restrictor plate

[supra90turbo]

lol restrictor plate... you redneck.

[rnoswal]

I am still trying to find the information on the valve in the intake that opens after a certain rpm that enhances torque at lower rpms and opens for greater flow at higher rpms for more upper end power. So, in a way it is a restrictor plate, but not for the same reasons that NASCAR uses it.

As for the other comments, try to get 850 reliable hp out a pushrod V-8. Most of these guys have college degrees and more. What is wrong with watching too much racing? Better than watching a bunch of overpaid babies toss a ball of what ever shape around and tell the rest of us to go f*&k ourselves because we aren't as good as they are, you can have them. I'll take too much racing anytime!

Don't let any of these guys intimidate you from asking any question here, most of us care enough to not insult you here.

Russ

[supra90turbo]

lol I watch racing, just not nascar.
There is no such thing as 850 reliable HP.

The misinformation and posting guesses on this site is hilarious.
It would not fly on any other forum, so enjoy!

I'll help, I suppose.

as for the "restrictor plate" as you refer to it, that's not what it's called.
The 7MGE uses a Y-Pipe after the throttle body that opens a secondary butterfly with vacuum at a set RPM. Toyota calls it ACIS; Acoustic Control Induction System.

For lack of a better explanation by my own words, I'll borrow Jong's explanation from SF.

Originally Posted by jong on SF

Acoustic Control Induction System -- ACIS--

There are a lot of people that haven't a clue what ACIS is or what it does. So, i did some research at work using our Toyota Technical Information System (TIS) and i dug up some technical training for the ACIS system. I then took that published information and created a webpage with text, diagrams and pictures. There is a wealth of information out there, the trouble is finding it. So i will do my best to describe the system, its operation, and the role it plays in performance.

http://www.geocities.com/mwsupra2003/acis.html

the above link has all of the information below. please goto the link for helpful diagrams and pictures.


---Theory----
Using laws of inertia, thermodynamics and physics the toyota engineers discovered that the opening and closing of the intake valves creates acoustic energy pulses that bounce around inside the intake manifold and chamber. They then developed a system, called ACIS, to control and manipulate those acoustic pulses to create a "supercharging" effect.

By varying the length of the intake runners through the use of valves, the toyota engineers found a way to time the acoustic pulses so they enter the cylinders through the intake valves. This means that after an intake valve closes and creates this acoustic pulse, the pulse bounces off the intake runner and chamber and then is timed to enter at the next intake cycle so the valve is opened with a pressurized acoustic wave being forced into the cylinder.


---Application---
Toyota has many NA engines that utilize the ACIS system. (7m-ge, 2jz-ge, 2jz-fe, 1mz-fe, ect, ect) In our case, the 7mge, there is a butterfly valve (intake air control valve(IAC)) placed in the middle of our intake manifold behind the union of the Y-pipe. This valve is controlled by an ACIS actuator. The Actuator is controlled via vacuum provided by the either the throttle, VSV's or the ECM ( or all three). There is a vacuum storage tank located beneath the intake manifold and that is connected to a port near the Intake air control valve.


---Operation---
I'm not sure on the switchover throttle position for the 7mge, but the activation RPM is 4200. Before that point at WOT, the Air control valve is closed, meaning that the cylinders are getting shared air from just behind the throttle body. This means that the engine is utilizing long intake runners. Under WOT, past 4200 rpms, the air control valve is opened and the cylinders are now getting shared air from the center of the intake manifold, meaning the engine now has shortened intake runners. ( see diagram on site)

On the 2JZ-FE engine, there is an activation rpm of 4,500 and a 30% throttle crossover map. meaning....

low throttle... ( less than 30%)
<4500 rpm = valve open ( short runners )
>4500 rpm = valve close ( long runners )

high throttle... ( more than 30%)
<4500 rpm = valve close ( long runners )
>4500 rpm = valve open (short runners )

This system ( two stage acis) essentially gives you two torque curves. The valve is timed to open on the downfall after the first peak, so the engine has potential to make equal or more power later on throught the power band.


--- Modification ---
Modifying the ACIS system is not recommended because it has been tuned for the specific engine. But the thought does provoke interest. If by changing the activation RPM and/or throttle %, could you tune where you want your torque to peak?

I have the ACIS system on my now turbocharged 7M-GE and remarkebly it has still provided two torque curves between the designated 4200rpm. I plan to do some experimentation with ACIS during my next trip to the dyno. I will perform runs with the valve closed ( long runners), with the valve open ( short) and then multiple runs using different activation RPMS. If this system can yield more power because of its changing attributes, then it may be a desired modification for mid-power performance enthusiasts.


----------------------------------------

The ACIS System's worth is very evident if you look at a dyno sheet of any 7MGE. It will rise once, and claim peak torque mid-powerband, then fall slightly, and rise again as you see the 2nd butterfly open around 4200rpm.

[frostburn]

thanks for all that info and all but it refers to every engine but the 7mgte... confused on how this could be of any assistance.

[supra90turbo]

ok. if you scroll up, the question was answered.
I'll re-answer it.

THERE IS NO RESTRICTOR PLATE.

My question was relevant to what moswal was describing.
Do yourself, and all of us a favor by doing what mrnickleye suggested. Find a mechanic that has experience with fuel injected vehicles. I can't believe that a mechanic suggested you have a restrictor plate. It's completely absurd of anyone in this day and age to even entertain that thought.

[frostburn]

oh i understood the no restrictor plate answer but the link you gave discribed all the different engines and where a restiction is... but it didnt show nor suggest anything about the 7mgte

[supra90turbo]

that's because the 7MGTE doesn't have that setup.
only the GE.

I was responding to moswal, who expressed the fact that he's been looking for information about ACIS.

[rnoswal]

500 miles, averaging at least 180 mph or more, I suppose it is all relative, but to me that is reliable for what it's intended purpose. Anyway, thanks for describing the acis system.

I was wondering how the system could work on a system like the 7mgte. The 7mge almost always has a negitive to zero manifold pressure and relies on the vacuum to work the acis. Since the turbo is mostly pressurizing the manifold under power, it would seem that the valve would have to be opened eletronically, but where there is a will there is a way I guess.

I wish people that only think the NASCAR watchers are rednecks and that watching any other kind of sport means you are automatically a college proffessor wold get off their high horse. All of us here love cars and want them to be better and get to know our cars better. Making more power and going faster is all that racing, NASCAR, is all about.

Russ