View Full Version : Exhaust question for the other Jeepers here

03-03-2010, 09:17 PM
I need to replace the exhaust on my 94 wrangler ( 6 cly ) from the cat back. I have ordered the muffler and tailpipe from napa. I am thinking that I am also going to cut off the cat converter. is there any reason to leave it on? I am also thinking about not putiing on the muffler. Putting a cheater pipe where the muffler goes. I would like to make it sound a little better, basically so I can hear it run, don't want it too loud, Just wnat to let'em know I'm here. Any advice? Cheap is one of the biggest factors here.

03-03-2010, 10:27 PM
Removing the cat will cause it to fail smog tests. At least here it would...

03-04-2010, 12:19 AM
If you have emissions testing then you will have to keep the cat and a muffler. If not, cut that thing off. You can put on glasspacks or another cheapo muffler and it should give you a little better sound. No cat and no muffler is gonna be loud and probably obnoxious. If you cut off the cat, then you will have to weld more pipe to make up for the reduction in length. Otherwise your tailpipe will exit below your jeep or you will need to relocate it to exit beyond the body. This will require welding and pipe bending. I would recommend taking it to a custom exhaust shop. I went to a local shop and the factory exhaust removed past the cat, put on a flowmaster, dualed it out and a some nice shiny exhaust tips completed the upgrade. I liked the sound better--you aren't going to get a real deep, throaty sound with a V6 but it should be an upgrade over what you hear now.

03-04-2010, 12:56 AM
Getting rid of the cat really won't get you anything in the way of performance unless your stock one is plugged. Maybe a very little bit up top, but with a factory replacement muffler and tailpipe it really won't matter.

If you're really looking for more power, forget the NAPA stock replacement muffler and pipe and go with a true 2.5-inch after-cat exhaust. The factory 4.0L cat is a 2.5-inch output, but the tail pipe is small diameter with kinked bends. I forget the exact diameter off the top of my head, but I seem to recall it's like 2-inch or something like that. If it's not too late, take it back.

One of the less-expensive systems out there is the Dynomax one. Runs $199.99 through Quadratec, www.quadratec.com under PN 17605.500 (quadratec's PN - they assign their own). The Super Turbo muffler won't be obnoxiously loud like a straight-through muffler will but will sound a bit louder than the stocker. NAPA can probably order it for you locally if you don't want to do it mail order.

Check your exhaust manifold. Most likely it's cracked. If you do replace it, I've used Edelbrock Ti-Tec coated header with great results. It's painted, not ceramic, but it doesn't fade chip or peel. Much less than a comparable stainless header like a Banks or Gibson (both of which I've used and recommend).

Finally, consider ordering a TJ header-to-cat pipe if yours needs it. They're larger diameter than the YJ pipe and will help wake up the 4.0L a little.

03-04-2010, 08:20 AM
No emissions testing here and a performance gain isn't the point, It is what it is, exhaust work isn't going to change it much. How can you tell if the cat is plugged? I am going to hang the new "system" myself. I plan to clamp it together and may have to have a piece made to fit whatever I eliminate, but that won't be a big deal. I do think that open is not the sound I am looking for, but how bout cat and no muffler or muffler and no cat? Or, am I kidding my self thinking this will make much difference at all?

03-04-2010, 10:22 AM
If it's running fine, the cat isn't plugged.
Regarding ditching the muffler, remember Jeeps are louder inside than most vehicles already and IMO, anything less than a V8 sounds like a ricer with no muffler. I think it will sound like you have a rotted exhaust system or a fart can, not a hot rod.
Cheap being a factor, I replaced the entire exhaust on my old CJ5 a couple years ago. Priced all the parts from Napa and Napa online. Then took it to a local shop that bends their own exhaust pipe. It was within $20 of Napa online parts to have them install a whole new exhaust, fully welded, new mounts and everything.
In the past, I've just taken the old parts to a similar shop and head them fab new ones. If I needed to mod the existing config, I layed it out and told them what to bend. Always ended up cheaper than buying from the parts store.

FWIW My '74 CJ has the same 258 6 cyl as your '94, minus the fuel injection and it sounded horrible with no muffler (rotted out).

03-04-2010, 11:03 AM
That is along the lines of the advice I was looking for. I didnn't check, but $30.00 for a muffler and $30.00 for a tailpipe + a few clamps sounded pretty cheap. I didn't think a custom shop could touch that. Maybe i should have checked.

Ricer with no muffler wasn't the sound I was going for.


03-04-2010, 01:02 PM
That's pretty cheap. Maybe the parts were more expensive for my "antique". It was $180+ for down pipe, front sect, muffler and tailpipe and hardware. Installed version was $200 fully welded and they had to extract one of the 2 manifold bolts. Good shop though.