Flat belly exhaust

[GordoSmasho]

So my 97 4.0 is low and I'm looking to tuck everything up and do a flat belly at the frame rails. I'm in California and need a legal cat and muffler setup that sounds good and fits above the frame rails. So two questions

1- what cat do I need. I have been reading and searching many a interwebs and Naxja and have not been able to nail down a small cat that is legal for cal. Any help is welcome there.

2- right now I have a flowmaster super 40 right now and would like something a bit more agressive sounding. However it needs to have a smaller case. 4" thick at most. I'm not a fan of glass packs because they don't bring the beef out of the 4.0. I like a deep tone. Just want a bit louder but deep. Any suddestions are welcome.

Thanks for your help guys.

 

[RCman]

I can't help you with the CA legal cat, I'm not sure about CA's requirements.
However, my Spintech muffler is probably what you are looking for. The model I have (Cruiser #7331) is 2.25" thick and has a nice deep, but not to loud, tone. A bit pricey, but it was the only thing I could find that fit the less than 3" thick I needed.

 

[#S194]

I replaced my cat with a Magnaflow CA legal replacement I picked up from Summit. It's pretty low profile, rides above the unibody rails. My muffler hangs lower than the cat.

 

[Spearfisher XJ]

Strait pipe it after the cat

 

[Johnnie Walker]

Magnaflow for the for muffler, choose your length. In theory you can use a universal cat, just make it really good and dirty by the time you smog it.

 

[GordoSmasho]

Thats kind of how I read the letter of the law there too. Magnaflow cat is 270$ on summit. Those spintech mufflers look pretty cool. I'm checking them out.

 

[Johnnie Walker]

Or, aeroturbine makes nice stuff.
Basically, as long as it looks the like cat was not installed "after" the date that the law changed should be fine.

 

[joe_peters]

Might check out these guys: http://performance-curve.com/index.aspx

Don't know if any of their products are CA approved.

 

[Bryan C.]

Just be careful about which cat you choose. Some smog shops are pretty picky about following the new CAT rules. If the smog tech sees an aftermarket cat installed the EOD number must be easily seen and it must be an approved part for your year and model XJ. Unless you can prove that the cat was installed before the cut-off date sometime in 2010 then they will most likely fail you.


http://www.arb.ca.gov/msprog/aftermkt/devices/amquery.php

This page is a bit of a PITA to navigate but this is the very same page that smog techs will use to determine if your new cat is approved for your vehicle or not. The new cats will have an EOD number stamped on them. Input this number into the search and see if it applies to your vehicle.

 

[GordoSmasho]

Yeah. I'm going to take a good look at my options for cats. The last few times I went to get smogged it was after really muddy wheeling trips and they did not want to see that cat. Haha. All the aero mufflers look cool but all the casings are 6" diameter. I'm debating on straight pipe or a spintech race muffler. I think a lot of the drone on the hiway will be reduced by running it out the back instead of a turndown. But I'm ok with it being loud.

 

[Johnnie Walker]

You can get Magnaflow/bullet performance rounds in the 4" variety

 

[Jes]

Yeah. I'm going to take a good look at my options for cats. The last few times I went to get smogged it was after really muddy wheeling trips and they did not want to see that cat. Haha. All the aero mufflers look cool but all the casings are 6" diameter. I'm debating on straight pipe or a spintech race muffler. I think a lot of the drone on the hiway will be reduced by running it out the back instead of a turndown. But I'm ok with it being loud.

Don't straight pipe it, your wife will hate you.

I'd get the spintech muffler. I have the magnaflow bullit muffler and it is basically just a glass pack and is really loud(at least with my 4.7 litre).

 

[Johnnie Walker]

Don't straight pipe it, your wife will hate you.

I'd get the spintech muffler. I have the magnaflow bullit muffler and it is basically just a glass pack and is really loud(at least with my 4.7 litre).

What length tho? Cuz these I believe are made up to 22-24"?

 

[GordoSmasho]

10-4 on that jes. It's pretty dronny now. I'll be looking forward to running it out the back. I'm calling spintech on Monday and ask them to recommend me something. They have a build your own option also. But don't have any sound clips. Looked on YouTube and can't find any good demos on jeeps. All v8s sound damn good though.

 

[Jes]

What length tho? Cuz these I believe are made up to 22-24"?

Uh... really short(12"?).

It was all I could fit, does sound really good at WOT though.

 

[Johnnie Walker]

I'm running a 14" 4x9 Oval maggy. Not too loud, nice tone.

 

[Jeep450r]

Strait pipe it after the cat

This.

Straight pipe ran out the back. Sounds deep and throaty. Surprisingly not too loud either. Quieter than my old flow master 40. I love the sound and get many compliments on it.

That turn down is what is making yours drone so much the noise is just resonating off the ground and your floor boards.

 

[Johnnie Walker]

I have a turndown, and have no issues with drone. Should not have an issue with a straight-thru style muffler/resonator. Failmasters, and others like them that are chambered are the main cause of drone.

 

[GordoSmasho]

I think I'm just going to get a new cat and straight it out the back and try it. If its too much that's when you say. "We'll honey I NEED a new muffler now because the old one won't work anymore" haha.

 

[ridgerunner97]

I'm running a Magnaflow Cat on mine but I don't have to worry about the Cali regs where i'm at and I have an 02 sim. For Muffler i'm running a 3in case 2.5in inlet/outlet 12in body cherrybomb glasspack on mine, nice and high with a turnout to the passenger side. Technically not legal but it works around here.