I have the Megan resonated testpipe and so far am very happy with it. It deepens the tone of the exhaust without the annoying "bubble-bee" sound. Check my sig for info on o2 simulators.

 

my straight pipe doesn't make my exhaust nearly as raspy as that

 

What causes that slight buzzing when the rpms drop? Is there a technical reason anyone knows about?

 

Are you talking about the clutch decel "buzz"? If so, I'll post again with an explanation.

 

I don't think it has anything to do with the clutch. I've notice a slight buzzing sound on every S I've ever ridden in that had a test pipe and aftermarket exhaust. It occurs just at the initial point of rpms dropping. Usually, this is during shifting. I've never heard a technical reason for it, and it's not too annoying (I hear it a bit on my car).

The audio file xman put up here has it too.

 

Ahh, just heard it. Having a cat back exhaust and a test pipe changes the resonance characteristics of the exhaust. This translates into added vibration throughout the system. (Some notice it as the dreaded drone, which is the most severe form of resonance alteration.) This vibration can do all sorts of things, from vibrating existing heat shields, to rattling muffler internals and exhaust tips depending upon the way the mufflers and tips are constructed. Hangers can even begin to vibrate and act like tuning forks (welds on the hangers can crack slightly). This can happen to the extent that a hanger can fracture and break (seen this one happen).

 

That makes sense. I rode in one where holding it at exactly 4,000 rpms would make it buzz constantly, like a tuning fork. Everytime you went thru 4k rpms, going up the band or down, you'd get that buzz for a second.

Thanks.

 

You can buy a Berk Test pipe if you are worried about CEL.

Berk has a CEL Fix on their test pipe

http://www.berktechnology.com/ This is what i ordered...

 

I installed a Berk test pipe last weekend and I give it . Great sound and the car is a lot more peppy. Seems to have helped with throttle response and smoothed out the powerband a little.

The smell at stop lights , but not too bad.

 

The Berk tripped my cel after about 40 miles. THe Megan with the anti-foulers (42002) has been on for about 700 miles and no cel. Exhaust is loud, but great sounding.