Bad noise getting worse since my HFCs were installed. Please help.

S

Squishymedic

Member
Location
New England
So I bought some HFCs from a brother iS-er. Has anyone who has them, experienced a shuttering type noise,especially when slowing down on an off ramp? The noise was confirmed by my wife who said it was right under her feet on the passenger side.

when they took the OEM cats off they also took off bracket that they said I no longer needed. Is that kosher? I don't want to remove these cats,, I love the sound! Help!!
 
Not sure what you mean by a shuttering type noise. Have you watched any videos online to see if you hear the sound? I only use cats that have the brace mounts now, since I didn't like the lack of mounts between the headers and rear section without them.
 
Doesn't sound like the bracket (which you can check) but rather some of the cells are loose inside the can and are moving under the the engines deceleration compression bursts. Really hard to tell without seeing it or as dracula said shaking the pipe. All connections are solid, no leaks at all?
 
When I had mine installed I had the heat shields removed as well just because I noticed there wasnt alot of space there. Could it be one of the cats is hitting the floor of the FX??? I've never had any issues with my hfc's hitting anything but it's something you shouldn't rule out.

Sent from my SAMSUNG-SGH-I337
 
Yea I think that is precicely the issue. As it was right under the passenger floor. I am actually sitting at the shop now and they're about to put it up on the lift.

they removed my heat shields too and a rather important looking bracket.

Who knows, I may be selling a pair of gently used HFCs soon. Thx for the help guys

---------- Post added at 01:52 PM ---------- Previous post was at 10:52 AM ----------

So, I saw it when it was up on the lift. The flex pipe on the passenger side had about 1/8-1/4" of clearance from the body. And there was signs of wear on the flex pipe where it was rubbing.
First the mechanic wanted to heat the pipe and bend it,but I wanted to wait to investigate all this madness.
He did loosen the fitting between the cat and the flex pipe and twisted the pipe slightly. That got me about 1/8" more clearance,so hopefully that'll do it. It did clear up the noise (thankfully).
But he did ask me to ask this forum if anyone ever had to bend their flex pipe or cats to improve te fit. Anyone?
 
I had mine installed normally with no bending of any kind, but as I stated before I noticed the lack of clearance with the heat shields installed and asked to have them removed and never had any problems with it. Hope that fixed your issue.
 
Oh yea, the only thing that I forgot to mention is that the driver's side flex pipe has tons of clearance while the passenger side is tight.
Is the anatomy of the body different or could his be a sign of an incorrect bend in the cat?
 
when i had my hfc installed. there was a KNOCKING sound when you down shift . It was from the passenger side. what it was is HFC was too close to the passenger foot well. Also check the clearance from the bottom bar/ support. I pushed the hfc up and took a hammer and hit the footwell up for more clearance. ( i have crawford cats). i also put a clamp on the rear bushing to lift the exhaust up ( or ou can get poly bushings)
 
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