The special relief valves - thanks to them there is no permanent damage, they allow precise control of pressure. Depending on which the construction of the boost system we have, valves whop air forced into the cylinders or exhaust fumes.

There are several types of the most commonly used elements. In case of petrol engines the waste-gate and blow-offs (they are valves in the intake) and the by-pass in the exhaust system are usually used. The valves remain closed while the engine is running at low speed to provide him with the rapid growth in air pressure. Conversely it happens at high speed – to make good portion of exhaust missed the turbine, the valve is opened by-pass, keeping the lower turnover. Water-gate valve is applicable when adjusting the pressure in the intake. It is normally controlled with the use of a solenoid by the computer. When it comes to excessive increase in pressure, the water-gate rises automatically, leading to its reduction by discharging a portion of the compressed load. Yet another function is performed by a blow-off valve, which is useful when we suddenly take a foot off the accelerator. This causes that the air embossed at high speed encounters a throttle, which is closed. This threatens the efficiency of the compressor and the efficiency of the vehicle. A blow-off valve lets avoid such situation by opening up when it comes to closing the throttle. There are the so-called intercoolers used in the cars. These are the charge-air coolers, based on the principles of thermodynamics, according to which the colder is denser and thus it gathers even more. Applying this rule to the turbochargers, there is more air that can be forced into the cylinders, if it will be cooled first. The power of engine is then significantly increased with minimal cost. This type of valve does not occur in diesel engines that do not have a throttle. The diesel engines do not have the by-pass valve, but there is a special steering wheel gradually introduced more and more. This creates turbocharger of variable geometry. Exhaust gas flow rate can be adjusted through the blades, sliding or rotating according to its axis. The steering wheel may be constructed with different types of blades that at low speed drives air flow tangentially to the turbine. This lets to increase the velocity and - when high - sets perpendicularly to the flow unimpeded.