Originally Posted by taylorking
what is a BTM? And I like a muffler also. What are some that will give a really deep throaty sound?
The BTM is a "Big Truck Muffler"
In my experiences, mufflers with glass or steel packing material reduce mid range and high frequencies, leaving you with a really low town. They have a great tone when accelerating. The bad thing is you usually have an annoying droan while cruising. They also kill a lot of the turbo sound.
I haven't tried all the mufflers out there, but Banks and Wicked Flow fit this category. They sound really deep, but no turbine sound.
My Flowmaster Outlaw race muffler doesn't have any packing, just rings that deflect sound. It sounds a lot like a straight pipe at idle and has a great growl when accelerating. It doesn't have the annoying droan, either. At highway speed it had a rumbling sound, but not too loud to in the cab. Flowmaster also has a new Hushpower Muffler out that should be even quieter than mine, but flows near what straight pipe does. I plan on trying one out some day.