Has anyone ever converted their IAC from the independent air source model to one that doesn't require the fresh air tube that looks like crap across the engine bay?? I know that the explorers use an IAC that doesn't use external air, could that be modified on the plenum? The tube is a sore thumb in my bay.

 

Wow that definitely is a sore thumb for you, it looks out of place. I'm also interested in this.

BUMP

 

Anyone?

 

i have a friend who had some custom type iac piping, that looked clean, ill ask for screenshots and info..

check into that though would look better then current IMO.

 

The IAC bypasses air that has been metered by the MAF, around the throttle body. The PCM controls the amount of air being bypassed to control the idle.

On some engines there's a port upstream of the throttle plate, and another downstream, built in to the TB. The TB in our cars is not designed in that manner however perhaps one so designed could be fitted.

In your setup it looks as though steps were taken to prevent boost from acting upon the IAC. This is likely a wise move as neither the IAC plumbing nor the valve itself were designed to deal with pressurized input air--the opposite actually, on a n/a setup the IAC only "sees" vacuum.

On my JRSC'd '90 Miata there was a similar hose--leading from just after the AFM and before the blower, around to the IAC (under a dummy TB)-- in which a low force check valve was placed to block a back flow of boost. You can see the 3/4" hose sweeping across the front, the check valve is the silver thingy near the radiator cap.



Other than trying to make it look as good as possible I don't know what to tell you--maybe get rid of the Helmholtz resonator (it's just noise suppression thing) and see if you can find a molded hose with a 90° bend, and couple it to a longer hose that can be routed more discretely.

 

tell the truth...you just like posting pics of your motor.

But yes...it does stick out...Maybe you could fabricate some nice chrome/alum piping for the long distances...similar to the replacement chrome radiator upper hose.

 

Good suggestion, very often if something cannot be succesfully hidden highlighting it is the best alternative.

 

http://sn95forums.com/index.php/topic,37375.0.html
Only one I've seen do this. I haven't tried it yet, but I'd like to.

 

I've seen that thread before although I couldn't remmeber where, thanks.


Cliff, what do you think about that ^?

Although I know of dozens of people running the IAC from the pressurized inlet after the S/C before the TB I have always been skeptical of it not affecting the system. I guess, their logic is that at idle is when the IAC is active it doesn't affect it during boost when the IAC isn't active.

 

I didn't read it in detail because of the reverse set type, however the thread seemed like a bunch of people who didn't know much tossing in there $0.02 worth...

The IAC has to have metered air as it's input, that is air in addition to the air bleed around the throttle plate. I have seen many plenums and TB's that accomplish this by having passage ways that feed air around the throttle plate--if you look at the IAC on our cars you can see that the casting is set up to allow for "in" and "out" ports.

The IAC air needs to be metered so that the PCM can see the air passed by the IAC and add fuel as needed--otherwise all that would happen would be a leaner mix.


The IAC is likely capable of handling the boost pressure, and is likely closed when boost is present. On the Miata the check value was a tweak that Jackson Racing added when they acquired the old Sebring s/c kit. It significantly improved idle control.