89 intake swap?

[Justin86]

Well I'm trying to swap the 89 Se-i intake manifold to my 86. I pretty much have it figured out. There is differences in the emissions box and there is the box thingie on the front of the manifold. What the hell does this do and do I really need it. This is my only problem cause I can't use it unless I swap the entire car wire harness.

[shepherd79]

you won't gain much with dual stage intake. you better off with single stage.

[Justin86]

Well I will be able to fix the secondary butteryfly valves on the 89 to get some more power. Right now I'm trying to get every little bit of power I can with as little money possible so that is why I'm doing this.

[AZmike]

The idle controls are completely different. You'd need to either modify or replace the engine wire harness and swap ECUs. I wouldn't bother.

[Justin86]

Well the only big difference in engine wire harness is the connector for the box-valve thingie on the front of the manifold. It has two wires and that is it. I plan on swaping the ECU I just need to know about this thing on the manifold. Look in the manual for what it does. I only have the manual for the 86.

[Justin86]

I still need to know what that valve on the front of the intake maniflod does??? It is about 2"x4" in size. Right in the middle. this is one of the big differences between the 86 and 89 intake.

[AZmike]

It's the electronic idle control valve (EACV). It's how the ECU regulates the idle under different conditions to compensate for a/c, alternator load, atmospheric conditions, etc.

[POS carb]

hmm, I don't think it would be THAT hard, if anything you probably can just swap the TB's and that would solve the hookup problem, the only thing is your ECU won't properly control the "Dual stage" intake from the 89 and also the passages may be cut different on the tb's
Also for sure the fuel rails will not bolt, you need the 88-89 rail for the SEi intake
the EGR system may not hook up to the exhaust the same either, check that. You can always use the 89 manifold with no EGR, it won't pass emmissions check though.
The "dual stage" can be hooked up to constant vacuum but it won't really work the way it is supposed to unless you hook up an RPM switch with a vacuum solenoid. It will open up pretty much anytime you get on the gas acting like a small manifold.

Please check thoroughly first though, I do not have an LXi/SEi car to compare it to, only the manifold in my garage.

[Justin86]

Yea I need a 88-89 Honda repair manual but they ae hard to get a really $$$. I know what the EVAC does now and I don't have emissions so I allready blocked my EGR. Well I'm swaping the whole 89 manifold that is why I was wondering about the EVAC. I'm going to try and reroute all the coolaint lines to the intake an TB and I want to keep the secondary butterfly valves open so I can block that vacum. I belive I have everthing figured out I just need to find the tinme to install everything.

[AZmike]

Let me know how it works. My car wouldn't idle the few times that I disconnected EACV.

[Justin86]

Well I hope it does work cause some people said that had problems with disconnecting the EVAC and others said they had no problems. But also on the 86-87 thay have a seperate A/C idle boost valve and if I disconnect it the car will idle like shit and I think that the EVAC is the upgradded model of it.