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Upgrading Exhaust.... what Muffler?

Had my installation at "Bud's Muffler" in Denver, Colorado and the installation took well over 10 hours! The mechanic working on it said that the installation of the header was a huge pain in the ass! He was thankful when it was in and he could concentrate on bending pipe :) Below are a series of pictures that were taken along the way.... My overall impression will be posted near the end of this posting..... enjoy, and thanks to all who posted their thoughts. Troubleshooting this issue has been a LONG work in progress for me so thanks to all!


When the cat was off the Jeep, as you lifted/turned/looked inside you could feel/hear/see a LOUD banging around of multiple pieces of broken "honeycomb filter" from inside the cat... also, there was a lot of rattling coming from the muffler, which the mechanic believes was pieces of honeycomb that worked there way into the muffler. More or less confirming that the cat/muffler was to blame for the excessive overheating I was experiencing.

This is a comparison of the old and the new Catalytic Converter and Flowmaster 10 Series Delta Flow muffler.....

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This next picture was a comparison of the factory header and the Gibson header.... got to the shop too late to take a "true" side by side comparison photo of the header... but this shows how different the pipes are ran and collected...

orig.jpg


This photos shows the crack that was found on the lower collector of the factory header...

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Below shows what the muffler looks like installed... using 2 1/2" pipe throughout....

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This shows the cat and muffler installed...

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I picked up my jeep after the above was installed.... I drove it home and by the time I got there (10 miles) I had a serious headache. The resonance and vibrations I was getting inside the cab was a little too much for me to handle. The next morning I called Bud's Muffler and explained my concerns. Bud recommended some type of "resonator" to help alleviate the resonance. Sure enough, they installed an 18" resonator in front of the muffler and it virtually eliminated all of the resonance and "drone" in the cab. Below is a pic of the exhaust with the resonator installed....

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I was able to barrow a video camera a take a couple videos of the jeep after the exhaust install. The quality and sound aren't great but in person it sounds awesome. The sound is not terribly loud but very smooth with very little if any resonance inside.

*NOTE* you will have to download the following links in order to view...

http://www.fototime.com/8A528F439717386/conv.wmv

http://www.fototime.com/EEF401DE82BD1BA/conv.wmv

My overall impressions of the install are that they seem to have fixed the original problem, which was the excessive overheating. I love the sound and the performance gains I have achieved. This Saturday I'm installing new fuel injectors from fiveomotorsports.com and a custom tuned ECU performance chip form "Unichip"... If the results are good I will post a thread about the install and performance gains.

THANK YOU! to everyone who posted reply's to my original post.... I valued every opinion I got and I truly thank you for helping me with this issue.
 
The reason I'm installing new injectors is that early on in the diagnosis stage of the overheating problem the engine had a couple miss-fires. When I took it in and had diagnosis computer hooked up, it showed miss-fires in cylinder 5. After pulling a few spark plugs there was a large white buildup on each. Based on the buildup on the plugs and the miss-fires that were throwing codes, it was suggested that the engine was running to lean and that the injectors could be playing a part.

I have a chip coming tuesday, so I plan on installing the injectors before the chip to ensure I'm starting fresh. I personally hate driving around knowing that there is possible problem inside the engine and neglecting to address it.
 
Well I got a little carried away with my impressions of the new exhaust system. The performance gains have not been what I was expecting. There seems to be a loss of power on the low end.... and this morning I filled up with gas, noted my mileage and compared my average miles per gallon with that of the past 8 months... a 3.3 mpg LOSS!!!! It was then that I new something was wrong.

I had a few people tell me that the exhaust I was putting on would cause some torque loss, but to my own detriment I was so focused on the 2.5" pipe throughout I didn't do enough research to follow up with there opinions.

Well I have an appointment at the muffler shop to have the problem fixed. They are putting in 2.25" from the header down to just before the cat then keep the 2.5" from there on... I hope it makes a difference.

I will post my NEW impressions after that.....

It's always something with these Jeep's isn't it?
 
hmm i like that flowmaster and cat. I use what ever the thrush turbo muffler is at Advanced cuz its $20, smaller then stock and I dont worry when i mangle the exhaust on something.... however that flowmaster one is tiny... I don't care what it sounds like so long as it doesn't get ripped off :D
 
I thought at first I may have lost the gas mileage due to a heavy foot, but this last tank of gas has been strictly to and from work under normal driving conditions.... I may have pedaled it hard a few times but In my opinion it was not enough to negate a 3+ mpg loss.

Keep in mind that there is a noticeable lag in power from 1st to 2nd gear and then a slow lag from 2nd to 3rd. The muffler shop owner as well as gearhead friends, 2 of which have personally driven the jeep, all agree there seems to be some real loss in power.

I will soon find out if its my driving or the exhaust thats the issue. The muffler shop is fixing the pipe on Wednesday.
 
Might be a stupid question but is the CAT in the right direction of flow (the arrow on top)? I couldn't tell by the pics but one end looks a little longer than the other and almost looked backwards.
 
silverslk: since you brought it up, I will double check tonight that its the right direction. I truly hope its in their correctly considering what I was charged to have it installed :)
 
did you replace the o2 sensors. a bad cat/exhaust may have ruined the o2 sensors. with all that was wrong with it, have you replaced the cap, rotor, and plugs?
 
i like the good ol cherry bomb
 
To answer both posts:

When I had the exhaust installed the owner of the shop told me that he would inspect and test the o2 sensors and replace them if necessary. When I picked the jeep up he told me that they seemed in "good working order" and didn't replace them.... so I'm taking his word that their ok.

I'm installing a chip this weekend and to install it I have to disconnect the battery... does disconnecting the battery "reset" the computer? If not, how do you do go about a proper "reset"??
 
Oh yeah, I forgot to mention that about 2 years ago I installed a D.U.I. Firepower Ignition Kit... which includes new coil, cap, plug wires and plugs.

I mentioned earlier that the plugs have a white build up on them... should I be replacing the plugs with new ones at this point?
 
Why not go with an engineered system... see http://www.naxja.org/forum/showthread.php?t=967802

There are 2 systems listed there at $99... I am mad because I just paid a shop $130 to weld in a muffler when I could have clamped in a cat-bak for less!
 
mine has a knock off of flowmaster and for some reason its loud as hell. have the cat and muffler wrapped with header wrap. i forgot the name but i want to say v-force???
 
**** UPDATE ****

As of today (Saturday, 27th) the XJ has had the exhaust fixed.... the muffler shop installed 2.25" pipe from the header to the cat and then left the existing pipe alone (2.5" cat back). I noticed a considerable power GAIN as soon as I drove away from the shop. On the highway the power is very noticeable, places the xj would struggle it now powers through without having to kick down to a lower gear.

Also, as of 30 minutes ago, the xj has a custom tuned "Unichip" installed as well as new fuel injectors. I'm working on a tread of the "Unichip" install today.

Sunday Im taking the misses on a day trip to test out all the new parts. We will be on city highway, mountain highway and some slow and easy 4 wheeling. Should be a good test to see how everything is working together.

For now though, everything is working great, the power is back and much improved over stock.... so thanks again to everyone who posted with your thoughts....

Keep your eyes out for the "Unichip" thread and my impressions with it.

Mike
 
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