questions about ACIS! and how it really functions

[SRZMK3]

i am beating a dead horse with the old hood of my car i know!! ::dead horse::

i got how it all opens and how it increases power when functioning properly and how it activates and how the ecu works to activate it... but there is one part i have never been able to rule out since nothing visualizes it properly.

k so when the acis is closed at low rpms the middle valve is open horizontal letting lots of air into the engine simulating long intake runners, and at 4200 rpm the vsv activates and the acis plunger system pulls downwards and closes the valve shut, valve goes vertical, and seals the hole inbetween the sides of the intake manifold simulating short intake runners? if i wrap my brain around it it seems when its shut the intake runners run longer.

:aigo::: snowart ::

 

[mshaw067]

that is the way it works. Shorter intake for better low end.

 

[SRZMK3]

funny thing is longer intake runners are for low end and short is for top end...

 

[CyFi6]

Theres a sticky on this
http://www.supramania.com/forums/showthread.php?144276-ACIS-Reference-Thread
While over 60% throttle and high RPM the valve is opened, effectively shortening the runners.

 

[SRZMK3]

lol then why is mine wokring backwards? when im at low rpm the valve is open and then i floor it the plunger pulls and closes the valve.

 

[CyFi6]

It could be malfunctioning. How are you watching it when you are flooring it and above 4,200 RPM anyways? At low throttle and low RPM it should be open, and it will close at throttle angles above 60% below 4,200 RPM.

 

[mshaw067]

i was mis informed. disregard my comment

 

[SRZMK3]

i can see it engage while i open the throttle by hand and see it move when rev. it functions like it should, it just seems with it my car just looses all power when it engages after 4200 rpm when i take the vacuum line off of the plunger actuator and plug the line the car just takes the hell off.

 

[AJ'S 88NA]

i can see it engage while i open the throttle by hand and see it move when rev. it functions like it should, it just seems with it my car just looses all power when it engages after 4200 rpm when i take the vacuum line off of the plunger actuator and plug the line the car just takes the hell off.

If the ACIS is working right you shouldn't "feel" anything.

 

[SRZMK3]

then how become it is functioning with the vacuum line and the plunger working and i feel something which is major power loss, and i dont feel anything when its unplugged the car just completley takes off at all rpms and is much faster in every way... its like the working function of acis is hindering my car greatly.

 

[MPR]

^Are you sure all vacuum lines and vsv associated with the ACIS is connected and hooked up correctly?

When you give it a good rev by hand, you should see it activate for a moment when you let off the throttle and the engine revs back down to idle.

Also; it is closed (butterfly vertical) below 60% throttle and 4200rpm. This lengthens the intake runners to increase intake air velocity, effectively increasing volumetric efficiency at lower rpms. At over 60% throttle and above 4200rpm, it opens (butterfly horizontal) which shortens the intake runner length to increase the volume flow rate, effectively increasing the volumetric efficiency at higher rpms.

If it is possible yours is operating in reverse, you may have a couple vacuum lines mixed up... ?

 

[Nick M]

k so when the acis is closed at low rpms the middle valve is open horizontal letting lots of air into the engine simulating long intake runners, and at 4200 rpm the vsv activates and the acis plunger system pulls downwards and closes the valve shut, valve goes vertical, and seals the hole inbetween the sides of the intake manifold simulating short intake runners? if i wrap my brain around it it seems when its shut the intake runners run longer.

That is backwards, and I think that has been pointed out by now. The default position of the plugner is open. Engine vacuum is applied via the VSV closing the valve when low speed torque is needed. And I have driven a Supra when the VSV was frozen, limiting the low speed torque and always open. It isn't better at all rangers, not even close. The engine is not large enough to fill the manifold. Which is why the two stage system was developed.