Presentation Title

Variable Back Pressure Exhaust System

Start Date

12-11-2016 10:30 AM

End Date

12-11-2016 10:45 AM

Location

MSE 113

Type of Presentation

Oral Talk

Abstract

In the automotive industry, there have been many claims involving whether or not higher exhaust pressure could lead to better performance for a normally aspirated internal combustion engine. Some automotive enthusiasts claim that smaller piping improves performance when vehicle runs at lower RPMs due to increased exhaust velocity, while others claim that the high pressure generated by the smaller cross sectional piping will always negatively affect engine performance. In this research a series of controlled experiments are designed to investigate these claims. We tested these claims by performing multiple dynamometer runs on vehicles fitted with different sized exhaust pipes for each run and comparing torque and horsepower results. To obtain the best results we utilized two different types of vehicles, one with a manual transmission and another with an automatic transmission. Both vehicles were tested with the same dynamometer and in the same way with different size exhaust systems. Through this testing we discovered that more exhaust flow is always better. Our dynamometer test data clearly shows that once a certain exhaust flows is achieved (usually around the middle of the engine's RPM range) a larger diameter pipe will always produce more power. Below this level however there was little difference between a more restrictive pipe size and the larger free flow system. Our conclusion disproves our initial theory of wanting a more restrictive exhaust at lower RPM. However we did see a fair increase in power and torque with a larger cross section of pipe at higher RPM.

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Nov 12th, 10:30 AM Nov 12th, 10:45 AM

Variable Back Pressure Exhaust System

MSE 113

In the automotive industry, there have been many claims involving whether or not higher exhaust pressure could lead to better performance for a normally aspirated internal combustion engine. Some automotive enthusiasts claim that smaller piping improves performance when vehicle runs at lower RPMs due to increased exhaust velocity, while others claim that the high pressure generated by the smaller cross sectional piping will always negatively affect engine performance. In this research a series of controlled experiments are designed to investigate these claims. We tested these claims by performing multiple dynamometer runs on vehicles fitted with different sized exhaust pipes for each run and comparing torque and horsepower results. To obtain the best results we utilized two different types of vehicles, one with a manual transmission and another with an automatic transmission. Both vehicles were tested with the same dynamometer and in the same way with different size exhaust systems. Through this testing we discovered that more exhaust flow is always better. Our dynamometer test data clearly shows that once a certain exhaust flows is achieved (usually around the middle of the engine's RPM range) a larger diameter pipe will always produce more power. Below this level however there was little difference between a more restrictive pipe size and the larger free flow system. Our conclusion disproves our initial theory of wanting a more restrictive exhaust at lower RPM. However we did see a fair increase in power and torque with a larger cross section of pipe at higher RPM.