StriderTacticaL

So I looked up the IAC mod in one of the sticky threads above and it sounds like a good mod. My rev's kinda hang when I rev up so i'd like to fix it. I was wondering if anyone knew any real cons to this mod that negatively effects the car??

The cons in the how-to weren't really real cons IMO I just wanna know if it does any bad because to my understanding the IAC is a bypass for when the TB is closed (off the gas pedal)....but if you make the hole smaller, wouldn't that make it harder to idle??


Thanks,
Brandon

mustang_pa

if you f it up, the car will stall constantly. Then u just go back to the way it was before. people have good and bad results with it. I didn't like it.

NinetySix GT

You can't really "f" it up. If it stalls just make the hole in your gasket a little bigger. I don't like how I lost my high idle on cold starts, so during the winter I take it out since I can't floor it anyways. Ford made our RPM's hang to be a little easier on our trannies, but this mod has to be one of my favorite free b's. Just takes some time to re-learn your car.

StriderTacticaL

So it basically makes idle more restricting....well thats not a good thing

jmac72187

To save synchros?

Jbauer

I did it..i'll give you the pros and cons..

Pros:
*Idle drops like panties on prom night.
*Lets you rev Quicker so you sound cool, like the carbd guys at the track.

Cons:
*The exhaust sounds like C.R.A.P, it sounds like a machine gun firing EVERY time you let off the throttle. I can't even stress how nasty it is, even back before my H pipe it sounded bad, and after my H pipe it got even worse. Just sounds flat out bad..think about how many times you let off the throttle or brake during normal driving, every time you do that it starts popping.

* I don't know if you ever noticed this, but stangs have a really cool sound with the factory IAC gasket with High performance H pipe and mufflers installed.. ever noticed how the engine goes 'drooo' when you clutch in? ..I love that sound..kiss it good bye with the IAC mod.

*I had a check engine light, but it went away by itself..it didn't come back again, the code was for manf. idle air control problems.

*The car just didn't feel right, it didn't feel like my baby..it just felt..i dunno.

I wouldn't do it again, the IAC mod left a sour taste in my mouth. At first, right after i did it i was like 'oh thats frikin cool' but then it was like 'man this sucks'

H0SS302

I did this mod and took it off a month or so later. I didnt like the fact that you damn near have to powershift to keep the rpms as high as stock IAC while speed shifting. I can deal with the 1 or 2 secs my car hangs at 1000rpm.. its not a big deal

NinetySix GT

I'm not sure exatly, but I assume so since the synchros and a weak spot in our trannies.

jmac72187

Where did you see that it is easier on our trannies?

I'm not arguing against it but I have never seen that so I was just wondering.

cliffyk

The modification, most easily done by drilling a hole in a 1/2" copper pipe cap in sticking that in the IAC inlet hose, places a restriction in the amount of air the IAC can pass--even if fully open.

Properly sized (0.310", 5/16", or so seems to work best), it will reduce the idle hang between shifts and have no impact on idle control--because the 5/16" hole can supply plenty of air for idling.

Having a small metal lathe I made a plug from aluminum, 0.700" OD x 0.300" ID x 0.5" long, which are basically the dimensions of a 1/2" copper pipe cap.



This plug is inserted into the IAC feed tube between the Helmholtz box and the IAC. Using the plug/pipe cap is much easier than making a custom gasket, and does no require removing the IAC to change the hole size or undo the mod.