IACV tubing questions sr20det - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Fournierjue · 05-08-2015, 08:24 AM

I am attempting to finish up a build on my sr20det and am stuck momentarily due to the fact that I cannot figure out where the tubing for the port in the pictures should go.

I've attempted to look through the forums to find correct information, but I've gotten several different answers and before I go listening to the wrong one, I figured I would see if anyone here could give me some advice.

I have read that it goes to the throttle body, to the intercooler, to the intake before the throttle body, etc...

Kingtal0n · 05-08-2015, 09:05 AM

So, what does that port do?

Does it
A: allow air to bypass the throttle body, thereby raising the idle
B: allow air to recirculate from the intake manifold back to the intake manifold
C: allow kittens to go for rides

Fournierjue · 05-08-2015, 09:41 AM

I'm going to have to go with C. Always C.

But on a serious note, I wish I knew the answer to your question because it would also be the answer to mine. If I knew the exact purpose of the port, then I would know where I need to rout it. I'm going to continue to research and see if I can figure anything else out in the mean time.

Thanks for the response.

Kingtal0n · 05-08-2015, 09:59 AM

the vacuum source occurs at the engine's valve. It takes whatever air molecules are available from the port in the head. The port in the head is connected to... the intake manifold. The intake manifold feeds the ports in the head with air molecules. Where does the intake manifold get the majority of it's atmospheric molecules?

From the throttle body, when it is open. And when it is not open... from the IACV.

the IACV steals air molecules from the other side (from the "cold pipe") of the throttle body to raise the engine RPM, exactly as if you open the throttle body by hand.

to involve computer control, to control idle, one must either open and close the throttle body (drive by wire or similar), or, one must install an additional electronically controlled valve (the IACV) and make it work with the same (metered if using a maf) air molecule source as the throttle body. If not using a maf, and not using a turbo, you could just put a little filter on it instead.

Fournierjue · 05-08-2015, 10:38 AM

The help is much appreciated. So I will need to tap into the intercooler piping connected to the throttle body and run a tube from that to the IACV?

livelovesole · 05-12-2015, 03:40 PM

Are you running a front mount intercooler ? Your cold pipe should have a port on italready that allows you to attach a hose at each end.

05-08-2015, 09:05 AM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 41 Posts: 4,829 Trader Rating: (17) Feedback Score: 17 reviews	So, what does that port do? Does it A: allow air to bypass the throttle body, thereby raising the idle B: allow air to recirculate from the intake manifold back to the intake manifold C: allow kittens to go for rides

05-08-2015, 09:41 AM	#3
Fournierjue Join Date: May 2015 Location: Connecticut Age: 32 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	I'm going to have to go with C. Always C. But on a serious note, I wish I knew the answer to your question because it would also be the answer to mine. If I knew the exact purpose of the port, then I would know where I need to rout it. I'm going to continue to research and see if I can figure anything else out in the mean time. Thanks for the response.

05-08-2015, 09:59 AM	#4
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 41 Posts: 4,829 Trader Rating: (17) Feedback Score: 17 reviews	the vacuum source occurs at the engine's valve. It takes whatever air molecules are available from the port in the head. The port in the head is connected to... the intake manifold. The intake manifold feeds the ports in the head with air molecules. Where does the intake manifold get the majority of it's atmospheric molecules? From the throttle body, when it is open. And when it is not open... from the IACV. the IACV steals air molecules from the other side (from the "cold pipe") of the throttle body to raise the engine RPM, exactly as if you open the throttle body by hand. to involve computer control, to control idle, one must either open and close the throttle body (drive by wire or similar), or, one must install an additional electronically controlled valve (the IACV) and make it work with the same (metered if using a maf) air molecule source as the throttle body. If not using a maf, and not using a turbo, you could just put a little filter on it instead.

05-08-2015, 10:38 AM	#5
Fournierjue Join Date: May 2015 Location: Connecticut Age: 32 Posts: 5 Trader Rating: (0) Feedback Score: 0 reviews	The help is much appreciated. So I will need to tap into the intercooler piping connected to the throttle body and run a tube from that to the IACV?

05-12-2015, 03:40 PM	#6
livelovesole Zilvia Member Join Date: Apr 2013 Location: Long Island, NY Age: 32 Posts: 216 Trader Rating: (5) Feedback Score: 5 reviews	Are you running a front mount intercooler ? Your cold pipe should have a port on italready that allows you to attach a hose at each end.