Abstract: A system for bench-testing a turbocharger before installing the turbocharger on an engine has the turbocharger with a turbocharger turbine inlet, a turbocharger lubricating oil inlet, and a turbocharger lubricating oil outlet. The turbocharger is mounted on a support. An air supply device provides a gas flow to run the turbocharger. The air supply device is mounted on a support and has an air supply device outlet. A diffusor directs the gas flow from the air supply device outlet to the turbocharger turbine inlet. A lubricating oil pump is connected to the turbocharger lubricating oil inlet; and pumps lubricating oil from a lubricating oil tank to the turbocharger. The turbocharger is disposed above the tank and the lubricating oil flows directly into the tank via a tank hole that is open to a surrounding atmosphere.