Hose coming from air box(S13)

[driftin240]

we were putting a new cone filter on my friends s13 just a $20 filter from autozone to see what it did and we took off the air box and there is a little hose coming from the side of the box and runs to a lil black box then to the header and we didnt know what it did and if we needed it connected....but the engine ran ok without it but still he doesnt want to mess anything up so any tips or hints for us?? thanks

[93Twiztid240]

That is the Air Induction valve, my suggestion is either removing it completely and getting the hole in the exhaust manifold (or aftermarket header) plugged or you could just buy you a breather and attach it to the black. All this does is allow fresh air into the cat to burn the gases up better and it runs a bit cleaner... so mostly it is just for emissions... if your state does emission testing you might want to go with the breather route.

[RefriedNismo240]

air induction valve(aiv). it routes exhuast air back into the air intake. safe to be capped off i hear and i guess it was just used as an emmisions device.

[ricebike]

refried... sorry i'm just gonna clarify that...

if it does route exhaust air back into the air intake, then the reed valves in the AIV is rusted/eroded... it should only allow fresh/filtered air into the exhaust, like twiztid says...

I prefer the little breather filter method over the plug the header...

my june 2001 NJ DMV dyno inspection

Gas/standard/readingNOx/1323/427HC/173/17CO%/.98/.04CO2%/na/15.0O2%/na/1.7

tank pressure/nagas cap/passpurge/passtampering/pass (WTF??? they gonna try to B like CA???)visible smoke/pass

[driftin240]

ok thanks for your help

[JJ240]

I dont have to worry about emissions testing, but I would really like to clean out my engine bay, I already have a breather right where the hose would enter the intake filter box. I am wondering if i could remove the first black plastic box, and also the other thing the hoses run through before they enter the exhaust. I wouldnt mind putting the breather on so fresh air could enter but can I get rid of the rest of the stuff?