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57TBirdWed Jun-08-05 11:40 AM
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"Cobra Intake on GEN I - using vacuum IMRCs"
Mon Jan-10-05 10:27 AM by 57TBird

          

I had posted this on the LOD site, but thought I'd also post here, as it may be of benefit for anyone trying this. Note that this is a very long post...

FIRST MESSAGE

I need some help with a particular problem I'm having with assembling a Cobra intake on my GEN I.

I never really liked how on the Cobra intake an electric motor holds my IMRC plates open, and know they tend to fail, so I decided to use the GEN I vacuum controllers with my Cobra IMRCs. I set them up as follows...

First, I put the cobra plates on the Mark controller rods, then I put the cobra IMRC adjusting screw stops in stock location, after cutting off that part of the bracket that wasn't needed.
finally, I modified the vacuum IMRC controller brackets and mounted them upside down, actuating the rods from a hole drilled on the opposite side of the lever. This closes the IMRC plates under vacuum, and they open up when vacuum is released, just as in the GEN I intake. I mounted the custom brackets to two tapped holes at the back of the block (in the meaty spots where the tranny mounts).
Finally I adjusted them to Service Manual specs. They now fully close at about 12lbs of vacuum, and open when vacuum is released.

I've got pictues of the IMRC setup with the vacuum lines and one of the mocked up intake. Note from the pictures that I've also added a coolant line from the drivers side water jacket, steeda underdrive pulleys and timing adjuster, 160 AMP alternator, accel coil packs, and I've powdercoated most everything with a clearcoated aluminum finish. To see the pictures, go to my cardomain site link (below), and go to page 2. The 3rd picture is the intake (mocked up). The 4th picture shows how I mounted the IMRC controls.

My problem is where and how to route the vacuum lines on the cobra intake. I have the GEN I IMRC vacuum lines, with 3 small connectors and 1 large connector. 2 of the small ones go on the two vacuum actuators on the IMRCs. I have no idea where the 3rd one goes (fuel pressure regulator maybe???)
The large connector goes to a vacuum port on the intake; It will just reach the back one, on the passenger side.

I'm not sure if there is some controller or solenoid that I am missing to release the vacuum and open the IMRCs at the right RPMs.
As I'm working with an unused crate engine, I don't have the original
setup to work backwards from.

I've been told that you can just hook to the intake, and that the vacuum drops after 3K RPM, which opens the IMRCs. I'm not completely convinced that it will work, because if there is any vacuum at all, the IMRCs wouldn't open all the way.

The Service Manual mentions both a "secondary air injection control solenoid vacuum valve" and "IMRC control solenoids", which I don't have and can't find a diagram of. Are either of these what I may be missing?
Also, if this is what is needed, where would I connect it/them to the manifold and how does it/they plug into the PCM?

Note that I will delete the EGR and the fuel canister vapor purge (not needed as this is going into a 57 TBird = no emissions requirements in GA). I'm also not using any manifold vacuum for my brakes, as I am installing a hydroboost unit from a late model mustang.

Any help/insight and especially pictures of a working setup are appreciated.

Thanks.

RESPONSE 1:

1st Gens have a separate RPM controlled valve that is open under 3k rmps (more or less) and closed above, restricting vacuum to the IMRC actuators and closing the IMRCs via the springs. The valve is mounted usually on the driver's side valve cover, right next to the EGR valve.

If you hook it up straight to vacuum, any time you go WOT (no vacuum), the IMRC will open, even at low RPMS(under 3k). That's not the way they were designed to work.

RESPONSE 2:

Looking at your pictures, it's pretty clear what you're missing: there should be a bracket bolted to your left rocker cover with two electronic vacuum solenoids on it-- the EVR and the IMRC control solenoid. If you've still got them around, you're laughing, but I'll talk to my parts guys on Monday and get you Ford part numbers anyway.

Here's what you'll need to make them work:

VACUUM-- Both solenoids need manifold vacuum to their lower nipples. You're going to have to run that source vacuum through a "tomato juice can" so it's not gone at WOT. The EVR's upper nipple goes directly to the EGR valve. The IMRC solenoid's upper nipple must feed through a tee to both IMRC actuators.

ELECTRICAL-- Both solenoids are commanded outputs of the PCM. They share a common keyed power source and the PCM controls them through ground side switching. The EVR's control is from pin spot# 33 on the PCM's 60-pin connector, and the IMRC's control is next to it, spot #32. In '93-'95, this was a light green/black stripe wire. When you wire them up, keep in mind that the solenoids are NOT polarity sensitive.

FOLLOW UP QUESTIONS:

Your right. I'm missing the vacuum solenoids for EGR and IMRC. I will definitely need the part number for a GEN I, as they did not come with my engine. I might not need the Juice can, as at WOT I'll go over 3200 rmps almost instantly with 4.11 gears; but I may try it both ways to see which one works out the best. Now I only have a few followup questions....

1.) Would the soleniod mount directly to the Cobra intake where the Cobra EGR solenoid is (drivers side, front of upper intake, right beside the IAC)?

2.) As I'm deleting the EGR, I would mount the solenoids at the stock cobra location above, then block off the EGR one, leaving only the IMRC solenoid operational. Does anyone know if this will cause problems? I will be using a 4-bank custom chip, so I'm assuming it can be programmed for this.

3,) Finally, There are the 3 little connections on my current vacuum harness, they look like this...

----------------* IMRC 1 (small connector)
|
---------------* IMRC 2 (small connector)
|
|
|---------------------* ? Third small connector
|
0 Large Vacuum supply connector

(A)If the vacuum supply goes to the solenoid, does the third go to
the fuel pressure regulator? Or...
(B) Does the 3rd small one go to the IMRC solenoid, and the larger vacuum supply goes straight to the manifold?

If someone with a GEN I has their beauty cover off, maybe they can check and see which of the above is the correct way.

Thanks,

Mike McNamee - building GEN I powered 57 TBird
cardomain site: http://www.cardomain.com/id/57tbird



  

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Subject Author Message Date ID
RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 10th 2005
1
RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 10th 2005
2
      RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 11th 2005
3
           RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 11th 2005
4
                RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 11th 2005
5
                     RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 12th 2005
6
                          RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 14th 2005
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                               RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 14th 2005
8
                                    RE: Cobra Intake on GEN I - using vacuum IMRCs
Jan 30th 2005
9

BlackIceLSCMon Jan-10-05 12:16 PM
Member since Jul 25th 2003
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#1. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 0
Mon Jan-10-05 12:17 PM by BlackIceLSC

  

          

Mike...I canot answer these questions. But, dave (HwyStar) and Jeremi have both dealt with the Cobra intake on a gen 1 engine. But I think they went with gen 2 IMRC's. I hope to one day be able to answer your questions, but for now, I am of no use to you. Sorry.

Good news is, whatever you figure out...you will be helping others that follow in your footsteps.



94 Mark VIII-SPRUNG/97 Mark VIII LSC
Founder/President-Club 16
see profile for mods.

  

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JeremiMon Jan-10-05 11:14 PM
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#2. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 1
Mon Jan-10-05 11:18 PM by Jeremi

          

It doesn't really matter what goes where as long as it has enough vacuum. Currently, I have the port under the TB split into the AFPR and the heater/blend door. The big output on the back of the intake is split to brake booster and EVAP. No EGR, no IMRC solenoids. The port on the driver's side goes directly to the PCV valve. Just discard most of the original vacuum lines, get the IMRC valve and either mount it on the valve cover as in stock 1st Gen configuration, or use the spot on the cobra intake where DPFE used to be. What ECU are you running ? I had problems with DZA1 computer and SCT when trying to shut off the EGR. Despite having set the parameter to skip EGR, I had to leave the DPFE plugged in without any lines going to it to avoid the CEL. As you know I am using the two leads to the IMRC solenoid to drive a relay and control the cobra IMRC control box. Works fine now for over a year. But I was thinking of going the same way you went.

One more thing: don't install the vacuum canistaer on the FPR line, it will cause the fuel pressure to sit constant despite the vacuum.

-------------------
1997 M8 LSC Deep Navy Blue/ Midnight Black

  

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57TBirdTue Jan-11-05 12:12 AM
Member since Jan 10th 2004
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#3. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 2


          

Thanks for the responses. With a lot of help, I've figured out I need to run at line off of upper intake with a TEE. One side will go direct to the Fuel Pressure Regulator (so it gets the actual vacuum signal), the other will go through a check valve, to a vacuum reservoir, then to the IMRC solenoid. That will TEE to the two IMRC actuators. This way, I won't loose vacuum at WOT under 3200 RPM.

I've ordered the parts. I'll take some more pictures when its done.

The hardest part about this mod is making the brackets for the "upside down" IMRC actuators and drilling the holes in the right places so that the IMRCs will have full range of travel.

The rest would have been "plug and play" if I hadn't been working with a crate engine. It didn't have anything on the intake but the Throttle body, IAC, and fuel rails, making it hard to figure out what I was missing. Still, I imagine its hard to find a 0 miles GEN I engine, so I should consider myself lucky. When I took the valve covers off to powdercoat them, it was nice and shiny inside, with the assembly lube still on all the surfaces.

As far as PCMs go. I have both a W3Z3 (1993) and a Z4H0 (1994) to choose from. Which one do you think would work best with an EGR delete, 350+HP J-MOD with 3500 stall, 4.11 Gears, Cobra Intake, headers, 180F thermostat, and no cats. I already have a 4-bank SCT chip, I'm just waiting to get the engine and tranny done, before I have it flashed.

Mike - "soon to be" Modular powered 1957 T-Bird. http://www.cardomain.com/id/57tbird

  

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JeremiTue Jan-11-05 10:01 AM
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#4. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 3


          

Neither to be honest. This is the main reason why I purchased the 2nd Gen car. The problem is the EEC IV computer. The newer EEC V is a lot easier to tune, and has a lot more parameters you can adjust to your liking. I am not saying this is always the way, but it didn't work in my case.

-------------------
1997 M8 LSC Deep Navy Blue/ Midnight Black

  

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HwyStarTue Jan-11-05 06:18 PM
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#5. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 4


  

          

If you were going to use a computer, I would use the 93. I have the Z4HO in my car and one thing I have a consistant problem with is the way it shifts the transmission. Levine had this same problem, even when he went for the MMnFF Luxobarge shoot out cover. I have driven the piss out of some 93s and had no problem, except when they had factory gear ratios.

Dave
MM1(SW)-N USS LINCOLN CVN-72
94 Mark VIII Under Construction
90 Cougar XR7 Alive! 325RWHP
81 Rabbit 1.6D 50-60mpg

  

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57TBirdWed Jan-12-05 10:38 AM
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#6. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 5


          

Also, one final follow up question. Should I use the Cobra IAC or the Mark VIII, bolted to the cobra position. The connectors look exactly the same.

Thanks,

Mike - "soon to be" Modular powered 1957 T-Bird. http://www.cardomain.com/id/57tbird

  

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57TBirdFri Jan-14-05 09:04 AM
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#7. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 6


          

I test fit both IACs so I can answer my own question above.
The IACs between the cobra and mark GEN I are comparable, however the harness connection is different.
I just bolted the Mark GEN I IAC on the cobra intake, looks the same as the cobra one, and I didn't have to modify the harness.

P. S. I'm not sure if the connectors are the same or different between the cobra and the GEN II.

Mike - "soon to be" Modular powered 1957 T-Bird. http://www.cardomain.com/id/57tbird

  

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JeremiFri Jan-14-05 03:48 PM
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#8. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 7


          

I am using my original 1st gen IAC on my cobra intake without any issues. It's one less plug to change, you know.

-------------------
1997 M8 LSC Deep Navy Blue/ Midnight Black

  

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57TBirdSun Jan-30-05 01:30 PM
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#9. "RE: Cobra Intake on GEN I - using vacuum IMRCs"
In response to Reply # 8
Sun Jan-30-05 01:31 PM by 57TBird

          

I would like to thank everyone for your help...

The completed engine pics are now on my cardomain site, page 2.
There's also some new pictures on page 3 of how the shortened rear end, wheels and tires, look mounted up.

I put in two detail pictures for how I did the vacuum IMRCs with the cobra intake.

One shows how I did the vacuum controls. If you look at the picture and go from left to right, you'll see the check valve, a small vacuum canister, and the vacuum control valve, all tucked in beside the cobra intake.

The other is a closeup of how the vacuum canisters were mounted upside down, with new holes drilled in lever on the IMRC rod. I also kept and modified the the cobra lever stop assemblies.

Thanks again. Since I've been pretty successful with DIY powdercoating, I'm going to ceramic coat my headers myself, too. I'm using the same stuff jet-hot uses; I'll post new pictures when I'm done.



Mike - "soon to be" Modular powered 1957 T-Bird. http://www.cardomain.com/id/57tbird

  

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