Buzz on right side ... exhaust

[TNTaylor]

I have a Kirkham Street 427 with an under car, side exit exhaust. Just before the exhaust pipe turns 90 degrees away from the car, just ahead of the rear wheel there is a stainless, rectangular 3" high muffler. When the car is idling warming up, and when I am mid rpm range and warmed up, on the right side only I get a metallic buzz sound. It's definitely right sided only and if I sit in the passenger seat it is much more noticeable than when I am driving.

I am guessing the noise is related to the muffler mentioned above.

Any similar experiences or thoughts.

Tim

[Ron61]

Could it be something inside the muffler that is either loose or to close to the outer cover that is vibrating and hitting the side of the muffler? Also have you tried having the car up where you can get under it with it running and listening with a stethoscope or some other means to see just where the sound is coming from. Maybe even use something that won't burn and put it against the exhaust pipe in the area where the sound is coming from and see if that changes it any.

Ron

[FatBoy]

Could it be the side vent in the front fender, they can buzz/rattle quite a bit? I took mine out and put duct tape across the tabs at the top and bottom to prevent them from rattling?

Paul

[TNTaylor]

Originally Posted by FatBoy

Could it be the side vent in the front fender, they can buzz/rattle quite a bit? I took mine out and put duct tape across the tabs at the top and bottom to prevent them from rattling?

Paul

Good suggestion. I will check.

[DanEC]

From the description of the muffler they may be SpinTech mufflers. I have them on the undercar exhaust on my ERA and I have a buzzing, tinny sound out of the passenger side when the car is warming up. There's nothing loose in the muffler (took it off and shook it and tapped on it with a mallet) and it tends to decrease once the whole car is warmed up. These are a baffled muffler similar to Flowmasters and I wonder if it could be some resonance in the baffles.

[TNTaylor]

Whatever muffler I have is what Kirkham put on the car. Interesting about Spintechs as I have been looking in to them to a.) address my buzzing problem if it turns out to be muffler related, and b.) see if I could improve the exhaust "note", and c.) see if I can find something a little smaller/thinner. Might you have any video/sound files of your cobra with Spintechs? Have you ever heard of people adding resonators?

[DanEC]

Originally Posted by TNTaylor

Whatever muffler I have is what Kirkham put on the car. Interesting about Spintechs as I have been looking in to them to a.) address my buzzing problem if it turns out to be muffler related, and b.) see if I could improve the exhaust "note", and c.) see if I can find something a little smaller/thinner. Might you have any video/sound files of your cobra with Spintechs? Have you ever heard of people adding resonators?

There is a video clip attached at the bottom of my posts - but only of idle. That your muffler is rectangular (square corners I assume) and only 3 inches deep is what makes me think it could be a Spintech - however, I can't remember if they produce a stainless steel version without checking. Stainless steel exhausts are known to sound a little different from mild steel. It's pretty tough finding mufflers only 3 inches thick - most are 4 inches. Spintech was about the only one I could find at a reasonable price.

If they are Spintechs - I've been reasonably pleased with the exhaust note on mine. I don't usually like Flowmasters which are another popular baffled muffler and I think the Spintechs beat them for sound - but there sound is not night and day different. It's not like a traditional glass pack or Magniflow type muffler with packing. I am running tailpipes which will also give my car a little different exhaust note than your side exit pipes.

But, I'm speculating. It could be something else vibrating on your car.

Here is my Spintech muffler: