I have what I believe is an H23 intake manifold complete with all the vacuum lines and components. Is there anyway to test the operation of the IAB's before installing the manifold?

 

yes, suck on one of the vac hoses until the IAB diaphram closes the IABs then a check valve should hold them there. Dumping a little current into the solenoid on the IAB vac chamber should release the vacuum, and the IABs should open. A 9v battery might do the trick but I'd consult the wiring diagram beforehand though. Either that or use a volt meter to test the voltage that's applied to the solenoid as you manually rev the enigne past 4000 rpm.

Pirate

 

Cool. So vacuum closes the IABs, and current releases the vacuum to open them? I could just run a long vacuum line from my engine to the manifold to close them, then connect the solenoid to my 12v cordless drill battery pack to release them, huh? I know the system will see vacuum most of the time, but should the vacuum 'reservoir' be able to hold the IAB's closed for a certain amount of time before they leak and open or is that really an issue?

 

That's the basics, yes.

I'd double check the voltage on the IAB solenoid though. It's just a coil in there. Too much power for too long and you can fry it.

The IAB check valve should be able to hold the vacuum for a while. longer is better but my SWAG is that if there's enough vacuum to keep the IABs closed for 30 seconds then you're alright.

 

Awesome, so I need to find out what voltage the solenoid operates at, maybe someone with a Haynes/Helms manual for a Prelude might be able to help me out.

 

The Helms manual should have the wiring diagram in the back. But if you don't have the manual then empirical observation might be more practical. Voltmeter, and a running engine with a hand at the throttle body pulley should answer your questions pretty quickly.

 

I'm not sure I follow...

 

With the engine running and the hood up splice a voltmeter into the IAB solenoid wires. The voltmeter should read zero at idle. Using your hand on the throttle body pulley, rev the engine up past the rpm that switches the ECU to open the IABs. When this happens you will see the IAB diaphram lever move and the voltmeter should have a different reading. Us a power source similar to the voltage you observed on the meter on the new IAB chamber and see if it opens.

This is of course assuming you have an engine that has IAB and an ECU that opens them.

 

I was under the impression that you needed an ECU that would close them?

 

Vacuum alone closes them. That's why if you're not paying attention and you swap to a chipped P28 on an H22 you can kill your top-end becuse there won't be anything to open the IABs after ~4000rpm. The solution is to pull the vac line or remove the IAB plate.

 

My F23 doesn't come with IABs, but I want to check the functions of this H23 manifold before I install it. I'm running a chipped P61 on which my tuner can activate IAB control. Pirate's wording had me under the impression that it might be possible to damage the IAB solenoid by applying 12v off a battery though. I don't want to burn up the solenoid if that's what he's trying to tell me.

EDIT: On the note of 'top-end'... I know most people pull the plates out completely to keep from restricting air flow. I want the top-end benefits of this H23 IM, but keeping in mind that my F23 makes ~150wtq right off idle, I don't want to lose my low-end either. I at least want to maintain the plates and control them initially so I can dyno and get a real comparison to decide whether to remove them or not by doing a run with them fully open and a run with them remaining closed. Kind of like dialing in a VTEC crossover.

 

I know I've run Crome on the P30 base code with no ill effects (besides them not closing, but who cares too much about that).

 

I might. lol

 

Oh right, they would be opening up around an Accord engine's redline, wouldn't they :p

 

Hey, I don't need to spin above 7k rpm to make power. I'm still over 160 at the wheels @ 6700rpm on stock exhaust/stock cam.