Straight-through, or flow-through, mufflers have perforated baffles and packing material that provides a conservative level of sound absorption while still keeping sound output moderately loud. Glasspack mufflers perform similar to resonators due to their design and lack of sound-absorbing packing material, so they tend to be louder and higher pitched. For compression-ignition (i.e., diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst (DOC). This catalyst converts particulate matter (PM), hydrocarbons, and carbon monoxide to carbon dioxide and water. These converters often operate at 90 percent efficiency, virtually eliminating diesel odor and helping reduce visible particulates. These catalysts are ineffective for NOx, so NOx emissions from diesel engines are controlled by exhaust gas recirculation (EGR).

Brands like Invidia, Borla, and Agency Power offer a wide range of options, allowing you to customize the sound and performance to suit your preferences. Upgrade your Subaru WRX, STI, Forester, and Crosstrek with these cat back exhausts to unlock additional horsepower, torque, and an exhilarating driving experience. Catback exhaust systems are typically made up of a rear pipe, a resonator and a muffler, though they can also include a mid-pipe, x-pipe, h-pipe or y-pipe, depending on the make and model. Upgrade the sound and performance of your Toyota Supra, GR86, or Subaru BRZ with a high-quality cat back exhaust system from FTSpeed. Our cat back exhausts are engineered to enhance exhaust flow, resulting in improved horsepower, torque, and throttle response. With a deep and aggressive tone, these exhaust systems not only amplify the sporty character of your vehicle but also provide a captivating driving experience.

Exhaust systems also play a role in reducing noise levels, improving engine performance and reducing fuel consumption. To get the power level up to 785 hp, Shelby installs a Ford Performance supercharger, as well as a new carbon-fiber air intake tube, high-performance fuel injectors, and an aluminum heat exchanger. A Borla (cat-back) exhaust system rounds out the list of powertrain modifications.

A stock system is designed to reduce and if possible eliminate all the noise produced by your vehicle. Because of this, the axle-back exhaust system does not impact the flow or pressure of the exhaust gases in any way. The axle-back exhaust system uses the factory exhaust pipe which does not have a large diameter. This offers even more breathing space for the engine thus better performance. Most cat-back exhaust systems are customized and not universal. One is to replace specific parts like with cat-back exhaust systems.

By running pipes from the catalytic converter to the muffler and from the muffler to the exhaust tip, cat back exhaust systems improve exhaust gas flow, providing small performance boosts. However, your performance gains may be limited if your catalytic converter restricts gas flow, as a catback exhaust system is installed ‘downstream’ of the converter. Header-back systems are increasingly rare, namely because of modern emissions systems. Since removing your vehicle’s factory emissions components is highly illegal, the previous two options are more common. However, header-back systems are still available for some older, pre-emissions applications. In these cases, header-back systems offer more performance and volume than cat-back or axle-back systems