My boost gauage read 20 at idle with the vortech set up, is that normal?

 

if its in the vacuum then yeah

 

that's 20 below 0. means -20, which means vaccum. so, yeah. that's normal.

 

if it's positive 20 (20psi instead of 20mmhg) then you probably have your boost sensor between the bypass valve and the blower which won't show vacuum. That port on the blower is for positive pressure only and not for your "boost/vac" gauge. You need it on the engine side of the throttle body.