Rep Power: 372

I put on my dc header, random tech hi flow cat and dc tcs 2 cat-back today. i have a major problem with the cat back...

right below my gear shift and right below my passanger side seat i hear a big thumping noise when i turn, go over bumps, or turn and go at the same time. the noise isnt being caused from my sway bar cause i took off the progress anti sway bar and its still making the noise bad below the mid section of the vehicle. could i possibly have torqued the bolts to much to cause the cat-back to be out of align which in turn is causing the noise? any help would be greatly apprecieated.

Thanks,
Injen

 
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that or you didnt torque them enough and theyre too loose

 
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its probablly rattling against the chasis..

 
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sounds all TOO FAMILIAR...same thing happened to me with the greddy evo...the noise is coming from where the midpipe hits the cat...its hitting against the underbody of the car...took off the evo and put the stock exhaust back on and the problem was gone...now i have a Thermal R&D and no more noise either...some guy on here took his car to an exhaust shop and they put new rubber hangers on it...u could try that....

 
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anyone else have any ideas?

 
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well i would get someone to pinch the pipe where its banging against the chasis.. it only happens to me when it gets really cold or wet out.. before it happened when it just got wet..

 
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i talked to greg from hondawerx and he states that its my hi flow cat that is causing the problem and to have a muffler shop look at it and they will either bend it or get some longer hangers for it to illiminate the problem.

Injen

 
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Injen,
The rattle is right by the center counsel between the seats correct? If so, this is HUGE with all of the aftermarket cat-backs. The larger diameter piping rattles against the chassis of the car where the mid pipe leaves the cat. There is a slight metal excasing around that area, bend that back a little and see if that helps. If that doesn't do it, Djmota has the exact same set-up and said he had some problems and was a real easy fix. PM him about it....BTW thanks for coming to me first...

 
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well the problems been fixed, thanks to a local muffler shop.. the cat was hitting the heat shield underneath, so they bent that back and get me a few new longer hangers and now its all good!!

i woulda came to you first but your aim s/n is never on...

 
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hows the setup working out for ur anyway?

didn't u check clearance when u installed it?

 
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Im glad I use the search function all the time.

Just got my MagnaFlow put on. There was no rattle like injencivic but after 2 miles or so, it started rattling. It only rattles in Neutral gear tho.

injencivic, which one did they bend? The heatshield? And the hanger, was it a generic hanger but longer?

thanks

 
Rep Power: 372

well clearance is no problem...

They bent the cat hanger but yesterday i took off the heat sheild and havent had any problems what so ever.

The rattling in neutral may be the exhaust hitting your sway bar. Believe it or not my tcs was still hitting my stock sway bar, so i had to modify that some as well.

Injen

 
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If the hanger is the one that will be bent, looks like Im gonna have to visit a muffler shop.

How did you modify your swaybar? Sounds like its just a matter of bend here and there.

Well, I will know for sure what is causing the rattle by tomorrow. I have a feeling that it's my swaybar since the sound is pretty solid. It doesnt sound like a tin can.

 
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turns out that it wasnt the swaybar. How could I even assume that it was the swaybar when the rattle is coming underneath the center console.

The rattle was coming from the subframe hitting the piping. I had the muffler shop welded all the C-clamp locations and the rattle has disappeared.

Is there any hanger that is stiffer than OEM? The exhaust moves too much for my taste.

btw, I installed the OBX Header and randomtech hi-flow cat.

I'm loving the sound, hardly noticable when in neutral.

 
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I have the same setup as you, and am looking for stronger muffler hangers because of the movement. What would happen if the rubber hangers were replaced with a metal hanger, will the exhaust shake the car, or will the solidness of the car settle down the movenent of the exhaust?

What do you mean by the c-clamp locations?

 
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So lets recap.

What actually fixed the problem? Different hangers? Modifying the exhaust? Bending the heat shield?

 
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I meant the joints where the c-clamps were have been welded.

With my system, all they did was spot-welding the locations I have mentioned above.

 
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cat heat shield...?

 
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Sorry, but I might be sounding dumb for this one:

What do you mean by c-clamp? I picture a c-clamp & see a device for clamping stuff toegether with a threaded plunger....are you referring to the hangers on the muffler or something else?

Thanks for clarification.

 
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There does seem to be a small heat shield on the high flow cat, but I have not removed it, I just cut & bent up the stock heat shield that wass covering the cat & ratteling on it. Anyone remove the cat heat shield yet? I am in Texas, and that might just be too much heat for my a$$ on some days.

 
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I apologize but I used the wrong terminology.

What I meant to say was a muffler clamp similar to this:



I dont know why Magnaflow used that as opposed to flanges. I dont think they tried to save money because muffler clamp costs 3 times more than the regular flange. Dont believe the picture you see on magnaflow website. When you click the PHOTO link, it will show you this:



See the flange after the muffler that connects to the resonator? There is no flange there but just a muffler clamp to hold them together. I had them welded the 3 joints instead of the muffler clamp. I should have asked the muffler shop to install a flange so its easier to remove if need be.

I hope I have clarified everything for you.

 
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it was probably not a good idea to mangle up ur heat shield...its there for a reason.

 
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Plus, there was no much room it can free if you take the heatshield off (the way I look at my system). I remember leaving the RandomTech labels on that cat. After a few minutes of driving, the labels got burnt. After a day, there were no sign of the labels at all

 
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Perfect clarification, I was mostly confused because looking at my exhaust, I have nothing like that there...

Thanks.

 
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So welding the piecies of the exhaust together to make a larger exhaust piece will supposedly make the rattling stop?

 
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bump

 
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I just installed my Random tech cat, and i get a rattle too, its weird because it only rattles after its all warmed up and if I am at idle. If I am driving its fine, and when I first start my car its fine. I guess I can live with it, but maybe I can try some of these suggestions.