This is the ultimate and will keep even high power engines safe - Insurance for your engine!
This is a water to air intercooler or which is more commonly known as a charge cooler. Water is a far better cooling medium than air, and takes heat away from the induction air far better. Why is this necessary? Any time you compress air (to create boost) the air heats up. This is bad for the engine and bad for power.
The standard intercooler on the BMW MINI is an air/air unit and is just about adequate for the standard engine, but is poorly positioned on top of the hot engine. With very restricted air flow (just look at the route it takes) having to travel down the engine against the restriction of the plenum and supercharger in the very small space between the engine and radiator - not the best which is why some people call the standard intercooler a chargeheater! This is because the hot engine can actually heat the induction charge making things worse. Intercoolers are fitted because they are cheap to make, cheap to fit, and there is little to go wrong, but they are not very good at cooling the air. They are even less effective when you start to modify the engine, because all turbo/boost engines prefer cool intake temperatures. The Cooper S engine is particularly partial to cool air for reliability and power.
An option would be to move the intercooler to the front of the car ahead of the radiator, but this would involve a tortuous route for the charge pipes and this would increase the boost loss (pressure drop) over the system, and increase boost lag - very counter productive.
A better option is to use a more effective device. The water/air charge cooler is that device. Water transfers heat at a much greater rate. There are also other advantages to this setup. The charge cooler uses a water jacket around the device to extract the heat from the induction charge. This water is then circulated using a pump to a front mounted radiator, which takes the heat from the water. This cool water is then circulated back to the charge cooler to start its job again. Another advantage of this system is that there is a significant reservoir of cold water to continue cooling the air even if the car stops or slows - this is not so on a conventional air/air intercooler - however large it is!
The actual charge cooler fits as a direct replacement for the standard air/air intercooler. The kit also includes the water pump, all hoses and the front mounted radiator. The job of fitting this device takes around 3 hours and should see an immediate power increase although this is far more noticeable when the temperatures are higher, and on up rated cars. Pressure drop is also negligible over the charge cooler.
*Power Figures. It is very difficult to quote actual power figures for your vehicle, as the actual output varies depending upon many factors, including the actual specification and condition of your engine, altitude, temperature, humidity, vehicle equipment levels, and numerous other factors. Those figures quoted are typical and are based upon our own experience of the kits listed above. They are not guaranteed on any particular vehicle.