I tackled the task this weekend. I didn't have a set of instructions, but it seemed like a pretty cut forward installation. 1st thing was getting prepped. Had to stock up on some brewsky and pop in some Blues music.. After the necessities were ready, it was time to remove all the surrounding parts(strut bar...ect..)


Note: It will take me a few minutes to complete the thread..

 

Before removing the plenum I had to remove all tubes and the intake tube. I removed just enough components to allow me to slip the spacer in...

 

After removing all the plenum bolts I used DavidV's suggestion of using a tie rope to suspend the upper plenum from the hood. I use a tie wrap and bungie cord. It came in real handy..

 

This is what the inside looks like. I removed the center metal piece to get the stock gasket out. A 10mm socket worked fine..

After everything was pulled out I layed it on the ground and snapped a photo so you guys could see what it looks like..

 

I had a bit of a delimma on this next step. Once I pulled the stock gasket out I knew I had to reattach the little metal plate again. I wasn't sure if it needed a gasket sandwiched between it or not, so I cut out the center portion of the stock gasket and reused it. The new MD spacer model has pre-attached gaskets on both sides of the spacer so you don't need the OEM gasket anymore. In the photos you can see where I cut out the center portion of the OEM gasket and reused it..

In the last pic, I test fitted the cut out portion of the OEM gasket with the MD spacer.

 

After the test fit was good, I snapped a couple pics of where the plastic internal spacers go. Even without instructions it's pretty obvious where they go

 

That's an excellent technique to keep the upper plenum out of the way.

 

Finally, reinstalled everything in reverse order. Make sure not to get the oil filler plastic thingy caught in the plenum. It will compromise your seal. I didn't have the bolt tightening sequence handy so I just torqued everything to 70inch lbs. I figure it was somewhere between 60-100inch lbs.

 

After everything was re-installed I started her up. I took her for a test drive. The Z seemed to respond well to the plenum and I did notice better response after 5k rpm, but my idle is rough. (BTW, it sounds pretty tough too, when you get on it.) .... The car tends to vibrate when sitting and vibrates even more when the A/C is on. It did not appear normal so I went back and checked all my hose connects. I even replaced the PCV valve as a precaution. The idle is still rough though. All temperatures and pressures are good. I haven't sprayed any dishwashing soap on the hoses yet to check for leaks because I was kind of hoping to avoid spotting up the engine with soap suds, but may have to if it comes down to it.

I just found the MD pdf file with instructions. http://www.motordyneengineering.com/manual.pdf
Perhaps by not torquing the plenum blots down in the proper squence, this is why my idle is rough. I'm not sure as of yet. Does anyone have any input on this or suggestions as to what I should check?

Thanks,
Val

 

I was going to say, you must not have skipped around the plenum enough when tighten things down. Kinda like putting on a rim, loosen everything and torque it back down in a random order. or follow the bolt sequence in the directions. If you didn't do this, it is probably preventing it from sealing properly.

 

The first time I cranked my car the idle was CHITTY! It was a leak that was too obvious because the damn thing whistling. Double checked to make sure they were torqued at 100in/lbs and one of them was hella loose. After it was tightened it idled fine.

I'm guessing you have a leak.

 

You guys are probably right. One other step I missed was removing the guiding pins. Those are the 2 plenum bolts that are attached to the lower plenum and have nuts used to torque down. I didn't know what to do about them at the time because I didn't have instructions. Now that I do, I can go back and remove them...

 

Dude, I did the exact same thing...

 

It obvious I probably have to remove everything now to get those 2 guiding pins out. While I have everything dissasembled, what do you guys think about the center piece of the OEM gasket I left in? Should I just leave it there or chunk it?

 

No instructions = pwnd

 

No light = pwned

I disassembled during the day and assembled with hardly any light.

 

i dont think the cut out portion of the gasket will have any affect either way. Opinions vary though.

 

Gotcha. Would you happen to know what the function of that metal center piece is? I looked at it thoroughly. It doesn't really cover up any hidden passage way or anything. Personally I couldn't see what purpose it serves.

 

If you felt some vibrating sensations (lol), take a look at your strut bar. See if the upper plenum and your strut bar are touching (or very close to touching). The engine moves while you drive and that may be the reason for the vibrations.

As for a rough idle, you mentioned that you didn't torque the plenum down in the correct order? You should just follow the instructions because sometimes if you don't torque it down in the correct order, it may cause the plenum and spacer not to seal up completely. I'm sure MD Tony will chime in any second now.

 

+1 on the strut bar touching. I tried using the spacers, but the hood was hitting the bar. I took the lessor of 2 evils and opt to have the bar touch the plenum. I'm thinking the vibration is more vaccum leak orientated. The vibration along with the sound it makes doesn't quite seem characteristic of the bar touching the plenum. Another thing that happened when I started the car up a second time, was it died on me. This has never happened before.