A boost gauge is an instrument that is used to show the amount of pressure a turbo charger or super charger is producing. Typically, a turbo or super charger system is designed to give the maximum benefit at a particular amount of boost pressure. By monitoring the boost gauge, the vehicle's operator is able to keep the vehicle's engine components in the proper power range to achieve the most performance from the vehicle.
Many components affect the boost gauge. The camshaft, the fuel adjustment and the ignition timing all have a hand in manipulating the instrument. Depending on the type of boost gauge that is installed in the vehicle, atmospheric pressure can also impact the gauge.
The importance of monitoring the boost gauge in a turbo or super-charged engine is increased as the engine begins to produce power in excess of the stock capabilities. The results of excessive boost in an engine can be catastrophic. Improper timing, as well as fuel with a low octane rating, can lead to detonation. This is a condition also called spark knock that can damage pistons, valves and connecting rods. An excessive reading on the boost gauge would indicate the need to reduce pressure through throttle manipulation.
Even though a vehicle might come equipped with a boost gauge, it may still be beneficial to install an after-market gauge. In a stock vehicle, the boost gauge is actually operated by the vehicle's on-board computer. The computer accomplishes the determination of boost by reading the input from many engine sensors. This reading may be off by a great deal.
In a high-performance application or when modifications have been completed to a vehicle equipped with a turbo or super charger, an aftermarket gauge should be installed to monitor boost. This will ensure that ignition timing and fuel management is being properly set to the engine's actual power level. Reliance on the original equipment gauge may result in not only an improperly-tuned engine, but catastrophic engine failure.
In this era of high horsepower, small displacement engines, turbo chargers as well as super chargers are depended upon to create the necessary boost to achieve the high power levels. Properly monitoring the engine's critical components is a must and should not be left to inexpensive and inaccurate factory gauges. The installation of a performance gauge to monitor boost pressure should accompany any performance component upgrade.