TII secondary THB mod (pros and cons).

[FRED]

The last time I looked the number two secondary plates do NOT stay open all the time. There is some linkage consisting of a damper.....rod and spring and a flat black cam that delay the opening of the number two secondary throttle plates.

That's why those parts EXIST on a USA turboII thorttle body.

You'll get no argument from me that on a NON TURBO engine the number two secondary throttle plates stay WIDE OPEN after the engine warms up. NOT so on a TURBOII car for the USA.

A jpg of a USA body is attached that I stole off the web. Pay no attention to the red arrows. To the left you can see the flat black cam that the piston of the damper rides on. Black cam is just to the left of the bottom 12mm wrench size nut..............the damper is the gold round object in the left bottom of the picture.......the rod and spring with 8mm wrench size nut are to the left and in the middle left of the picture.

The cam.......rod and spring....damper cause the number two secondary plates to open slower than the number one secondary plates for Driveablility purposes and this happens long after the engine is fully warmed up.

If the double throttle diaphram is installed and if the water is still cold.......the number two secondary stay fully closed and the black cam etc play no part whatsoever til the engine gets hot.