Stock Underframe exhaust, bash plate design and build. (Completed)

[Rusty Marlin]

My underframe (stock) exhaust took quite a hit last June and almost ripped the O2 sensor out of the pipe.

Never again! (or at least this is my first attempt).

This is the bash plate skeleton tack welded together. It's 1/4" A36 plate. There will be a couple more gussets added and an additional vertical support.

The flat on the left mounts to the two outside bolts that hold the transfer case support plate in.

The vertical gusset with the single slotted hole mounts over the U-bolt that clamps on the rock sliders.
The new plate goes between the outside of the RS gusset and the nut and washers, no new hardware.

The as yet unmade support will take advantage of the GIS skid plate frame mounting hardware and go here, probably going to need a longer bolt:

To get my bends in plate stock, I slot about 1/3 through with a cut off wheel and the angle grinder, then give them the old heave ho in the BIG bench vice. I made up cardboard templates to get my numbers before just going at it.
Before I weld them up, they get gouged out with a snagging wheel to get enough room to lay in a good root pass and a couple of top passes to replace the material.

I have off tomorrow for the Federal Holiday, so baring anything unforseen, I'll get it finished up and mounted. Then show ya'll the final result.

 

[Squeegee]

Why not just do a 105 exhaust manifold and run the exhaust inside the frame?

 

[jfz80]

Or re-route exhaust over frame. Love the thinking and engineering but have to weigh cost of this mod against exhaust work which also nets ground clearance or avoidance of damage possibilities. Keep us posted.

 

[baldilocks]

Obviously a lot of thought has gone into this but in the end you’ll have an exhaust pipe that can hang you up.

 

[Rusty Marlin]

Why not just do a 105 exhaust manifold and run the exhaust inside the frame?

In no particular order...
1) brand new exhaust put on early last year, be kind of a shame to toss all that...
2) More materials and time than cash right now, so guatrding the new hardware makes sense to me.
3) Didn't know this was a thing, or might have considered it when I changed out the exhaust, a little late now.
4) The new guard doesn't hang down any further than the Cat guards on the WKOR sliders.
5) So if I do the 105 mod, what do you do with the cats, is there room between the frame and the transfer case? Do you just delete them? If they get jammed between the t-case and the frame it seems like they'd cook the t-case.
6) Does the inside frame rail exhaust play nice with the GIS DIY t-case armour? Looks like it would pass right through the mounting points of the t-case armour.

Maybe when the current stock exhaust rots out I'll look into moving inside the frame rail....by that time converting it to e-drive and batteries might be cheaper. LOL

 

[jfz80]

I do love it. But seems like it’s more tailored to your situation than the masses. If trying to market it just got to consider who would pursue this than other options.

105 setup cost is ??? ———-
Over frame rail cost me $400 for cat back with new car and muffler. (But 10 yrs ago)

 

[Squeegee]

In no particular order...
1) brand new exhaust put on early last year, be kind of a shame to toss all that...
2) More materials and time than cash right now, so guatrding the new hardware makes sense to me.
3) Didn't know this was a thing, or might have considered it when I changed out the exhaust, a little late now.
4) The new guard doesn't hang down any further than the Cat guards on the WKOR sliders.
5) So if I do the 105 mod, what do you do with the cats, is there room between the frame and the transfer case? Do you just delete them? If they get jammed between the t-case and the frame it seems like they'd cook the t-case.
6) Does the inside frame rail exhaust play nice with the GIS DIY t-case armour? Looks like it would pass right through the mounting points of the t-case armour.

Maybe when the current stock exhaust rots out I'll look into moving inside the frame rail....by that time converting it to e-drive and batteries might be cheaper. LOL

All fair points!

 

[Rusty Marlin]

And here it is; all completed and installed.
I'll have to pull it back out, sand blast it and paint at some point, but for now it's installed.

As you can see it doesn't hang down any further than the Cat sliders or the transfer case armour.

So keep in mind this for my rig, with mounting points based on the collection of other gear I have mounted.
Look at as a way to jump start ya'lls creative side and get out in the shop or driveway and build something for your rig.
Then share, 'cuz we all like projects.