A boost gauge is used to ensure excessive pressure is not being generated when boost pressure is being modified to levels higher than OEM standard on a production turbocharged car.

What is the difference between boost and vacuum?

Any gas engine will naturally produce measurable vacuum any time that it is running. This is the result of the down-sweep of the pistons while the intake valves are open. Boost is when the positive pressure of the super charger becomes greater than the negative pressure (vacuum) that the engine creates.

How is turbo Boost measured?

The amount of pressure a turbo can generate is measured in pounds per square inch above atmospheric pressure. So a turbocharged engine with 15 pounds of boost would be moving roughly twice the air of a naturally aspirated engine, and all things being equal, would make roughly twice the power.

Does Tuning shorten engine life?

More horsepower means greater stress for all the units of the aggregate and more wear of the moving parts. However, this does not necessarily mean that tuning will shorten engine life. If done properly tuning will not leave any consequence on the engine other than improving its performance.