Help understanding acis

[stanno]

okay, i understand the concept and theory of how it works. but below is a diagram i got off toyodiy.com from a 2nd gen 3s-ge engine, where does the air enter and where does the acis feature work here ???

[white90dx]

For the 3s-ge with ACIS:

The throttle body is located on the far right of the upper part of the manifold shown. During normal operation air flows to the first plenum and splits into the four runner shown and travel independantly to each of the four cylinders.

During high RPM operation, flaps on the second plenum open (shown where near where the two manifolds attach - it has the extra cover shown in the diagram). This effectively shortens the intake runners to allow air to be 'shared' between the runners for more effective use of the runners.

Basically, Long runners = good for low end torque, short runners = good for high end power.

ACIS stands for (I think!) "Acustic Controlled Intake System." Really, it means the resonance of the two different runner lengths is used to help optimize performance and low and high engine speeds - like a weaker version of VVTL-i or VTEC. It is used on the generation 3s-ge shown and most of the newer Camry V6's.

This is not to be confused with TVIS, which is a different style system...

-Charlie

[stanno]

Originally Posted by white90dx

For the 3s-ge with ACIS:

The throttle body is located on the far right of the upper part of the manifold shown. During normal operation air flows to the first plenum and splits into the four runner shown and travel independantly to each of the four cylinders.

During high RPM operation, flaps on the second plenum open (shown where near where the two manifolds attach - it has the extra cover shown in the diagram). This effectively shortens the intake runners to allow air to be 'shared' between the runners for more effective use of the runners.

Basically, Long runners = good for low end torque, short runners = good for high end power.

ACIS stands for (I think!) "Acustic Controlled Intake System." Really, it means the resonance of the two different runner lengths is used to help optimize performance and low and high engine speeds - like a weaker version of VVTL-i or VTEC. It is used on the generation 3s-ge shown and most of the newer Camry V6's.

This is not to be confused with TVIS, which is a different style system...

-Charlie

ok, just seeing if i thoroughly comprehend

long runners are better for low-mid power/torque, and short runners for higher rpm operations... during low rpm air would flow like what is below...



ok, for when the switch is made, where exactly is the air re-routed?

[white90dx]

Originally Posted by stanno

ok, for when the switch is made, where exactly is the air re-routed?

So far, so good. The air isn't re-routed. All that happens is the flaps that go to the extra plenum that sits in the middle of the runners are opened. Looking back up from the intake valve to the manifold/plenum, the distance to a 'large' volume of air to draw from gets much shorter.

-Charlie