IAB Black Box

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I've been giving this a lot of thought. When I swapped in my prelude engine, the black box was busted on arrival. Most of us wire up the IAB, then run a hose from the intake manifold to the IAB. However, if the engine made more power without the black box, I can't think of any reason why Honda would add it. The secondary butterfly stays closed at low RPMs, which supposedly makes more low end power, and the solenoid opens the butterfly at higher RPMs. An engine makes less vacuum at higher speeds than lower. Does this black box store vacuum to be used to open the secondary butterfly?

Dunno.
I'm putting one back on because it is original equipment, and I believe the research teams at Honda to be smarter than I am. I just won an auction on Ebay to replace my broken one.

IAB auction

 

[sleepn_accord]

Just remove the secondaries. I'm going to go for it. After a lot of discussion on some other boards..the concensus seems to be that removing the secondaries only gives gains.

 

[H22AdelSol]

Helps with low end torque and i wouldnt be surprised if it also helped with smog. I definetly keep it its a daily driven car. I bet youll get sick of the loss of power real quick but whatever.

 

[sleepn_accord]

All the dynos that I've seen posted, when the secondaries are removed, show no loss of torque at any RPM range and an average of 1-2% HP gain at the top

 

[tab]

Originally posted by sleepn_accord@Apr 19 2004, 06:50 PM
All the dynos that I've seen posted, when the secondaries are removed, show no loss of torque at any RPM range and an average of 1-2% HP gain at the top

I believe you, but if you could post a link to any info that would be great.

 

[H22AdelSol]

if that were true honda would not have put it in there.

 

[sleepn_accord]

lazy to search right now.. but check hondasociety, it's deep in the h-tech section ...

if I have time I'll search for it.

 

[tab]

Originally posted by H22AdelSol@Apr 20 2004, 02:05 AM
if that were true honda would not have put it in there.

That was my train of thought. Unless it helps with mileage. Like a two barrel carbeurator with vacuum secondaries. I have a feeling that the box is meant to store vacuum, to pop the secondary butterfly open quickly on activation. Just a hunch, wish I knew.

 

[driver1]

i dont beleive that it was put there to necessarily increase power....because why else would they not have one on the type s h22's? I realize the type s is higher compressionand whatnot but i still think that without them you would be better off

 

[tab]

Originally posted by driver1@Apr 20 2004, 08:00 PM
because why else would they not have one on the type s h22's?

I had no idea that it was not present in the Type S

 

[Slammed90Lude]

please don't say that the IAB on the B18C doesn't help any until you read some articles on exactly how a variable length intake manifold works- yes, the butterflies help produce more power in the low end- no, you don't know more than honda engineers or audi engineers or BMW engineers

don't believe me?

Click here and learn something

 

[highperboi]

ok the box does not store vacume it is closed at rpm because the vacum sucks the diaphram in which causes the arm to close the butterflies. at high rpm the solenoid closes which prevents vacum from reaching the diaphram and a spring pulls the arm to open the butterflies.

i dont know about it giving more torque though. I disconnect mine and it feels the same as when it is connected. my friends gsr is differnt tho when his is connected it seems to have a worse throttle responce and less mid range power. This then leads me to believe that it does not work. Why would they put this on a gsr and not the type R? if it is a better design why take it out of the type R which is a higher performance car?

 

[tab]

Originally posted by Slammed90Lude@Apr 20 2004, 08:32 PM
please don't say that the IAB on the B18C doesn't help any until you read some articles on exactly how a variable length intake manifold works- yes, the butterflies help produce more power in the low end- no, you don't know more than honda engineers or audi engineers or BMW engineers

don't believe me?

Click here and learn something

Great Article!!!!

I started this thread to learn more about how the IAB works, thank you.

 

[Slammed90Lude]

see it isn't as pointless as everyone thinks, thanks for taking the time to read that, it's really a pretty good simple write up

 

[sleepn_accord]

I never said it was ineffective on the b18c.

I do, however, find that the low-end power loss from removal of the secondaries is nominal compared to the overall improvement in power. It is my impression that the IAB on the h/f was desgined with economy in mind as, quite simply, more air = more fuel.

If you remove the IAB; at low rpm's you're providing more available air to the combustion chamber. If we assume that even 2% more air goes into the combustion chamber, the o2 sensor regards this as the engine running lean and compensates with more fuel thereby raising your fuel comsumption at lower rpms.

While the off-line amount of available torque may be reduced, I don't think many of us here are that concerned with available power in stop and go traffic.

I've read numerous articles, tried numerous tricks and have found myself happiest with running the secondaries directly off of the intake manifold as the butterflies, in essence, are controlled by the throttle.

But that's my .02. I'm not an engineer, in fact very few of us are. Correct, we do not know better than the Honda engineers, however the overall objective of Honda engineers is different from the majority of us racers. Engineers are concerned with overall performance and fuel economy. To gain one you must sacrifice something from the other. But I'm just a lead-footed street racer who has way too much time on his hands.

 

[tab]

It's hard to agree with everyone, but I kinda do

Um, there's more to it than overall flow rates, if you read the article posted above.

Also, as a sidenote, vacuum is greater in your engine at low rpms. At WOT with the rpms up, your vacuum goes down. I am not sure how this would effect the secondary, but I thought it would be worth mentioning.

I have had mine hooked up directly from my intake since the beginning. My black box was broken, and a replacement was not readily available. I will install it after I recieve it, and decide for myself. A little economy and overall driveability aren't bad things.

 

[Canuck 93 Civic Si]

When Yamaha designed the cylinder head for the SHO ford engine, they used duel length intake runners as well. The only difference is that they have no butterfly valves in them. The intake charge will take the past of least resistance, it doesnt really need a valve to direct it. Its all in the dynamics people.

 

[ohmstable]

I'm pretty sure the box acts as a buffer between the vacuum system and the butterfly valves. It probably takes alot of vacuum to open those valves so therefore instead of having the valves run directly of the engine vacuum they put this "buffer" black box inline to build up vacuum pressure and inturn you will have quick (response), opening or closing of the butterfly valves when that soleniod on the box is activated.