Free flow exhaust question

I got an 03 xterra a couple months ago and it gets 14mpg.  I am trying a lot of stuff to get that mpg up and I am now to the exhaust.  I can't decide whether I want to cut the convertor off or get a better flowing muffler and leave the convertor on.  What do you guys think and which muffler would you recommend?  I don't want to sound like a redneck going down the road with straight pipes by the way so a quieter muffler.

grcthird wrote: .  I was actually impressed that it did not have the stupid loud popping sound that some glasspacks give off.

If the converter restricts flow than you will only make a gain if the muffler selected decreases back-pressure. I've used magnaflow and flow-master both in the past. I saw the best gains when I tore out the stock converter and replaced it with a larger diameter, aftermarket unit to reduce the back-pressure. On a 95 Cherokee I gained about 2 mpg with the cat-back system when I kept my foot out of it. With the converter replaced I felt more torque out of the engine and gained up to 4 mpg with my foot out of it. It also sounded much nicer. Good low tone.

 

The guy who bought my Cherokee added a K&N intake and throttle body spacer and on the highway said he gained a few more MPG's. I actually did it more for power gains than mpg's.

 

As far as no converter goes, with modern vehicals this can cause more sensor head-aches than it's worth. I've had a bad sensor actualy blow apart the core in a converter before on a 99 Silverado.  

 

Good luck with what-ever you choose to do. At least you should get some performance gains, so if you don't gain mileage in the end you'll have more fun burning gas when you hit the skinny pedal in the passing lane.