Post by
R240NA »
https://forums.nicoclub.com/r240na-u1367.html
Wed Oct 16, 2002 3:34 pm
First off, the secondary butterflies are only found on 91-early 93 DOHCs. They are located right at the end of the upper plenum by the head, and actuated by a vacuum pump mounted behind the head by the firewall. Removing them requires removing the intake manifold. Each plate is screwed into a long rod, the rod is held in place by a set screw in the center and a bolt at the end. You'll ned to remove each plate first, then draw the rod out the back end. Replace the center set screw and tap or seal the bolt hole at the back and you're done. Pull the vacuum actuator off and cap the line going into it, or trace it back to it's originating point and cap it there. While you've got it off, you might as well ditch the TB cooling lines, as well as the cooling loop on the lower plenum. Whole job takes a few hours if you're a novice, and you'll need to order the upper plenum gasket to replace the existing one, it usually tears when the manifold is removed. Enough info for you?