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Hey I'm sorry if I missed a thread on this, but did anyone find a good clamp for the catalytic converter hissing Noise, and drone? you know the noise from the cat removal mod. Anyone find a cure yet?
 

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I have no noise from gutting my cat...
i have heard ppl talk about this problem but it didnt happen to me.
I wonder if porting my primaries helped prevent some turbulance that might be the culprit.
 

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joshweaver said:
I have no noise from gutting my cat...
OK. My wife saw this over my shoulder and said, "I like that line. Once you gut 'em they probably aren't going to make any more noise." :rofl :rofl :rofl :rofl
 

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In the process of tracing down a rattle this morning i heard the noise you were talking about, but it required me being underneath my truck. I bet i cant hear it because of my CAI and dumped magnaflow!
 

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collector bolts tight?

I had a thin metal ting noise at first but after awhile the carbon build up from exhaust i think fixed that.
 

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The catalyst can is made from stainless steel. The cast iron is welded to the catalyst ss can. The hole diameter of the cast iron going into the cat can is smaller than the diamaiter of the catalyst ss can.

It's diameter is about 1/2 in larger, so now you have exhaust flowing into an empty cat can. The exhaust expands into the larger diameter and then is squezed back into the same diameter as the cast iron hole.

Then the exhaust travels down a horn shaped pipe in to a 2" diameter hole and that is where your collector is.

My opinion is that the empty cat can acts like a poorly tuned helholtz resonator, which creates that tin can ting sound.

It's really all about frequencys.

The 2wd trucks have it better than the 4wd. my opinion is that the mid-pipe is more round and not smashed due to 4x4 extra junk that the 2wd does not have.

So, my thinking is that the more flow the less heat build up and less interior resonace.

all the flatten pipe areas just create heat which speeds up the hi pitched frequency.

Exhaust is very much the same as sound freaquency/waves/pulse.

hope this makes some sense, i know it's more than you want to know , but can't find any other way to explain.

I have taken my manifold off and cut it in two. I have seen what's inside the 3.5L manifold.

I sleeved my manifold to get rid of the 1/2 gap. so now it has a strait shot to the horn(90* elbow).

later.
exo
 

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? Which year? I have an 05 and am looking to do it when it warms up. Right now it's in the dealer for the cylinder head replacement deal.
 

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I was going to put a clamp on the can to try to cancel any annoying sound, but it doesn't sound bad, or that loud, so I let it be. I've got a stock exhaust except for the cat mod.
 

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I have the same tinny noise on startup. For some reason reminds me of a deisel truck. Goes away a bit after it has run for a while, but it's always there.

I have yet to see anyone solve this. I tried taking it to my muffler guy and asking him to put a straight pipe through it, but that is obviously not an option haha.

Hopefully someone can figure this out.
 

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find a friend who knows how to weld stainless steel.

that is what i did. muffler shops would put my manifold on, but would have nothing to do with gutting it.

Is is possible to sleeve over the cat instead of inside the cat.

the cat gut mod has been dynoed at 10hp gain.

If you use the search engine, their are many pages of info to read about the prodject.
 

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Re: mileage

MDColorado said:
What differences have you gotten? Mileage & power?
When I had it done to mine, I got as much as 23 mpg on the highway where I usually only got about 20.5 to 21. Also, there was definitely an increase in power. I wimped out and bought a replacement manifold because I was concerned the dealership would notice the sound and I would lose my warranty if they found out... like if they were replacing the head or something. :wink: (chance they would notice it then).
 

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Exousia said:
I sleeved my manifold to get rid of the 1/2 gap. so now it has a strait shot to the horn(90* elbow).

later.
exo
how exactly would one go about doing this?
 
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