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What happens if I don't use an IAC system

Posted: Mon Sep 08, 2014 8:44 am
by Charlescrown
I have a Mitsubishi Starion fitted with an Adaptronics system. I would prefer a Delco but have come up with a problem designing a suitable IAC setup. I won't be fitting multipiont because I want it to look as close to original as possible. Question is can I not run the IAC system? I have looked at all the settings in $12P and wonder just how well it will work.

Re: What happens if I don't use an IAC system

Posted: Mon Sep 08, 2014 9:42 am
by Holden202T
it will work ok, it will just loose things like cold start increased rpm and such, also if its an auto when putting it into drive etc the revs will probably drop more than it would normally, so you'll just have to play with the butterfly to get it to idle ok.

Re: What happens if I don't use an IAC system

Posted: Mon Sep 08, 2014 4:56 pm
by Charlescrown
Thanks, that's what I hoped would happen. It's manual and they use a wax pellet for cold idle speed up and throttle stop adjustment for idle so it should be quiet easy. The injectors are low impedance so I plan to run them in series with a dropping resistor to overcome that problem.

Re: What happens if I don't use an IAC system

Posted: Mon Sep 08, 2014 9:16 pm
by delcowizzid
watch out for running the resistors you will have less injector flow than before

Re: What happens if I don't use an IAC system

Posted: Mon Sep 08, 2014 9:35 pm
by VK_3800
You can get IAC valves that run inline via a hose so you can put it straight to the manifold and bypass the throttle body altogether, maybe that would be an option if there's no way to accommodate it in the throttle body?

Re: What happens if I don't use an IAC system

Posted: Tue Sep 09, 2014 12:58 pm
by antus
VK_3800 do you have a link to such an item? All I see are the jeep ones when searching, but by eye it looks like the movement in the IAC is different to the GM/Daewoo OEM ones, though Im not sure. Ive seen people hit GM TBs with an angle grinder to cut out the iac portion and then tap the alloy and put some taps on the holes, this works pretty well.

With the dropping resistors, yes you'll probably need to massage the injector opening time tables although you would have to do that anyway with an injector swap.

Re: What happens if I don't use an IAC system

Posted: Tue Sep 09, 2014 1:32 pm
by Charlescrown
Like Antus I would like to know what car or where you can get one that fits inline. I tried to bore out a Ford one but when it came to a little alloy welding my skills excelled and I melted it. OK on the injector settings. Just how much resistance do I need for a delco? The original setup uses a dropping resistor setup already so I suppose it could stay. I would have to look and see if it's still there with the Adaptronic ECU setup. Anyway thanks for the feedback it all helps to make it a bit easier.

Re: What happens if I don't use an IAC system

Posted: Tue Sep 09, 2014 2:12 pm
by Holden202T
I have actually seen them before on a petrol/gas motor, it was a plastic setup with hose in and out and GM IAC on it! couldn't tell you much more than that though!

Re: What happens if I don't use an IAC system

Posted: Tue Sep 09, 2014 7:35 pm
by vlad01
Holden202T wrote:I have actually seen them before on a petrol/gas motor, it was a plastic setup with hose in and out and GM IAC on it! couldn't tell you much more than that though!
yep, pretty standard on modern conversational gas conversions. My Niece's xh ute uses one of those.

Re: What happens if I don't use an IAC system

Posted: Tue Sep 09, 2014 8:58 pm
by Dazza92VP
http://www.ebay.com.au/itm/Commodore-Ho ... 4ac87a2c56

quick search for commodore gas systems and this showed up