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View Full Version : Re-routing vacuum lines


warrior
05-20-2007, 06:12 PM
Can I re-route that line that comes off the intake tube right after the MAF to somewhere on the airbox (torque box) or connect it to the smaller line with a 'T' fitting.

https://sl-i.net/FORUM/images/imported/2007/05/iacline-1.jpg

The reason being.. I was told the drone/hum sound you get after you remove the silencer (snorkus) was because of the round piece that protrudes off the intake pipe. I custom installed a 3" x 7" metal pipe and added the fitting for the bottom IAC line that was on the stock tube.. same annoying drone sound.

My only option is to re-route that line somewhere else off the air box but will it change anything in regards to how my car operates? I would like to mate a 'T' fitting on the 1/2" line but will the IAC be starved of air if I did that since it's a 3/4" line.
badbasser98
05-20-2007, 09:36 PM
From what I have heard from other people, the drone was caused by the flex portion of the intake tubing. It didn't bother me enough to change anything when I had my BD, but other people claimed that replacing that portion of the intake with a smooth piece of pipe got rid of the drone sound at idle.
warrior
05-20-2007, 10:13 PM
Thanks for your response Matt, but according to my observation that is not the case. As I stated in my previous post, I did replace the whole flex portion of the pipe with a 3" x 7" metal smooth pipe. In that pipe I added an elbow for the IAC vacuum line.. I still get the drone sound.

My theory is; the drone sound is produced by the IAC vacuum line at the elbow that connects to the main tube after the MAF. In my setup, that is the only piece left, that's why I asked if I could re-route it to somewhere else on the air box.
Wiscon_Mark
05-21-2007, 10:12 AM
It has to be post MAF otherwise your car won't idle, it'll just die. That line is the idle air bypass valve, and you have to run it off the intake system.

What exactly is the arrow pointing to? A part of the EGR system?
warrior
05-21-2007, 02:01 PM
It has to be post MAF otherwise your car won't idle, it'll just die. That line is the idle air bypass valve, and you have to run it off the intake system.

What exactly is the arrow pointing to? A part of the EGR system?

It's pointing to the air box... there's a smaller 1/2" line coming off the air box, I was thinking of drilling a hole on the air box and adding it there beside the smaller line. Before I go about making holes and what not... just wanted to make sure I could do that..
Wiscon_Mark
05-21-2007, 10:19 PM
Oh, you mean the Plenum box, not the airbox, right? I consider the airbox to be the one with the filter in it, which is pre-MAF.
warrior
05-22-2007, 05:54 AM
Oh, you mean the Plenum box, not the airbox, right? I consider the airbox to be the one with the filter in it, which is pre-MAF.

Yes, that's the one! I guess other people call it torque box as well?
warrior
05-23-2007, 03:23 PM
so.. can someone answer my question?
Wiscon_Mark
05-23-2007, 04:20 PM
I'd imagine so. I don't think it'd hurt to try - worst you could do is not get enough air or an accurate MAF reading and the engine wouldn't idle. Then just pop things back to normal, and forget about it if it doesn't work.

But I'm pretty sure it'll work.