Little black box by stock intake

[VBaccord24]

ok i removed my stock intake and replaced it with a short ram. but down near the battery and the existing intake tubes there is a little black box with some plugs that look to plug into the old intake tube. what heck is it and can i take it out? is it a sensor?

[Neriah06]

those tubes are for the stock filter to suck the air straight from the wheel well, but if you have a short ram it will suck in the air so you dont need those tubes IMO

[minoreparations]

safe to take it out.

[TonK]

Take those tubes out and make your own ram air by adding a channel from the front of the car to the filter on your short ram...

Woo hah!

[Mike]

it doesnt sound like hes taking about the intake tubes.....its sounds like hes talking about an o2 sencer or something

[owequitit]

That little black box is a vacuum tank with a solenoid that opened the secondary ("high power intake duct" in Honda speak) intake duct. Basically below 3500 RPMs the bottom intake tube has a flapper valve in it that kept it closed to help quiet the engine. Then at 3500 RPMS, the little black box and solenoid (the little round thing) would release the vacuum, causing the little flapper valve in the bottom duct to open, allowing more air into the airbox with less restriction. Removing it isn't going to hurt anything, although I would keep it around in case you ever need it in the future, and those little solenoids are potentially expensive.

[prodigymb]

That little black box is a vacuum tank with a solenoid that opened the secondary ("high power intake duct" in Honda speak) intake duct. Basically below 3500 RPMs the bottom intake tube has a flapper valve in it that kept it closed to help quiet the engine. Then at 3500 RPMS, the little black box and solenoid (the little round thing) would release the vacuum, causing the little flapper valve in the bottom duct to open, allowing more air into the airbox with less restriction. Removing it isn't going to hurt anything, although I would keep it around in case you ever need it in the future, and those little solenoids are potentially expensive.

what he said except it opens the secondaries at 4800 rpms

[Mike]

this sounds noobish but im curios.......u say it opens at like 3500rpm does that mean it could posslibly give a tiny tiny bit of bottom end torche if u romove it?

[owequitit]

what he said except it opens the secondaries at 4800 rpms

It doesn't open the secondaries at 4800 RPM. That is the IAB system and is mounted to the intake manifold. It is an entirely different system.

ALL 1990-1993 Accords have the "high power" intake duct solenoid. The solenoid was mounted on the frame rail just behind the passenger side headlight. It opens a flapper valve in one of the two round tubes running from just behind the headlight into the stock airbox. The flapper valve resides in the lower stock intake tube (the one closest to the sheetmetal) and is opened by the ECU at 3500 RPMs.

Realistically, the flapper valve doesn't affect bottom end at all compared to removing it, on a stock intake. It was put there primarily for noise control, and just doesn't make a difference on the stock intake. You will possibly gain a bit of low end (I actually lost some) with the new intake on there, but that is mostly because both tubes on the stock intake are restrictive. I have actually found the best compromise by removing the upper stock intake tube and replacing it with a larger 2" diameter pipe running to the stock airbox. I haven't gotten around to fabbing a lower tube yet, but from a mathematical standpoint, the 1.5" tube plus the 2" tube should equal a flow area approximately equal to the diameter of the TB.

Anyways, to make a long story short. That little flapper doesn't really do anything except make it a little quieter.

[alb_accord]

u my friend asnwered something that was in my mind for a long time. lol since i changed that damn air box on my old dx i always wondered why there was a valve in there. lmao

[Granite CB7]

The system is very effective, it keeps the engine extremely quiet. It was funny, at the last CT meet I saw about 3 cars w/ SR's and they left the solenoids and ducting in, so I told them all to take it all out! When I cut my air box, I did lose alittle low end but gained alot of throttle response and higher end power.

[owequitit]

I didn't really think it made a difference LOL. I could never tell if it was working anyway. When I unhooked it, it just sounded the same. Maybe I just spent too much time above 3500 .

Seriously though, I have a modified stock airbox in there now, and it really isn't that much louder than stock. It sounds really good because it is nice and mean, but not loud or obnoxious like a cold air or SR. It sounds just as refined as stock, but slightly more aggressive. I used to have an AEM cold air on it, and I don't really notice a power difference now, and like I said, it isn't much louder than stock. Much like Comptech's Icebox intakes.

If you wanted to modify the stock airbox though, you would want to make sure you could build another, larger diameter tube to stick in there, otherwise it will sound just like a Short Ram.

[DhN]

i took mine off..helps me reach vtec at 3500 rpm[/end sarcasm]

[sj960]

Yeah, I read somewhere that that box actually is supposed to be a "muffler" for the intake, keep the sound down on stock intake systems