Originally Posted by relecom
I was under the impression that the B18c manifold had a set of betterflies in it that directed exhast depending on the RPM.
Mark
You are correct. To complicate matters, OBD1 triggers them with ground, and OBD2 triggers them with 12v.
I MAY HAVE THAT BACKWARDS.
So, you have a little research to do, this may help:
http://www.ff-squad.com/tech/im/p72.im_1.jpg
http://www.ff-squad.com/tech/im/p72.im_2.jpg
-PHiZ