putting. An alternative to a supercharger would be a turbocharger. It runs on the power of exhaust expulsion rather than being attached to the crank shaft, and has a sound that can be described as a guttural growl.
Talk to the best turbocharger supplier in Johor Bahru. Their expertise and range of products are sure to give you the best value for your vehicle. In the meantime, find out how you can choose the right turbocharger for your vehicle.