Roots blowers are popular in motorsports for making more power. They are made up of a simple blower case with two rotors inside. The rotors spin from an engine driven blower drive. This pumps extra air into the engine. With extra air and the appropriate extra fuel, extra power!
The blower case design was changed in later years to improve performance. One of these areas is the size of the blower case discharge opening.
Original Roots blowers ran on industrial engines. They were simple mass flow devices running at atmospheric pressure. In the mid 19th century, motorsports racers put them on racing engines. They pumped a lot more air into the engine causing boost. This became an easy way to make more power.
However, because they were originally designed to operate at atmospheric pressure, they were inefficient with boost. While they made more power, it was not that much more for the amount of increased air into the engine.
One of the design areas affecting efficiency is the blower case discharge opening. That is discussed in several of our publications. Here are two examples: Continue reading