The importance of an IAB controller!!!!!!!!!

[19dabeast85]

Bumping this up so the newer members get the info.

[EJX_Michael]

Bumping this up so the newer members get the info.

Weirdly enough, on my car the IABs dont open till around 4700-5000 RPMs. It just felt like power was being robbed so I hooked them straight vacuum.

[Extacee]

i did test this today, since my IAB were open all the time i decided to hook it up to the plenum. i did feel a difference, but i noticed if the throttle was half the butterflies would open and i would lose some torque. now i must try the solenoid method to see what the true capabilities are of the JDM F22A. Bwahaha

[F20A CB7]

i appreicate this experiment, thank you so much!!!

i understand now.

[sombra13]

Hmmm I see it now quick question may sound dumb but here it goes
Ok so back like a year my a6 crank snapped so I needed a motor asap so they put in an a1 and I didn't come wit iab right? If so wouldnt the connection still be there ? Where would I find it?
Fyi(I'm going H22!!!! as of yesterday swap continues)

[19dabeast85]

Weirdly enough, on my car the IABs dont open till around 4700-5000 RPMs. It just felt like power was being robbed so I hooked them straight vacuum.

Not weird at all, the IAB's open at 4900rpms. The engine could benefit some if they opened a bit earlier (4500) but I'm guessing the 4900 switch is there to retain fuel economy. A chipped ecu will let you adjust where you want the IAB's to open. The problem with hooking straight to vacuum is the IAB's will open at any mid-throttle point past ~2k rpms which makes you loose some low-end efficiency.

Hmmm I see it now quick question may sound dumb but here it goes
Ok so back like a year my a6 crank snapped so I needed a motor asap so they put in an a1 and I didn't come wit iab right? If so wouldnt the connection still be there ? Where would I find it?
Fyi(I'm going H22!!!! as of yesterday swap continues)

The plug is probably just hanging back there under the intake manifold above the oil filter. That'll make the H22 swap easier since it'll be straight plug-n-play for the IAB's.

[19dabeast85]

i did test this today, since my IAB were open all the time i decided to hook it up to the plenum. i did feel a difference, but i noticed if the throttle was half the butterflies would open and i would lose some torque. now i must try the solenoid method to see what the true capabilities are of the JDM F22A. Bwahaha

Hooking straight to vacuum is the worse option among the three, best being running IAB switch and second best being capped vacuum with IAB's open all the time. When the IAB's are hooked straight to vacuum they operate way too erratically to promote smooth, efficient engine operation.

Note we're only talking a couple hp difference with IAB's operational or not and anyone with turbo or high-hp N/A will benefit from removing the IAB's altogether. But with a stock block, having the IAB's work as intended promotes the best engine operation.

[F20A CB7]

^^^ thanks again for goin more indepth. i really should look into my iab blk box.


for some reason, when i did the h23 plenum swap, with all the vac lines hooked up rite, my secondaries wouldnt close when the car is on, idk i didnt even touch the iab bx for it 2 mess up.

can you explain to me why having them open all the time is also a good thing.

wont you loose low end?? but i for dam sure you will b makin it up in the top end.

[EJX_Michael]

Not weird at all, the IAB's open at 4900rpms. The engine could benefit some if they opened a bit earlier (4500) but I'm guessing the 4900 switch is there to retain fuel economy. A chipped ecu will let you adjust where you want the IAB's to open. The problem with hooking straight to vacuum is the IAB's will open at any mid-throttle point past ~2k rpms which makes you loose some low-end efficiency.

Well I think I read a DIY a while back about using an adjustable shift light as a switch. It was something like taking the bulb out of the shift light and using the +12v that would make the bulb light up act as the switch. Since the point the light would turn on is adjustable, you can change where the IABs would activate without any ECU modification.

[foamypirate]

Here is a fun little dyno chart demonstrating the IABs opening. You can see the torque curve flatten out and carry just a little longer once they open, as well as horsepower continuing to climb.

[F20A CB7]

thanks for the chart.

but im ashamed to say this, i forgot how to read a hp chart. to me i just see lines.

[gloryaccordy]

On the highway in 5th I get better engine response at part throttle than full.... still scouring the earth for an IAB box

[19dabeast85]

^^^ thanks again for goin more indepth. i really should look into my iab blk box.


for some reason, when i did the h23 plenum swap, with all the vac lines hooked up rite, my secondaries wouldnt close when the car is on, idk i didnt even touch the iab bx for it 2 mess up.

can you explain to me why having them open all the time is also a good thing.

wont you loose low end?? but i for dam sure you will b makin it up in the top end.

It sounds like the IAB switch is malfunctioning or you don't have the vacuum lines attached correctly.

Having the IAB's open all the time on a stock block&head engine WILL NEVER be a good thing. If they're open all the time, intake air charge velocity at lower rpms will be too low to properly mix the fuel into the air and the burn won't be as efficient as it could be. Having them open all the time will not give you more power above 5k because they're normally already opened above 5k. I think the a6 cam head would benefit from them opening at 4500 instead of 4900 and you can see this in the dyno chart posted on page2.

Those running performance cams with ported head and high-comp pistons will want to completely remove the IAB's or gut the plate and put it back because the plate will restrict upper rpm flow capacity which is where most performance cams make their power anyway.

[19dabeast85]

On the highway in 5th I get better engine response at part throttle than full.... still scouring the earth for an IAB box

They are very hard to find in good condition, usually the nipples are broken off. I finally resorted to purchasing a new one ~$25 I think.

[DJ metadelic]

Ugh, I had troubles as well. Much better off just purchasing one new or, a reman? maybe that'd be cheaper if they can even reman. those...