The job of your intercooler is to cool compressed air coming from your turbocharger or supercharger, before it enters your engine. In case you didn’t already know, when you compress air it heats up. Turbochargers are also naturally very hot because half the unit has exhaust gases running through it.
The whole point of a turbocharger is to force compressed air into your engine which allows for more fuel, and ultimately more power. There is one problem, however, hot air can cause detonation and is less oxygen dense than cool air.
Air being forced into your engine by the turbocharger is naturally going to be very hot from the turbocharger being hot and the air being compressed. The intercooler is designed to cool this hot compressed air down to a more reasonable temperature before it enters the engine.
How Does it Work?
Typically an intercooler used in an automotive application will feature either air-to-air or liquid-cooled design. A liquid-cooled intercooler has much greater cooling potential, but the liquid will eventually become too hot unless an auxiliary radiator is used. For this reason, most intercoolers you’ll find on turbocharged vehicles use an air-to-air design.
Intercoolers work similar to radiators, by using fins to extract heat from the core of the intercooler. In order for this work effectively, airflow through the fins is required, which is one of the downsides of air-to-air intercoolers, but this issue is typically so minor that it doesn’t affect real-world performance.
How an Aftermarket Intercooler Helps
To keep production costs down often times the OEM intercooler is fairly small. It will typically get the job done, but as soon as you start increasing boost pressure or adding bolt-on modifications, the OEM intercooler can hold you back.
Adding a larger intercooler without any tuning will not really add any power. The charge air temperature will be lower resulting in denser air, but the larger intercooler can add a slight amount of drag which can somewhat negate any power gains.
The real magic of installing an aftermarket intercooler is the ability to run a more aggressive tune without running into detonation. A larger intercooler is also less susceptible to heat soaking which means you can stay out on the drag strip or race track longer without losing power.
To put it simply: no, a larger intercooler will not really add any horsepower to your car. It does, however, give you much more wiggle room for a more aggressive tune without the risk of harming your engine.
It should be noted, however, that too large of an intercooler can actually do more harm than good. If you have an extremely massive intercooler, you will cause more turbocharger lag and more drag inside the whole system.
- Will a Bigger Intercooler Increase Power? – Without proper tuning, an intercooler by itself won’t increase power by any substantial amount, because your OEM ECU tune may not increase boost or ignite timing when it sees safer charge air temperatures.
- What Does an Intercooler Do? – The job of your intercooler is simple – cool the hot compressed air coming from your turbocharger before it enters your engine.
- Will it Decrease Boost Pressure? – Depending on your application, the size of the turbocharger, and the size of the intercooler, it’s possible to see decreased boost pressure after installing an aftermarket intercooler.
- Do I Need a Tune? – Technically, no you don’t need an aftermarket tune with an aftermarket intercooler for the majority of applications, however, we highly recommend installing an ECU tune or piggyback system to capitalize on your lower charge air temperatures.
Luckily you will almost never run into this problem as spatial constraints will force you to run an intercooler that typically isn’t too much larger than the factory unit.