Great reasons for choosing a sports system
The manufacturer of your vehicle needs to meet the demands of all potential purchasers. Some might want the car to be as cheap or as quiet as possible, while others just want the most power. As a result, the stock manifold your car comes with is usually constructed from cheaper cast iron, with a restrictive internal diameter to keep the noise levels down.
Pit Stop lists a number of benefits of modifying your car by installing a sports exhaust system:
- Increased power for towing
- Improved fuel economy
- Helps extend your engine life
- Engines run cooler and more efficiently
- More torque for your 4-wheel-drive
- Ideal for diesel applications
How does fitting a new exhaust system work?
The traditional restrictive exhaust system is replaced with a set of lighter tubular extractors that will allow a greater volume of gas to pass through without causing a loss in speed. The flow of gas will be much smoother and when the gas from each exhaust port converges into two or one, the progression is smoother and faster.
The aim is for the gas to pass through without slowing down as it exits the engine. As the gas cools it becomes heavier and denser – hot gas pushed out of the engine retains its speed as it leaves the engine and exits via the exhaust pipe. Also, the exhaust exits the engine in pulses. Each pulse leaves an area of low pressure behind it so that the following pulse meets less resistance, and flows faster.
But how big is too big? It’s not always best to have a massive exhaust diameter. An exhaust pipe that is too wide can reduce power and torque gains. The trick is to increase the pipe diameter of both the manifold and the exhaust – without going too big.
Opinions differ on the ideal diameter. A slight sacrifice in size usually improves drivability and low- to mid-range performance. A larger-sized option helps at the top end of the speed scale. Remember, most of your driving will likely be in the low to mid range.
For example, for a 350 hp Evo with mild turbo work, go for a 2.5-inch setup. Go for a 3-inch setup if it spends a lot of time above 5000 RPM.
What is the best material for an exhaust system?
Opinions vary. Some recommend stainless steel, while others suggest that mild steel is adequate. Stainless steel is more expensive, but more resistant to corrosion. Mild steel is cheaper and easier to weld if you manage to damage your pipework. Stainless steel also tends to be more brittle, which can lead to cracking if the exhaust has to flex a lot.
To make the most of that extra engine power, find out if you should lower your car.