Forced Air Induction (Superchargers and Turbochargers): Whats the Difference? How do they Work?
The most common forms of forced air induction to a car engine are superchargers and turbocharges. Superchargers and turbochargers are two automotive parts designed and used for similar purposes. Both of these parts are designed to enhance engine performance and generate more power. Supercharges and turbocharges both work by supplying the engine with extra oxygen. The oxygen:fuel ratio within the combustion chamber must be kept in a constant ratio. This ratio is 14 parts oxygen to one part fuel. Having extra oxygen allows more fuel to be burned per cycle. The more fuel burned each cycle, the more power your engine is producing. The way in which these components work are different and the effects produced by each are also different.
How Do Superchargers Work?
Superchargers attach to the crankshaft and draw energy from the engine. As the crankshaft turns, part of it’s energy powers the supercharger which in turn supplies extra oxygen to the engine. A simplified way of thinking of a supercharger is as an air compressor. In practicality it’s a little bit more complicated because there is typically a belt connected to the crankshaft to power the air compressor. The air is typically cooled by an intercooler or aftercooler. The purpose of cooling the air is built upon the physics of gases. At higher temperatures, gases expand and take up more space, this equates to less oxygen fitting into the combustion and less fuel the engine will be able to burn per cycle. At cooler temperatures, air is more condensed, and more air can fit into the engine’s combustion chamber allowing more fuel to be burned per cycle.
How Do Turbochargers Work?
Turbochargers like superchargers is a form of forced air induction to your engine. Turbochargers are also going to function like an air compressor. The difference is that instead of a belt attached to the crankshaft the air compressor is powered by the exhaust. The exhaust from the engine powers a turbine which in turn powers the air compressor effectively supplying the engine with more air per cycle.
Intercoolers and Aftercoolers
An intercooler or aftercooler is usually used in conjuction with superchargers/afterchargers. Intercoolers and aftercoolers fulfill the same purpose. They cool the air before it reaches the engine. The difference is that intercoolers uses outside air to cool the contained air and aftercoolers use water. There is not direct contact between these outside components and the contained air, rather the heat is transferred through metal plates. Aftercoolers usually perform better than intercoolers because water is much better at transferring heat than air. Water is about four times better at transferring heat than air. The drawback with aftercoolers is with sustained use over long periods, the water can heat up and maintain it’s heat. The same way water is more effective at absorbing heat, it’s just as effective at maintaining heat.
The reason that aftercoolers are more effective at cooling is the same reason that your body will lose heat faster is water than standing outside. Your body will be cooled much faster swimming in 70°F water than it will if your standing outside in 70°F weather. This of course is not factoring in wind. You feel colder when it’s windy outside because the wind is functioning the same way as an intercooler. Wind is a stream of air transferring heat away from your body. As the air absorbs heat from your body it keeps moving past you so that new air is constantly coming into contact with your body ready to absorb heat. The only difference is that an intercooler is using a stream of air to transfer heat away from the air going to your car engine and wind is a stream of air transferring heat away from your body.
How to Choose Between a Supercharger and Turbocharger?
It can be difficult to choose whether you would rather install a supercharger or turbocharger into your vehicle. Even the most experienced automotive enthusiasts debate which option is better. It is most important to consider the pros and cons of each and consider which fits your specific needs.
Pros of A Supercharger
The benefit of a supercharger is that extra power is being created regardless of the rpm. Nothing in life can really match the roar of a supercharger.
If you are choosing to install your forced induction system yourself, you will find that superchargers are easier to install. Superchargers and turbochargers are both often sold in kits but the process of installing a supercharger are less intensive than a turbocharger. Superchargers are simply bolted to the top of the engine.
The maintenance of a supercharged engine is easier than with a turbocharger. There are some aspects of maintenance you have to take into account. You are going to have to change your oil more often compared to a vehicle without a forced air induction system. Supercharger belts should be changed at roughly 100,000 miles. You should also check your coolant and air filter regularly to ensure proper functioning.
Cons of a Supercharger
The major drawback of a supercharger is that it connects directly to the crankshaft of the engine. This means that a portion of all energy produced by the engine goes towards powering the supercharger. This reduces the fuel economy because they are draining power from the engine even when the extra power is not needed. Remember that when your sitting in traffic, your supercharger is still causing your engine to burn more fuel per cycle.
For some, the tuning of a supercharger is a drawback. In most cases, you’re not going to need to tune a supercharger but if you wanted too you would need to order specialized pulleys and proper equipment to gear them.
Pros of a Turbocharger
The turbocharger has been gaining more and more popularity in recent years. One reason is that it is more fuel efficient than a supercharger. Manufacturers are also steadily improving turbocharger technology and in today’s market many more car companies produce models with turbochargers than superchargers due to the industry’s focus on fuel efficiency and reducing vehicle emissions.
The tuning of a turbocharger is much easier than with a supercharger. It will be a different process depending on the make and model of the vehicle but it’s most likely going to involve using a kit included with the purchase of your turbocharger.
Cons of a Turbocharger
The age old disadvantage of a turbocharger is that it doesn’t function as instantaneously as a supercharger. Since it’s not directly connected to the engine, it’s simply not as responsive as a supercharger. It takes some time for enough exhaust to be produced in order for the compressor to start functioning. It is a cool experience to be accelerating and suddenly feel your car jolt forward but knowing that your engine has to reach certain rpm parameters to benefit from your turbocharger turns off many driving enthusiasts.
Another con of turbochargers is the upkeep. Since turbocharges spin at a very high rate, they require frequent oil changes (not in the engine, but the turbocharger itself). You can also expect to replace most turbocharges at around 150,000 miles.
Installation of a turbocharger is more difficult. There often sold in kits, much like superchargers, but the installation process itself is a bit more difficult. You will need to modify the exhaust system.
The Future Debate Over Supercharges and Turbochargers
The debate over whether superchargers are better than turbochargers will come to end in the next few upcoming years. We are going to see more and more hybrid systems. There have always been cars with both a supercharger and turbocharger installed but it’s the technology that is going to make the difference. There are already electric superchargers that run on electricity rather than drawing power from the engine and car companies work endlessly to continue improving turbochargers to function as well at low rpms as they do high rpms.
Costs of Superchargers and Turbochargers
I can’t give you details how much your next supercharger or turbocharger will cost you. There is wide range in price depending on the make and model of your car as well as the results you are looking to obtain. For a supercharger you can expect to pay between $3,000 and $10,000. Turbochargers are going to most likely be easier on your wallet. You can expect to pay between $500 and $5,000. If you are simply replacing your current turbocharger, you may get off easy with that $500 price tag. If your car doesn’t already have a turbo charger and you’re planning to install a high-end turbocharger the price is more likely to be in the $5,000 range.
I wish you luck with all of your automotive endeavors, and let me know what you think in the comments.