just like the topic says, why does the iacv have coolant lines on it at all? it just seems like it makes the intake air hot for no reason. anyone here know why?

 

s it will lower the idle when the engine gets up to temperature

 

Not sure exactly why, but it's effect of warming the intake air can give higher gas milage, it's an old method applied to many cars to obtain slightly better mpg. If one were to re-position the intake tube under the exhaust manifold it would have a similar effect, Some older cars (not honda) did just this with a thermostat flapper valve in the intake pipe. Probably didn't help with your question, just what I've come across in the past. Probably some of the honda ghuru's here will explain exactly why in your case.
-john-

 

Are you sure its the IACV? On my mustang the EGR is right there behind the TB and it has coolant lines running through it. Those are there because the exhaust gasses get extremely hot and the coolant keeps the temp in check. I haven't looked at the honda engine to see if thats the case so I could be incorrect here.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sit22 II &raquo;</TD></TR><TR><TD CLASS="quote">s it will lower the idle when the engine gets up to temperature</TD></TR></TABLE>

This guy is right.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sit22 II &raquo;</TD></TR><TR><TD CLASS="quote">s it will lower the idle when the engine gets up to temperature</TD></TR></TABLE>

exactly

Not enough air is flowing through it under throttle position to effect intake temp that much.

 

Dont forget the FITv, it plays a role in this too, lol.

 

Sorry that's false. You can bypass the coolant lines to your IACV and the idle will remain the same. The reason for it is to unfreeze the IACV in colder climates where moisture in the air can cause it to freeze into position. That's the same reason they mounted the FITV to the throttle body on many Hondas.

A warm air intake will improve your gas mileage if you drive like a grandma. If you drive like you're always in a hurry, bypassing the coolant around IACV and throttle body, and then plugging the FITV will net you a small hp gain and a couple mpg.

 

ok, that makes total sense. I was just curious because between the iacv and the fitv, my whole intake gets pretty warm. never too hot to touch, but it seems like any easy way to negate the effects of a cai. it seemed pointless, but I do live in a very cold climate at times, so making sure the ICAV doesnt freeze makes sense.

 

Because that's the way the engineers designed it.

 

hahah, i dont trust engineers, so that is why i ask