factory dent in exhaust pipe

[kastein]

They are likely present on a 2WD because Chrysler did not want to stock two different exhaust manifolds.

 

[joe_peters]

They are likely present on a 2WD because Chrysler did not want to stock two different exhaust manifolds.

Yep, cheap and efficient counting of beans.

 

[rocknxj]

I had my OE downpipe replaced with a straighter pipe when I had my Magnaflow muffler installed, and the muffler shop refused to believe my "dent" was factory. Problem is, I just found out this weekend that the piece they replaced it with is far more constrictive than the OE pipe.

 

[spikeypuck]

You can still put a hole in that dent.

:wierd: Ok it wasn't quite that big but I took the grinder to it before fixing. I sounded like a Cessna coming home that day.. lol

 

[mizzutgr]

lol djb that dent you showed isnt factory

That is where the dent is in my 99 ...

 

[new1998]

Hmm hubs97x, mine is way worse than yours. I would say I have 50% restriction. I notice everyones picture is different, so to say it is "factory" cant be correct. So, they all had no dents when new and do to some engineering defect, they soon get their dents. Wish I could post a picture on here but the only choice I see is to post it somewhere else and refer to that url.

 

[hubs97xj]

That's not the factory downpipe- that's what the front driveshaft did when I hit the gas in 4WD while pulling into a friend's driveway in the snow. The stock pipe had a dent there, which exactly matched 3 other Jeeps I've been under. The pipe in my picture is the Maremont/Cherry Bomb replacement, which didn't have a dent in it when I put it on.

 

[rapom]

I've found mine on my 98 cherokee 5 years ago when I bought it. I took off the pipe and heated it up and pushed out the dent. Never had any clearance problems since. I still have it today. Of course I never do any major off roading.

 

[xjman96]

I've found mine on my 98 cherokee 5 years ago when I bought it. I took off the pipe and heated it up and pushed out the dent. Never had any clearance problems since. I still have it today. Of course I never do any major off roading.

According to one mechanic, it is a factory restriction to tune the exhaust.
One of my Jeeps has three equidistant dents as if a special tool put them there for a purpose.

 

[cruiser54]

I heard from a Chrysler engineer buddy a while back that the "dents" in the later models were to help get the catalytic converter up to temp quicker.

 

[bchulett]

I heard from a Chrysler engineer buddy a while back that the "dents" in the later models were to help get the catalytic converter up to temp quicker.

This is probably true... on my '91 during the bi-annual inspection, the Zen Master I always go to races the motor for several minutes before he performs the test... he claims it heats up the catalytic converter in order to get better smog numbers.

Check out my test results thread, some think I'm cheating... :laugh3:

http://www.naxja.org/forum/showthread.php?t=1038761&highlight=smog+test

.

 

[katuah]

So... I bashed my pipe on a branch and put in another dent. The question is, since I already had one "factory" dent, does the second dent affect the airflow all that much? Do I really need a dent if I've got a 4" lift? Or could I buy an aftermarket with NO dents and get better airflow?

 

[cruiser54]

4" lift you don't need no stinkin' dents. BTW, quit adding them.

 

[hillbillypajeeps]

i have three xjs and all have the down pipe where it meets the exhaust manifold are "factory crushed" to make them fit. is that right? just seems weird all 3 of them. the rest of the dents are courtesy of BIG rocks. the rest is missing .lol

 

[cruiser54]

i have three xjs and all have the down pipe where it meets the exhaust manifold are "factory crushed" to make them fit. is that right? just seems weird all 3 of them. the rest of the dents are courtesy of BIG rocks. the rest is missing .lol

It appears that the "crush" is there to clear the front driveshaft u-joint.I also heard it was put in that location to "appear" to be there for clearance but was actually there to help pre-heat the catalytic converter for emissions. Who knows? I know that having a custom downpipe made to eliminate the "crush" is noticeable on the old "butt dyno".

 

[joe_peters]

Without the "dent", at stock suspension height, there will be contact.

Agree with Cruiser54, over 4" of lift and it shouldn't be an issue.

 

[kastein]

It should not be an issue at over 4" of lift when driving on the road. Depending on your bumpstopping and track bar setup it may be just as much of an issue, or even worse, when flexed out or fully compressed in the front.

If you redrill your track bar and use a stock length one, and set your suspension up to not require more than stock bumpstopping, you are going to be very displeased when you compress that front suspension and put the pinion/driveshaft into the downpipe.

Basically what I'm saying is - build your suspension, assemble it minus the coils, flex it out and compress it with a couple of jacks / hi-lifts / jackstands, see if it will contact. If it will, fix the problem or bumpstop till it won't. Then install springs and have a blast.

 

[katuah]

Adding an adjustable track bar in just a bit... I do need to get some better bumpstops on, though. (Dick's has glow in the dark hockey pucks...!)

So, if I put on a non-dented pipe, I should get some horsepower improvement, or maybe MPG improvement?

I can't figure out which pipe is which, though. Morris 4x4 shows the '98 front pipe as being almost 5x as expensive as the older models (over $200 vs about $50), why the heck is that? Did something significant change? Rock Auto shows the '98 front pipe at the same price as the older ones... which is right? Are either of them "non-dented"? Is there a JY non-dent version? Am I over-thinking this?

(and I fully expect to keep denting stuff! ;-) It's a Jeep!)

 

[joe_peters]

Adding an adjustable track bar in just a bit... I do need to get some better bumpstops on, though. (Dick's has glow in the dark hockey pucks...!)

So, if I put on a non-dented pipe, I should get some horsepower improvement, or maybe MPG improvement?

I can't figure out which pipe is which, though. Morris 4x4 shows the '98 front pipe as being almost 5x as expensive as the older models (over $200 vs about $50), why the heck is that? Did something significant change? Rock Auto shows the '98 front pipe at the same price as the older ones... which is right? Are either of them "non-dented"? Is there a JY non-dent version? Am I over-thinking this?

(and I fully expect to keep denting stuff! ;-) It's a Jeep!)

Personally, I would check your local muffler shops for a downpipe quote, you might be pleasantly surprised.

 

[cruiser54]

Local muffler shop built me a new headpipe without the dent installed for $50. No brainer for me.I didn't even get dirt in my eyes.