Before understanding the purpose of induction kits it would be necessary to know about the working and reason behind the presence of air filter in the car. Your car, for movement require fuel of course but the mere presence of fuel does not do the trick alone as many other ingredients are necessary to move your car which includes besides fuel, air and some sparks.
That’s right now understanding the phenomenon of moving the car is that your car intakes air containing oxygen, pushes that air into the piston area of the engine and then there’s a drizzle of fuel droplets which is combusted with the spark created by the car batteries. When fuel droplets come in the contact of a flare caused by the battery and in the presence of oxygen it causes explosion which causes the piston to move and eventually the whole car(imagine hundreds of these explosions happening per second).
Now keeping in mind the above phenomenon and the pre-requisites to move a car we can guess that without the presence of air/oxygen it would be difficult to move a conventional car and more the quality of the air i. e the more the oxygen in the air the better will be the performance of the car. This is what air filters do they intake oxygen and send it to the piston part of the engine. So if a car has an air filter with larger diameter the air filter will be able to intake more oxygen. So it is advised to keep your air filter clean in order to increase your horse power.
Now coming to the purpose of the induction kits. The idea behind introducing induction kit instead of air filter and air box is that induction kit intakes more cool air than these two without any extra effort thus allowing more oxygen because cool air contains more oxygen than warm air. This does not mean that air filter and air box are not fit for their purpose but as the time passes they become full of dust and therefore less efficient.
A normal induction kit has a cone shaped filter and necessary brackets and pipework to fit into the specific car. Good quality induction kits last for a longer time than the air filters because they can be easily washed, oiled and cleaned thus enhancing their life span. One more change which is eventually brought by the introduction of induction kit is that it makes a roaring sound thus giving car a more sporty image.
So I reckon if you are a car enthusiast and looking forward to modify your car you should try these kits. Specific induction kits are available in the market for many of their respective cars but problem occurs when the model of your car is not listed so in this case you will have to buy universal kits which can fit into numbers of other vehicles after some alteration in the brackets and pipe works.