Suspension lift solution - using AHC spacers? (1 Viewer)

[skookum]

I’m currently baselining my ‘99 LC and completely revamping the suspension (shocks, bushings, arms etc.) and the topic of a modest lift has popped into my mind.
My goal is a 1.5-2” lift with 99% of driving on pavement or mild gravel.
Aside from running all OME parts for example (coils, shocks, TBs) I want to know if this arrangement would work on my rig:
- stock shocks in all 4 corners (non-AHC)
- shock spacers for AHC mounted to them to “extend” them
- OME TBs
- new rear coils (Eibach, Ironman etc.)
- diff drop bracket
- stock UCAs

Would this combination work? Are there any rigs using these spacers with a non-AHC suspension?

 

[GTV]

For your use case don't bother with them. Stock shocks will be fine, just make sure you have enough droop after your lift.

 

[skookum]

For your use case don't bother with them. Stock shocks will be fine, just make sure you have enough droop after your lift.

So essentially just the coils for the back and cranking the bars? (Aside from the diff drop)

 

[GTV]

So essentially just the coils for the back and cranking the bars? (Aside from the diff drop)

Yes. Even the rear coils are optional, 30mm coil spacers will be fine if you're not loading up the rear with a bunch of weight. 30mm is only about 1 1/4" lift if you're ok with that.

 

[skookum]

Yes. Even the rear coils are optional, 30mm coil spacers will be fine if you're not loading up the rear with a bunch of weight. 30mm is only about 1 1/4" lift if you're ok with that.

Thank you! This is very helpful/reassuring.

 

[Viio]

I installed these shock spacers on my 1.5 inch lifted AHC and I experienced precisely zero difference in ride

 

[OEMGUY0720]

The reason why the AHC strut spacers were made is to reduce the pressure / load on the shocks after the height level link sensor is shortened (lifting the vehicle a little). The F&R dynamic/AHC shocks share carrying the load of the truck with the torsion bars; whereas on a conventional LC (non-AHC suspension system) it’s just the torsion bars that carries the weight of the vehicle and the shocks control the damping and mostly the rebound the torsion bars and the rear coil springs create. So using the above mentioned stock shocks will do as it has enough length even at full droop.

 

[porschenut]

I went through stages with my AHC mods and this is what I’d found.

1. Just a sensor lift with nothing else. I didn’t read the pressures at the time but found that I was getting an occasional clunking noise in the front end.
2. Then I added 30mm Ironman spring spacers, Perry Parts extended bump stops (all 6) and cranked the torsion bars by 6 turns. Clunking noise remained.
3. Then added Japan 4x4 shock spacers. Clunking noise seemed to be gone but would realize later that the spacers probably had nothing to do with the noise going away.
4. Got a scan tool to read AHC pressures. Front pressure was vey high (with steel bumper, winch and pod lights). Rear pressure was right in spec (lighter than stock with spare tire and bracket removed, no 3rd row seating and no cargo). I cranked the torsion bars as far as they would go which brought the front pressures right into spec.
5. Recently got some SPC upper control arms after my service shop advised that the OEM UCAs had been impacting and denting the front shock shrouds (upon full droop). That explained the clunking noise. The SPCs leave more room between themselves and the shrouds so no more worries about the clunk. I probably just didn’t notice the clunk after the shock spacers since the shrouds were already dented. That left had left a little more room between them and the OEM UCAs. I also hadn’t been doing any hard wheeling right after the shock spacers.
6. I fabricated a rear sensor extension to get more lift and I’m now running a 3 bar roof rack and roof box (both very light). The pressures are running about 1.0 higher than spec in both the front and rear now.

Future #7. Wanting to get supplemental air bags in the rear so I can compensate for the occasional weight of overlanding gear. I don’t have a solution for bringing the front pressure down yet.

Ultimately I’ve concluded that an AHC sensor lift should run all the same upgrades (and not leave any out), especially if you run a rear sensor extension.

 

[harshjay]

I went through stages with my AHC mods and this is what I’d found.

1. Just a sensor lift with nothing else. I didn’t read the pressures at the time but found that I was getting an occasional clunking noise in the front end.
2. Then I added 30mm Ironman spring spacers, Perry Parts extended bump stops (all 6) and cranked the torsion bars by 6 turns. Clunking noise remained.
3. Then added Japan 4x4 shock spacers. Clunking noise seemed to be gone but would realize later that the spacers probably had nothing to do with the noise going away.
4. Got a scan tool to read AHC pressures. Front pressure was vey high (with steel bumper, winch and pod lights). Rear pressure was right in spec (lighter than stock with spare tire and bracket removed, no 3rd row seating and no cargo). I cranked the torsion bars as far as they would go which brought the front pressures right into spec.
5. Recently got some SPC upper control arms after my service shop advised that the OEM UCAs had been impacting and denting the front shock shrouds (upon full droop). That explained the clunking noise. The SPCs leave more room between themselves and the shrouds so no more worries about the clunk. I probably just didn’t notice the clunk after the shock spacers since the shrouds were already dented. That left had left a little more room between them and the OEM UCAs. I also hadn’t been doing any hard wheeling right after the shock spacers.
6. I fabricated a rear sensor extension to get more lift and I’m now running a 3 bar roof rack and roof box (both very light). The pressures are running about 1.0 higher than spec in both the front and rear now.

Future #7. Wanting to get supplemental air bags in the rear so I can compensate for the occasional weight of overlanding gear. I don’t have a solution for bringing the front pressure down yet.

Ultimately I’ve concluded that an AHC sensor lift should run all the same upgrades (and not leave any out), especially if you run a rear sensor extension.

simply swap in non ahc front torsion bars, they are thicker and stronger, thus allowing for more static assistance

if you are in the USA, Sway-away makes a nice set vs spending money on Chinese produced OME / Ironman

 

[porschenut]

simply swap in non ahc front torsion bars, they are thicker and stronger, thus allowing for more static assistance

if you are in the USA, Sway-away makes a nice set vs spending money on Chinese produced OME / Ironman

I’ve since found out that I can re-index the torsion bars after all. I’d thought they had a hex shaped engagement but learned that they’re splined so can be indexed in small increments. I think that should help with my minor over pressure issue up front. I would assume that non AHC torsion bars will have too much spring rate and lead to a harsh ride quality.

 

[harshjay]

I’ve since found out that I can re-index the torsion bars after all. I’d thought they had a hex shaped engagement but learned that they’re splined so can be indexed in small increments. I think that should help with my minor over pressure issue up front. I would assume that non AHC torsion bars will have too much spring rate and lead to a harsh ride quality.

Nope, they work just fine. I have used sway-away’s TB to have the pressures sit perfectly

 

[GTV]

I’ve since found out that I can re-index the torsion bars after all. I’d thought they had a hex shaped engagement but learned that they’re splined so can be indexed in small increments. I think that should help with my minor over pressure issue up front. I would assume that non AHC torsion bars will have too much spring rate and lead to a harsh ride quality.

If you're carrying a lot of weight non AHC bars can work well.