Originally Posted by
GraphiteGhost
Is that vacuum present during a 'boost' condition? OP said took it out for a 15 min hard run and found all the oil?
Should always be negative at the vacuum line point - if it wasnt there's no driving force to suck air into the engine.
The positive boost condition is after the intercooler>>supercharger which is after >> the throttle body.
Not to confuse things...most of the time the MAP registers negative prs anyways until you're over 2500rpm and you'll find during casual city driving this is not very often unless you hook it.