Looking for input: optimizing suspension plan (1 Viewer)

[jaewastooshort]

So my original plan when I bought my LX470 (circa 2018) was to put on fabricated bumpers and remove AHC in favor of a conventional 1.5" suspension lift with differential drop. I had planned to do this when either: A) AHC failed, or B) once I got my fabricated bumpers. Early on I had issues with AHC not wanting to adjust, or (likely diagnosis after-the-fact) being over-pressure while towing and dropping into Low.

Around 2020 I bought an OME static lift setup with differential mount, so these parts are currently sitting in my garage. Now that I've done a lot more reading here about servicing/adjusting the AHC system, I'm thinking it might be more desirable to just service, adjust, and maintain the AHC, but I'm trying to figure out the best way to get there. My first step regardless will be to get TechStream running and see if I can get my front back into spec at stock height, and evaluate whether the stock torsion bars are sufficient for now or if they will need to be re-indexed or swapped for something slightly stronger. The CO rear bumper is significantly heavier than stock, especially with the spare tire swing-out, and I will work on adapting a hitch back on to occasionally tow, though I'd be surprised if any towing I did was over 5,000 lb gross (trailer+load). Our last trip to CO saw 5 people plus a bunch of junk inside the cargo area, and I wouldn't mind adding a stronger roof rack with RTT, but generally do not plan that a RTT would stay on normally.

My current thoughts:
- The Coastal Offroad front bumper doesn't seem to be terribly heavy, but I do have plans to add a winch, and would still like to do some additional lift. I'm still reading through threads and trying to see what I should expect out of a similar setup so as not to be under-sprung on the front. If anyone has specific experience on a similar setup I would be very interested to read more.
FRONT:
- I would utilize the differential drop bracket I have
- Purchase the AHC shock lift brackets (to keep droop in-spec)
- Do a sensor adjustment to get desired lift at "N" position (and adjust torsion bars to get correct pressures)
- Extended sway bar mounts (time to redo all the sway bar bushings anyway, and one of the stock links had actually snapped in tension after nearly rusting through around the time I bought the truck, so probably wouldn't be a bad idea to go ahead and replace the other regardless)

REAR:
- New rear springs: I need recommendations. I keep seeing King springs recommended, not sure what to look for since I'm looking for an AHC-friendly spring rate that's also higher-than-stock lift without being too stiff. edit: more reading has led to slightly higher comprehension of the interaction of AHC pressures/spring rate effectiveness/height as set by sensor, and the King KTRS-79 appears to be the spring that I should probably start with... now to find somewhere to purchase them
[- spacers or helper air bag needed (to adjust with varying loads)?]
[- rear shock spacers needed?]
again, comprehension of what I've been reading tells me that this is going to be entirely dependent on AHC pressures and where I have "N" set at with the sensors once I'm at normal weight. if it gets overloaded with occasional loads it might be worth it to put in helper bags.

Questions:
1) What rear springs are recommended for my setup? answer: probably KTRS-79
2) With a 1.5" suspension lift in this manner, what other components are recommended to maintain acceptable suspension travel (modified geometry UCA/LCA, extended range ball joints, etc)?
3) Are extended bump stocks going to be needed? answer: if lifting with sensors and shock spacers, yes, they're a very good idea to avoid excessive compression
4) What else do I need to consider that I didn't mention here?

 

[jaewastooshort]

edited to add some notes based on reading this afternoon. I think I answered most of my own questions, but would still like input on what I've neglected to consider out of ignorance.

 

[jaewastooshort]

So, ordered the King KTRS79 springs and Japan4x4 AHC shock spacers, and have finally arrived. I'll work on getting the rear springs installed this weekend and then take another look at AHC system pressures at stock height. Pressures were pretty high on worn out stock springs once I had the bumper and spare swing out arm back on, so I'll see how close it is with the springs.

Plan after that is to get the shock spacers and differential drop installed and start working on the sensor lift and see if I can get to 1-1.5" and keep pressures in the normal range. I have extended rear sway bar links from superpro on order (along with their panhard bar bushings), and really leaning toward ordering the SuperPro TRC6720 UCA's based on the geometry correction they offer when doing a sensor lift.

 

[LJE]

So, ordered the King KTRS79 springs and Japan4x4 AHC shock spacers, and have finally arrived. I'll work on getting the rear springs installed this weekend and then take another look at AHC system pressures at stock height. Pressures were pretty high on worn out stock springs once I had the bumper and spare swing out arm back on, so I'll see how close it is with the springs.

Plan after that is to get the shock spacers and differential drop installed and start working on the sensor lift and see if I can get to 1-1.5" and keep pressures in the normal range. I have extended rear sway bar links from superpro on order (along with their panhard bar bushings), and really leaning toward ordering the SuperPro TRC6720 UCA's based on the geometry correction they offer when doing a sensor lift.

Looks like you've got a really good plan! I'm very curious to see how this turns out, as if I lift my LX in the future this is how I'd want to do it. You *may* need spring spacers with those Kings with both all that weight and the lift, but I'd wait and see.

 

[Foehammer]

If you're willing/able to maintain the AHC it sounds like you answered your own question. Can always sell the conventional suspension components you're sitting on.

I deleted my AHC and lifted it with zero regrets but mainly cause the hard lines were rotten and I didn't want to deal with the headache.