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Boost Gauge

Turbochargers are being fitted to an increasing number of stock performance cars these days, but these components need to be carefully monitored so that everything works correctly.


Very Easy

What Is a Boost Gauge?

In any vehicle with forced induction, extra power is delivered to the engine by compressing the air that enters the combustion chamber. It’s important to regulate the amount of air going in and to make sure that it is monitored at all times, so that the mixture of fuel to air is correct. This is where a special instrument known as a boost gauge comes in, as if the situation were not monitored, damage could be caused to the engine itself.

How Does a Boost Gauge Work?

Whether fitted with a turbocharger, a supercharger or both, the bottom line is that the vehicle’s engine relies on a steady and very controlled injection of compressed air.

The boost gauge measures the pressure of that air, as it enters the combustion chamber. To achieve this, a special tube is attached to the intake manifold of the engine, and this will gather a tiny amount of the incoming air and present it to the gauge, located on the dashboard. The internal components of a mechanical boost gauge center around a Bourdon tube, which inflates and stiffens as the incoming pressurized air meets it. As this happens the tube moves a link, which in turn activates a pointer through a series of cogs and springs to indicate the associated pressure on the screen of the device. However, some vehicles are fitted with a digital boost gauge that’s meant to electronically measure the boost provided, by monitoring the air compressor and providing an estimate of the output to the gauge. This indicates the number of bars of pressure, or the pounds per square inch.

How Is a Boost Gauge Made?

A boost gauge is manufactured as a unit within a cylindrical outer covering that’s mounted to the dashboard of the vehicle. In mechanical terms, most of these gauges operate the Bourdon tube method to display the reading and may be connected to the vehicle’s power source to provide a means of illumination. This type of gauge will be connected to the inlet manifold through a small diameter, rubber pipe.

How Does a Boost Gauge Fail?

  • Damage to the supply hose
  • Internal component failure

What Are the Symptoms of Failure?

  • Failure to operate
  • Inconsistent readings when the mixture is otherwise correct

What Are the Consequences of Failure?

  • Damage to the engine and other components if boost pressure is not adequately monitored

To avoid the need for an expensive rebuild, the boost gauge should be monitored carefully to ensure that everything is working within defined parameters.

If you have questions or concerns about Boost Gauges or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.