I'm a little desperate, could someone help me out? Ever since I installed the DC header and carsound cat, I get a loud buzzing from the engine. Sounds like a marble on metal.
Funny thing it's only right at 4000-4150 RPM.
Suspecting an exhaust leak, or lose heat shield I took it to a local shop where we jacked it up to listen... no leak, but it is coming from header area, but too loud to pinpoint. The guy says that my header, being that it's stainless, probably hasn't "carboned up yet". ...that it will take a while for the noise to go away.
Does this sound valid? What do you think?
Also... Can jacking with a distributor make a similar sound at a specific RPM?

thanks!

 

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Cat heat sheild rattle... either learn to live with it, or remove it.

Craig - Who just turns up the radio

 

I found this to be an inherent property of tubular type headers which lack the stiffness and thickness of the stock cast manifold ( which muffles this sound much better). What you are hearing are the exhaust pulses of the motor hit the walls of the header primaries. I had this same problem on my Mugen 4-1 and on the Spoon 4-2-1 that I have on the car now. As the header "carbons up" you will notice a slight reduction in this noise - but this is the price you pay for changing the header from cast to tubular (steel or SS). I even noticed this sound on the Borla header I put on my Jeep. I removed ALL the heat shields on my car and the sound still persists. You have to live with it.

As a side note - I once put the stock exhaust back one (header and exhaust) for emissions testing. All the sound went away.

 

Stop your complainin'...you are too ****.

 

You are the man! thanks!