When installed a performance muffler, it's can be as part of upgrading the cat-back system. What is cat-back system? Cat-back is the part from catalytic converter to the back of the car which including center pipes, a resonator and muffler. In some states, it's illegal if remove the catalytic converter due to the environmental regulations, but it's still permissible to upgrade the cat-back parts. Besides of upgrade the cat-back system which will increase the overall performances, the manifold & downpipe plays an important role too.
Looking for better performance in increasing power and save fuel economy? You just need to replace the stock muffler with an aftermarket performance muffler. An aftermarket performance mufflers are designed with couple of tubes inside, few internal baffles, perforated tube wrapped with fibre glass to reduce noise or other materials that absorb noise and they are often made of quality stainless steel for corrosion protection. So, the stainless steel mufflers are slightly expensive than the normal mufflers, but will often last longer. Both types can significantly reduce back pressure, but the trade-off is usually a noticeably louder exhaust.
When the back pressure is low, it's means that the breathe of engine more freely. This will optimal horsepower and improves fuel economy. Moreover, by changing the stock muffler to an aftermarket performance muffler, you are allow to expect the performance gains from a few percent to double digits due to the restriction of your stock muffler has been replaced with an aftermarket performance mufflers. When accelerating or towing you will notice the newfound power.
Performance Muffler Design
Some mufflers are designed with remove all the restrictions in the path of the exhaust for example, no baffles, s-flow, reverse flow, diffusers to hinder flow etc. This type of muffler gives up too much in terms of noise control to achieve ultra low back pressure. Consequently, may be too noisy for anyone except a hardcore performance enthusiast. This type of muffler is more suitable for those who equates noise with power.
On the another hand, there are another type of performance mufflers which can reduce the back pressure without increasing noise. Such design features are allow the exhaust flow more smoothly through the muffler itself. Performance mufflers ( eg: Matola mufflers ) use a special arrangement of baffles in order to get the perfect combination of tone, sound reduction and smoother flow. Matola mufflers have done dyno-test on their performance muffles, there are an increases in performances such as power, torque and the sounds is acceptable of 99% of regular people.
Tips of choosing a performance mufflers
There are many "universal" fit mufflers which required some fabrication and cutting to install. You have to make sure the length of the performance muffler is perfectly fit under your vehicle, and the inlet and outlet pipe diameters are the right size to match to your existing pipes ( Unless you did changed to the larger diameter pipes. ) The pipe adapters can be fitted to almost any muffler to any exhaust system, but you are not suggest to change the pipe diameter that bigger than a quarter inch at the muffler inlet or outlet. Most performance mufflers come with 2-inch or larger inlets and outlets.