Car Performance Modifications – change how it breathes!

There are many ways in which you can improve your car’s performance. These include electronic modifications, such as reprogramming or replacing the ECU (known as re-mapping and re-chipping) and mechanical ones, such as increasing the compression ratio by removing metal from the cylinder head.

One of the simplest ways of improving performance is changing the “breathing” of the engine. This is a very popular DIY modification and involves changing the engine induction (air intake) and exhaust. The induction is modified by replacing the air filter with one with less resistance to airflow. Air filters are designed to reduce noise as well as filtering the air, but by reducing the former of these air flow can be increased and performance, particularly at the high end of the rev range, can be improved. Of course, your car will be noisier.

To improve breathing at the exhaust end, you will need to replace the exhaust system and the most popular way to do that is to use a large-bore exhaust. This allows the gases to be removed efficiently. Getting rid of the exhaust gasses efficiently reduces the back pressure experience by the engine and consequently improves engine efficiency and brake horsepower (bhp).

A normal exhaust system has a silencer which causes the exhaust gases to pass through a number of baffles. This quietens the exhaust noise, but creates back pressure and slows down the removal of exhaust gases. By replacing this with a sports silencer (often called a straight-through silencer) which has no baffles, the back pressure is reduced considerably. The combination of sports silencer and large bore exhaust can add a considerable amount of power to a car, again mainly at the high end of the rev range.

A word of caution however; by changing the way your car breathes, you can considerably improve its performance, but there is a modern tendency for young men to fit their cars with the largest bore exhausts they can find. Although they might like the sound of those exhausts, they can actually reduce the car’s performance. If they are not matched to the engine’s capacity they will impede the flow of exhaust gases. When modifying a vehicle is it often best to do this on a used car to avoid cancelling out your warranty.