Best Sounding Muffler for 4.0L?

[Boze]

After spending the better part of my morning tearing out my old muffler, (after 15 years the cat and muffler basicaly became one unit), I installed the Cheap-O-Cherry Bomb Turbo Muffler I got for 15 bucks at Auto Zone and fired up the YJ. I wanted to puke. I don't know why I was surprised, it sounded like a fifteen dollar muffler should sound...cheap. I'm thinking of just getting the good old stand by, Flowmaster 40 series, but I've never heard one on a straight 6. I was wondering what mufflers you guys were running and what you thought. I don't want to **** the neighbors off too bad when I go to work at 5 am, but I don't mind setting off a few car alarms in parking garages either. 8) OH! and I'm not doing the whole cat-back setup, just a muffler. Thanks guys.

 

[Bounty__Hunter]

I think they sound better, even a cheap glass-pack, if you run a catalytic converter. They can be had for under $100. The flowmaster and other performance mufflers sound better behind a converter.

 

[Boze]

I did get the cat and muffler separated eventualy, and left the cat on. HOWEVER, that brings up another question. Where I'm from in Oregon there is no emmissions testing, and so most guys will just cut the cats out on thier older trucks and muscle cars. But I've heard that if you remove the cat on a newer vehicle, mid 80's and up, it will throw the computer out of whack. Is there any truth to that? AND, as my cat has 15 years and 200,000 miles of exhaust run through it, should it be replaced?

 

[xt master]

Depends on where you have sensors.I am pretty sure the TJ's have an O2 sensor before and after the cat.So if you hack it out what do you do with the second O2 sensor.It could mess something up in the way it runs.200,000 miles on the cat It should have been replaced a long time ago.Unfortunately where I live at we have emission test.

 

[Bounty__Hunter]

YJ's do NOT have an o2 sensor after the converter, so your jeep will run fine without a converter.

 

[buckaroo kid]

mine 89 yj runs just fine without a converter. i use a flowmaster muffler with 3 inch pipe

 

[YuriSouder]

my yj converter got clogged, so i stuck a crow bar in it, hollowed it out, then re attached it. Sounds good for being free.

 

[Boze]

I left the cat for now. Just clamped on a 40 series Delta Flow Flow Master. Not sure how I feel about it... Sort of sounds like a ricer fart can on steroids. Still better than stock though.