My idea- cut stock pipe just before muffler, then get an exhaust tip and just bolt that tip over where I cut the stock pipe. So the only cash I spend on a cat back system is a tip! Has anyone done this? Think it will sound good?

 

x2 It'll be ultra loud and cool for the first half hour, then it'll just make your brain hurt

 

I actually drove my jeep for about 6 months with no muffler. It sounds really good and about the same as a flowmaster 40 series. I didn't notice any change in fuel mileage but after reading some post about how driving without a muffler could potentially cause long term damage to the engine I decided to put it back on. The nice thing is that it's one nut to remove and replace the muffler. Periodically I take it off to enjoy the sound of the engine. Check out the video of my jeep with no muffler. High rpms sound whiny but under 2500 it sounds throaty.

http://www.youtube.com/watch?v=8Cm3V2qF30A&sns=em

 

By the way, just to be clear. TAKE OFF YOUR MUFFLER! You will like the sound and it costs you nothing, an if you change your mind you can put it right back on without any issues. Drove mine for 6-8 months with no muffler and my friend drove his JKU for over a year without his muffler.

 

I bought a Flowmaster for a Cobra Mustang, took off the factory muffler, put the new muffler before the rear axle, put a turndown on it and it sounds sick! All in all it cost me about $85.

 

If you're interested despite everyone's warnings, here's my write-up> https://www.jk-forum.com/forums/show...muffler+delete

Yes there is a loss in back pressure, I found it pretty negligible. Yes it is loud. On cold start ups it will give a little crackling off throttle, but this is a V6 so it's expected.
http://s391.photobucket.com/albums/oo351/runit3/Rubicon%20Muffler%20Delete%20and%20Spacers/?action=view&current=VID00006-20091014-1730.flv Camera way too close^
http://s391.photobucket.com/albums/oo351/runit3/Rubicon%20Muffler%20Delete%20and%20Spacers/?action=view&current=VID00005-20091014-1442.flv Sorry stupid photobucket moved the links on my pictures...here's just a link to the album>*edit* going through and updating the links- should be vis in 30min.

I've been running w/out muffler for almost 30k miles now. I like it enough to not buy any muffler...ever...and it doesn't piss enough cops or people in my neighborhood off for them to yell at me for it. As long as you keep your revs to a respectable level and aren't burning around town @5k RPM it's not above a noise ordinance.

 

Here is mine with a flowmaster 40 series. You get the sound and not loss in back pressure. Will only run you about $100.
http://www.youtube.com/watch?v=stbUSm96ouo

 

I did what you are thinking of. I cut off my muffler and put a tip on. It sounded beefy, but it was buzzing and annoying. Went to flowmaster delta 40 and it was tinny and quiet. Went MBRP and it's perfect.

 

I doubt the exhaust system of a Wrangler is optimized to scavenge gas to provide any improvement in it's performance.

Anyone have a reason on why less back pressure will harm this engine?

 

The catalytic converters provide adequate back pressure, anyway.