SolaraGuy.com

This post relates to gen 2 and 2.5 V6's.

If you have ever accelerated hard you should notice an unevenness in power delivery with a distinct power bump around 4.2K rpm, this is due to the ACIS system activating (google it). On my car at least, the when the ACIS engages it is very noticeable and annoying as it makes aggressive acceleration very uneven, and it feels like it should activate earlier to avoid this jump in power delivery.

I wanted to activate the ACIS earlier to avoid this jolt in power delivery. What I did was connect the vacuum actuator valve (the thing that activates the ACIS) to the vacuum switching valve (the thing that controls the opening of the secondary intake). The secondary intake supposedly is activated at 3.2 K rpm, nearly 1K rpm earlier than the ACIS actuator ( at 4.2K rpm). All I had to buy was a few feet of vacuum tubing, other than that its just a matter of moving a few other vacuum tubes around. My initial impression is that power delivery is smoother but am not sure if the car pulls harder overall. I cant post pics but If you need more details to try this yourself email me at ahausheer@yahoo.com and I can give clear and specific details. Anyone ever try other ACIS mods, like keeping it permanently engaged? Cant find a dam thing online but ill keep experimenting.

Very happy with my Solara but I seriously want more power and speed, is there nothing we can do?

ahausheer wrote: Cant find a dam thing online

Like this? http://www.toyotanation.com/forum/showt ... p?t=123467

By the looks of it, Maybe something I'd consider when hot lapping, but not daily driving or auto-x. Just depends on what you're looking for.

Dr J

Yeah kinda like that link but im using the VSV to actuate the ACIS not just straight vacuum. Using direct vacuum will cause the ACIS to be permanently activated and you will loose power on the low end. My technique largely prevents this loss of low end power and smooths out overall power delivery. One thing that is interesting is that if you hook up the vac lines so that ACIS is permanently engaged, the engine revs freer and seems to have less engine braking, it also however, is slower on the low end. Anyone else experimented with ACIS?

no experience with the acis but i'm subscribing to this topic. that'd be amazing if you really found out a way to get rid of the lag.

*edit*
I hadn't read the other SG threads on this so I'm reading through them now. Sounds like everyone has different ideas to what it'd do. I'm gonna have to do some more reading before I toy around with it.

p.s. if you're reading the link from the TN link Thurz posted, change the link to .com instead of .org and the page will work.

Yeah there is a lot of confusion out there about the ACIS. Point is, under heavy throttle, I believe it activates at 4.2 K rpm. What activate means (opens butterfly valve?, closes valve?.. whatever) I don't care. To be clear there is still a significant lag around 10-20 mpg, especially when accelerating out of a turn. This mod doesn't affect that at all, nothing will get rid of that. Theoretically this mod will cause you to loose a little mid range HP and torque while gaining a smoother power delivery, but the power loss is so subtle I don't feel it at all. If you don't notice a weird bump in acceleration around 4.2K rpm when stock then this mod would be pointless for you. ACIS effectively switches between two intake lengths depending on rpm and throttle angle and to me it felt like it was activating too late, perhaps as a result of age/ wear on various engine parts. I have a few days with this mod now and am very satisfied, pulls the same to me but feels smoother. Also please note that I have done doc johns intake mod which keeps the secondary intake permanently open. I have switched back and forth between fully stock a few times and the ACIS mod and secondary intake mod and will permanently keep both mod in place.

This is all in relation to the stock intake set-up, right?

GzNutz wrote:This is all in relation to the stock intake set-up, right?

Yeah but, it seems like something to leave alone unless you're FI.
Probably a better idea is a variable intake, but way beyond the scope of most bolt-on modders.

Dr J

Yeah stock intake. Mod is easy and reversible and if you like to tinker then try it out, you should probably replace the vac lines anyway and whats the worst that could happen, you learn about VSV's and vac lines?. I like it, and am keeping it. My next mod will be a dynomax vt exhaust, the one with the valve, and the next mod after that will be a different, faster car. Until then, if I can experiment on my car safely, I will.

Little hard to admit after all my praise of my own home made mod but.......... I am back to fully stock on intake mods (and intake). Guess the power of placebo and trying to believe I made just a little bit of power is strong and convincing. Stock feels as good or better than all the vacuum experimenting I have tried. I did find a cracked vac line though so you all might want to check for that at some point. Well here's to learning about cars and having fun experimenting.