Performance exhaust components are commonly used to increase horsepower in a motor. However they also raise gas mileage by decreasing backpressure on the pistons and increasing engine efficiency. In addition to free flowing mufflers, high flow catalytic converters can be used to increase exhaust flow and gain better gas mileage. Gains of 1-2 MPG have been documented when switching to high flow exhaust systems.
1. High Flow Muffler
Replace your stock muffler with a high flowing performance exhaust. There are many brands on the market including Borla, Magnaflow, Flowmaster and Dynomax to name a few. Do your own research to determine the best system and manufacturer for your vehicle. Changing the muffler alone can free up enough pressure on the pistons to improve your gas mileage by 5% or more.
2. High Flow Catalytic Converter (also referred to as a “cat”)
Replace your stock catalytic converter with a high flow catalytic converter. This will not provide as much of an increase in gas mileage as a high flow exhaust may, but it could increase gas mileage by 1 mpg.
3. Mandrel Bent Exhaust Tubing
Mandrel bending refers to a process by which smooth bend transitions are formed in exhaust piping so that sharp abrupt angle transitions do not occur. This process of smoothing the pipe increases exhaust flow and can help to improve fuel economy. However as compared to changing to a performance muffler or high flow catalytic converter the gas benefit results of mandrel bending are negligible to less than 1 mpg gain.
We do not have personal documented evidence of improving mpg’s by changing exhaust here at MPGEnhance.com as high performance exhausts were added on our vehicles years ago before we ever started logging fuel mileage benefit. However, improvements in engine power and efficiency were certainly noticeable.