Switching to conventional suspension?

[SlowBuild]

Hmmmm. Something contradictory going on here...

I (as I mentioned in my last post) agree that it works well enough to leave alone until something costly lets go. Or it doesn’t function as it should in the circumstances I use the vehicle in. You just experienced that. It worked out okay at Big Bend (great photos by the way) but you might find it not so good if that scenario happens again at HIH or Moab, or Rubicon, or...

My understanding is that AHC maintains its height according to the position set by the height sensors. It is always at one of three levels: lo, n, or hi. It never sags. When it is overloaded then the pressure may not be enough to maintain hi setting and it will revert to n. This is an incremental, stepped shift in height level, not a sag, and is not a failure of the system. It is designed to do this to maintain effectiveness. If only loaded occasionally, this may be acceptable, but if it happens a lot then it can be adjusted like @geanes is planning (King Springs).

To be fair, a conventional suspension does the same thing when overloaded with two differences. First, it will sag with the weight. It won’t resist the weight to maintain height like the AHC does (until it reaches its pressure limit) it will just compress with weight gradually. A 2” lift with an extra 2k lbs will not give you 2” of height. The second difference is the light on the dash. The AHC will tell you when you lose your 2” lift. Up until that point, you’re still raised. Conventional setup won’t let you know, it just keeps sagging. By the time you’ve lost that 2” and are back down to stock height, you’ve actually been lowering gradually for a while.

Both setups can be tuned/built appropriately for stock rigs or heavy ones.

AHC requires periodic maintenance but the payoff is increased adjustability and customization. Conventional system is lower maintenance and likely more robust in the most extreme conditions. I think it would NEVER make sense to tear out a conventional setup and install AHC (just stupid and crazy expensive). But if you have AHC I think it’s usually best to get it tuned right and keep it as long as you can. Or better yet, tear it out and SAS!

 

[joseywales]

It seems like you guys all think I dislike AHC. I never said I don’t like it, just that I prefer the ride, handling, cheaper cost to repair and simplicity of the coil/tb suspension. We with conventional suspension can add airbags to help with big loads and eliminate sag for $300 or less.

If my LC had been the same truck only with AHC, I’d still have bought it. I’d just have moved the sensors or whatever it is you do to maintain the high ride height.

 

[kolyo]

To AHC, or not to AHC, that is the question bothering me!

The dilemma became even more acute since I rode in a 2009 Lexus lx a week ago. Until then I thought my OEM '06 LC's ride was a godsend. having owned only leaf or solid axle Land Cruisers all my life. But the ride in '09 200 made me think I was back in a 70-series.

My Hundy switches from Lo to Hi promptly and without a hitch every time I need it, with nearly 9 ticks difference on the fluid can. Visually the globes, the lines and and accumulator appear in good shape, with hardly any rust on them. Still unable to measure pressures due to lack of courage and knowledge how to do it, despite reading all @PADDO posts on the subject I bought the truck at 123K miles and I presume the fluid has never been replaced. i know I should do it but keep asking myself is it worth it.

 

[kolyo]

OK, I'll but it bluntly: Is there a way that an AHC equipped Hundy can be made as comfortable as the 200 series?

I am asking this because comfort is very high on my priorities. After having a ride in my neighbor's super comfortable '09 I am torn between the urge to buy an early 200, despite the fact that I find them uglier than the 100. If anyone can advise me how to equal the ride of the my '06 UZJ I won't spare the $$$.

Thanks in advance!

 

[PADDO]

OK, I'll but it bluntly: Is there a way that an AHC equipped Hundy can be made as comfortable as the 200 series?

I am asking this because comfort is very high on my priorities. After having a ride in my neighbor's super comfortable '09 I am torn between the urge to buy an early 200, despite the fact that I find them uglier than the 100. If anyone can advise me how to equal the ride of the my '06 UZJ I won't spare the $$$.

Thanks in advance!

New AHC vehicles provide an amazingly smooth, compliant and comfortable ride. I still remember the 2 hour drive home from the dealership in my first LX, a ‘98. Your ‘06 with 9 grads on the reservoir needs some work if you want it to come close comfort wise to where it was when new. On my current ‘03 I changed damper accumulators out at 9 grads because at that reduced level of charge they are not far from being functionally unserviceable: new globes return 14 grads, worn out return 7 or less. On other vehicles I’ve replaced accumulators that were at 7 grads or so with serviceable takeoffs that return 9 or 10 and the ride is somewhat improved, but definitely not on par with 14 grads and new. Think of the damper accumulator’s serviceability (dampening capacity) on a diminishing scale with 14 grads being 100% and 7 being 0%. Accordingly, if you’re serious about ride quality then fit four new damper accumulators and get your neutral pressures optimized with fresh fluid cycled through. Old and worn sway bar links, bushings, rubber cushions and shock bushings all contribute to noise, vibration and harshness too.

 

[ChuckB]

New AHC vehicles provide an amazingly smooth, compliant and comfortable ride. I still remember the 2 hour drive home from the dealership in my first LX, a ‘98. Your ‘06 with 9 grads on the reservoir needs some work if you want it to come close comfort wise to where it was when new. On my current ‘03 I changed damper accumulators out at 9 grads because at that reduced level of charge they are not far from being functionally unserviceable: new globes return 14 grads, worn out return 7 or less. On other vehicles I’ve replaced accumulators that were at 7 grads or so with serviceable takeoffs that return 9 or 10 and the ride is somewhat improved, but definitely not on par with 14 grads and new. Think of the damper accumulator’s serviceability (dampening capacity) on a diminishing scale with 14 grads being 100% and 7 being 0%. Accordingly, if you’re serious about ride quality then fit four new damper accumulators and get your neutral pressures optimized with fresh fluid cycled through. Old and worn sway bar links, bushings, rubber cushions and shock bushings all contribute to noise, vibration and harshness too.

Thanks to @PADDO's instructions and constant (and seemingly tireless!) mentorship to us all, I just finished the system flush (2 times) and replaced rear springs with new OEM and 30mm spacers yesterday. I was actually shocked at how black the fluid was on the second time around. We were fairly meticulous with the measurements at 500mm front and 520mm rear for the heights and my pressures are now 6.7/6.3 rear. The ride is vastly improved from where we started with pressures in the 7.1-7.7 range front and rear.

However, I felt like in my mind it should be even smoother than it is now. Reading again through various threads and PADDO's above comments confirms what my butt-meter has been telling me. During my grad check I was only showing 7-8 grads. Based on the above info, it looks like I'm going to need to replace the accumulators if I want to take it to the next level.

I'm going to ride it out (no pun intended) for a little while longer since I'm fairly stock at the moment. But, ultimately I think I'm going to find myself in the great debate in the future with regard to AHC removal. Regardless, I'm in a better place now thanks to this forum!!

Thanks again to @PADDO and the collective group for all the knowledge and wisdom gained here.

 

[kolyo]

New AHC vehicles provide an amazingly smooth, compliant and comfortable ride. I still remember the 2 hour drive home from the dealership in my first LX, a ‘98. Your ‘06 with 9 grads on the reservoir needs some work if you want it to come close comfort wise to where it was when new. On my current ‘03 I changed damper accumulators out at 9 grads because at that reduced level of charge they are not far from being functionally unserviceable: new globes return 14 grads, worn out return 7 or less. On other vehicles I’ve replaced accumulators that were at 7 grads or so with serviceable takeoffs that return 9 or 10 and the ride is somewhat improved, but definitely not on par with 14 grads and new. Think of the damper accumulator’s serviceability (dampening capacity) on a diminishing scale with 14 grads being 100% and 7 being 0%. Accordingly, if you’re serious about ride quality then fit four new damper accumulators and get your neutral pressures optimized with fresh fluid cycled through. Old and worn sway bar links, bushings, rubber cushions and shock bushings all contribute to noise, vibration and harshness too.

Hello down under mate, and thanks for taking the time! Your post has made things perfectly clear even to a technical dummy like me. If I have understood you correctly, I need to replace the damper accumulators and replace the AHC in the prosses. I presume the damper accumulators are also known as globes, correct? I'll be happy and content to invest whatever it takes to bring back my '06 LC's as near as possible to it's original "smooth, compliant and comfortable ride" rather than spend quite a bit more money to enjoy the same in an uglier (to me) if more powerful 200 LC. Your reasoning has convinced me that with proper maintenance, care and replacement of worn out elements I can enjoy, say 90% of the comfort of a new truck. I have absolutely no need for the extra power of the newer 570 engine, and the much more complicated and electronically dependent 200 series frightens me. Plus, I live in a country where high-end technological aid is far from readily available in case of breakdown in the wild. Apart from the somewhat rougher ride of my "06 rig compared to the '09 200 I rode last week, I have nothing to complain about. My truck runs buttery smooth, fuel consumption is up to factory specs and all aggregates seem to function flawlessly. Even the leather on the seats looks file a 20K miles automobile rather than a 11-years old one with 123000 on the ODO.

Thanks again, @PADDO

what my butt-meter has been telling me

That reminded me about one forgotten question to all of you AHC fans: Is there some way of measuring comfort objectively?

 

[PADDO]

Hello down under mate, and thanks for taking the time! Your post has made things perfectly clear even to a technical dummy like me. If I have understood you correctly, I need to replace the damper accumulators and replace the AHC in the prosses. I presume the damper accumulators are also known as globes, correct? I'll be happy and content to invest whatever it takes to bring back my '06 LC's as near as possible to it's original "smooth, compliant and comfortable ride" rather than spend quite a bit more money to enjoy the same in an uglier (to me) if more powerful 200 LC. Your reasoning has convinced me that with proper maintenance, care and replacement of worn out elements I can enjoy, say 90% of the comfort of a new truck. I have absolutely no need for the extra power of the newer 570 engine, and the much more complicated and electronically dependent 200 series frightens me. Plus, I live in a country where high-end technological aid is far from readily available in case of breakdown in the wild. Apart from the somewhat rougher ride of my "06 rig compared to the '09 200 I rode last week, I have nothing to complain about. My truck runs buttery smooth, fuel consumption is up to factory specs and all aggregates seem to function flawlessly. Even the leather on the seats looks file a 20K miles automobile rather than a 11-years old one with 123000 on the ODO.

Thanks again, @PADDO



That reminded me about one forgotten question to all of you AHC fans: Is there some way of measuring comfort objectively?

Just got back to the US from down under actually, 100s and 105s aplenty with no shortage of 200s which are the preferred touring tow vehicle now. Yes, spheres = globes = gas springs = damper accumulators. With new globes, the correct neutral pressures and clean, gas free hydraulic fluid you should be pleasantly surprised at how good the adaptive variable suspension can be.
Some time back I fiddled with trying to quantify AHC/AVS comfort objectively; messed around with a seismic warning app on my phone to measure and log shock/dampening parameters. Didn’t amount to much, just rough data in isolation. Harking back to my Test & Trials Engineering days where we’d rig new construction Frigates up with a ton of accelerometers and other data acquisition sensors and drive it like we stole it