Another muffler thread.

[Mr45]

Finally got my Dynomax muffler installed, with a new tail-piece (S/S tip).
Sounds great, but is horrendous on the highway, anything above 75MPH, and it gets very loud.

WTF? Anything that can be done to this?

Here is the muffler I got:
http://www.jegs.com/i/Dynomax/289/17233/10002/-1

 

[Volant1]

You can add a resnator, that will help quite things up