A really good explaination of KDSS - Video

C

Canon_Bob

New member
First - My apologies if this has been posted here before. I tried searching and didn't see any results that included this video.

I think it does a really great job of showing exactly what KDSS is, and exactly how it works.

Toyota Land Cruiser 150 - KDSS (Kinetic Dynamic Suspension System) - YouTube

In my case, I didn't know anything about it (or 4Runners for that matter) when I bought mine. They just had one on the lot in a color I liked, so I negotiated a deal on a 2014 Trail with KDSS instead of an SR5. Now that I've been driving it, I love it. I found this video while trying to explain it to a friend.
 
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Good video--best explanation I've seen yet. I only wish someone would explain the infamous "KDSS Lean" and then describe how to fix it.

After living with KDSS for six months now, I really like the system.
 
I can't speak to the "lean" issue, as I haven't seen it myself....but I can say that now that I understand the system better and what it does, I'm less inclined to lift this vehicle and alter the suspension geometry. Seems to me that KDSS is best left for those who have no intent on doing a build (like me).

I know many here have lifted KDSS vehicles, but I can't imagine that it hasn't had an impact on the performance of the KDSS system...especially the Accumulators that supposedly smooth out the rough rides. Honestly, I think if I were going to lift my KDSS equipped vehicle, I'd consider just removing that $1800.00 option when I did it. Big time waste of money if you're planning a build. I may be wrong, and will probably hear it from a few here. Now that I understand the system better, I'm pretty sure I will not be lifting mine. I like the performance of the KDSS system for everyday life and the short offroading trips I take as a photographer. If I ever want to do a build, I'd likely trade this one in for an SR5 and do what I wanted then. Just my opinion.
 
Canon_Bob said:
I can't speak to the "lean" issue, as I haven't seen it myself....but I can say that now that I understand the system better and what it does, I'm less inclined to lift this vehicle and alter the suspension geometry. Seems to me that KDSS is best left for those who have no intent on doing a build (like me).

I know many here have lifted KDSS vehicles, but I can't imagine that it hasn't had an impact on the performance of the KDSS system...especially the Accumulators that supposedly smooth out the rough rides. Honestly, I think if I were going to lift my KDSS equipped vehicle, I'd consider just removing that $1800.00 option when I did it. Big time waste of money if you're planning a build. I may be wrong, and will probably hear it from a few here. Now that I understand the system better, I'm pretty sure I will not be lifting mine. I like the performance of the KDSS system for everyday life and the short offroading trips I take as a photographer. If I ever want to do a build, I'd likely trade this one in for an SR5 and do what I wanted then. Just my opinion.
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KDSS on lifted 4R: http://www.youtube.com/watch?v=JQigYmZmWC4


heavymetal.jpg~original
 
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yeah, that was Nathan's TE. one of the early, cool builds. he sold it pretty quickly and got a used '09 Trail, iirc.
 
RickC5 said:
Good video--best explanation I've seen yet. I only wish someone would explain the infamous "KDSS Lean" and then describe how to fix it.

After living with KDSS for six months now, I really like the system.
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I could give a complete explanation. Don't take this the wrong way but nobody would really care and not a lot of people here have the knowledge to completely understand the explanation. Its not that I know a lot but what I do know has to do with mobile equipment and machines. (See below)
In the past I have taken time to explain a lot of the operational physics and mechanics of vehicles. I either get a "thanks" or a joking response or no response. Every now and then I will get questions. Don't get me wrong here...many of you guys understand the explanations I give and most at least understand the concepts. The problem is, and I feel the same way about other topics, who cares? Who really wants to know to the Nth degree about lug bolt torque? So I have backed off spending an hour to answer a question completely because of lack of interest.
The lean could easily be fixed by Toyota. Problem is, besides it is intermittent, it would take another $2K and that prices it out of the market.
Canon_Bob said:
I can't speak to the "lean" issue, as I haven't seen it myself....but I can say that now that I understand the system better and what it does, I'm less inclined to lift this vehicle and alter the suspension geometry. Seems to me that KDSS is best left for those who have no intent on doing a build (like me).

I know many here have lifted KDSS vehicles, but I can't imagine that it hasn't had an impact on the performance of the KDSS system...especially the Accumulators that supposedly smooth out the rough rides. Honestly, I think if I were going to lift my KDSS equipped vehicle, I'd consider just removing that $1800.00 option when I did it. Big time waste of money if you're planning a build. I may be wrong, and will probably hear it from a few here. Now that I understand the system better, I'm pretty sure I will not be lifting mine. I like the performance of the KDSS system for everyday life and the short offroading trips I take as a photographer. If I ever want to do a build, I'd likely trade this one in for an SR5 and do what I wanted then. Just my opinion.
Click to expand...

Lifting a KDSS equipped vehicle won't change the system operation much. The accumulator system operates solely on pressure drop to move the fluid from one point to another. Sure, extending the cylinders a bit more would drop the pressure but not enough to render the system ineffective.
I don't modify vehicles much anymore because I enjoy the reliability and durability of a vehicle as designed. I used to, back in the day, but no more.

This is in no way, shape or form critizing you guys. I started out to just make a brief comment and this post just happened lol. BTW this a great video and everyone should watch it (its been shown several times here) but most will watch it and forget it. If you guys want me to go in depth and explain this using the Ideal Gas Laws and other formulas I will be glad to do it. It will require quite a bit of math though.
 
1engineer said:
I could give a complete explanation... <snip>
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Yeah, but will I be able to fit 315/70/17s with KDSS?

:hiding:

To the OP, not sure why someone wouldn't lift a KDSS vehicle. You're not putting any more stress, etc. on it than you are on other expensive components when you lift it. :noidea:
 
i had it wrong. he got an '07...
iDRiVaT4R said:
Hey everyone,

I sold my TE yesterday. I loved everything about it except for the payments. It went to a good home though. I guarantee the new owner will post pics here shortly. He hangs out with "the_josh" from the 4th gen forum section here. It's a matter of time before it has bumpers, skids, Lights, etc..

I found myself a used 2007 4Runner V8 4x4 in White in great condition to replace the TE. Time to start saving for the new mods.
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1engineer said:
Lifting a KDSS equipped vehicle won't change the system operation much. The accumulator system operates solely on pressure drop to move the fluid from one point to another. Sure, extending the cylinders a bit more would drop the pressure but not enough to render the system ineffective.
I don't modify vehicles much anymore because I enjoy the reliability and durability of a vehicle as designed. I used to, back in the day, but no more.

This is in no way, shape or form critizing you guys. I started out to just make a brief comment and this post just happened lol. BTW this a great video and everyone should watch it (its been shown several times here) but most will watch it and forget it. If you guys want me to go in depth and explain this using the Ideal Gas Laws and other formulas I will be glad to do it. It will require quite a bit of math though.
Click to expand...

For what it's worth, I too love your engineering insight. I think I am incorrectly thinking that the Accumulators were a dampening sensor, and not pressure actuated. What you say makes sense. If they were, in fact dampening (vibration) sensors, then I would think that the significantly stiffened suspension associated with most lifts would put them into overtime mode. BTW - I'm a math major, and have a really healthy case of OCD as well. Looking at the video and then thinking about what a lift would effect has all kinds of Differential Equation flashbacks firing in my head. Bad juju for sure.

Since I was already in the 95+ percentile that I didn't want to lift this one, I think I'm just going to move the needle to 100 percent and call it good. Time to order my new tires in factory size, as my busy photography season is about to start, and I don't want to take on the swamps with the Dunlops. Thanks again for your insight!
 
Canon_Bob said:
For what it's worth, I too love your engineering insight. I think I am incorrectly thinking that the Accumulators were a dampening sensor, and not pressure actuated. What you say makes sense. If they were, in fact dampening (vibration) sensors, then I would think that the significantly stiffened suspension associated with most lifts would put them into overtime mode. BTW - I'm a math major, and have a really healthy case of OCD as well. Looking at the video and then thinking about what a lift would effect has all kinds of Differential Equation flashbacks firing in my head. Bad juju for sure.

Since I was already in the 95+ percentile that I didn't want to lift this one, I think I'm just going to move the needle to 100 percent and call it good. Time to order my new tires in factory size, as my busy photography season is about to start, and I don't want to take on the swamps with the Dunlops. Thanks again for your insight!
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Watch the video again with this concept in mind: Accumulators are like batteries in a sense - Instead of storing electricity they store hydraulic fluid under pressure, releasing it when pressure has dropped in the system. The accumulators have a nitrogen precharge to "X" pressure on one side and hydraulic fluid on the other side. Now watch the video.
 
1engineer said:
Watch the video again with this concept in mind: Accumulators are like batteries in a sense - Instead of storing electricity they store hydraulic fluid under pressure, releasing it when pressure has dropped in the system. The accumulators have a nitrogen precharge to "X" pressure on one side and hydraulic fluid on the other side. Now watch the video.
Click to expand...

Completely makes sense now. So in reality, the only real impact of a modest lift would be to the fore and aft cylinders. It looks like you think it is negligible, but I'm wondering if there might be a way to modify the mounting brackets for those cylinders to set the unit back to "factory zero" depending on the lift height? Or is it truly too little a pressure change to worry about?
 
Canon_Bob said:
Completely makes sense now. So in reality, the only real impact of a modest lift would be to the fore and aft cylinders. It looks like you think it is negligible, but I'm wondering if there might be a way to modify the mounting brackets for those cylinders to set the unit back to "factory zero" depending on the lift height? Or is it truly too little a pressure change to worry about?
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Not enough to worry about. Remember that it has to have enough pressure to operate from one end of it's stroke to the other anyway. You are just moving that "center" a bit.
 
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