Let's talk about the good old ACIS.

[Ma70.Ent]

So, from what I recall, the ACIS limits the amount of air that is let through so the 7MGE can maintain low end torque. If the ACIS were to be disabled, would there be any way to take advantage of that extra air thats going through? (IE: What modifications could you do?)

I have a few guesses, but I'm pretty sure I'll get butchered for making this thread

 

[foreverpsycotic]

from what i have heard, ACIS combinds a short runner and a long runner, and opens it up under certain conditions(Throttle possition and rpm), and is activated by vaccum. it has been tried and proven that when closed all the time, you loose top end and when open all the time, you loose bottom end. the way it is now is the best way for it to be.

edit 300th post YAY

 

[s383mmber1]

After i researched this for a while when i was NA, i learned from several that toyota designers spent hundreds of hours working on this system (guess) and i doubt your gonna be able to find a better soulution in a few minutes!

IE: Its best left the way it is!

 

[corylee316]

There have been people who have tried to leave it open all the time manually and what not with no gains. If you are keeping things stock up top you might as well not change the ACIS.

 

[phoenix6]

i have no cat, and pretty much a straight through system. Before my rebuild my ACIS wasnt plugged in, the wire was busted. When I hit 3500 rpms the car felt like it boosted 2 or 3 psi and lauchned HARDER, Im not kidding and I dont know why. Now that ACIS is plugged back in its a straight through powerband, I dont know if I had less low end as well, didnt pay attention.

 

[Big Wang Bandit]

If you can feel it it isn working properly

 

[phoenix6]

If you can feel it it isn working properly

You mean the gain I FELT at 3500? Hrmmm

Hey get outta here 1jz man....

 

[Big Wang Bandit]

I still Own an NA =P

Any motor will coem alive at 3500 RPM.

The ACIS is really just there to smooth the torque band in higher RPMs.

 

[phoenix6]

I still Own an NA =P

Any motor will coem alive at 3500 RPM.

The ACIS is really just there to smooth the torque band in higher RPMs.

yeah but are u really enjoying that NA anymore? lol

yeah I guess you could say it smooths it, my car kicked at 3500 without it, I kinda liked it....

 

[Ma70.Ent]

Apparently most GE owners say theres starts working at 3k-ish rpms.

 

[phoenix6]

Id say about 3500-3800 is when I noticed it

 

[CRE]

I can't feel mine KICK in... I know it's working there is a difference, but it's not harsh like most owners report.

 

[corylee316]

At about 3800-4000 I get a little push, no kick. I had read in the TSRM that it was supposed to be around that range depending on the TP. I didn't read in the TSRM about it "kicking" anything.

 

[Ma70.Ent]

Yeah, mine doesn't "kick in", it just comes alive at around 3k-3.5k rpm.

 

[corylee316]

I think everyone is being a little over zealous in their description. It is something that you can feel though.

 

[ValgeKotkas]

Duh, ofcourse it isn't like an airplane gathering speed after the "warm-up":biglaugh:

 

[corylee316]

I know that but the way that some people describe it it sounds like they get a huge kick in the pants.

 

[bowsercake]

it's not vtak, it doesn't kick in yo.

 

[jetjock]

Maybe this will help. I don't have one on my car but this is what the tech manuals say:

The ACIS is designed to shift the torque band higher along the rpm range. It does this by responding to changes in the throttle opening angle (VTA signal of the TPS) and engine rpm (NE signal in the CPS). The air control valve is then opened or closed by the ECU via a VSV and vacuum actuator.

The valve is located in the center of the manifold and when closed divides it into two sections - a front chamber for cylinders 1 to 3 and a rear chamber for cylinders 4 to 6. A closed ACIS valve has the same effect as lengthening the intake manifold while an open valve has the same effect as shortening the intake manifold. In other words flow efficiency what's being controlled.

When the ECU turns on the VSV vacuum is applied to the actuator and closes the valve. When the VSV is turned off atmospheric pressure is applied to the actuator and opens the valve. There are four combinations of speed and throttle angle the ECU uses to decide when to open or close the ACIS:

1) Above 60% throttle angle and above 4,200 rpm: VSV off, ACIS open.

2) Above 60% throttle angle and below 4,200 rpm: VSV on, ACIS closed.

3) Below 60% throttle angle and above 4,200 rpm: VSV on, ACIS closed.

4) Below 60% throttle angle and below 4,200 rpm: VSV off, ACIS open.

 

[da89soup]

Um, its NA with or without acis we are slow!!!! I got to go with dont fix it if it aint broke..............:icon_razz