How can I check to see if supercharger on 2006 4.2L XKR is working? If wish to hook up a mechanical boost gauge what exact line would I install a "T" in and where to hook up power for the gauge illumination? Pictures would be of great help as word in other posts have not been specific enough. I have used a Foxwell scan tool which tells in MAP (Manifold air pressure) but I do not know how this will relate to supercharger boost pressure.. No check engine light is on .Question arose as the acceleration seems less than would expect with 390HP but I have no reference point t know if this is "normal." Thank you.