32V Lower Plenum Questions

[345 DeSoto]

Why are half of the intake ports in the lower plenum of my 32 valve heads square, and the other half round? And WHAT is/are the butterflies in half of the ports for? The shafts are hooked up to linkage/mechanical cables which run into a black box that has nothing else going into it but a wire plug connector...

 

[Blenderhead]

Those are the IMRCs. At low rpms, they are closed, so all the air is forced through the one port, which helps keep velocity up and give you more low end torque. Around 3K, those butterflies open up, and now, with the higher volume of air moving through the intake, you can get the higher peak hp without sacrificing low end. As for why one port is square and one is round, I don't know. Presumably some engineer somewhere figured that a square port will flow better at low rpms or something like that.

 

[jhargarage]

http://www.lincolnvscadillac.com/showthread.php?t=40740



Desoto this talks a bit about the imrc's, hope it helps

 

[345 DeSoto]

Thanks..again..guys. LOTS of needed info on the included links...especially about the mysterious "box". Now that I know what it does, and the different ways to actuate it, it knocks down one more problem I didn't know I had... Don't worry, I'll have more questions. I guess the biggest, one for down the road that's been lurking in the back of my mind, is how to get rid of all the "crap" inputs I don't need for my application. All I'll actually need is ignition, fuel, transmission shifting. But that's later...

 

[jhargarage]

Could painless or one of the wiring companies make you something? I think in the V8 fieros I was building I used Ron Francis his company is RonFrancis wireworks

 

[345 DeSoto]

It's not the wiring/connectors/sensors that's the problem, its the EEC. I'll be using a EEC IV because it's not as sophisticated as the newer EEC's, but still is a dynamite EEC module...that SHOULD be easier to remove the unnecassary functions I won't be needing. And I will be using it with an EDIS system, which should further simplify things. I've got all SORTS of books and publications coming, which I hope will get me over the hump...me being an old time carburetor and distributor type of guy.....

 

[Blenderhead]

You really should reconsider using an EEC-V. OBD2 is so nice when you are trying to diagnose drivability issues. Removing the functions you don't want will be exactly the same for both EEC-IV and EEC-V; both will require a tune to change the settings and turn off what you don't want. As for the DIS vs COP, its relatively easy to go back and forth between the 2, you just need to do a little re-wiring. There's no reason you can't run DIS with a computer that was originally designed for COP. You just wouldn't use half of the coil control terminals on the PCM. Personally, I would think you would want to keep the COP for a cleaner look to the motor, but either way will work just fine.

 

[98LSC32V]

The gen 1 is the only B head with the round and square ports on the intake. It is a remnant from the A head design that never made it to production.

 

[94m5]

The gen 1 is the only B head with the round and square ports on the intake. It is a remnant from the A head design that never made it to production.

?


B-Heads went fron 93 to 98~99 Ish


not only gen 1.



BTW serge.... i installed that SFI balancer last saturday. MUCH nicer

I had to buy a 2 inch shorter belt because of the Diameter difference, but twas worth it.


Mike

 

[98LSC32V]

Sorry I meant to say the intake ports on the gen 1 are two circles which came from the A head design which Ford tested on the 4.6 DOHC but never made it to production on the Cobra. So the gen 1 has B heads with A head ports on the intake. Here is a picture of the gen 1 ports:

And here is the Gen 2 and 96-98 Cobra ports:

My opinion is that the smaller ports on the gen 1 give it better throttle response versus the gen 2 (anyone who has driven both gens knows what im talking about) but the larger ports of the gen 2 make it possible to rev to 7000rpm and not drop off in power as much as the gen 1.


Mike, did you notice any difference in power or how fast the engine revs with the March SFI dampener?

 

[94m5]

Both power AND revs.....



The Gen 1 IMRCs adapt that intake to the B heads.......You know this right?