Intercoolers can breath some new life into a turbo engine, but might not give you the gains you’re dreaming about.
Nothing makes a car sound quite as impressive as the words ‘turbo-charged engine’. Having a turbo is going to boost your car’s performance, reduce the size of the engine, and give you a better fuel economy. These are some huge benefits from a system that basically just pushes down on air. The air in a turbocharged diesel engine is compressed before the fuel is injected. When the air is compressed the oxygen molecules are packed closer together and this means that more fuel can be added for the same size naturally aspirated engine. You get more efficiency from the engine and more bang for your buck!
The only problem is that when this air gets drawn into the turbocharger and boosted, it gets really hot. Hot air is not good for the engine and can have some seriously negative effects for the combustion process. So how does an engine keep the dense air cold? This is where the car intercooler system comes into play. Here is our guide to what the intercooler is, how it works, and any possible problems that the system might have.
What is a turbo intercooler?
When air is drawn into the turbocharger it is ‘boosted’ and then forced into the engine. During this process, however, it gets very hot. If air heats up, it becomes less dense. Since the point of using a turbo is to compress the air and make it more dense, if the air is warm it will mean that some of the extra power that the turbo can give to an engine is lost through the change in temperature. In order to cool this air down, many turbocharged engines use an intercooler to keep the air cool and dense.
How does the intercooler work?
An intercooler is basically an air-to-air radiator. At one end, the hot air from the turbo enters and is cooled as it passes through the intercooler (just like water in a car’s radiator). This means it can enter the engine at a much lower temperature. Why an intercooler is used is simple physics: Cooler air is more dense than hot air, meaning that there is more oxygen in the same volume of air. More oxygen in the same space means more efficient combustion and better engine performance.
People often wonder ‘do intercoolers increase horsepower?’ and unfortunately, no, a turbo intercooler does not add horsepower to your car. That said, however, it does give you better and more responsive performance as your car has more access to oxygen and it can mean that you can tune your car more aggressively without risking damage to your engine.
Intercooler vs Radiator
The battle of the century! (not quite). Many people think that an intercooler replaces the radiator in your car. This is a little tricky to answer as the intercooler is, in fact, a type of radiator and they both have the same job (to cool things down). The difference between the intercooler and the radiator, however, is that radiators are used in almost all vehicles to keep the engine cool, while intercoolers are used specifically to help cars fitted with a turbocharger to produce the most power. Cars which have to produce great acceleration and speed have to get a maximum amount of air and an intercooler makes it possible.
The radiator can also affect where the intercooler is located. Some cars mount their intercoolers on the side of the car, though this might compromise the aesthetics of the car. Other brands choose to locate their intercoolers next to or in line with the radiators. Intercoolers can be located in front of or behind the radiator, depending on the heat dissipation needs of the engine.
Is an intercooler upgrade worth it?
Your car might have a turbo charger, but either not come with an intercooler as standard or you might already be driving without one. There are ways of installing an intercooler to help boost your car’s performance though. A good aftermarket intercooler should be easy to get a hold of and aftermarket versions can be even better the OEM intercoolers, as these are fairly small.
The main benefit of an intercooler is that it will be less susceptible to heat soaking, which means you can stay out on the drag strip or race track longer without losing power. If you are spending every Saturday at the track or are going to be doing any kind of performance driving, then an intercooler will increase the durability of your engine and can give you the boost you need.
That sound, adding a larger intercooler without any tuning will not add an unbelievable power to your engine, despite the increased oxygen and theoretical increase in performance. 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 benefits come if you combine this intercooler system with some engine tuning. On balance, it is worth checking out how much an intercooler would cost you and thinking about exactly what you will be using your car for.
Common Intercooler problems
Since intercoolers are fairly simple systems, there isn’t that much that can go wrong. The problems usually come from installation issues or leaks. Here are some of the common issues and any intercooler leak symptoms you might need to watch out for.
One of the most common areas affected is the rubber boost hoses and the clamps that hold them in place. Over time the rubber will perish, and clamps can lose their clamping force, which can result in the boost hoses actually allowing boosted air to escape. What happens when intercoolers leak? You get a sluggish, underperforming car. You may even be able to hear a ‘whooshing’ sound (although not always), which is the air escaping as you drive. Though this isn’t great, you can still drive with a broken intercooler, it just won’t have the same performance as you’re used to.
Luckily, the repairs are fairly simple – get new hoses and a new clamp. Car intercooler repair can be done either by yourself or at a garage.
Damage from impacts
Since intercoolers can be found right at the front of the car, it means that they are susceptible to damage from small collisions or impacts, particularly from stones and debris from the road.
This can damage the delicate cooling fins, reducing the cooling efficiency of the intercooler, and is extreme cases and also damage the tubes through which the boosted air passes through.
The most common effect is an underperforming intercooler, resulting in increased inlet air temperatures, but in the worst cases the intercooler can piece and you can end up with a boost leak. Sadly, this is going to require a whole new intercooler as replacing it can be fiddly and often isn’t an effective solution.
As the air that enters the intercooler comes directly from the turbocharger, it does mean that any problems that you have had in the past with the turbo are likely to affect the cooling system too.
For example, if a turbo is suffering from an oil leak due to worn out seals, then it is likely that this oil has leaked onto the intercooler itself.
This means the oil gathers in the bottom of the intercooler, reducing the performance of the intercooler itself. The boosted air is also going to contain oil vapour and this will have a negative effect on engine performance too.
To check whether this has happened, remove the boost hoses and inspect for signs of oil contamination. If you can see any oil there, remove the intercooler and flush it out with engine degreaser to remove all the oil from the inside of the intercooler.