Test Your Wastegate Cracking Pressure

How to Test Your Wastegate Cracking Pressure

Over the course of tuning, issues that weren’t noticeable with stock boost and power levels may become annoyingly obvious. Boost flutter, boost levels lower than expected, or a drastic loss in fuel economy can all be signs of a wastegate issue. In order to properly diagnose the cause of your vehicle’s symptoms, we may ask you to check the wastegate cracking pressure. Metered air is the most accurate way to go. Using a regulated air compressor or a Mityvac*, you can determine the cracking pressure and adjust from there.

• Connect tubing to metered air source and the wastegate actuator nipple.
• Slowly apply pressure while watching the actuator arm for movement.
• Note the pressure required to move the actuator, this is your cracking pressure.

If you have a boost gauge installed, you can bypass the N75 valve to test the cracking pressure. If you need more information on N75 plumbing, click here.

Simply run a line from the turbo to the wastegate actuator, bypassing the N75 valve completely. With the N75 bypassed and the wastegate connected directly the waste gate will open as soon as the turbo generates enough pressure to overcome the waste gate cracking pressure. Simply drive the car and the maximum boost indicated on your boost gauge or by our data logger is the wastegate cracking pressure.

Bypassing the N75 to check wastegate pressure.

*Mityvac is not connected with Motoza Performance in any way. The MV8500 is the current model that tests both vacuum and pressure. It is similar to the older model used in this video.