Intake manifold crud

[jonmon6691]

I decided to completely clean out my intake manifold, replace all the gaskets and remove the noise reduction horns behind the butterflies today.But I have some questions. My first is whether removing the noise reduction horns will have any adverse effects, I can't help but think that they have some reason for being there other than making it quieter. And also I found a HUGE layer of black crap coating my intake runners, ports, and the tanks. It was almost 2mm thick in some places. I was wondering if this is a sign of trouble or just a sign that it has been neglected for a long time.

And if I remove the noise reduction horns, do I still use two gaskets between the secondaries and the tank?

 

[jonmon6691]

Here is some relevant pictures:

 

[1993MTXSHO]

Keep the horns for power, lose them if you want more sound and a little power loss over 4k rpm. The horns are there to add length to the runners, and to get air pulling from the center of the surge tanks. Removing them will shorten the runner and make them pull from the side of the surge tank, making the car have a very screwed up intake path when it hits 4k. That's is why you see modded cars' dyno's, and see that dip of power at 4k rpm or so when they have BBB with the horns taken out

 

[Phoenix]

If you're keeping it stock , keep the horns.

If you remove them , only one gasket is needed.

And the gunk , its somewhat nomal , the SHO has a poor PCV system that does that. On some its minor , others its more , depending on too much variables (oil-temps-etc-etc)

 

[Kens1992mtxSHO]

Get all that gunk cleaned out and you'll notice a big difference in performance. I use BG throttle body cleaner to clean mine. It's amazing how the carbon/gunk just falls away when I spray it with that stuff

 

[jonmon6691]

Ya, I used 4 cans of carb cleaner and a Scotch Brite pad and it was fairly easy. How often can I expect this material to build up?

 

[yamahaSHO]

It'll build within a couple thousand miles for sure

It's not really a big deal. Even without the PVC and CCV connected, it STILL happens

 

[Rubix]

Damn you got away with only 4 cans for all that gunk? I went through at least 6+. Be easy with carb cleaner though, you might notice some peeling if you let the carb cleaner puddle up in places.

 

[jthod]

Berrymans B-12 FTW.

 

[jonmon6691]

Wow! The sho is pulling like it never has! The first time I tried to start it up I forgot to tighten the 12 intake runner bolts down, and Damn it sounds good for the 2 seconds that it runs, the loud popping ruins the moment though

 

[SHO GoDz 89]

I cleaned my intake out by pouring acetone through it, then boiling water, then after that I would fill them up as much as possible with water, shove it in the oven at 350 degrees. Once it cooled down, i poured it out and all the gunk came out.

Takes a while, but works pretty well to really clean out those hard to reach spots in the long runners.

 

[Vnuk1]

I'm scared to what I will find in there this summer when I do that to mine:scared:. From what I have seen on my Throttle Body so far (Really Dirty:vomit I think I'm in for a real treat.

 

[SHOZ123]

Just need a good condensing catch can between the oil separator and the TB PCV hose. Won't hardly ever have to clean it again......

 

[yamahaSHO]

I disagree... My intake will prove that.

 

[SHOZ123]

Don't know what you have.

 

[MD Ever]

Oven cleaner works wonders. One can of Easy-off oven cleaner made my intake spotless in 15 minutes. No scrubbing at all. The only problem is that it stains the paint so be prepared to paint the intake after cleaning or be real careful not to get any on the outside.

 

[yamahaSHO]

Don't know what you have.

An intake free of any PCV and CCV. The only inlet to my intake is through the TB, and only air goes through.

 

[SHO GoDz 89]

Oven cleaner works wonders. One can of Easy-off oven cleaner made my intake spotless in 15 minutes. No scrubbing at all. The only problem is that it stains the paint so be prepared to paint the intake after cleaning or be real careful not to get any on the outside.

I totally agree, I forgot I tried oven cleaner as well, and that worked better than anything else I had. After all, that's exactly the kind of crud its meant to take off.

 

[gmail]

Keep the horns for power, lose them if you want more sound and a little power loss over 4k rpm. The horns are there to add length to the runners, and to get air pulling from the center of the surge tanks. Removing them will shorten the runner and make them pull from the side of the surge tank, making the car have a very screwed up intake path when it hits 4k. That's is why you see modded cars' dyno's, and see that dip of power at 4k rpm or so when they have BBB with the horns taken out

theif :swing:

 

[yamahaSHO]

Keep the horns for power, lose them if you want more sound and a little power loss over 4k rpm. The horns are there to add length to the runners, and to get air pulling from the center of the surge tanks. Removing them will shorten the runner and make them pull from the side of the surge tank, making the car have a very screwed up intake path when it hits 4k. That's is why you see modded cars' dyno's, and see that dip of power at 4k rpm or so when they have BBB with the horns taken out

Close, but not quite.... The horns are pulse tuning. The length is there to match the intake pulse (valves opening and closing) at a given RPM.