hey people with turbo user.....want to know if pressure built up when it at neutral? when you set gear at neutral and hit on the gas for about 3-4 rpm does your pressure built up?(does the blow off valve went off when do so)?mine doesnt built up at all.....by the way, i replace a boost sping from 8lb to 5.8lb psi but then when i run it it still over boost why is that?

 

Usually the turbo isn't spinning fast enough at idle to build any positive pressure.

If you're not running a good boost controller you will have boost spikes. During the time it takes for the wastegate to fully open the turbo is still building lots of positive pressure creating a "spike" until the wastegate does open. Good electronic boost controllers will detect when you're about to hit full boost and will begin opening the wastegate earler in an attempt to eliminate the spike. No system is perfect but some are definately better than others.