3S-GE ACIS/Beams discussion, Discussion about ACIS, TVIS, VVT-i, etc. applicable to 3S-GE motors Options

[delusionz]

thats alright

how would i go about modding my ACIS?

rather than tell you how to mod it heres a way how not to mod it
http://toymods.net/forums/showthread.php?t...;highlight=ACIS

(also I recommend a new thread for 3SGE ACIS/Beams discussion)

I've been playing around with ACIS recently and I've discovered a few things about it,

The basics ... when the vacuum diaphragm pulls the throttles, the larger diameter in the corner of the inlet pipes open up (under the lid) for high rpm and when there is no vacuum to pull the throttles are free to return to the constricted low rpm position.

A few problems noted with ACIS:

1. When switching between high and low rpm modes, the vacuum diaphragm sometimes get stuck in the high rpm mode
2. The engage point is too late

First experiment was to see how the car behaved with the throttle pull lever tied up with cable ties as to lock the throttles in the high rpm position,

What I observed with the butt dyno was that under full throttle the rpm range where the car would "suddenly get up and go" was lower down, noticed in terms of road speed 65kph before, 55kph after (2nd gear) so in other words 5000-7000 was the get up and go range, without ACIS constriction in the intake the get up and go range was observed from 4000 to 7000.

No loss in acceleration was noticed from idle to 3000 under part throttle, but loss was noticed under full throttle, between 3000 and 4000 I couldn't tell either way in neither part throttle nor full throttle whether ACIS was better in low rpm or high rpm mode....

This suggests to me that 4000 is a better changeover point than 4800 for performance. 4800 is an rpm not reached by normal driving due to speed limits & gear selection thus ACIS seems to exist for the purpose of keeping intake noise down at legal road speeds rather than for improving low rpm torque as midrange torque takes a hit with this setup.

My proposed solution on how TO mod the ACIS, is to gutt the vacuum actuator system and replace it with a motorised cable pulling actuator triggered by a frequency switch relay at 4000 rpm the signal could be obtained by the ignitor right behind there.

[eazy2001x]

For those of you who are running ACIS you may want to try a change over from 5200 to 4800, i lowered my 1/4 mile times by doing so in a MR2. I was running a turbo transmission so the engine performed different from you S54 guys but it deff made a difference. My best times at 3000 lbs was a 14.53 logged in my MR2. you also may want to try connecting a VAFC to the ACIS system to control it. It makes things fun. you can leave the ACIS in open for a window of time rather than just open and close you can really customize it. example. if you use a 4800 switch over point and you are on the track. you switch from 2nd to 3rd and drop to 4600 and have to wait a second for it to open at 4800 you lose time. with the VAFC you leave open for a little bit so that you dont have to wait for it to pop open and take advantage of the higher RPMS. also if you notice.. the stock ECU is tuned for a change over point of 5200 so even though you set to anything besides that. at 5200 the ecu will make adjustments to fuel and timing based on its switch over point of 5200. I also have a VAFC jumper harness for sale if anyone wants to play around.

one of my old threads.. enjoy..

Project 5S-GE V-AFC Fun today (Feels Good!)
http://www.mr2oc.com/showthread.php?t=200927