I have just picked up an extra set of "07 mufflers to drill out, and discovered that they are quite different. The left hand muffler is basically an open cannister, with a "baffled' plate approx 9 inches from the back.

The Right hand muffler is completely different. It seems to to have an inner pipe with a raised section approx in the center of the muffler.

Any suggestions as to why the difference?

How would the stock mufflers run in a true dual set up?

It would appear that the right muffler would have more back pressure and a different sound.

Thanks for any advice etc.

 

The bulk of the rear cylinder flow in the stock headpipes goes out the right muffler, which is of conventional construction. The left-side muffler is really more of a resonating chamber. You should be able to just about totally cover the outlet of the left muffler and not cause too much problem for the engine at idle. In fact, if I recall correctly, it will offer little resistance to your efforts.

Some have said that they feel the left muffler flows better than the right. I don't think so. If that were the case, why would it be better to use a smaller baffle on the left than on the right with aftermarket mufflers like has fairly-well been determined? See http://fuelmotousa.com/ and look at their "Jackpot" mufflers for an example. He developed a set with a 1.75" baffle on the left and 2.0" baffle on the right. What's more, he ended up welding a washer with a 3/4" hole in front of the left baffle during his testing and found that offered the greatest overall horsepower and torque.

I would not even attempt to use a stock pair of 07/08 mufflers on a "true dual" set of pipes.

 

Thanks for the reply. Makes sense, I guess I'll have to look for an older set! (or stop being so cheap, and purchase what I really want!)

 

it might not hurt to hang onto a set of those in pristine condition. In a couple years they may become valuable as pass-around parts for folks needing to be physically compliant come registration renewal time. What's cheaper, buying a new set of factory mufflers or renting mine for a case of beer?