It's done, but I'll ask, why would you not do this?

[William]

Sort of late for me to ask now.. But I might as well know..

I got SOO tired of my exhaust hitting my track bar, shock, gas tank or frame and of the 3 times I had it redone so it wouldn't, and hitting it somewhere on a rock so that it'd hit again..

That I had it fixed. I had the stock exhaust cut off, and a new (dynomax or something) exhaust put on and just at the exit, the pipe ends pointed down. So, essentially the exhaust ends right before the axle.

Any thoughts that will make me go "Dam, I screwed up!"?

[Paradiddle]

You might have an issue with the smell. I drove a hot rod'ed Comet for a couple weeks in high school (belonged to an uncle) and the exhaust was turned down in front of the axle. At the stop lights you could really smell the exhaust.

You Jeep will be louder as well.

Jeff

[Iceman]

Like Jeff mentions the fumes getting into the Jeep might become a problem.
On mine I cut off the end of the tailpipe (the downward tip) to keep it from smacking into rocks, but that's it .... no problems with exhaust gasses on that one
exhaust 'tip' removed ....

[Allen]

On my first TJ I ran a muffler, without a tailpipe nor any turndown tip for a while.

The exhaust gasses extremely corroded all the bolts on that side of the TJ, behind the exhaust. Control arms, sway bar mounts, end links, shocks.

Not good.

Allen

[Hellbender]

William, go get it fixed right now! Seriously!

Your gas tank is thin PLASTIC!

Do you remember my posts a coupla years ago showing the whole top of my gas tank melted down?

It also burned up a bunch of my rear wiring harness!

At certian speeds the air will blow the hot exhaust gasses up and they will trap above the tank, if you don't have much fuel in the tank for a heat sink it will melt it down!

Another guy (CYMK?? I think) on the POR board said he had been doing this with no problems.........

2 weeks later, he posted an "eat crow" report with a pic of his tank melted.

Find a better exhaust shop or put up with the clunk, but don't drive it til it's fixed!

HB

[TJRON]

I ran mine for a long time cut off after and at the bottom of the axle bend just as it bends to go towards the rear. I cut it at an angle to keep the exhaust pointing down as much as possible. I did this as a temperary fix after accordian the thing my first trip to Moab but kept it that way much longer than I expected. It did put out some fumes and kicked up a lot of dust on the trail but heat never seemed to be a problem.
I also thought it unsafe and finally had it fixed proper. That area is tight and I found the stock pipe does not have to arch so high over the diff. My muffler guy fixed me up with a proper job and I've had no problems with the new correct system.
William, find a new muffler shop!

[Art Welch]

As long as the end points straight down or nearly so you'll be fine. I've had it like this for quite a while and the only side effect will be bigger dust clouds when you drive in dry conditions.

There is that whole exhaust in the cab thing but as something that never runs with a top I haven't been concerned.

[cbassett]

I run a turndown on my exhaust, no problems.

Having seen my success with this configuration, a buddy with a similar rear suspension setup (triangulated 4 link) on his TJ decided to go with a turndown as well. He's not had a single complaint.

[TJRON]

Originally posted by Art Welch
As long as the end points straight down or nearly so you'll be fine. I've had it like this for quite a while and the only side effect will be bigger dust clouds when you drive in dry conditions.

There is that whole exhaust in the cab thing but as something that never runs with a top I haven't been concerned.

Big Cloud has spoken!
I think big tires plus the engine kick up so much dust on those powder trails a little exhaust dust only matters when you're standing still. And then it only matters to the guy behind you.......

[Hellbender]

I had a 45 degree turndown, straight off the muffler. It did this during highway driving.


Make up your own mind.
If it is an off-road only rig you may never get enough upward airflow to do this.

[Art Welch]

That's an interesting picture Hellbender, not where I would have expected to see damage.

Seeing that I should qualify my earlier statement to include the fact that my gas tank is pushed up several inches higher than where it would be with a stock Kilby skid, the top where yours was damaged is very high on mine. At regular height I can see where it might be more of a risk.

[TJRON]

Yep, mine's also in a Kilby and the exhaust was as low as it can be when cutting from the stock system. I think it was Brad's picture that got me moving on a proper set up.

[Hellbender]

Art, it also melted all of my tail light wiring on that side.

And melted part of the rear inner fender cover, below the tail light.

The heat bottled up at the very rear corner.


The other Guy's (CYMK ????) tank was very similar, only actually had a small hole melted in it, I think. He was bragging how he had run it that way for several months w/ no problems, but was good enough to be honest, brought up the old post and "ate crow".

HB

[seajeeper]

Sounds like a new topic of study for Daless2

If he wouldn't mind melting a few tanks for us....

[mrblaine]

Originally posted by seajeeper
Sounds like a new topic of study for Daless2

If he wouldn't mind melting a few tanks for us....

What is Frank going to tell you that the pictures don't?

Do you really want to chance melting your tank?

[William]

HB,

I had your post about this in mind when I had it done. It has a 45 degree down and about 2 inches of down pipe with that.

However, I was under the impression that you had a strait back exhaust, not pointed down.

Which made it all seem kosher.

Of course now, I have some really serious doubts.

Was yours with a stock exhaust? How long was the exit pipe from the muffler? Did you have a flat skid on at the time, and what type of gas tank skid did you have at the time as well?

I am of course not doubting the risk! I am trying to qaulify the factors. Of course this morning before I go to work, I'll be getting under the jeep to look for any signs of the beggining of a problem.

[Hellbender]

William, I had a little piece of old exhaust pipe stuck on it, straight off the muffler, about 6-8 inches long (I had cut it off the bend over the axle) just temporarily on it (until I could get the tailpipe on).

I had a Tera skid on at the time, but the Kilby skid will hold even more heat up there than the Tera (more enclosed). I think the other guy had a Kilby.

Your's may work perfectly for 2 years, and then you hit a constant, 10 minute long wind blowing just the wrong way.

Your tailpipe may be longer and more downward (probably is), but is it even worth a chance to save $50-75?

I have a triangulated 4 link w/ NO body lift, if they can snake a pipe through that, they can do yours, too

HB

Edit: I may have had my Kilby skid on there at the time, I'm not sure.

[Milan]

I'm with Hellbender. I ran a straight pipe with the tip turned down for a while and the heat was so great as to heat up my 3/16 Mopar gas tank skid so that I could not put my hand on it. This pipe replaced the muffler I took off and so I ran with the catalitic and no muffler. It's the catalitic convertor that heats the exhaust gases so much. I think if you did not run a cat and just a muffler with a pipe pointing down at the tip, you might be OK. But with the cat it seemed to get the gas tank too hot even in the winter.

[Chris L]

[William]

Originally posted by Hellbender
William, I had a little piece of old exhaust pipe stuck on it, straight off the muffler, about 6-8 inches long (I had cut it off the bend over the axle) just temporarily on it (until I could get the tailpipe on).

(SNIP)
Your tailpipe may be longer and more downward (probably is), but is it even worth a chance to save $50-75?

I have a triangulated 4 link w/ NO body lift, if they can snake a pipe through that, they can do yours, too

HB

Edit: I may have had my Kilby skid on there at the time, I'm not sure.

HB,

Well, I have not drivin it much out of fear of massive explosion, and don't have time to get it to the muffler shop.

But I took some measurements Sunday after I destroyed my back (lots of laying down for me to do now..).

The new exhaust is about 1/2 the size of a stock muffler. The down pipe exiting the exhaust ends approx 1 inch below the new muffler. From the exact middle of the exit pipe to the front side of the muffler is 6 inches, and then there is of course the space between the axle and the gas tank skid.

I thought of running a temp check on it, but while it's sitting in place, it's not a fair check. The time after when I drove it on the freeway during mid summer day, I stopped 4 times to check temps on a "touch" basis, and nothing was hotter on one side vs. the other. But still, there's enough worry here that I'm not driving it much.

It's not about the money really, it's about elminating the 30 million clunks and clanks I have and identifying several problems that have arisen: the side lean, brake clunk, pop noise from rear track bar or control arms.. amongst other things. I've had the exhaust routed 3 times now, and it seems to be that it can never remain static enough to get it right.

I'll post a picture.

Chris, not to knock your picture, but you posted a picture that I assume comes from a exhaust leak. Can you qaulify that with an explanation? I.E. what type of muffler, down tube length, etc?

[Chris L]

William--
I cut my stock exhuast off the ZJ right at the back of the muffler with no down tube. There was a good 2 feet between tank and muffler and that was the result of hot exhuast hitting straight back at the tank two feet away.

[JEEP_TJ_FREAK]

Originally posted by Hellbender
I have a triangulated 4 link w/ NO body lift, if they can snake a pipe through that, they can do yours, too.

Pics?

Mine is turned down at the transfercase's rear output simply because I cannot figure out how else to do it.