KDSS offroad behavior question

[Jetboy]

FWIW - there are other types of anti-sway mechanisms that will also work very well with long travel rear suspension. I also think KDSS could be modified to fit one an alternative system as well, but it won't be easy - or cheap if you don't do your own fabrication. If you do - a few trips to the pick and pull and a long weekend.

There's really two ways I can see to go about keeping an active sway bar. One would be a set of longer travel pistons with smaller bore (assuming you retain similar fluid volume). This would give you more travel but less force, so maybe not quite as effective? Not sure. You'd also probably need a new mount on the fixed side that allows more travel. The other would result in a pretty similar function - use the same cylinder but re-mount it so it's on a lever arm that results in greater travel.

The alternative mechanism that I've seen on a trail rig - and thought was the most effective anti-sway mechanism I've ever seen - uses a torsion bar mounted longitudinally. It runs parallel to the drive shaft using a torsion bar from one of the old ifs designs - on the axle end the axle has a bracket mounted to it with a u-joint. From there it runs up like a drive shaft with a slip joint until it reaches a transfer gear box that is offset to the side of the transfer case. This is on a 2nd gen 4runner - and that's a narrowed Dana 60 axle.

In a 4runner keeping KDSS you could build the rear half of this system, and use the KDSS cylinder to move a lever arm on a rotating base near the transfer case to achieve the same moment of force on the rear axle and effectively the same functionality with a torsion spring longitudinally rather than laterally mounted. But it will take a lot of custom work.

 

[Jetboy]

In kicking this around in my head for a while. There are a few more alternatives I had thought of.

Keep the KDSS up front, but do it as a stand alone. Just use an accumulator and an electronic valve so you can lock it out for street use, and open it up for offroad. Easy to do, and pretty cheap. Good highway manners. Good offroad manners. And when you're going into a side hill, just lock it out and have anti-sway.

In the rear, use a shaft style like the above 4runner. At the frame end, mount a bearing with a simple disc brake. I'd just use one of the off the shelf setups for a land cruiser - my FJ40 for example has a brake on the ouput of the transfer case, the flange is there - it's basically everything you'd need. Then have an actuator for the brake. For on road you "lock" the brake and it's a tight sway bar. Off road you release the brake and it's no sway bar, until you want it.

 

[Vrrooom]

The electronically controlled front sway on the JK Rubicon is a nice design as well.

 

[Intruder]

The electronically controlled front sway on the JK Rubicon is a nice design as well.

And I've heard from several Rubicon owners that one hit can mean they won't reconnect again when they get off the trail.

 

[Jeremy556]

Not following, but I think we are talking about two different things.

Yea, I was thinking of your scenario 2. I don't know if KDSS is smart enough to keep the sway bars rigid in scenario 1, or of an easy way to tell.

 

[Jetboy]

And I've heard from several Rubicon owners that one hit can mean they won't reconnect again when they get off the trail.

That's unfortunate as the design has a lot of things going for it. Possibly the teraflex version is better? They have a pin style release rather than a sliding collar. I like the collar for the reason that you could possibly get the body leaned one way, engage the collar, then go on a side hill that is the other way - if that makes any sense. Basically induce a lean before you start to counteract the hillside. With the teraflex option you only get one locked position.

 

[wfo9]

Yea, I was thinking of your scenario 2. I don't know if KDSS is smart enough to keep the sway bars rigid in scenario 1, or of an easy way to tell.

That is exactly what I was thinking. I don't see how it would be smart enough to know the difference. One way to test, which would be difficult, would be to get on a good slide slope and then take some photos of the piston positions. I'm assuming this would provide enough info.

 

[wfo9]

In kicking this around in my head for a while. There are a few more alternatives I had thought of.

Keep the KDSS up front, but do it as a stand alone. Just use an accumulator and an electronic valve so you can lock it out for street use, and open it up for offroad. Easy to do, and pretty cheap. Good highway manners. Good offroad manners. And when you're going into a side hill, just lock it out and have anti-sway.

In the rear, use a shaft style like the above 4runner. At the frame end, mount a bearing with a simple disc brake. I'd just use one of the off the shelf setups for a land cruiser - my FJ40 for example has a brake on the ouput of the transfer case, the flange is there - it's basically everything you'd need. Then have an actuator for the brake. For on road you "lock" the brake and it's a tight sway bar. Off road you release the brake and it's no sway bar, until you want it.

Ultimately, this is almost exactly what I would want. A manual KDSS of sorts. But I would want to be able to engage it on a side hill after compression had already taken place. Don't think a brake would allow that scenario. The airbag solution I was thinking of would only really work on the side hill scenario (it would have no value on road), but would allow for some really interesting capabilities off-road.

On and off road... Is an interesting design challenge that I doubt I'll ever get around to addressing.

In the meantime, I think I'm going to go back to running a rear sway with extended links. It felt like a great compromise that way before, but I need to try it with the LT rear and extended travel in the front.

 

[Jetboy]

Ultimately, this is almost exactly what I would want. A manual KDSS of sorts. But I would want to be able to engage it on a side hill after compression had already taken place. Don't think a brake would allow that scenario. The airbag solution I was thinking of would only really work on the side hill scenario (it would have no value on road), but would allow for some really interesting capabilities off-road.

On and off road... Is an interesting design challenge that I doubt I'll ever get around to addressing.

In the meantime, I think I'm going to go back to running a rear sway with extended links. It felt like a great compromise that way before, but I need to try it with the LT rear and extended travel in the front.

Maybe you could get really crazy with something like an actuator that could pre-load the bar when you wanted? If it was fast enough acting it could just operate against a lever arm on the end of the torsion bar and use a sensor to measure body roll and it would extend/retract to adjust to the terrain. It would probably work really well in very slow speed situations, but not very well or at all at high speed. Or something like a very small winch with the drum removed and a chain mechanism or something attaching it to the shaft as the motive force. Could have a wireless remote and it would be a pretty compact package.

 

[1engineer]

Ultimately, this is almost exactly what I would want. A manual KDSS of sorts. But I would want to be able to engage it on a side hill after compression had already taken place. Don't think a brake would allow that scenario. The airbag solution I was thinking of would only really work on the side hill scenario (it would have no value on road), but would allow for some really interesting capabilities off-road.

On and off road... Is an interesting design challenge that I doubt I'll ever get around to addressing.

In the meantime, I think I'm going to go back to running a rear sway with extended links. It felt like a great compromise that way before, but I need to try it with the LT rear and extended travel in the front.

Maybe you could get really crazy with something like an actuator that could pre-load the bar when you wanted? If it was fast enough acting it could just operate against a lever arm on the end of the torsion bar and use a sensor to measure body roll and it would extend/retract to adjust to the terrain. It would probably work really well in very slow speed situations, but not very well or at all at high speed.

The KDSS system was not designed, nor is smart enough, for the conditions you are showing.

Now, why re invent the wheel? This spy shot was taken outside of [MENTION=66300]Intruder[/MENTION]'s house showing a prototype of what he is going to do with his 4Runner. Just copy this and you can go on all the side hills you want:

 

[happy4runner]

I would like a way to flip a switch to disengage the sway bars via the kdss. This would be nice for mild speed off-road when crossing diagonal ditches or water bars so I don't need to slow down so much.

 

[Jetboy]

I would like a way to flip a switch to disengage the sway bars via the kdss. This would be nice for mild speed off-road when crossing diagonal ditches or water bars so I don't need to slow down so much.

I think you could probably find a bypass electronically to open the valving. The problem is that I dont think the orifices and plumbing will flow fluid fast enough to do what you want. My guess is this is one reason 12mph was chosen as the fluid will limit how fast the sway bars actuators can cycle in either direction. Just guessing, but it probably wouldn't work to just open the solenoid and allow the fluid to flow.