DIY: ENG- Adjustable IAB Control...w/o ECU!

[lucid]

I don't know, dude. That worked fine for me with a stock ECU and a friend of mine's chipped one.
Technically adding a spacer plate or changing an intake manifold alone requires tuning to get the most out of it, but it's not required and by no means hurts reliability unless you're running a pretty aggressive or specific tune.
Consider all the people with H22 swaps who don't use the butterflies their ECUs were programmed for.
It is always suggested to get a good tune for the parts that are on your car.
This system works best with stock cams that are made to be in VTEC only about 100 rpm or so after the IABs open.
You can imagine how fast 100rpm goes by even in 3rd gear, hardly enough time to choke.
Most people's basic H22 tunes from what I've seen cut VTEC in at 4800 rpm, which is exactly where the stock IABs open, so in that case, it seems ideal.

My shit runs rich, so maybe there's a good spot in the map this way

[WiKKeDV16]

you can have w.e modifications you want.. its not the point of having diff variations aka no iabs.. or skunk2 manifold.. or intake.. etc.. its the point of the change in CFM being directly in correlation with when vtec activates.. hence why its set at 4800 stock and vtec 5200 anyone who sets there vtec at 4800rpm is hurting their powerband anyway unless heavily modified and has higher compression.. youll powerband will drop then rise around were stock engagement was suppose to be.. this is the same as that other thread with the exhaust cutout and it activated when vtec hit.. ive seen it lean out.. im not saying its gonna detonate.. but why purposely allow the engine to lean out if it doesnt have to..

the idea is awesome thou.. 2 points for that

the way ive done it (and still havent done a damn DIY)
is using the shift light feature in crome and using power from the CEL light.. and removing power to the bulb(via switch so u still have CEL checking abilities) so when it activates it doesnt come on

was awesome to be able to adjust it on the fly via the ecu

[Ghetto_CB7]

V-tech and IAB

Ok first of all we need to get this straight.

You could cause a slight leaning at the exact v-tec engagement if you have them opening in correlation with v-tech. This sounds correct.

However, opening them anywhere before v-tec would not cause any issues.

This brings up a good discussion however and possibly a better way to enhance our partial throttle low end torque.

The reason honda chose the 4800 rpm open position is most likely due to only WOT testing. This is probably the correct opening for anyone with a stock setup running at WOT. This does not mean it is the correct opening at partial throttle or tuned setups.

Perhaps the most comprehensive method for opening these things is not rpm dependent but CFM dependent. In which case we should look into opening them using a MAF sensor and rigging the relay to open at a certain CFM reading, not rpms.

For the time being however if you use this setup and have them open at or around the original time then you should be fine.

Whatever CFM it is must be the flow that our stock manifolds begin having resistance from narrow / long runners and the short open runners become more ideal.

(This is why I love honda's, you couldn't be having this conversation about a cheap 1992 engine made by anyone else)

EDIT: Hold on, I just read what I posted and it didn't make sense...

Let me explain. If we are discussing opening the butterflies late (at or after v-tec) then the flow of air would be less then desired making the v-tec engagement rich not lean... Someone please verify this or explain why my reasoning is wrong.

[Ghetto_CB7]

Lucid FTW

Another good point that lucid brings up is that he is indeed running rich,

AND the ecu never checks for iab's there is no check engine light, no anything. This is not something honda does, there are very few things you can do that are bad for our engines without the ecu getting pissed off and retarding timing and so on. The IAB's are not even checked for. So the ecu would NEVER compensate for you running them or not.

The only place you could be running lean would be if you are just not running them at low rpm. (always open)

Well I am not going to rod the piss out of my car till I get this fixed now... LOL I ruined all my fun

EDIT: On the other hand the O2 sensor could, but now I am just having a debate with myself, so I will shut up and get back to homework...

[WiKKeDV16]

i never meant it as the ecu checking for iabs.. simply the change in CFM making the air/fuel curve not optimal hence when you add modifications like.. i/h/e cams/tb/intake manifold etc.. all of that changes the flow characteristics of the engine.. so you slapping open 4 butterflies right at the crest of lowcam will change cfm dramtically its like going from half throttle to full.. as for him running rich.. he may very well be.. but is he rich right at vtec engagement? you wont know unless you slap a wideband on it

[lucid]

My Stock H22A1 Prelude hits vtec at 4900 or 5000 rpm with the stock P13, not 5200. I feel like we're pointing out problems that don't really exist.
The shift light method is better for tuning and custom setups, but the relay-direct way works great too. When I was building this system, before I figured out the electrical part, I had the intake open at idle and close at vtec, oops!
That's what you don't want, but it didn't blow up or anything, it just had no ass at any point since it went from a weak bottom end to vtec without acceleration, haha.

So should we be worried about opening the throttle too fast because the ECU can't keep up? That sounds pretty silly...
The relay power has to release the intake before it can engage the vtec solenoid, so there's no lag or perceivable choke there. I understand your concern but it's basically a non-issue. If you are concerned about the perceived risks of this solution, use the shiftlight and set things the way you like.

[Ghetto_CB7]

5500

My v-tec hits about 5500 Hmmm... LOL well at least that is where I think it does. Oh well, One way or the other this method still works even if you keep the engagement stock.