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· Dr. Jeff Lange
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Just because Toyota started calling it ACIS in 93 with the advent of the 2JZ-GE doesn't mean the 7M-GE didn't use it.

Toyota's own words: "The ACIS system is identical to the Intake Air Control System in the 7M-GE" (Source: 1993 Supra New Features Brochure, Page 32).
 

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Robbman said:
1. Show me a proven reference that Toyota calls the 7M-GE system an ACIS system. There is almost a decade between motor designs between a 7M-GE and a 2JZ-GE. The 7M system operates exactly opposite to what you wrote about the ACIS system. Either Toyota is wrong, or you are. They are different... period. If you call the 2JZ system an ACIS system you can't call the 7M system an ACIS system. Maybe there's a reason why there was no mention of 'ACIS' until after the 2JZ and 1MZ were introduced (93 and 94 respectively...)

A carburetor and TBI both do the same thing, provide fuel for a motor, but you don't call one the other on that basis do you?

2. Using two throttle bodies, the runners are still separated. The length of the Y-pipe now becomes the length of the throttle bodies. I see where you're getting confues though... I'm saying to attach the throttle bodies directly to the upper manifold.

3. Speaking of comparing apples to an orange...

If there were little room for improvement, and Toyota acoustically designed the 7M-GE, then there would have been no need to change the design so drastically as they did on the 2JZ-GE. Larger diameter runners, larger diameter Y-pipe, different upper manifold design, etc all affect the acoustics of the manifold.
1. I'm going to work tommorrow. I'll do just that. And if you want to get technical, the M series motor was around 30 years before Toyota even knew what a JZ series motor was. I'm calling both systems ACIS systems, because they vary the length of the intake runners, which is what ACIS is all about. I would call a TBI and carb "means of providing fuel to an engine" becuase that its what they do.

Please tell me how the system on the 7m-ge DOES NOT change the length of the intake runners.. i would love to hear you explain.

And, of coarse, I must be the incorrect one, or possibly even toyota, for labeling a system that is doing exactly what its name describes.......

2. No.. i'm not confused at all about what you are saying. Lets simplify things and look at it from a single dimension; length. Lets measure the distance from the intake valve seat to the point where each runner gets the same amount of air ( shared air). Ok... now, using guesstimated numbers, we can see a difference here. With the ACIS valve closed... The shared air is just behind the TB, lets say it has a distance of 28 inches before reaching the valves. When the ACIS valve is open, the shared air is in the middle of the intake manifold. Lets say that has a distance of 19 inches before reaching the valves... The difference is 9 inches.

Remove that Y-pipe, and there is no longer "SHARED AIR" in the ACIS valve closed stage... Thus making it POINTLESS... The length difference then becomes about 2 inches, and you wouldn't gain anything except throttle response.



3. You are comparing Apples to oranges... The M series and JZ series are completely different engines! Aside from obvious things... Thats like saying toyota improved the 5s-fe with the 3s-gte... come on! thats just dumb. toyota did improve the M series engine over 30 years, but calling the JZ an improvement of the M engine is pointless becuase its a different engine series. Of COARSE, they are going to change the ACIS system "drastically" on a DIFFERENT ENGINE... I'm sure the Toyota engineers said " oh ok, well, lets take the exact ACIS system from the 7m and throw it on the 2JZ, even though the compression ratios, valves, and pretty much entire air flow through the head is different!"

hey, heres a good idea, lets take the ACIS off the 3s-ge and throw it on a 2UZ!! that makes sense.

of coarse they are going to change the system, its a DIFFERENT ENGINE!!! Derrrrrr :stickpoke:

-------------------
A little history for ya...

In the 1980s toyota developed a system they called T-VIS. Toyota - Variable Air Induction Systems. They put this system on the 3S-GE, 3S GTE, and 4A-GE engines. It effectively changed the volumetric efficiency of the engine and Intake manifold. This system utilized long thin runners at low engine speed to keep intake air velocity up, and wide runners at high speed to help the engine breath.

In 1986, with the introduction of the 7m-ge, toyota introduced ACIS.

"The Acoustic Control Induction System (ACIS) is used on the 7M-GE, 3VZ-FE and 2JZ-GE engines. As with the T-VIS system, the purpose of this system is to improve engine torque throughout the engine rpm range. The system consists of the same basic components as T-VIS and operates similarly. The ACIS system uses a single intake air control valve located in the intake air chamber which effectively changes intake runner length as it opens and closes."

oh.. btw.. the ACIS on the 7m-ge is Throttle staged. So, that makes it as true of an ACIS system as it can get. It has it all. The Crossover throttle angle is 60%. with engine speed a 4200 rpms... which means....

10% throttle, 1000 rpms === ACIS valve open
10% throttle, 5000 rpms === ACIS valve closed
100% throttle, 1000 rpms === ACIS valve closed
100% throttle, 5000 rpms === ACIS valve open

I'm pretty sure thats EXACTLY what i said. Need proof???



thats a toyota diagram... more of those can be found on this site,

http://turbomr2.com/MR2/Reference/TVIS/TVIS.htm

...and i will dig and dig through my TIS computer and storage rooms full of Toyota Documentation at my dealership if you still can't face the fact that the 7m-ge has a 100%, full, true, toyota ACIS system. CUT AND DRY!

:rolleyes:
 

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Like i promised. I dug through our stuff, and found a lot of interesting material. Including the 1986 New Car Features for the supra. As well as the 1987 New car Features for teh 7m-gte. A lot of good info in there. I'm probably the second person to open this book too. ;)


This picture is of a 1993 1/2 "NCF" book describing the 2JZ-GE engine.


This picture is off of our TIS database.



And here we have the Complete TOYOTA description of the ACIS system on the 7mge.



 

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haha.. i didn't even notice it was p.32

nice work jeff

edit: Jeff, i have a copy of almost all the mk3 years "new car features" book's for the supra... I think i might start making copies.
 

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jong, if you had bothered to put any of this info here on the page you wrote, it would have made more sense.

The butterfly valve on the 7M-GE is not closed at idle. In order for the system to work as your saying, at it has to close after idle, and then open back up.

AT 4200 RPM, it either leaves the valve closed, or opens it, depending on WOT or not.

On the 7M, when the valve closes, fuel pressure up also occurs. If the valve opens up again t 4200 RPM FPU cuts off. That's what doesn't make sense to me.

Isn't anything more than 60% throttle considered WOT on a TCCS system? I seem to recall a discussion about this before...




You've shown me is that the system on the 7M is called the Intake Air Control System (IACS), which makes sense, as that is what the VSV that controls the butterfly is called.

There has to be some reason why Toyota chose to call the same system something different on the 2JZ... i.e ACIS.

To quote you...
Of COARSE, they are going to change the ACIS system "drastically" on a DIFFERENT ENGINE... I'm sure the Toyota engineers said " oh ok, well, lets take the exact ACIS system from the 7m and throw it on the 2JZ, even though the compression ratios, valves, and pretty much entire air flow through the head is different!"
Exactly my POINT... What they did was take the identical IACS system on the 7M and modified it into ACIS.



As for runner lentgh using two throttle bodies....

As long as you make the length of the runner from the dual throttle bodies to the head the same as the distance with the single throttle body, the system is not affected.

I.e, the axis of the dual throttle bodies mut be colinear with the axis of the single throttle body.

The only time 'shared air' is in effect is when the butterfly vavle is open (i.e, short runner)... when the valve is closed, the runner length is now from the throttle plate.




not to all gang up on you..but dont misinform the public w/o hard cold facts to back you up
Wu tang....

Don't post a page and link to it if you don't have all your facts there either...

I was disputing the 'facts' presented, not informing. It wasn't until this thread that any facts showed up. Had they been there to begin with...

You need to go read every thread on this forum and then post that....
 

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robbman--

I didn't even realize i had all this information until i dug through our back library. Upon the initial write up of my ACIS explanation, i just got general system information. You are correct in saying that it wasn't right for me to make assumptions on the 7m-ge system w/o documentation, but its the theory and basic operation that i was trying to get across.

AT 4200 RPM, it either leaves the valve closed, or opens it, depending on WOT or not.
WRONG!! At idle, the valve is always going to be open. At 4200 rpms, if the VTA ( throttle angle) is below 60% then it will close. At 4000 rpms with a VTA of 70% or higher the valve is closed, heck, at 1500 rpms with same VTA the valve is CLOSED, as it passes 4200 rpms, the valve OPENS.

ITS A TWO STAGE ACIS SYSTEM!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I understand about what your saying, about the valve being open at idle. Which is understandable, but that doesn't change anything about how the system operates.

as far as FPU....

The NA doesn't even have FPU. Thats a GTE function. Sorry to dissapoint you. And FPU doesn't even have anything to do with 4200rpms. FPU is a vsv that opened the turbo fuel regulator to atmosphere during hot starts, so the regulator see's no vacuum or boost.
Quoted from Toyota EWD: "The fuel pressure up system causes the VSV (for FPU) to come on for high temp. starts in order to increase the fuel pressure, improve startability at high temperatures and provide stable idling. The ECU evaluates the input signals from each sensor (1, 2, 10, 11) outputs current to terminal FPU and controls the VSV.
That rise in fuel pressure you see at 4200 rpms is the Fuel pump relay/resistor changing the fuel pump into 12v mode. IT has no correlation with any VSV's.

The ACIS vsv on the GE is for solely ACIS actuator movement and is controlled by the ECM.

If you look at the vacuum routing diagrams, you'll see what i'm talking about.

On the GE, the fuel pressure regulator and vac. tank are T'ed into the same line. The Vac tank has an internal check valve, and the VSV controls the application of vacuum to only the ACIS actuator.



On the GTE, the fuel pressure regulator line goes through the FPU vsv. When the ECM sense hot start, it opens that VSV to allow atmosphere to the FPR, then later, the ECU closes that VSV to allow the FPR to run off vacuum or boost.



As for the name change, Toyota has changed maby names and abreviations over time. Most of which occured when the auto industry tried to standardize most abbreviations. For instance, a THW sensor and ECT sensor are the same thing, Coolant temperature. ( THA = IAT, ect..) Toyota has also changed the name of systems over time.



Toyota didn't modify the system on the 2JZ in terms of basic system operation. They did however change the intake diameters, manifold design, ect. ect. Each ACIS system is designed for that specific engine, a 7m ACIS will not work as effectively on a 2JZ and vice versa.

And, you still are not getting the point on the dual throttle bodies. First, there is always "Shared Air." There are two stages that vary where the Shared air is. The first stage is just behind the throttle body. The second stage is in the middle of the manifold. by removing that Y-pipe you are also removing that first stage just behind the single throttle. Maybe if you made the runners and throttle plates EXACTLY in line down to the smallest degree, it may be possible, but any difference between the two would cause a difference between the airflow to half the engine.

2. Using two throttle bodies, the runners are still separated. The length of the Y-pipe now becomes the length of the throttle bodies. I see where you're getting confues though... I'm saying to attach the throttle bodies directly to the upper manifold.
That statement led me to think you wanted to bolt the throttle bodies directly to the manifold. Which is what you said.... And now you said you don't want to do that? Which is it? Because attaching throttle bodies directly to the manifold would ruin ACIS. creating runners so that the throttle plates, on each, are EXACTLY where the original throttle plate is MAY work. maybe...

AS for the comment made to Wu_tang... I had all my facts, i don't see any varience between what i published in my ACIS description and the operation on the 7m. its identical, aside from the VSV map and the throttle activation %. But i stated in there i hadn't found that information yet. The facts presented are not in dispute, as they are facts. your perception is what is being disputed. There have been facts about the ACIS system long before this thread. A little searching on both the internet and supraforums would have revealed that.

I mean, his comment wasn't totally out of line. You said things that aren't true, and you made those claims without hard evidence to support your argument. And it doesn't take a person who has "read every thread on this forum" to recongnize the difference between a strong and weak argument-- or the presentation of a statement without accountable information to back that statement up.
 

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Getting a little long here...

Pre 89 NA's do have a FPU, and it's activated by a VSV (it's pin 10 on the 24 pin ECU connector), on post 89s, it's simply vaccuum activated. I was wrong about the post 89s, I thought that the VSV was in-line with both systems.

Note the missing identifier on pin 10 for the post 89s...




If the fuel pump crossover is at 4200 rpm, that would explain the simplification on the post 89s.




That statement led me to think you wanted to bolt the throttle bodies directly to the manifold. Which is what you said.... And now you said you don't want to do that?
I should have inserted a 'not' in that statement. I never preview what I type... I do now though.



AT 4200 RPM, it either leaves the valve closed, or opens it, depending on WOT or not.
WRONG!! At idle, the valve is always going to be open. At 4200 rpms, if the VTA ( throttle angle) is below 60% then it will close. At 4000 rpms with a VTA of 70% or higher the valve is closed, heck, at 1500 rpms with same VTA the valve is CLOSED, as it passes 4200 rpms, the valve OPENS.
How is that statement wrong? At 4200 RPM, the valve either stays closed, or opens. Did you read the sentence prior to the one you quoted? I.e...

The butterfly valve on the 7M-GE is not closed at idle. In order for the system to work as your saying, at it has to close after idle, and then open back up. AT 4200 RPM, it either leaves the valve closed, or opens it, depending on WOT or not.

The valve being open at idle was my main point of contention to begin with...


Never-the-less, we've covered it, etc... Sorry for any consternation.
 

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That statement, to me is wrong, because it sounds like your saying the valve is always closed below 4200 rpms, and then after that point, it may stay closed or open. Truth is, depending on throttle angle, the valve may be either open or closed before 4200 rpms and then change opposite after 4200 rpms.

The valve does close after idle when you slam down the gas, then reopens after 4200rpms.

i'm tired of beating this to death. i don't care anymore
 

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Damn this is Interesting as hell. I'm an na guy and my acis is all hooked up and it works pretty good... Closes under full load under 4grand for some decent torque then opens at 4k for high rpm power.. But what got me is that there's a fuel pressure up vsv? are u talking about the vsv mounted on the vaccum tank that operates the acis or the other vsv close by mounted on the intake manifold? I'm just worried since there was one vsv that i didn't reinstall when i did my rebuild... i don't think the computer adjust for the greater air volume entering the engine when ACIS is in operation.... My car seems to become lean when acis is activated... it's almost like theres a slight lost when in short and long runner mode.. like the computer doesn't adjust for more fuel thats why im worried about that fuel vsv that is associated with the acis... I have Some questions for someone who has some good knowledge about the components and operation of the acis..... THANKS!!!!
 

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Yeah, I've been hooked on finding what is causing my problem.. and Damn i figured it out.. I think..... there's the fuel pressure up vsv that hooks up to the vaccum tree and runs from the ACIS to the Fuel pressure regulator... god I'M HAPPY That i think i might be able to fix my problem and Gain some frickin power... :) :)
 
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