doublee

Have an actuator of sorts on the front of the intake, looks to be vacuum operated, definitely moves something inside the intake.

First what is it?

Second, do i need it? This engine is going in my NA6 so the fuel rail needed is from a 99, the feed line runs right where this actuator is.

technicalninja

VTCS - Variable Tumble Control System.
All 01-05 had this. Most folks delete this system (remove the butterflies and the shaft).
Better to just use the entire intake off the 99-00 engine.
VTCS helped reduce emissions during cold start operation.
The butterflies and the shaft are a restriction of the intake track.

The earlier manifolds (99-00) had the VICS system which changed the length of the intake track depending on RPM.
VICS helps the engine make slightly more torque at specific RPM ranges. VTCS does not.

Biggest issue with the VICS is the outer vacuum actuator are now 20+ years old and new actuators are expensive.
If you purchase a VICS manifold make sure the actuator works.

Another option is the "flat top" intake from non-USA cars. No VTCS or VICS on this one.

My suggestions are flat top, followed by VICS (with working actuator), and finally VTCS with the butterflies and shaft removed (have to seal the shaft holes).

doublee

Awesome, thanks! Seems the 99-00 intake would probably fit the 99 fuel rail a little better.

doublee

Actually found a flat top. Thanks!