Boost Gauges

Do you know how much boost your turbo or supercharger is delivering, and whether the engine pulls normal vacuum at idle? A boost gauge shows the intake pressure directly, so you can keep track of your project and spot deviations before they turn into problems.

What does a boost gauge show?

The gauge shows the pressure in the intake manifold. Under load you see boost pressure in PSI. On combination boost/vacuum gauges you can also read vacuum in inHg at idle and light throttle. Unusual vacuum or boost that does not reach the expected level can point to issues such as leaks or a fault in boost control. The cause depends on the engine. We stock gauges from AutoMeter in series such as Phantom, Cobalt, Sport-Comp II and Ultra-Lite.

How to choose a boost gauge

There are four main things to consider:

• Range: The scale should cover your highest expected boost with a little margin, e.g. 0-15, 0-35 or 0-60 PSI. An unnecessarily wide scale can make small fluctuations harder to read.
• Boost-only or combination: A boost-only gauge shows positive pressure only. A 30 inHg/30 PSI gauge also shows vacuum.
• Mechanical or digital: A mechanical gauge receives pressure through a hose from the intake. A digital gauge typically requires a sensor and power, depending on the model. Air-drive versions are also available.
• Size and design: The gauges are typically 52 mm (2-1/16"). Choose a series and dial colour that match your other individual gauges.

Installation and use with other gauges

Connect the gauge to the manifold after the throttle body if you want to see vacuum. Route the hose or wiring away from heat and moving parts. Check the connections for leaks, as they can cause incorrect readings. Boost pressure does not tell you everything about the engine. You get a better overview of the engine's condition if you add a wideband air/fuel ratio gauge and an oil pressure gauge.

Frequently asked questions

Should I choose a mechanical or a digital boost gauge?

A mechanical gauge is simple and only requires a pressure hose from the intake. A digital gauge typically requires a sensor and power, but gives a precise numeric readout. The choice depends on your installation and how you prefer to read the pressure.

Which range should I choose?

It depends on your project. Choose a scale where your maximum boost sits well within the scale. For low boost this could be 0-15 PSI, for higher boost 0-35 or 0-60 PSI.

Why doesn't my gauge show vacuum?

A boost-only gauge shows positive pressure only. For vacuum you need a combination boost/vacuum gauge. If a combination gauge does not show vacuum, the connection may be before the throttle body, or there may be a leak in the hose.