AIV???

[zanilth]

On my 1992 240, with a KA24DE, there is a little black box on the right hand side, with a hose leading from the air intake box. Some people, when they install a custom intake, take that out, while some people leave it in. I have disconnected the hose and driven for a while, and don't notice a difference...Anyone know exactly what this is, and what it does?

Also, near the block, there is a fourth air hose leading from the bottom of the air intake assembly....Most air intakes I have seen have three air hose outlets. Is that something that needs to be fabricated onto an air intake, or can one of those hoses be disconnected and not reconnected?

[rsmithdrift]

This is what I did with my 93 240 ka24de. It has the stock airbox still (still waiting on my intake to arrive) but I had heard of them leaking backwards and I just decided to not let that happen and get rid of the black box at the same time. I put that breather on the rubber tube leading to where the black box used to be and taped off the hole in the airbox for now (I want my short ram damn it!!)

Anyways.....trust me that black box does nothing and it makes no difference if the aiv has a breather or goes to the intake, it all runs the same. It'll only improve your performance if the aiv was leaking.

[zanilth]

k, thanks...

any clue what the fourth air hose on the intake housing right in front of the block leads to? Haven't found an aftermarket intake with four hose adapters yet....so I think it has to be disconnected...Not sure though.

[rsmithdrift]

actually, I was wondering that myself, since I too am awaiting my short ram and I was looking at that last night. It's odd.

[onosqv]

trust me that black box does nothing and it makes no difference if the aiv has a breather or goes to the intake, it all runs the same. It'll only improve your performance if the aiv was leaking.

The black box may not do much, but running a breather to it is not a good idea. Here's why:

If your aiv solenoid failed, which is why a lot of ppl remove the entire assembly, it will allow exhaust gas to go back out that hose -> goes in to your engine bay - not as bad as having the hose directly connected, but I don't like having exhaust gases dumping in my engine bay either.

The other hoses near the throttle body are for idle and crank case ventilation etc. You "need" most of them.

Just get an injen intake or something - that has all the connections you need.

[zanilth]

k, I traced the fourth hose on the bottom, and it runs to my radiator...which leads me to assume it is the air cooler for the radiator...

So, I need that...

I can't afford an injen air intake right now, but I do have a JDM from Ebay (don't actually think it is a jdm, but oh well...) Also, every intake I have seen (including some specifically meant for a 240) does not have the fourth hose attachment. ??? I am at a loss lol.

About letting the gas back through, if the black box allows the gas back through and into your air intake, wouldn't that get sucked back into your engine? Since the intake valve for the hose is above the filter, it doesn't get pushed through the air filter...Unless the black box is a filter itself...

As you can tell, I don't have much experience with nissans lol.

[onosqv]

Can you take a picture of that 4th hose you are talking about?

There shouldn't be any hose going to your radiator.

The black box is just a resonator box. It is a solenoid that controls whether air goes to the exhaust or not - and typically w/ this aiv, it gets dirty/clogged etc and lets air go back the other way (not meant to do that factory).

You can look for AIV removal guide on this forum, very thorough.

[zanilth]

Did a search on the hose and such...Found out it goes to the fan shroud, not the radiator. It is a resonator lol, just to quiet the intake some. Most people stuff a bottle cap in it or something, thats what was on the threads I read. Thanks for the info about the AIV stuff