Author Topic: Idle control valve necessary?  (Read 4624 times)

bbarnumboy

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Idle control valve necessary?
« on: January 25, 2012, 02:23:28 PM »
In doing my supercharger project i have started to think about the idle control valve and i have 2 questions.....

Do I need it?

If i use it, will it be a point of possible boost leak on the intake side under boosting conditions.

What have some of you supercharger and turbo guys done?

I will be tuning the engine, so i could probably just tune the idle to run without the ICV perhaps.
1993 318is SC Twin Screw supercharger build in progress.

http://m42club.com/forums/showthread.php?t=14314

MLM

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Idle control valve necessary?
« Reply #1 on: January 26, 2012, 03:11:20 PM »
Do you need it? I would say yes. The idle control does more than set you idle speed it aids warm up and compensates for load on the engine such as ps ac and alternator. It also helps prevent stalling when manovering the car.

Boost leak on a super charger? No it should not see boost. A sc arangement should be:

Air filter>throttle plate>supercharger>cooler if any>engine.

The ICV bypasses the throttle plate which is on the low pressure side of the supercharger.

A turbo on the other hand would be different and could be avoided by using hose clamps and possibly a one way valve.

Hope that helps.

cristimm

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Idle control valve necessary?
« Reply #2 on: January 27, 2012, 07:07:27 AM »
For a track-only car you don't need the ICV. If you disconnect it the idle will stay around 1800-2000rpm which is fine for a track car.

bbarnumboy

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Idle control valve necessary?
« Reply #3 on: January 27, 2012, 08:23:37 AM »
Doesn't the ICV go from pre-throttle body Via intake Boot to the icv and from the icv to the intake manifold Post throttle, body?

I was wondering how i should set mine up if i must keep it.  My setup will be, pretty much like you said

Air filter  >  AFM  >  intake boot  >  throttle body  >  Supercharger  >  Airbox/internal cooler  > Intake manifold  > engine

So the stock setup goes from pre-throttle body, and bypasses the throttle body correct?  so if i did that, it would end up on the boost side, because anything after my throttle body will be boost, since the throttle body is pretty much right on the supercharger.   Any thoughts?  Is it OK to run the ICV on the boost side with sufficient clamping.  Curious to know if it will leak internally in the Valve itself, if exposed to a boost condition.

Would it be best for me to make a bung for the icv on my small pipe that connects the throttle plate to the supercharger? Would that be a correct way to do this?

Stock setup

« Last Edit: January 27, 2012, 08:29:11 AM by bbarnumboy »
1993 318is SC Twin Screw supercharger build in progress.

http://m42club.com/forums/showthread.php?t=14314

bbarnumboy

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Idle control valve necessary?
« Reply #4 on: January 27, 2012, 03:24:40 PM »
So i was really Bored and thought you guys could use a good laugh at my MS Paint skills :D

so this picture describes my question.

option 1 grabs fresh filtered and metered air through the ICV and routes it to the non pressurized intake flange pre supercharger.

option 2 grabs fresh filtered and metered air through the ICV and routes it to the pressurized intake box, post supercharger

Which one would work best for me ?



1993 318is SC Twin Screw supercharger build in progress.

http://m42club.com/forums/showthread.php?t=14314

E36-italia

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Idle control valve necessary?
« Reply #5 on: January 27, 2012, 04:01:33 PM »
imo option 1 is better since it doesn't interfere with the blower.
(as far as I understand your paint skills)

with option 2 there is a chance of blowing air back into the intake boot... if boost is high enough...thus anything more then ambient air pressure!

But don't hang me on it... I have exactly zero experience boosting cars.
950kg E36 from 3/94 ex M42B18, now with Saab B204l turbo power.

bbarnumboy

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Idle control valve necessary?
« Reply #6 on: January 27, 2012, 04:04:49 PM »
Yeah i am not sure if the valve can handle boost or not.....i'm wondering if it will idle rough giving it the icv air before the blower.
1993 318is SC Twin Screw supercharger build in progress.

http://m42club.com/forums/showthread.php?t=14314

MLM

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Idle control valve necessary?
« Reply #7 on: January 27, 2012, 05:40:21 PM »
option one is the way to go. It wont see boost there and it will control idle fine.

bwawuz02

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Idle control valve necessary?
« Reply #8 on: January 29, 2012, 12:41:41 AM »
Quote from: MLM;109852
option one is the way to go. It wont see boost there and it will control idle fine.


+1

bbarnumboy

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Idle control valve necessary?
« Reply #9 on: January 29, 2012, 01:37:23 AM »
Thanks guys,. I will go with option 1
1993 318is SC Twin Screw supercharger build in progress.

http://m42club.com/forums/showthread.php?t=14314