by fivebob » Mon May 02, 2005 7:33 am
Several possible causes for a lower boost, firstly I would check for boost leaks anywhere in the system, particularly the BOV. If that doesn't find the cause then I'd check to see if you've actually reduced the flow from the airbox which would cause a low pressure area before the turbo making it produce less boost.
Stock boost should be around 13psi but that varies depending on load & RPM, generally you'll only see that sort of level in the mid RPM range, from 3rd gear up (on a manual).