The infamous IRIS Valve

Johnybeas · #1 11-24-2008, 08:17 PM

Is it needed? Is it beneficial to remove? Will the car run without it on the stock ECU??? Please explain to me why so many people remove it...

sicksubie · #2 11-24-2008, 09:19 PM

I dont know of anyone who has removed their IRIS valve....

svxpert · #3 11-24-2008, 10:24 PM

<<I dont know of anyone who has removed their IRIS valve....>>

+1 here. never heard of that...

subbieatnz · #4 11-24-2008, 10:39 PM

What is the IRIS valve, what does it do? and what does it look like?

Johnybeas · #5 11-25-2008, 12:01 AM

There was mention of messing with it in rally bob's build and nevin wanted me to ship my intake manifold to him without it as a core for him to send me his polished intake manifold, I've not heard back from him yet as to if he runs his without it or why he removed his

So that is why I was curious, because I'd seen it a few other places around. I'll do some searching and post some links so it'll be more clear. I'm just really confused what it is and why people are messing with it.

PS: Bobby did you get my voicemail I left ya? I misplaced your paypal addy to send ya the cash for the radio cage, also still wondering if you found that visor and how much you wanted for it. let me know.

Johnybeas · #6 11-25-2008, 12:08 AM

Quote:

Originally Posted by RallyBob

It's removed completely from the intake.

http://www.subaru-svx.net/forum/show...+Valve&page=14

I'm confused... what is it... what is it used for... and why did they remove it, and why did nevin remove his....

b3lha · #7 11-25-2008, 03:24 AM

I've been trying to find the part of the ECU that controls it to experiment whether there is any benefit to opening/closing it at a different rpm than stock. But I haven't managed to find it yet.

As I understand it, with the iris closed, you get more power at low rpm. With it open, you get more power at high rpm. I can't imagine it would be benefical to remove it unless you were doing other mods to the intake system.

sicksubie · #8 11-25-2008, 08:34 AM

personally I think removing it would be a bad idea...

SURTEESS · #9 11-25-2008, 10:06 AM

I would imagine the iris is acting like a secondary valve in a carb. setup, with the iris closed you get a lean mixture at start-up (less airflow) - slowly getting more richer to compensate for increased airflow at higher road speed???

Steve (1 OF 1)

SVXRide · #10 11-25-2008, 10:26 AM

I've always thought that the opening and closing of the IRIS valve was purely driven by engine vacuum and not by a signal from the ECU. If this is, in fact, the case, then you could rig up a cable to manually open and close the valve any time you wanted to

-Bill

TomsSVX · #11 11-25-2008, 10:59 AM

Bill you are partially correct. The valve is operated by a vacuum diaphram but the vacuum is controlled via a solenoid under the intake. It stores intake vacuum in the black canister under the intake w/ a check valve so that when the ECU initiates the solenoid the vacuum stored can operate the valve.

It can be rigged manually, but thats a PITA. The gains and/or losses of using it to not using it are going to be minimal. If you are running the stock ECU, there is no reason to get rid of it, just make sure it operates properly. I may fiddle with it when I am working with the hyrda on an extra output from the ECU but that is only if I am REALLY bored

Tom

SVXRide · #12 11-25-2008, 11:41 AM

Quote:

Originally Posted by TomsSVX

Bill you are partially correct. The valve is operated by a vacuum diaphram but the vacuum is controlled via a solenoid under the intake. It stores intake vacuum in the black canister under the intake w/ a check valve so that when the ECU initiates the solenoid the vacuum stored can operate the valve.

It can be rigged manually, but thats a PITA. The gains and/or losses of using it to not using it are going to be minimal. If you are running the stock ECU, there is no reason to get rid of it, just make sure it operates properly. I may fiddle with it when I am working with the hyrda on an extra output from the ECU but that is only if I am REALLY bored

Tom

YT,
Yeah, I forgot about the solenoid

Help my memory here. Actuation of the solenoid causes the diaphram to open the IRIS, thus creating a single plane intake?
-Bill

dennyo · #13 11-25-2008, 03:43 PM

Quote:

Originally Posted by TomsSVX

Bill you are partially correct. The valve is operated by a vacuum diaphram but the vacuum is controlled via a solenoid under the intake. It stores intake vacuum in the black canister under the intake w/ a check valve so that when the ECU initiates the solenoid the vacuum stored can operate the valve.

It can be rigged manually, but thats a PITA. The gains and/or losses of using it to not using it are going to be minimal. If you are running the stock ECU, there is no reason to get rid of it, just make sure it operates properly. I may fiddle with it when I am working with the hyrda on an extra output from the ECU but that is only if I am REALLY bored

Tom

tom, if it's not operating properly what would be the symptoms say if it didn't open?Is there a cel code for that condition?Thanks dennis

SVXRide · #14 11-25-2008, 04:10 PM

You'll be down on power, but you probably won't even notice it. What usually happens is that the check valve - in line with the vacuum line from the intake to the vacuum canister - cracks. Little guy is way too expensive for what it does...
-Bill

Nevin · #15 11-25-2008, 04:23 PM

Just to be clear, I have NOT removed my IRIS valve. I removed it on a spare IM that has been polished, and I was just telling him to remove it merely to help keep down on weight (and therefore shipping cost) when I ship my polished one to him.

And no, I would see no merit in taking out the IRIS valve on one of these motors unless possibly in forced induction.

It would be possible to control the opening and closing of it, but that woudl only be necessary if you were changing cams, adding headers, etc... and you would NEED a couple dynos to figure out the optimal point.

The easy way to do it would just be to use an MSD window switch and then you could use whatever pills you need to open/close the valve.