The Roots supercharger is an external compression supercharger.

The Roots supercharger is an external compression supercharger.

• A. True
• B. False
• C. Not specified
• D. Only at sea level

Answer: (A)

The Roots blower is a positive-displacement device that compresses air inside its own housing before it reaches the engine. As the rotors trap and push air toward the discharge, the pressure rises outside the cylinder, in the blower itself, not inside the combustion chamber. That placement of compression is why it’s described as external compression. So, the statement is true. Note that at higher altitudes the absolute pressure changes, but the compression location and mechanism remain the same, which is why it isn’t limited to sea level.

The Roots blower is a positive-displacement device that compresses air inside its own housing before it reaches the engine. As the rotors trap and push air toward the discharge, the pressure rises outside the cylinder, in the blower itself, not inside the combustion chamber. That placement of compression is why it’s described as external compression. So, the statement is true.

Note that at higher altitudes the absolute pressure changes, but the compression location and mechanism remain the same, which is why it isn’t limited to sea level.