I've got a flowmaster 3" cat back on my car w/ dual catco cats. At about 1500-2000 rpm the catylitic converter head sheild make a very nasty resonating sound. Sounds like the bass buzz bombs you hear cruisin the streets. How do I get rid or this resonance? The bolts are tight, and nothing seems to be contacting. I don't wanna just rip it out, it's there for a purpose. Any idea's?

 

Hmm, I have no heat shield on my cat, it's not near anything to hurt .

 

Don't konw if you've looked or not, but check the sheild and make sure it's not making contact witht the cat itself. I've never seen a Catco Cat before so I don't know how thin the shield is but if it's touching the cat itself, it could be making the noise. Also, do you have the heat shield that factory installs on the body? It's possible that could be making the noise also. Make sure it's not contacting the anything and vibrating.

Hope that helps.

 

Well it's not the cats vibrating, it's the body heat sheild. All the bolts seem tight, and i can put my hand between the two so they are not contacting

 

You sure it's not the heater valve in the y pipe causing this noise. Does it sound like rattling at all?

 

His car doesn't have a heater valve in the exhaust.

I know how annoying things like that are. Are you sure all of your exhaust is making good clearance? Can you hear the noice when you go over bumps ever?

Who boxed your control arms? Did you notice any difference?

 

i get this noise when im just idlein and i think its something in the back of the car but when i go above 7-800 rpms it stops. any clues

 

I used to think mine was some heat shield or something to...... but it turned out to be the junk inside the cat.

You may want to check that

AJ

 

Junk inside the cat? I don't know, they are fairly new. No heater valve thingy either. It dos'nt seem to be contacting any were but i'll check again. As for the boxed LCA's BIG difference. i have a poor mans set up back there. The LCA's where boxed by my friend with .25" thick steel plate. Along with new sway bar end links and panhard bar bushings, and a Prothane Torque arm bushing. No more axle hop. Consistant hooking every time. And it handles tighter back there. A bit more controlable if I hang it out too.