Intake vacuum line question
 

Non turbo but I figured you guys would know since most cold side intercooler piping is straight into the manifold.
Doing a true cold air intake (rerouting the AFM/MAF) so that it never crosses in front of the engine where hot air can be absorbed. However, on the OEM intake piping before the maf, there are three hoses, all of which I assume are just vacuum lines. Is it common to just plug these off and not have a second thought or do I need to continue trying to figure out how to have the piping and maintain these hose connections.

<p>If it is before the MAF then it isn't vacuum. Where do the 3 hoses run. Picture?</p>

I will grab a photo shortly, one goes to the valve cover, the other goes into the throttle body. Didn't see where the third goes

<p>Valve cover is crankcase venting.&nbsp;</p>

Oh and to clarify these are right after the throttle body, so between the intake resonator and throttle body incase I was misleading

<p>Umm yeah thats not before the maf...</p>

My apologies was thinking backwards for some reason.

Here is a reference photo
https://www.miataturbo.net/attachmen...ine=1435169481

<p>Left side is idle valve. Right side is a resonator or something I think. Middle is crank case ventilation. You need all of them if running stock ecu. Maybe not the resonator thing.</p>

I've seen some guys run a mini filter mini directly on the inlet on the crank case, I assume that they are able to because of a tune or would it act the same as taping into the intake piping
I'll likely retain all three then and just implement it into my new piping

<p>Idle valve 100% needs to be there. Resonator pipe will be gone when you remove the stock intake. You should have seen that already. Aren't you turboing? So you will have an ECU anyways.</p>

Won't be able to run a turbo setup for about two more months till I can restore the savings I had for a turbo. I've only got two events before then likely so I'm just looking for some stuff to keep me busy till then

<p>cold side piping is a waste on a stock motor. Just wait until you turbo.</p>

Stock plumbing or force feed, nothing else is worth it. Leave the PCV valve cover breather plumed into the intake AFTER the AFM meter, otherwise it will leak a bit of unmetered air.

The resonator makes torque down low, and you won't make anything better than it, seriously, leave it alone.