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Rigid exhaust?

Austin

Austin

Blame Canada
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I've got a few sections of my exhaust where it's squeezing between other components. I feel like typical exhaust hangers may give it just enough swing to tap other parts. Do the U4 guys use hangers? I'd really like to rigid mount some sections but am worried the expanding and contracting would bust those at some point.

Whats the best way to keep an exhaust in place ?!?
 
I just did mine with similar clearance issues. I ran a flex pipe right off the header and used two of these poly bushing hangers. The exhaust is almost rigid but has a little flex in it.

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On the Unimog? Mine was braced off the engines/trans till it went to the stack. Had a flex pipe there.
 
What about the high speed, low drag hangers like this?

shopping.jpeg


Mounted parallel with tubing might mitigate movement.
 
AKnate said:
On the Unimog? Mine was braced off the engines/trans till it went to the stack. Had a flex pipe there.
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Yea. By the time I got my hands on this smog, I don’t think much of the exhaust was stock. I’m thinking about going rigid from the turbo to where the powertrain pivots on the frame, a flex pipe there, then rigid till the end.

I’ve read a lot about the expansion and contraction of the exhaust can cause those ridged welds to eventually pop.
 
NDCjeepsmith said:
What about the high speed, low drag hangers like this?

shopping.jpeg


Mounted parallel with tubing might mitigate movement.
Click to expand...

I used those on my exhaust mounted parallel like you mentioned. they seem like they could absorb 1/4" of movement in either direction. Mine ended up very close to the exhaust pipe, I'll know if they melt as soon as I fire up the engine.
 
Austin said:
It’s stainless
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Austin said:
It’s stainless
Click to expand...

What grade? 304 expands slightly more than 321. Not by much, but the text books do say there is a slight difference.

You can always add a flex pipe if you have the room as has been posted already. If not, a simple slip fit section can also absorb the growth in length.

Don't know the size of pipe you're working with, but here's a 3"dia slip with a 2" slip length. So if you install it with the other pipe only 3/4" deep when cold, you'd have 1.25" before it bottoms out together.

burnsstainless.com

Single Slips

Single Slips are most commonly used for naturally aspirated exhaust applications where a pipe joint is needed. The single slip can be butt-welded to the end of one pipe and will slip over the other end. Single slips are available in a wide range of tube sizes between 1-1/4” OD to 5” OD. The slip...
burnsstainless.com burnsstainless.com
 
You can also use springs to help keep the slip form coming apart. I had to use them where tubes came into collectors and couldn't weld all the way around them. Helps keep things where they should be.

slipfits.JPG
 
Austin said:
Yea. By the time I got my hands on this smog, I don’t think much of the exhaust was stock. I’m thinking about going rigid from the turbo to where the powertrain pivots on the frame, a flex pipe there, then rigid till the end.

I’ve read a lot about the expansion and contraction of the exhaust can cause those ridged welds to eventually pop.
Click to expand...
I think rigid mounted will be ok if you don’t overly rigid mount them. Example - XJs or alike Chrysler vintage including Cummins dodge rams have their downpipe semi rigid mounted via the exhaust manifold or turbo connection in front and a rubber bushed hanger next to transmission mount. This one hanger is pinned vehicle-lengthwise, effectively allow length change or movement forward-backward only. The rubber bushed rigid mount hanger at trans also provide some NVH dampening but don’t allow much movement. Down pipe’s bends, if close to 90* or so, should be sufficient to compensate for expansion and contraction also. Similar concept to how factory hard brake lines lives via with loops next to master cylinder.
 
TrailTamer said:
I think rigid mounted will be ok if you don’t overly rigid mount them. Example - XJs or alike Chrysler vintage including Cummins dodge rams have their downpipe semi rigid mounted via the exhaust manifold or turbo connection in front and a rubber bushed hanger next to transmission mount. This one hanger is pinned vehicle-lengthwise, effectively allow length change or movement forward-backward only. The rubber bushed rigid mount hanger at trans also provide some NVH dampening but don’t allow much movement. Down pipe’s bends, if close to 90* or so, should be sufficient to compensate for expansion and contraction also. Similar concept to how factory hard brake lines lives via with loops next to master cylinder.
Click to expand...


Pretty much every subaru has the exhaust mounted with flanges at the heads, a hard mount at the trans then a spring flange with donut and flex hangers from there on back.

As long as you don't over constrain it it's fine.
 
1) what'll it break if it does tap into something?

2) use more rigider mounts

3) absolutely deform the exhaust tubing to be shaped about what you need. smooth cross section area is more important than "round"
 
Squamch said:
What do you do for flex in a 10' long exhaust system behind the engine? Or is the whole thing hard mounted and bulletproof?
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something I really don't know for a turbo diesel application, but how far back is the exhaust "hot" ?

it's not going to move much if it's just hot enough for "don't touch" rather than instant burns

edit: can't imagine you are getting much color change 10' back from the engine
 
Squamch said:
What do you do for flex in a 10' long exhaust system behind the engine? Or is the whole thing hard mounted and bulletproof?
Click to expand...

Mine behind the LS is two 2.5" into one muffler, muffler is strap mounted with 1"x1/8 sandwiched between two pieces of heavy hard rubber on both ends of a 30+" muffler. The 3" from muffler to rear has 1 of them walker hard rubber hangers with the 1/4" round bar. Done very short. Has less than 1/4" clearance all around it.

Its an exhaust... No flexible part in it. Other than maybe those thin stainless butt connector sleeve clamps.

Poly engine mounts keep it all in control.
 
total newb said:
How ridged is the chassis on mogs?
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Squamch said:
If I recall correctly, very not.
Like they use 3 body mounts on the cab to allow for frame flex.
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Not rigid, the frames are designed to flex on a pivoting crossmember you can see right behind the tcase in this pic.
IMG_9616.jpeg


The drivetrain is only mounted to that crossmember and a swinging engine mount at the front of the engine. So I made a rigid exhaust that hangs off the drivetrain and will add a flex joint near the crossmember and add the rest of the exhaust to the frame after the flex joint
 
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