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JDM intake manifold unknown part

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Dashnizzle

Proven Member
158
140
Jun 5, 2021
Montana
(1991 galant vr4)
I took my coil pack off the car because the power transistor was just dangling from the harness. I’m trying to figure out where to mount the power transistor when I encounter this strange bell shaped valve with a vacuum port underneath my fuel pressure regulator. I’ve been looking all day and I can’t for the life of me figure out what it is. The intake manifold is in fact a JDM OEM manifold because it doesn’t have EGR on it at all and the throttle body only has one vac port.

this valve kind of interferes with where your coil pack and power transistor usually mount which makes sense why the PO left it dangling…so can anyone tell me what it is?

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Sure looks like the SAS setup that some JDM Evos seemed to have. It's a rudimentary anti-lag setup - it lets a tiny puff of fresh air pass into the exhaust just before the turbo, which is added to a tiny bit of extra fuel in the system when the throttle snaps shut, to make a minor kapow on shifts to keep the turbo rolling. For reference this is a later Evo setup.

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Sure looks like the SAS setup that some JDM Evos seemed to have. It's a rudimentary anti-lag setup - it lets a tiny puff of fresh air pass into the exhaust just before the turbo, which is added to a tiny bit of fuel by the ECU, to make a minor kapow on shifts to keep the turbo rolling. For reference this is a later Evo setup.

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Interesting, that’s exactly the shape on the bottom however there is only a tiny spring valve on this one with no hoses or cables just the one vacuum port you can see. Pretty much the whole unit is shown in the pics I provided this is substantially larger.
 
It's the actuator to control the butterfly valves.
You nailed it. I had no idea my manifold worked like this! This is new territory for me. There’s basically 8 intake ports on the head the way I see it. I ran out to the garage just to check, can’t believe I hadn’t noticed that yet. I have so many questions about how this works but will search some other threads.

here is a photo of the top of the manifold which shows the 8 ‘plenums’ for lack of better term.

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I tried to provide a somewhat decent description on how the jdm cyclone intake dual runner intake manifold works on post #37 and #44 in my build thread. I actuated the butterflies (for the second intake manifold runners) similar to how the factory did it using a solenoid valve (re-purposed fuel pressure solenoid activated by ecmlink), vacuum canister, and the cyclone actuator.

 
That's the actuator for cyclone intake manifold butterfly valve as mentioned above. When you don't connect anything, the butterfly valve should always be open. Originally it's controlled by a solenoid, DO NOT connect a boost source directly, you would blow its diaphragm sooner or later for sure and would cause boost leak. There is a possibility that it's already leaking though. Before people were using a turbo actuator to activate it.
 
Good info guys. Talon77, I read both of your posts in the build description and correct me if I’m wrong but would it be true that by having the valves closed you see spool improvement and open you’re basically at normal operating conditions compared to a US intake? I love the idea of programming the solenoid for use with link too. Would this have a serious impact on tuning the car? I suppose it’s the same volume of air just a different velocity right? … the boost leak potential is there, that’s why my throttle body is off for now but I’ll listen closer when I have it all hooked up and airtight.

Overall, are you happier with the cyclone intake Talon77?
 
It's 8 runners. Switches from long runners to short runners based on RPM (as factory did it). Leaving it as you have it, it does not activate the longer runners resulting in the manifold flowing the same CFM as a USDM manifold (201cfm vs 203).

The method of using a turbo actuator was clever as it could be tweaked to open around the RPM window. 4400 I think.

I locked mine so the long runners are only used in the interest of gaining some spool time. Never got around to activating it. My method was going to be using a shift light, have it trigger a relay instead of the bulb, then go from there. Few ways to skin the cat.
 
It's 8 runners. Switches from long runners to short runners based on RPM (as factory did it). Leaving it as you have it, it does not activate the longer runners resulting in the manifold flowing the same CFM as a USDM manifold (201cfm vs 203).

The method of using a turbo actuator was clever as it could be tweaked to open around the RPM window. 4400 I think.

I locked mine so the long runners are only used in the interest of gaining some spool time. Never got around to activating it. My method was going to be using a shift light, have it trigger a relay instead of the bulb, then go from there. Few ways to skin the cat.
Turbo actuator like a wastegate?

I wonder if I can use my ingersol rand boost control solenoid to also activate the runners somehow..

oh and another point of this post. Where to mount my power transistor and my coil packs??
 
Yes, someone used a T25 actuator. Whenever it saw 9psi, or whatever psi that actuator starts at, it obviously moved. This can be delayed of course with a boost controller. It's not the best way but it's damn simple.
 
Good info guys. Talon77, I read both of your posts in the build description and correct me if I’m wrong but would it be true that by having the valves closed you see spool improvement and open you’re basically at normal operating conditions compared to a US intake? I love the idea of programming the solenoid for use with link too. Would this have a serious impact on tuning the car? I suppose it’s the same volume of air just a different velocity right? … the boost leak potential is there, that’s why my throttle body is off for now but I’ll listen closer when I have it all hooked up and airtight.

Overall, are you happier with the cyclone intake Talon77?
I'm not sure I understand your question, but having the cyclone actuator valve closed is intended to help spool and bottom end grunt, but that does not compare to the normal conditions of the US intake. I would think having the actuator valve open all the time would compare more similarly to the US intake flow wise (cfms), but leaving the valve open all the time would result in non-ideal spool.

As for tuning, you just tune the car as you normally would after you set the activation point.

Yes boost leak potential is possible if you don't do a good job sealing the manifold, since it is 3 pieces sealed by gaskets compared to the US manifold which is one piece.

I was happy with the mid-range performance of the intake, but the intake manifold is kind of heavy. I'm trying something else for now (I may switch back in the future), but my car is on a diet for now.
 
It's 8 runners. Switches from long runners to short runners based on RPM (as factory did it). Leaving it as you have it, it does not activate the longer runners resulting in the manifold flowing the same CFM as a USDM manifold (201cfm vs 203).

The method of using a turbo actuator was clever as it could be tweaked to open around the RPM window. 4400 I think.

I locked mine so the long runners are only used in the interest of gaining some spool time. Never got around to activating it. My method was going to be using a shift light, have it trigger a relay instead of the bulb, then go from there. Few ways to skin the cat.
Hey Stapl3, I'm not sure I agree here. The way he has it now (cyclone actuator not hooked up to anything) results in both the long runners AND the short runners open all the time (giving him the full 201cfm, which can only be obtained when all 8 runners are open). However, this will give him non-ideal spool.

This is my recolllection: By default, the butterfly valves inside the cyclone manifold want to open all 8 runners all the time via spring pressure. Activating the cyclone actuator valve (ie: via vacuum) forces the butterfly valves closed, which causes the short runners to be capped off, such that only the long runners are active. Once vacuum is removed, then all 8 runners are fully simultaneously active again.

You would be leaving some flow on the table if you've forced the actuator to be closed all the time because you would only be flowing 4 out of 8 runners. I would think that would be great spool all the time, but you would not be getting the full flow. I recommend you look more into the activation so that you can benefit from the full flow :)
 
Yes, someone used a T25 actuator. Whenever it saw 9psi, or whatever psi that actuator starts at, it obviously moved. This can be delayed of course with a boost controller. It's not the best way but it's damn simple.
I kind of like the T25 idea, I would have liked to have tried that, but never got around to experimenting with it.
 
Turbo actuator like a wastegate?

I wonder if I can use my ingersol rand boost control solenoid to also activate the runners somehow..

oh and another point of this post. Where to mount my power transistor and my coil packs??
I think I drilled 2 new holes on my stock US spec power transistor mounting plate and mounted the PT to the factory-tapped holes provided on the backside of the cyclone manifold (facing the firewall).

I don't have any pics on what I did with the coil pack but I made a bracket and just moved it to the driver's side, somewhere in front of the strut tower.

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You're going to have to make the gaskets... oem gaskets have been discontinued years ago... I used rolled gasket, and a combination of exacto knife and small hobby scissors to cut out the runner "holes" and a single hole punch to punch out the bolt holes. I smeared a very very thin film of grey rtv on the gaskets after I was done and installed bolts finger tight, then tightened them down after the rtv dried up a little. It sucked making the gaskets.
 
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