Walker is your one-stop exhaust shop, offering a full line of mufflers, pipes, hardware and accessories. Cat to Y pipe intersection showing after cat O2 sensor location. This qualifies as one of the STRANGEST stock exhaust parts I have seen. For some reason Toyota/Lexus decided to weld a straight section of 60mm pipe to the cat outlet flange, angle cut it, weld a 50mm pipe pipe that has its last couple of inches expanded to 60mm and match angle cut. Also note the O2 placement is in the 50mm sections of the Y pipe where the sensor tip takes up a good portion of the available flow area.
In layman’s terms, a catback exhaust system provides a smoother, more streamlined path for exhaust gases to exit your car, allowing your engine to work more efficiently. When catalytic converters were first introduced, most vehicles used carburetors that provided a relatively rich air-fuel ratio. Oxygen (O2) levels in the exhaust stream were therefore generally insufficient for the catalytic reaction to occur efficiently.
The difference in fuel economy is, however, more obvious while driving on a freeway. They also do not offer the best performance due to many reasons. If you're looking for an off-road exhaust with