Depends on which ACIS system you put it on. The twin TB intakes, nobody has figured out what is optimal yet. The older single flap ACIS systems, velocity is increased by leaving it closed, giving you more power.
The engine will still take off around 4000rpm because the ECU's don't advance timing until it also opens the ACIS's VSV.
A/T's stall @ 2400rpm. Giving them a few more coals on the fire for that split second let's them accelerate into the fat of the powerband where the car v6's take off.
Instead of going from peak torque @ stall speed, dropping 10lb-ft, then gaining it back a half second later, it feels slower. You don't get's the burst of acceleration @ 4100-4200rpm when the flap would normally be closed.
The only way you can see what happens, is locking the torque convertor (To prevent torque multiplication skewing data) on a dyno, or accurate road testing that takes into account the smoother onset of power.
The screw is simply an adjustment as to how far the ACIS flap closes. Unbolt it from the manifold and look at it to see how it's closing... That's the only way you're going to know. Once it's closed, it's not gonna close any more.
It's been a few years now, but I remember mine being about a screw turn off from as perfect as it'll get without sealing the seams.
Posted: Fri Feb 03, 2006 6:56 pm
