Hello guys,

Working on a LS swap 5.3L on my 04 TJ Unlimited. I am using the Camero SS headers, and now need to build the exhaust. Possible to get some info on what Cats will work best?
Possible to also see some images of how you are routing your exhaust pipes? I saw a few exhaust builder kits that include a few different bends (90, 180, 45 degrees), are these kits worth it?

Thanks

 

2010 Camaro Manifolds with Holley mounts. 2.5" merged into 3". I later added a 3" resonator because it was a little loud for me.

 

very nice, I like that. Looks like you used 90 and 45 degrees bends? Where did you buy these pieces?
Making these without the cats looks easier and cleaner, not sure if I need the cats on mine.

 

Thanks. It was 2020-2021 so some of the bends were hard to find in stainless but they mostly came from Summit. I believe the stainless flanges to match the manifolds came from eBay & were ridiculously expensive.

I had to do some pie cutting in the circled area because it was turning tight and going up at the same time. Other than that, I think all of the pieces were out of the box 90⁰ & 45⁰.

 

@nleming Cool. Stainless is always expensive, I will attempt to make mine with steel. Are the two down pipe with the flange to manifold 90 or 45?

 

I have a 98 Wrangler with a 2002 LS6 4L60E combo. Did it about 15 years ago and its been bullet proof.
Exhaust wise I used 1.75" block hugger headers so the both sides of the header points mostly straight down in the middle of the engine. Then using 2.5" mild steel tubing bends from Summit I came straight down and then around the front of the oil pan to the passenger side. After that I ran the drivers side tube "low" and the passenger side tube "high" withe 2:1 merge positioned vertically. I used a Flow Master 2:1 merge. 2.5" in with 3" out. I used a long 3" Dynomax turbo muffler. Then 3" out tail pipe of a 2008? Grand Cherokke tail pipe with the the Hemi engine option over the axle. Had to mod it a bit but it fit well.
Couple of pics.
PM me if you want better pics.

 

@LS1 TJ That thing look brand new, out of the box.
What is the benefit of using 3" pipes at the end ? I already have the rear curved up pipe, and a muffler, but they are 2" 1/2 ID, so was thinking about making the all exhaust with 2" 1/2 pipes.

 

I looked under the Jeep this morning and for sure the passenger side is a 90 bend. I believe the driver is a 90 also but it is cocked in the flange to get the right angle. I did also want to warn you that my Jeep had a budget 2" puck lift before the engine/trans swap. The additional weight did make it sag a little and on compression the front driveshaft would touch the exhaust. I removed the pucks and installed 3.5" Rubicon Express springs to remedy this. The additional lift and what I assume to be a better spring rate brought the Jeep back to near level.

 

Since I was building the exhaust from new 3" from the merge I thought 3" made sense. Muffler wise I did use a shorter muffler but it was a bit loud for my tastes. The LS6 has a small cam with just a bit of a lope. Sounds great IMO. Doesn't need low range to plow snow anymore.

 

I am on a 3" suspension lift, hopefully that will help. Is your exhaust build out of pipe kit or you purchased just the pipes you needed?

My challenge is adding Cats to the exhaust build, i have to find small ones

 

In the front I eyeballed what I thought I needed and then ordered a few extras. For the back I'm fairly certain I ordered the cheapest pre-bent 3" stainless tailpipe and then cut it up to make it work. I think if you copied my setup and used a shorter muffler you could put a single cat before the muffler. I did squeeze a resonator into this setup after the first few drives.

 

Oh yea!! I didn't think about a single Cat, that may work

 

I came across these cats out of a 2014 camero ss. I think they may work, may have to route the exhaust differently as show in the image below. Are those two smaller one the rear cats?
Can I plug the rear o2 plugs, and just leave those rear cats there?

 

Since my 98 Wrangler is now considered a "classic" so no cats or inspections. I run a 3" high flow cat. No rear O2 sensors. They can easily be programmed out of the ECM.
I got the 3" cat from Summit.
The pics above the big cats are the front cats.
Just FYI the first pic of the Camaro exhaust is stainless. Unless you have a TIG welder it adds some problems.
The second pic looks like some type of modded exhaust with cats from some where? Not GM unless they are older or aftermarket.

 

The rear o2 were turned off in the pcm. Yes the bottom image is after market, It just to show how I may route the exhaust if I use two cata.
I didn't know the camero ss cats pipes were stainless. That may cause an issue, or maybe i can clamp them down?. Though they were steel .

 

You will find that nearly ALL catalytic converters are usually 409 stainless steel.

 

It's not optimal, but muffler guys MIG stainless to mild steel all the time. I've seen plenty of "cat deletes" with regular muffler pipe.

 

Could possibly delete the cats but they are require in MA.