How To Check Boost Pressure.

Equipment Required:

Accurate boost gauge, length of hose, hose connectors.

Connection

• Check the manufacturer's data to establish the boost pressure limits.

• On the majority of petrol engine vehicles, the boost reading is taken from the inlet manifold.

• Connect the boost gauge hose into a convenient take-off pipe on the inlet manifold. Ensure that the connection is after the throttle butterfly valve (a vacuum will be present with the engine ticking over).

• Do NOT connect boost gauge hose into brake servo vacuum line.

• Carefully route the boost gauge hose back to the dashboard. Do not allow hose to foul throttle linkage or any other moving parts i.e., cooling fan, alternator or water pump.

• Connect the boost gauge to the hose and place in a convenient position which can easily be read from the driving position.

Testing

• Drive the vehicle until a normal water temperature reading is attained.

• Choose a long straight empty road (preferably with a gentle incline). Steady the engine speed to around 3000 rev/min and select either third or fourth gear, depending on road speed.

• Using your left foot on the brake pedal, gently increase throttle whilst applying the brakes to maintain 3000 revs/min.

• When full throttle is reached at 3000 rev/min check the boost reading on the gauge.

• If the boost pressure requires adjustment, consult the manufacture's recommendations.

 

IMPORTANT NOTES:

• If, whilst taking a boost reading, pinking or detonation is audible from the engine, the test should be aborted to prevent damaging the engine.

• This test will overheat the vehicle's brakes in a short time. The test procedure must be conducted within five seconds to prevent brake fade.

• Only conduct testing on a private test ground or closed road.