4 link v8 guys....exhaust question

[Cody]

I just had the rear of my newest ZJ redone to a triangulated 4 link...almost identical to my last ZJ. I took it to the guys who originally did my last one and he doesn't think there will be a problem running the 3" out the same way, but the shop won't let me supply my own cat or use a 3" cat because it doesn't match a part in the book and the fed government blah blah blah...so I took it to another shop who said they had no problem with the 3" cat but he doesn't think he can get the 3" pipe all the way out. (his suggestion was to lower the skid plate 3" to fit things under "it wouldn't change anything because my lowest point is the bottom of the diff"...he's a hot rod guy so I guess he's forgiven).

So, anyway, has anyone stuffed a muffler up above the rear axle, just forward of the gas tank? There is a big void up there that a muffler fits in, and it looks like we could put in a flowmaster type muffler and bring the exhaust out the driver side rear. Anyone done that?

[OverkillZJ]

I don't think I've seen one routed through a 4 link yet without burning a hole in the gas tank, but I could be wrong.. Ended up doing a turn down myself.

[jsteves]

Mine is routed all the way out the back. Used 2 1/2 pipe instead of 3" Put the cat before the crossmember, muffler behind and routed pipe the rest of the way.

[ZJ TINS]

Run 2x 2 1/8 or 3x 1 3/4 pipes in parallel (fake dualies or triples and start a trend).

[Cody]

The other problem I have to contend with is the flat-belly skid I have. I really dont' want just a turndown, it's absolutely obnoxious right now.

[OverkillZJ]

I hear you on obnoxios, I'm never doing it again!

It would take work, but I THINK you might be able to squeeze it above a flat-belly skid, its something I'd been thinking about doing on the buggy, but I was concerned about how close it would be to the transmission, not to mention the floorboard.

[Cody]

ya, a 3" tube through the flatbell will be right next to the tranny and essentially on the heat shield of the floor board.

I may have to go to a 2.5" pipe after all. I guess it's better than the 2.25 that is in there now...

why does everything have to be a PITA for me?

[BigDaveZJ]

Look at it this way, regardless of what size exhaust pipe you run, whether it be 2.5" or 3", you'll have a lot more power than you did with the 4.0!

[ATL ZJ]

Just run it up against the floor board and wrap it as they do on comp rigs...

[Cody]

Look at it this way, regardless of what size exhaust pipe you run, whether it be 2.5" or 3", you'll have a lot more power than you did with the 4.0!

Very true. I only plan on doing the exhaust and intake on this rig, but want to get the most out of those mods so I can still pull my off-road travel trailer over the mountain at 75 mph.

[J B]

Just run it up against the floor board and wrap it as they do on comp rigs...

Yep, wrapping the pipe with header wrap in a short section won't be a problem.

But of course, don't let it contact the floorboard.....

[Cody]

the header wrap or the pipe? what about if there is a heat shield on the floorboard where it is contacting?

[J B]

You don't want the pipe to contact anything but an exhaust hanger that's rubber mounted. The amount of vibration in those pipes is unreal. If you think the drone drives you nuts, get an exhaust pipe in direct contact with the structure somehow. The vibration, over time (and not as much time as you'd think) will start to loosen bolts and screws all over the damn jeep as well.

EDIT: The wrap being in contact is just about as bad.

[Cody]

I see...

[OverkillZJ]

I once had the most godawful noise on trip.. took me awhile to find it, but at the very exit of my exhaust, it was hitting the gas tank skid. It seriously sounded like a chainsaw next to my head.

[ATL ZJ]

On my old 6.5, right after I put the turbo back system on, the downpipe was touching the frame. I might as well have bolted my seat to the motor.

[MoonWorks]

It can be done as others have said but the person doing the work better be damn good with a bender and know how your suspension articulates. I'd also make sure they don't have a problem with you coming back to get it tweaked a bit just in case it does rub when you get it on the trail.

I was in need a very small muffler. I ended up ordering a 12" long by 4" wide glasspack from jcwitney for lik $25 or something. Fits good (and might for you with a flat belly) and doesn't sound too bad. Would probably sound better if I had a cat and it didn't dump behind the muffler.

[IndyZJ]

could you hard mount the exhaust to the unibody (possibly the floor?) but use a flex joint before any of the hard mounts? if heat's a problem and you aren't too concerned about price you could have the tubing ceramic coated, or just stick with the wrap but watch for rust. I've seen it done that way on a few hotrods that can't have anything below the frame rails.

[5.9 ANDY]

sorry for my newbie question, but what is this wrap you guys keep speaking of?

i would assume it is some sort of a heat shielding/blocking form of insulation.

Mine is routed all the way out the back. Used 2 1/2 pipe instead of 3" Put the cat before the crossmember, muffler behind and routed pipe the rest of the way.

do you have pics of your setup, i am going to be doing a fair amount of exhaust modding, primairly getting my cat and muffler up higher and less prone to being smashed by rocks. i would also like to get my cat and muffler farther foward, so pics of your setup would be great.

thanks.

[jsteves]

I'll take some pics this weekend. Of course, I still managed to smack the muffler.

[ILikeMud]

If your not opposed to trimming the floors
Sorry, I like to cut things.

I've got an idea for a 'high clearance' exhaust and tail pipe (turn down is just too loud) but I'm ages away from attempting to carry it out.

[DND]

My exhaust guy managed to build a full 3" system, using pre-made bends routed through Calyton's 4-Link rear arms. The muffler he used is called a Red-Devil, it's tubular and positioned in the upswing as the system goes over the axle. Pics are in an older thread - http://www.mallcrawlin.com/forum/sho...xhaust+routing

The only contact I have is against the driver side shock at full stuff. So it can be done, it just takes someone skilled. Also, expect to pay.

[FearTheDentist]

I can't compare my WJ directly to your situation, but FWIW I stuffed a Flowmaster 40 series under my diff. skid w\o any trouble, and then a turndown instead of routing it out the back. It's not too obnoxious and it'll fit in a pretty tight space.