what do you mean you hooked it from the wastegate?
http://www.belitski.com/cars/talonmo...aqhallman.html
ignore the part about t'ing into the BOV line, you don't want to do that on a t28.
Turbo boost nipple on the compressor
(see left hand turbo)
to
Voodoo MBC inlet (that's oppposite the screw adjuster!!!)
MBC outlet (90 degrees to screw) to wastegate port.
It doesn't take much to increase boost from 8 to 16 psi
You have teh MBC with the screw turned counterclockwise as far as you can? you try applying pressurized air to the MBC to make sure it is good and to get close on boost level before installing in the car?
Crappy sketch: