revolt_allmotor

EDIT IF YOU DO THIS, DO NOT CAP THE WATER PORTS (intake manifold and rear water line) WITH LOW-QUALITY CAPS!!!!!

I have had the TB/IACV coolant circuit bypassed for quite some time, today one of the cheap pep boys caps I got ruptured and my car lost almost all coolant and started overheating really bad. Luckily I caught it in time and was able to pull over before it got to the red zone. Limped it home pulling over to add water every 5 mins. Gonna try to find some better-quality caps for now, when the motor is out next time I am gonna weld both water ports shut.

As an alternative you could run a coolant line from the port on the manifold to the one on the water line.

BTW car idles fine with no coolant in the IACV or TB.....


OK I have an LS/VTEC with b18a block and b16 head in my EG. The coolant lines are currently setup in the stock configuration where the small hose comes off the coolant port on the cylinder head and runs to the throttle body. Then another hose runs from the thottle body to that valve thing on the back of the intake manifold (the IACV?). Then another hose from there to the big coolant pipe on the back of the block.

Now I have been told that it would be benificial to performance to bypass the throttle body, since when the car is hot these lines pump hot coolant through the throttle body making it hotter and thus heating the intake air.

My question is should I also bypass that valve on the back of the intake manifold (is that the IACV?)? If I did that then I would basically be routing a hose directly from the port on the head to the big coolant pipe on the back of the block. Or at that point couldn't I just cap both those ports?

Or does the IACV (if that's what it is) need to have coolant running through it? If so then I should route the hose from the port on the head to the IACV and then leave the return line from the IACV to the pipe on the block. Then cap the tubes on the throttle body that the coolant lines used to run through.


Modified by slowegxxrevolt at 7:21 PM 8/29/2005

rmcdaniels

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowegxxrevolt &raquo;</TD></TR><TR><TD CLASS="quote">
Or does the IACV (if that's what it is) need to have coolant running through it? If so then I should route the hose from the port on the head to the IACV and then leave the return line from the IACV to the pipe on the block. Then cap the tubes on the throttle body that the coolant lines used to run through.</TD></TR></TABLE>

That's what I did a couple years ago. I don't know if the IACV needs the water or not, but I figure it's not hurting anything. I've had no problems with it bypassing the throttle body though.

revolt_allmotor

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">That's what I did a couple years ago. I don't know if the IACV needs the water or not, but I figure it's not hurting anything. I've had no problems with it bypassing the throttle body though.</TD></TR></TABLE>

yeah just wondering if it would be okay to bypass the IACV as it would allow me to eliminate those lines entirely and clean up the engine bay a little...

EK k kay

THe IACV uses coolant to control your idle.

revolt_allmotor

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chowmien &raquo;</TD></TR><TR><TD CLASS="quote">THe IACV uses coolant to control your idle.</TD></TR></TABLE>

How? How exactly does that thing work anyway?

Falqon

Huh? There's a plunger that lets air through depending on the voltage sent from the ECU. I don't believe coolant plays a part in that process.

revolt_allmotor

Thats what I thought too. Sooooo,

Does the IACV need coolant to go through it or can I bypass it??

Jayboy

It needs it for the cold start. The temp from the water tells the iacv to have high or low idle. you could bypass it but it will make the motor idle pretty high, around 1500-2000

revolt_allmotor

so basically if I bypass it the IACV will think that the motor is cold all the time so it will idle high (like it does when you cold start) all the time?

thanks.

Turbogixxer

The Fast Idle Valve (FIV) is the thing under your TB (unless you are running a type-r TB). What the FIV does is allow more air past the TB when it is cold. The FIV uses coolant temp (via of a wax pallet) to open and close it. Your gains will but be big by bypassing it. If you bypass, you have a high chance of it running like **** then you first start it up.

The IACV only have coolant running to it so that the vavle does not get frozen/ice on it on very cold days. You live in CA, you can bypass it will no problem.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HollywoodEG2 &raquo;</TD></TR><TR><TD CLASS="quote">It needs it for the cold start. The temp from the water tells the iacv to have high or low idle. you could bypass it but it will make the motor idle pretty high, around 1500-2000 </TD></TR></TABLE>

No, it will not. The IACV has no way to tell if the coolant that is going to it is warm or cold. Your FIV helps cold starts.

revolt_allmotor

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbogixxer &raquo;</TD></TR><TR><TD CLASS="quote">The Fast Idle Valve (FIV) is the thing under your TB (unless you are running a type-r TB). What the FIV does is allow more air past the TB when it is cold. The FIV uses coolant temp (via of a wax pallet) to open and close it. Your gains will but be big by bypassing it. If you bypass, you have a high chance of it running like **** then you first start it up.

The IACV only have coolant running to it so that the vavle does not get frozen/ice on it on very cold days. You live in CA, you can bypass it will no problem.

No, it will not. The IACV has no way to tell if the coolant that is going to it is warm or cold. Your FIV helps cold starts. </TD></TR></TABLE>

I have a type-r throttle body and intake manifold. I was wondering why I didn't have this FIV thing that everyone kept talking about!

Anyway thanks for the answer on the IACV... I'm just gonna cap the coolant inlets on it and cap the outlets on the head and the coolant rail on back of block then...

Falqon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HollywoodEG2 &raquo;</TD></TR><TR><TD CLASS="quote">It needs it for the cold start. The temp from the water tells the iacv to have high or low idle. you could bypass it but it will make the motor idle pretty high, around 1500-2000 </TD></TR></TABLE>

The IACV does not have a temperature sensor.

blackbmagic

yea since u live in ca it souldnt be a problem since its warm weather.. u prob wont notice a difference but it might help a lil...there should be 2 lines goin into the t/b one is for the sit goin in ones for the **** coming out just unplug the 2 some coolent or w/e might drip out just connect the 2 with a small pipe that will fit snugly ito the 2 wholes so all its doing is bypassing the t/b and running in a continous cycle. make sure everything is tight so nothing is leaking in ur engin bay...

revolt_allmotor

brought this back from the dead to warn people, read original post...

CRX_1.8T

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by revolt_allmotor &raquo;</TD></TR><TR><TD CLASS="quote">brought this back from the dead to warn people, read original post...</TD></TR></TABLE>

Back from the dead... where did you get the better-quality caps from? I am doing this same thing right now and do not want mine to rupture as well. Thanks brother.