Is the 392 Under Damped Off-Road?

[BradyW]

I’ve had my 392 out on the trails and rocks four trips in my first month of ownership.

Does anyone else feel as though the 392 needs a little more progressive valving/damping on the shocks than what ships stock? (I do have an XR with Mopar shocks instead of the Foxes that come with the std 392) The bump stops are harsh and I’ve hit them on every trip despite my best efforts to avoid it. It feels as though the weight of this beast just blows through travel.

Has anyone else noticed similar traits on their 392? Would upgrading to the Fox 2.0s for stock height help or what options should I be looking at to prevent bottoming as often?

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[Moto_21]

Im sure they are. Off the shelf might not be much better, could be same softer or stiffer, dunno what they are valved at. Best bet is to get something from @AccuTunedJL and they will dial it in

 

[BradyW]

I am attacking this in a three-phased approach, in the hopes that phases two and three are unnecessary and not initiated.

1. Upgrade shocks to Fox 2.5 DSC 883-26-050/054 (2-3" lift)
2. Install a 2.5" lift kit, such as Clayton or Metalcloack. This should net ~1" more up-travel on the 392 as long as you do not increase tire size or change bump stop setup.
3. Install hydro/air bump stops

The Fox 050/054's have shorter compressed lengths than the OEM shocks (which means they will be safe with the OEM bump stop setup), but slightly longer extended lengths. (24" vs 26.5" and 27" vs. 28.6") As a result of this change here are the questions I'm hoping to answer for current and future 392 owners with phase one of this project.

1. Are the Fox 2.5 DSCs alone sufficient to solve the bottom issue?
2. Does the 392 require special valving in the 2.5 DSC due to its weight over the std wrangler? (Some feedback from other members that stock valving works great with the 392)
3. Does the front driveshaft contact the transfer case at full droop or stuff with the slightly longer DSCs?
4. Do the front shocks contact anything at full droop? (Can a 2.5" lift be installed without brackets. If brackets are required then wheel spacers or new wheels are required as well)
5. Can the stock springs handle the longer shocks without becoming unseated at full droop?
6. This final question is only relevant if phase one is a failure and requires phase two. Is the 392 truly engine clearance limited as the reason for the extended bump stop towers? If not then the inner fender liners could be removed to allow some bump stop removal on the stock 35" tires as long as doing so wouldn't bottom out the 2.5 DSCs.

I will report back on my findings from phase one. Hoping that only phase one is required.

 

[Moto_21]

1. Most likely, a lot depends on available up travel, you can adjust the shocks to be pretty firm.

2. The stock valving will probably be sufficient. If at some point you find it not, get it revalved. The adjusters work well.

3. Front driveshaft wont hit until 30” plus of shock length.

4. No contact at full droop with those lengths.

5. Not sure on stock spring lengths, im gonna assume it will be okay, worst casemight need 1” longer springs or a .5” puck, but i think it will be okay.

6. Not sure havent seen a 392…im poor

 

[Moto_21]

If you only have 3” or less of uptravel, youre still gonna be at 3” of up travel, only way to keep off bumps more is stiffer valving. Which with only that little travel will need to be pretty damn stiff to keep that from bottoming. Just saying. Youll likely need to go taller in the end

 

[BradyW]

If you only have 3” or less of uptravel, youre still gonna be at 3” of up travel, only way to keep off bumps more is stiffer valving. Which with only that little travel will need to be pretty damn stiff to keep that from bottoming. Just saying. Youll likely need to go taller in the end

I fear you are spot on and I feel the same. I told myself I’d purchase one step at a time just in case it’s not all needed.

I’m only 2.5hrs away from Cross Bar Ranch in OK where they ran the ultra 4 nationals this year so I have a great course to go out and test the Jeep in a mix of terrain and speed.

 

[Moto_21]

I fear you are spot on and I feel the same. I told myself I’d purchase one step at a time just in case it’s not all needed.

I’m only 2.5hrs away from Cross Bar Ranch in OK where they ran the ultra 4 nationals this year so I have a great course to go out and test the Jeep in a mix of terrain and speed.

Yeah youll be needing to increase that height. Problem is if you start with those shock lengths, and then get taller springs, youre gonna want longer shocks…so better to figure it out first shot

 

[1996cc]

I am attacking this in a three-phased approach, in the hopes that phases two and three are unnecessary and not initiated.

1. Upgrade shocks to Fox 2.5 DSC 883-26-050/054 (2-3" lift)
2. Install a 2.5" lift kit, such as Clayton or Metalcloack. This should net ~1" more up-travel on the 392 as long as you do not increase tire size or change bump stop setup.
3. Install hydro/air bump stops

The Fox 050/054's have shorter compressed lengths than the OEM shocks (which means they will be safe with the OEM bump stop setup), but slightly longer extended lengths. (24" vs 26.5" and 27" vs. 28.6") As a result of this change here are the questions I'm hoping to answer for current and future 392 owners with phase one of this project.

1. Are the Fox 2.5 DSCs alone sufficient to solve the bottom issue?
2. Does the 392 require special valving in the 2.5 DSC due to its weight over the std wrangler? (Some feedback from other members that stock valving works great with the 392)
3. Does the front driveshaft contact the transfer case at full droop or stuff with the slightly longer DSCs?
4. Do the front shocks contact anything at full droop? (Can a 2.5" lift be installed without brackets. If brackets are required then wheel spacers or new wheels are required as well)
5. Can the stock springs handle the longer shocks without becoming unseated at full droop?
6. This final question is only relevant if phase one is a failure and requires phase two. Is the 392 truly engine clearance limited as the reason for the extended bump stop towers? If not then the inner fender liners could be removed to allow some bump stop removal on the stock 35" tires as long as doing so wouldn't bottom out the 2.5 DSCs.

I will report back on my findings from phase one. Hoping that only phase one is required.

Regarding #6. The 392 motor mounts are bigger. A lift with straight upper control arms will hit there first, if you are trying for every last in much of uptravel. I cut my factory bumps stops off to install King hydro bumps, so my bump heights are close to regular JL Rubicon ones (I had a 2019). I swapped my Metalcloak UCAs for EVOs because the EVOs have a slight bend that clears the motor mounts. By doing that, I gained roughly an inch of uptravel. I have 3.5” lift springs with 10” travel King shocks and at ride height, I have 5” up and 5” down for travel.

 

[BradyW]

Regarding #6. The 392 motor mounts are bigger. A lift with straight upper control arms will hit there first, if you are trying for every last in much of uptravel. I cut my factory bumps stops off to install King hydro bumps, so my bump heights are close to regular JL Rubicon ones (I had a 2019). I swapped my Metalcloak UCAs for EVOs because the EVOs have a slight bend that clears the motor mounts. By doing that, I gained roughly an inch of uptravel. I have 3.5” lift springs with 10” travel King shocks and at ride height, I have 5” up and 5” down for travel.

I went with a 2.5” lift and kept the stock 35” tires and stock bump stop height. This combined with the 2.5” Fox‘s gives me all the fade-free travel I need for crawling and a moderate pace on smoother trails. Hopefully the Bronco Raptor will put a little pressure on Jeep to give the 392 the suspension it needs from the factory.

 

[kkarnage]

Went with the AEV lift and the 8300 Bilstein shocks: haven’t bottomed it out since they’ve been in.

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