2020 Toyota Land Cruiser vs. 2020 Lexus LX 570 Suspension Flex Test: A 200-Series Frame-Twist Battle (1 Viewer)

[Madtiger]

Study the diagram. Right rear and left front are a circuit, left rear and right front are a circuit. When RR/LF are stuffed the center suspension control cylinder can send the increased pressure in that side to the other, cross-linking the suspension. It isn’t automatic as in KDSS but the suspension position sensors tell the control computer opposite corners are getting stuffed and enables the cross linking.

Yes, i see that. X-linked. But NOT cross-linked across SAME axle, as i described above.

Correct me if i am wrong, but this type of X-linked is mainly for ON-road handling, such as going around a corner. (Not the same, but the benefits of AHC is similar to 4runner’s XREAS system...also X-linked.). As you go around a hard right corner, the driver’s front tire gets compressed, the AHC (and XREAS) then hydraulically push the passenger rear tire down to maintain traction at the opposite corner of the vehicle which would lift during such cornering.

The only system (that i know of) that does the cross-linking across SAME axle is the Range Rover. Even though it is a s***ty air suspension, the RR can increase articulation across uneven ground because as one tire gets pushed up (“stuffed”), the other tire on the SAME axle gets actively pushed down to maintain vehicle balance.

 

[TeCKis300]

Teckis why wouldn’t there be damping force control actuators on the rear circuits of the system?

The label is missing, but damping force control is integrated into the No.1 Gas Chamber at the rear. As it was in the previous LX470 on all 4 positions. The LX570 front axle is unique this time around, splitting overall function into two components - No.1 and No.2. This because the front axle now has two selectable springs rates, to help handling with cornering and brake dive.

Yeah, sorry, don’t see it. And as can be seen in video at beginning of this thread, there is no such “active” cross-linking where one side is up pushing the other side down.

Such meanness from you.

You're wrong. And continue to be wrong.

I'm happy to actually have a technology discussion if that was the purpose, but I refuse to get mired into your trolling.

 

[Madtiger]

The label is missing, but damping force control is integrated into the No.1 Gas Chamber at the rear. As it was in the previous LX470 on all 4 positions. The LX570 front axle is unique this time around, splitting overall function into two components - No.1 and No.2. This because the front axle now has two selectable springs rates, to help handling with cornering and brake dive.



You're wrong. And continue to be wrong.

I'm happy to actually have a technology discussion if that was the purpose, but I refuse to get mired into your trolling.

Ok...fine...answer me this...does AHC “actively” cross-link across the SAME axle?? What do i mean by “active”? If your front driver side tire is pushed up, then does the front passenger tire gets pushed down hydraulically beyond normal droop? Again, across same axle.

If it does, then where does it say that in the diagram? Lexus has stated in past that AHC does X-linked. Now you’re telling me something else. Thus, my initial inquiry.

EDIT:

Lexus refers to LX system as....." X-AHC"

And according Wiki, " The AVS provides more immediate damper firmness adjustments that are diagonally cross-linked through a mechanical system using hydraulic fluid, similar to the 4Runner's X-REAS system. "

 

[Madtiger]

Just to add to what i wrote...and that i am correct...here is what Lexus says:

2010 LX 570 Luxury Utility Vehicle Receives Technology and Entertainment Updates - Lexus USA Newsroom

Updates to navigation, audio, safety and entertainment systems keep the eight-passenger LX 570 premium luxury utility vehicle at the top of its segment with technology enhancements for 2010.

pressroom.lexus.com

" The compression chambers of the shock absorbers are diagonally linked (front left shock linked to rear right, and front right linked to rear left) by a center-control valve. Passing small body motions from front-to-rear increases overall vertical suspension damping."


This diagonally linked system is for on-road handling.

EDIT: in fact, from Lexus literatures, they mention how similar in function b/w AVS/AHC and 4runner's XREAS due to the X-linked shocks. So, yeah, i ain't too bad at tracing that diagram after all.....

 

[bloc]

Anything you do to one axle has an effect on the other, so what’s the point of isolating your actions to only one?

 

[Madtiger]

Anything you do to one axle has an effect on the other, so what’s the point of isolating your actions to only one?

Range Rover cross-links laterally on both axles; thus improving articulation front and rear axle (independently) while off-roading. (Now, i don't know if the newest RR do this...but back in 2013 or so, they had this system.) RR does this to simulate disconnected sway bars front and back...in RR case, it overcomes the limits of independent suspension.

On the other hand, X-linked suspension may actually decrease RTI score (in theory). As you go up the RTI ramp, the front driver tire compresses. This hydraulically then pushes fluid to the rear passenger tire.....and that tire is also compressed. So, in an X-linked system, both tires will exert pressure on each other, preventing full compression of both?? At least in theory...i am not sure if Lexus AHC has a bypass or whatever computer it has to compensate.

X-linking shocks help with on-road handling. Off-road, it is up for debate...probably not helpful.

EDIT: looks like the new Defender has the RR's same axle cross-linking suspension:

"Now, Land Rover’s cross-linked air suspension systems are able to function both fully-independently, or replicate the pendulum effect of a solid axle, raising one wheel on the “axle” when the other droops down."

 

[M1911]

From what I've seen on videos, it looks to me as though the new Defender has poor articulation.

 

[Madtiger]

From what I've seen on videos, it looks to me as though the new Defender has poor articulation.

Well, that may be...still dealing with limits of IFS/IRS with short control arms.

Motortrend had this to say: (@M1911)

”Land Rover claims the Defender has 19.7 inches of wheel articulation. A rough calculation suggests that would give a Ramp Travel Index (RTI) score (based on a test of how far a vehicle can travel up a 20-degree ramp before the opposite front wheel lifts off the ground, standardized for variations in wheelbase) of about 560 for the Defender 90 and about 480 for the Defender 110. Although our experience with air-suspension Land Rovers suggests these best-guess numbers are likely conservative....”


In contrast, LC200 has rear total vertical articulation of 27.6 inches.

 

[bloc]

So, in an X-linked system, both tires will exert pressure on each other, preventing full compression of both?? At least in theory...i am not sure if Lexus AHC has a bypass or whatever computer it has to compensate.

That is exactly what the center suspension control cylinder does. It allows the increased pressure in the LF+RR circuit to bleed into the RF+LR, pushing those corners down against the ground.

 

[Madtiger]

That is exactly what the center suspension control cylinder does. It allows the increased pressure in the LF+RR circuit to bleed into the RF+LR, pushing those corners down against the ground.

If it does that, then that’s excellent. But is there more info on this? Is there service manual that states this?

 

[bloc]

I'm not sure where I read it. Have been a member of this section for three years now.

But anecdotally, if it didn't do that, the LX wouldn't ramp for s***. Your stuffed corners would see contact patch force rise dramatically, as well as the sway bars would fight the dropped out corners dropping out. It would have a lot of trouble ramping anywhere close to a landcruiser with its static suspension with effectively disconnected sway bars.. and yet.. it is practically neck-and-neck on the ramp as long as the LX doesn't have dumb chin spoilers.

 

[Madtiger]

I'm not sure where I read it. Have been a member of this section for three years now.

But anecdotally, if it didn't do that, the LX wouldn't ramp for s***. Your stuffed corners would see contact patch force rise dramatically, as well as the sway bars would fight the dropped out corners dropping out. It would have a lot of trouble ramping anywhere close to a landcruiser with its static suspension with effectively disconnected sway bars.. and yet.. it is practically neck-and-neck on the ramp as long as the LX doesn't have dumb chin spoilers.

It does have thinner sway bars. How tightly wound is the hydraulic? Is it a highly pressurized system or is there some give to allow fluctuations?

Like I said above, all I have heard about X-AHC is that it is diagonally linked. I welcome more information. It’s time like this that I wish we have a Toyota engineer on board.

 

[tbisaacs]

It does have thinner sway bars. How tightly wound is the hydraulic? Is it a highly pressurized system or is there some give to allow fluctuations?

Like I said above, all I have heard about X-AHC is that it is diagonally linked. I welcome more information. It’s time like this that I wish we have a Toyota engineer on board.

I once tried to do my best @kreiten impression and set the rear quarter panel on the ground in 570. I ran out of turf before flex. In my experience the suspension is quite soft, even at high ride height unlike air springs which get super stiff in high.

 

[M1911]

Dan Lyons just posted a test for the 4Runner TRD Off-Road: Toyota 4Runner TRD Off-Road Suspension Flex Test | How does KDSS work and what does it do?

To cut to the chase:

 

[AnyMal]

After reading through this, I hate to bump this old horse but the test video is trash.
He is using an F sport aero kit LX? God why?

I want to see this test with EQUAL vehicles.
If it were two LC 200s one with AHC and one without, I would actually still put my money on AHC.

 

[Madtiger]

After reading through this, I hate to bump this old horse but the test video is trash.
He is using an F sport aero kit LX? God why?

I want to see this test with EQUAL vehicles.
If it were two LC 200s one with AHC and one without, I would actually still put my money on AHC.

AHC RTI score goes down when you raise it. That is just physics.

 

[AnyMal]

AHC RTI score goes down when you raise it. That is just physics.

Thats interesting. How though?
I thought AHC would actively equalize the leading wheel shock pressure to the other corners?

 

[NYC570]

After reading through this, I hate to bump this old horse but the test video is trash.
He is using an F sport aero kit LX? God why?

I want to see this test with EQUAL vehicles.
If it were two LC 200s one with AHC and one without, I would actually still put my money on AHC.

This kinda has been done before with previews MYs LC and LX where they scored similarly. This just shows how the front fascia from the newer models limits the LX

 

[TeCKis300]

After reading through this, I hate to bump this old horse but the test video is trash.
He is using an F sport aero kit LX? God why?

I want to see this test with EQUAL vehicles.
If it were two LC 200s one with AHC and one without, I would actually still put my money on AHC.

We already know this from historical tests. For all intents and purposes, both LC and LX can equally flex to the max of the platforms suspension travel, producing practically equivalent RTI numbers. Tire flex plays into this and the LC is doing the dirty on 18s whereas the LX is putting up the numbers on 20s.

Thats interesting. How though?
I thought AHC would actively equalize the leading wheel shock pressure to the other corners?

This isn't unexpected. Max RTI happens when two tires are at full stuff into the bumpstops, and opposite corner tires are at full droop.

AHC H is asking to prioritize height and obstacle clearance - basically saying don't allow the suspension to compress as much. AHC High Mode or even normal suspension lifts on the LC, would potentially keep the two compressed corners from fully stuffing, in order to prioritize clearance. Hence the impact to RTI.

They are two different priorities. Great things about AHC is that you can choose on the fly.

 

[AnyMal]

We already know this from historical tests. For all intents and purposes, both LC and LX can equally flex to the max of the platforms suspension travel, producing practically equivalent RTI numbers. Tire flex plays into this and the LC is doing the dirty on 18s whereas the LX is putting up the numbers on 20s.

View attachment 2737671





This isn't unexpected. Max RTI happens when two tires are at full stuff into the bumpstops, and opposite corner tires are at full droop.

AHC H is asking to prioritize height and obstacle clearance - basically saying don't allow the suspension to compress as much. AHC High Mode or even normal suspension lifts on the LC, would potentially keep the two compressed corners from fully stuffing, in order to prioritize clearance. Hence the impact to RTI.

They are two different priorities. Great things about AHC is that you can choose on the fly.

That makes sense thank you.

I was thinking that the when the AHC is detecting these flex values, it would distribute the pressure accordingly. It makes sense that to fulfill high position pressures, it would resist compression that much more.

Once again I really wish we knew more about the decisions the AHC controller is making.

VERY interested what upgrades LX600 will bring to this platform. Since it seems Toyota did enhance the kdss system im hoping the AHC remains and gets smarter. I’m ready for disappointment though.