AHC system offroad (1 Viewer)

[PhysicsHammer]

Hey everyone,

I have done a search of all "LX" threads in the 200 series forum. Lots of good information on the AHC and the LC200 vs. LX pros and cons. What I can't find is many examples of people using the LX570 offroad, and their experience with AHC.

I'm wondering because I think it might be worth it - to me - to replace the running boards with rocker panels and sliders, on an LX, if the AHC is pretty functionally equivalent to a 2" lift, when it matters...

I think some 285-70-17's on rock warrior rims , with the AHC at 2", and rock sliders, would be sufficient for my purposes - but are there people actually DOING this?

Thanks

 

[PhysicsHammer]

these guys might be using AHC with STOCK tire sizes : I can't tell if it's AHC on a LC200 in Australia - or if it's a 2" or so lift on the same.... Someone in the comments said it was AHC but I can't tell if that's the owner.

 

[crazy1323]

I have an LX with AHC. Looking at where the accumulators are, you might have trouble mounting the sliders.

 

[EverywhereBear]

I have used AHC on mild off-road trails a few times with stock tires - worked well - nothing got scrapped, hit or snagged.

 

[PhysicsHammer]

Nice Bawa, great video thanks. How do you feel about wheeling the 570 on mild stuff like that? Any downsides? At some point I'm looking at the LC200 vs. LX and I'd like to do the LX as long as the AHC is good enough, with bigger wheels, for some mild wheeling like that...

 

[EverywhereBear]

I think the LX is great on the mild stuff I have taken it on. I was concerned about the running boards, but with the AHS in High mode it has been fine so far!

The looks from others on trails seeing a stock LX coming thru is fun to see.

 

[jwestpro]

Nice Bawa, great video thanks. How do you feel about wheeling the 570 on mild stuff like that? Any downsides? At some point I'm looking at the LC200 vs. LX and I'd like to do the LX as long as the AHC is good enough, with bigger wheels, for some mild wheeling like that...

I'm liking your plan. Good to see people who like the niceties of the LX but will still take it out to play.

I think you mean "bigger" TIRES, not "wheels". In fact, you'd be better with SMALLER wheels, like 18", plus bigger tires like 32" - 33" (275/65x18 - 275/70x18). With your on-demand lift it would be quite the fun vehicle and your AHC will also allow you to still park in garages, possibly with a rack even.

 

[PhysicsHammer]

Yeah good catch jwestpro, I meant tires. Definitely liking the 17" TRD Rock Warrior wheels, with bigger tires.

I see a lot of 2" lifted LC200's , and I wonder, why not just use the AHC 2" lift, and then still have a lower ride on the highway which is mostly where I drive anyway? I've loved my 80's series, but there are times when I would like a little more speed driving uphill at high altitudes. I know the LX would have some limits.. but I think I might find them acceptable for my purposes. And who doesn't need seat ventilation?

 

[tempestv8]

I can't tell if it's AHC on a LC200 in Australia - or if it's a 2" or so lift on the same....

200 Series in Australia does not come with Active Height Control - simply not available at all, not an orderable option. Instead Aussie 200 Series come equipped (mostly) with KDSS as standard.

 

[PhysicsHammer]

well that's depressing , I was hoping you all would have some more information on using the AHC a good amount. I'm a little worried it won't be truly robust if Toyota won't sell it there.

 

[jwestpro]

Australian auto market is not the measure of what's available. The LC200 can be had almost any way you like in other countries.

 

[jwestpro]

well that's depressing , I was hoping you all would have some more information on using the AHC a good amount. I'm a little worried it won't be truly robust if Toyota won't sell it there.

To be clear, you do know that in the US you have to choose between LX and LC not just for trim but also mechanical features?
LX has AHC, but NOT KDSS. While AHC gains you ground clearance when needed and better handling at high speed as well as less worry for large tires rubbing at articulations, the lack of KDSS I'm pretty sure limits it's off road articulation. The KDSS on the LC improves off road wheel articulation and thus traction.

So, LC people add a lift for clearance, living with it full time of course, but then have better traction in uneven terrain via KDSS.

What I do not know is how much the suspension on the LX allows for more articulation, if any, beyond standard steel springs. It's design/function is kind of between the KDSS idea with a disconnecting/loosening sway bar on the LC vs the much wider articulation on my Land Rover LR3 with the cross linked air suspension. In stock form my rear wheels have about 13" range on each side.

I'd like to see an articulation comparison on ramps between the LC with just KDSS and LX with only AHC.

Anyway, you can't have both in the US unless the GX can be ordered with KDSS and AHC?

 

[kreiten]

not sure how accurate this are, but here's what the internet said
538 - 2009 Lexus LX 570 with Adaptive Variable Suspension
542 - 2008 Toyota Land Cruiser with KDSS
although on another test the LC got (647 - 2010 Toyota Land Cruiser with KDSS)
not saying these are accurate but it's the best I could find so far...
https://plus.google.com/+ToshiClark/posts/4UjKS2hBWR9

 

[jwestpro]

^those look almost like the 542 LC was without the KDSS engaged seeing as it's so close to the LX score. Maybe I'll just borrow one of each and test on my super scientific driveway retaining wall ramp system

Regardless, if the LX in the US has fully connected normal sway bars, that don't disconnect, then it can't get close to the range of a stock LC 200 with KDSS.

Have you tested yours on any ramp with KDSS off vs on? We could just use my bridging ladders up onto something.

 

[gaijin]

Have you tested yours on any ramp with KDSS off vs on? We could just use my bridging ladders up onto something.

I'm obviously having a brain fart ... how does one turn the KDSS ON/OFF on a LC200? I was under the impression that it automatically switched between ON/OFF based on the difference/amount of articulation side-to-side and front-to-back.

 

[jwestpro]

Well, I could be wrong, but I thought it would not disconnect sway bars if you're in "high" range but automatically engage when "low" range is selected.

 

[elkaholic]

There is no "off" and "on" AFAIK. It is somewhat of a closed loop hydraulic system. The setup is that the actuators or cylinders are on the same side of the rig (US driver's side). The cylinders are plumbed together so that they cannot both compress or extend at the same time since they share fluid. Yes, I am overly simplifying this but the concepts are valid.

If you are on the road and going into, let's say, a hard left hand turn, then both of the left hand tires will tend to droop relative to static ride height as the body rolls right. In this case both KDSS cylinders will want to lengthen a bit but they are hydraulically linked so that both cylinders cannot extend.

In an articulation event such as crossing a ditch or going up an articulation ramp with the left side tires, the front wheel will go I to compression and the rear will droop. They KDSS actuators / cylinders will move since as the front compresses, it pushes fluid to the rear cylinder allowing it to extend.

With the cylinders attached between the anti-roll bars and the suspension, they end up acting as semi solid links in cornering events and variable length links in articulation events giving increased articulation while maintaining some roll control at the same time.

Clear as mud, right?!


On edit: after I typed the above, I found this reference on the system
http://wardsauto.com/news-amp-analysis/toyota-hopes-dynamic-suspension-boosts-land-cruiser

Misspellings courtesy of autocorrect from my iPad using IH8MUD Forum

 

[gaijin]

Quote from the 2007 Wards Auto article for those who don't like clicking and reading:

KDSS is totally mechanical, activating when it senses a wheel has dropped.

For the next-generation of the Land Cruiser's luxury twin, the Lexus LX 570, Toyota has said it will employ an “electro-mechanical” suspension system.

“More than the hydraulic aspect of the LX suspension, there (are) four points that work cross-wise and together in different ways,” Land Cruiser Assistant Chief Engineer Toshihiko Kanai tells Ward's. “That's the main point of the LX suspension. It's as good as KDSS. It's a really fantastic, advanced system.”

Confirms KDSS is a full-time system, but interesting info on the LX suspension.

HTH

 

[PhysicsHammer]

Interesting - I had seen the RTI numbers quoted above before, which appears to me to make the AHC close enough to the KDSS system - at least in terms of that measurement. I had never seen that quote before, from Toshihiko Kanai - that is extremely interesting to me. Many thanks to kreiten for posting the RTI info, and to gaijin for finding the quote from Toshihiko.

Here's a discussion:

http://wardsauto.com/news-amp-analysis/toyota-hopes-dynamic-suspension-boosts-land-cruiser

 

[Mago]

Interesting - I had seen the RTI numbers quoted above before, which appears to me to make the AHC close enough to the KDSS system - at least in terms of that measurement. I had never seen that quote before, from Toshihiko Kanai - that is extremely interesting to me. Many thanks to kreiten for posting the RTI info, and to gaijin for finding the quote from Toshihiko.

Here's a discussion:

http://wardsauto.com/news-amp-analysis/toyota-hopes-dynamic-suspension-boosts-land-cruiser

I can confirm AVS (Auto Vehicle Stability) which comes standard with AHC does exactly what KDSS does offroad plus much more on road.
I have a LC200 European version with is AHC equipped. You will not find both AHC and KDSS on the same car because one mimicks the other.