Turbo Boost

I have a problem with Z20LET turbo boost. Car will boost up to 12-15psi on boost gauge that boost drops off. Will reboost again but looses boost at around same figure.
All the usual things checked - fault codes, leak check in vacuum and pressure side and turbo, new solenoids etc. Been to BOT but still the same.

Is this how VXTs actually run? It has Courtenay stage 2 upgrade. Plenty of torque at lower end. Don’t understand why boost dies

Any ideas?


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these cars are setup to over boost then hold 3 psi or so lower

 

E.g Stage 2 is around 15/16psi over boost for a second or so then hold around 12-13psi.

 

If your car does this, this is normal if he peaks at 15psi then falls below 10 or even lower you have an issue, or boost leak

 

Also worth noting you will not hold high boost in low gears, so do a 4th gear pull from say 40mph and the boost guage shoot go round peak then fall back a little bit

Edited by scw02102, 22 July 2019 - 05:38 PM.

Blow off valve or boost solonoid