Any performance impact from disconnecting IAC?

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Mar 14, 2002 | 09:25 AM

CHRISPY

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Any performance impact from disconnecting IAC?

Hi guys,
I am wondering if I will suffer any timing, performance loss from unplugging the IAC all together and setting my idle totally based on the T-body blade hole.
If I unplug it I know I will set a code but will it cause the computer to go into limp mode or something just as bad? Also do I need to push the plunger all the way in or out?
thanks,
Chris

Mar 14, 2002 | 09:38 AM

Camaroholic

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From: Waco, TX

Re: Any performance impact from disconnecting IAC?

I just gotta ask... Why are you considering doing this? Seems like a 'hack' of a way to go about getting a smoother idle. The IAC is there to adjust for differing environmental and engine load conditions... Do you still have A/C? If so, I'd leave the IAC enabled and try a different approach.

I personally haven't explored how the IAC passage system works on the LS1 car, though. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> But you might look at how the air passages travel through the TB and in to the intake, and see if there's any improvements you can make in the passageways. Just an idea. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

-Andrew

Mar 14, 2002 | 10:16 AM

CHRISPY

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Re: Any performance impact from disconnecting IAC?

My car has no AC <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I am running a rather large 226/234 554/575 lift 112LSA cam with stock tuning. My idle is around 1100 rpm now in gear with the T-body drilled but the IAC is causing it to ride up and down occassionally. If there is no performance impact to disconnecting it I can set my idle to be 1000rpm in gear regardless and not have to worry about it. I was just curious on the performance impact if any of doing this.
BTW here is a rundown of my combo:
ARE S1 5.3L heads 11:1 compression
226/234 112LSA 554/575 lift cam
MAC headers with 3 inch offroad Ypipe, cutout custom catback
stock tuning with HPP+ for 6600rpm rev limit, 160 stat, and gears.
4L70 trans with TP4400 converter
12 bolt with spool and 4.11's
No AC or EGR though I still have my AIR pump hooked up LOL.
Your thoughts are appreciated.
Chris

Mar 14, 2002 | 02:28 PM

GeorgeC

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From: Melbourne, FL

Re: Any performance impact from disconnecting IAC?

You may have a slight issue with cold start ups, since the IAC won't be able to let the car "fast idle" for that short little bit til temps come up. I had mine disconnected for a short time for the same (surging idle) reason as you, but sometimes the car was a bitch to crank up and keep running when it was dead cold...

Mar 14, 2002 | 06:32 PM

Pro Stock John

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From: Chicago, IL

Re: Any performance impact from disconnecting IAC?

During cold start, your car will be richer and the IAC cannot compensate... That is the only issue I can see.

Mar 15, 2002 | 08:57 AM

CHRISPY

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Re: Any performance impact from disconnecting IAC?

Well I unplugged it and besides having to hold the throttle at 1500rpm for about 15 seconds at cold startup everything worked fine. Nice and stable idle. 1050 in gear and 1100-1200 out of gear (Still need to close up the T-body hole a bit <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> ) No difference in WOT power. Anyone know of any possible problems this might cause?

Cheers,
Chris

Mar 15, 2002 | 08:08 PM

99 WS6

Launching!

Joined: Nov 2001

Posts: 215

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From: Marlboro, NY

Re: Any performance impact from disconnecting IAC?

It should be okay. There was someone who posted about an idle control that they installed using a controller to run the IAC with a toggle switch to step up/down the idle. They did not mention any problems, so you should be okay.

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Mar 15, 2002 | 09:37 PM

nevrenuf

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From: Suwanee, Georgia

Re: Any performance impact from disconnecting IAC?

<blockquote>quote:<hr />Originally posted by Chris ARE 360:
My car has no AC <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I am running a rather large 226/234 554/575 lift 112LSA cam with stock tuning. My idle is around 1100 rpm now in gear with the T-body drilled but the IAC is causing it to ride up and down occassionally. If there is no performance impact to disconnecting it I can set my idle to be 1000rpm in gear regardless and not have to worry about it. I was just curious on the performance impact if any of doing this.
Your thoughts are appreciated.
Chris<hr /></blockquote>I ran the exact same cam for a long time and took a different approach. I worked with Steve Cole through a couple of revisions and ended up with a stable idle, at 850 rpms, with NO HOLE in the TB...

I recently installed a stroker and put in a very large cam.. 612/612/242/242.. I now idle at 950, stable, still with NO HOLE..