AHC vs Coilovers

[TeCKis300]

No way currently to reprogram AHC. Though you can adjust the damping to soft/comfort/sport and get the dampening you prefer for the situation.

Neutral height can be tweaked to ride higher by ~1.5". Extra high in crawl mode almost maxes out the suspension with minimal droop left, regardless of load. So AHC can get the body way up there.

This is what I was talking about. How do you think it would feel with BFG KO2s? Would that poorly damped rebound be more pronounced? Is there a way to adjust AHC to compensate for that? If I had an LX I would most likely reprogram the AHC to its tallest setting, not sure if that will ruin comfort?

I drove a number of LX570's, most of the newer ones have 20-21" wheels which I think would make things worse? I prefer a tall sidewall and would put Rock Warriors with KO2s on an LX even thought it may look absurd on the street.

 

[UCrazyKid]

Another plus for AHC, when my ARB bumpers were added front and rear, there was no sag or drop in ride height and no additional dipping during braking.

 

[SWUtah]

I'm still unsure of the "bouncing" you're referring to. There's no bouncing to speak of in my experience, regardless of load. That would be unbecoming of a Lexus if it were tuned anything like that.

I alternate between my LX570 and 911 Turbo daily, which has high end coilovers and solid bushings at key mounts. I certainly know my way around suspension modifications having tuned and done all my own work. So my tush is quite calibrated to suspension feedback. I don't in anyway feel AHC is disconnected.

On the contrary, it allows the tank of a car, on solid axle rear suspension no less, to be more than just a bit competent. Absolutely controlled damping (which I would expect as it's fully active). Flat cornering. No brake dive (as it implements a secondary spring rate at the front axle just to handle this).

I found since I installed the heavier BFG AT/KO2’s “56lbs” versus stock “29lb” Dunlop’s, that driving at higher speeds on the interstate “sport” setting is ideal, feels like it’s on rails and very connected to the road. With the suspension set to normal at high speeds on the interstate not as connected, less perceived control. Normal city driving and the normal setting is perfect. I figure this is because of the bigger heavier BFG‘s. Size wise I’m still within 3% of the stock wheel size placed on 200 series so I don’t think they’re too big. If my suspension was not adjustable I would not be as happy with the tire change example if I had a Land Cruiser and went to A larger heavier tire and then had the same driving sensations I know I would then have to go with heavier shocks to compensate and hope I got it right

 

[Markuson]

I found since I installed the heavier BFG AT/KO2’s “56lbs” versus stock “29lb” Dunlop’s, that driving at higher speeds on the interstate “sport” setting is ideal, feels like it’s on rails and very connected to the road. With the suspension set to normal at high speeds on the interstate not as connected, less perceived control. Normal city driving and the normal setting is perfect. I figure this is because of the bigger heavier BFG‘s. Size wise I’m still within 3% of the stock wheel size placed on 200 series so I don’t think they’re too big. If my suspension was not adjustable I would not be as happy with the tire change example if I had a Land Cruiser and went to A larger heavier tire and then had the same driving sensations I know I would then have to go with heavier shocks to compensate and hope I got it right

As an LC guy, I really do see the appeal of that last point re having to sort of “guess” when trying to achieve a particular ride height via rear springs and coilover preload when adding mod weight to the LC, or just a lift. Certainly cool to be able set height after the fact, no matter what with AHC. Spring weights and response to loads are complicated to figure out, and not an exact science...so total control after the fact is appealing for sure.

 

[TeCKis300]

Super Plush and razor sharp handling.

Reckless, you mentioned this in your other post on coilovers. I thought it would be more appropriately addressed in this thread.

This is the very reason why AHC is so incredible as it does exactly that. It's actually two systems - AHC and AVS (Active Height Control + Adaptive Variable Suspension). With normal static suspensions, it's incredibly hard, if not impossible, to accomplish these qualities with a static calibration. To be soft to soak up bumps yet firm for great on road handling are generally completely diametric qualities of a suspension.

There are some analogue system that can give somewhat of a dual personality nature with spool and bypass valves. Other manufacturers accomplish aspects of this with adjustable or dynamic dampening. There's even more sophisticated magnetorheological type systems that can adjust on the fly.

Then there's AVS. It's a monotube, remote reservoir, remote valve style dynamic damping system that's even more sophisticated than those above. Damping actuator consists of the 16 steps step motor, a spool valve, a soft damping force valve and hard damping force valve. All with multiple accelerometer and individual suspension position feedback. It continuously adjusts the damping orifice to produce just the right compression and rebound damping. It's list of abilities is long:

The LX 570 AVS system also has (source Pressroom - Lexus - Press Kit Details):

• Thumping Sensitive Control: to ensure damper force does not increase while driving on rough roads.
  
• Large-amplitude Control: to decrease spring vibration when the suspension control ECU detects any large fluctuation in wheel stroke at low speeds.
  
• Roll-posture Control: to ensure stability and controllability during cornering, increasing the damping force and therefore reducing rolling movement.
  
• Anti-dive and Anti-squat Control: to maintain vehicle posture under braking and acceleration.
  
• High-speed Control: to vary damper force according to vehicle speed, to increase comfort at low speeds and maintain vehicle posture at high speeds.
  
• Absorber Control: to provide the three driver-selectable damper modes.
  
• L4 Range Control: to maximise comfort in off-road driving.

And that's just highlights of the AVS portions (though it's really an intertwined system with AHC). The height control manages spring pre-load and height control to allow for suspension clearance on demand or maintain clearance with load. The front axle implements 2 distinct spring rates for added control against brake dive and cornering. Lift is up to 80mm lift (3"+). And lowering ingress mode which drops 60mm from neutral height. I've been to 1800lb payload towing without any squat in the system, and the suspension still being fully controlled and composed.

AVS and AHC was created for the very reason to allow for on road performance yet off road compliance across a spectrum of loads and conditions. For the duality of super plush and razor sharp handling, it's unmatched.

 

[Reckless]

I agree with you that AHC/AVS is an amazing system. I had the old version on my LX470. The new version is even more sophisticated. I saw some old awesome Toyota videos showing the capabilities comparing it to non AHC suspensions (i believe one of them mentioned 80% less body roll). I was AHC fan when I had it on my LX470. Then when it starting having issues I switched to OME suspension (I hated it at first but grew to love it even though I sort of hate the firm spring now).

I think all of this is great in theory but when put to practical we just couldn't get comfortable in the LX570. We did not find the ride to ever be plush. It was dipping and diving in a weird way that my buddies and I couldn't figure out. We test drove 8 different LX570 (new and used). I had my heart set on one and originally planned to have the AHC removed like I did on my LX470. I do think the issue was in part due to the tires, I hate low profile tires. The salesman would come in the car with us and also observe what we were observing. We tried every setting, we also tried driving the vehicle nice and we tried driving it aggressively and we noticed the bumpiness in every setting, especially when going through curves. We thought it was weird as we didn't have these issues in my 100. I think it has something to do with how the suspension is tuned and that's why its not as nice as it should be in theory.

After putting on my Icon Coilovers, I feel its a much superior ride in terms of comfort, handling and overall performance at the moment. My buddies and I are planning to go and test drive an LX570 again after 2 years to see if we can grow to like it. I do want to get a second 200 sometime this year.

 

[Reckless]

 

[TeCKis300]

...I think all of this is great in theory but when put to practical we just couldn't get comfortable in the LX570. We did not find the ride to ever be plush. It was dipping and diving in a weird way that my buddies and I couldn't figure out. We test drove 8 different LX570 (new and used). I had my heart set on one and originally planned to have the AHC removed like I did on my LX470. I do think the issue was in part due to the tires, I hate low profile tires. The salesman would come in the car with us and also observe what we were observing. We tried every setting, we also tried driving the vehicle nice and we tried driving it aggressively and we noticed the bumpiness in every setting, especially when going through curves. We thought it was weird as we didn't have these issues in my 100. I think it has something to do with how the suspension is tuned and that's why its not as nice as it should be in theory.

I agree that it might not be for everyone. Everyone has their needs and wants, and they're entitled to their preferences without qualification. Just like some people like sporty cars vs others that like floating deprivation chambers. We tweak our own cars to suit our tastes right? And I certainly have that disease where I can't leave things well enough alone. Car manufacturers tune their cars for the nominal target audience. From there, it's awesome that we have these boards to share information and experiences that help inform our personal tailoring.

 

[Markuson]

I agree that it might not be for everyone. Everyone has their needs and wants, and they're entitled to their preferences without qualification. Just like some people like sporty cars vs others that like floating deprivation chambers. We tweak our own cars to suit our tastes right? And I certainly have that disease where I can't leave things well enough alone. Car manufacturers tune their cars for the nominal target audience. From there, it's awesome that we have these boards to share information and experiences that help inform our personal tailoring.

Honestly, my 200 felt similar to what you describe with stock suspension. Really disliked the way it handled stuff as mild as uneven pavement. Lots of bouncing of the suspension that you could hear...way too mushy.

 

[Reckless]

To me the soul of the Land Cruiser is the suspension. It is a do it all amazing go anywhere no nonsense military spec vehicle with the RIGHT suspension. With the stock suspension, it isn't really there. The LX is soo close, but it needs some fine tuning. I wonder if there is a way to hack into it and adjust settings. I think Toyota did an amazing job with the technology but built for mainstream when it could be the offroaders dream. I don't know why they didn't leave the system open so people can hack it the way they want it even if it reduces the life of some of the components.

 

[RyanR]

I agree with you that AHC/AVS is an amazing system. I had the old version on my LX470. The new version is even more sophisticated. I saw some old awesome Toyota videos showing the capabilities comparing it to non AHC suspensions (i believe one of them mentioned 80% less body roll). I was AHC fan when I had it on my LX470. Then when it starting having issues I switched to OME suspension (I hated it at first but grew to love it even though I sort of hate the firm spring now).

I think all of this is great in theory but when put to practical we just couldn't get comfortable in the LX570. We did not find the ride to ever be plush. It was dipping and diving in a weird way that my buddies and I couldn't figure out. We test drove 8 different LX570 (new and used). I had my heart set on one and originally planned to have the AHC removed like I did on my LX470. I do think the issue was in part due to the tires, I hate low profile tires. The salesman would come in the car with us and also observe what we were observing. We tried every setting, we also tried driving the vehicle nice and we tried driving it aggressively and we noticed the bumpiness in every setting, especially when going through curves. We thought it was weird as we didn't have these issues in my 100. I think it has something to do with how the suspension is tuned and that's why its not as nice as it should be in theory.

After putting on my Icon Coilovers, I feel its a much superior ride in terms of comfort, handling and overall performance at the moment. My buddies and I are planning to go and test drive an LX570 again after 2 years to see if we can grow to like it. I do want to get a second 200 sometime this year.

I'd try to find an LX to test drive that is running LT tires. The squishy low profile P rate tires just ruin what is otherwise a great handling/riding machine. I kept my stock 20" wheels but went to a 34" Falken Wildpeak AT3W All Terrain and it feels so different now.

 

[SWUtah]

Seems like the feel from changing the stock 29lb P rated tire's and installing 56lb BFG AT/KO2 "D" rated truck tire's made a huge difference in feel to me. I also had several LX470's and finally with the last one had Slee install OME 2" lift med. springs and then installed BFG AT/KO's and loved the ride/feel

 

[SWUtah]

I'd try to find an LX to test drive that is running LT tires. The squishy low profile P rate tires just ruin what is otherwise a great handling/riding machine. I kept my stock 20" wheels but went to a 34" Falken Wildpeak AT3W All Terrain and it feels so different now.

Your tire's are "E" rated and weigh 71 lbs each. 15lbs more then my BFG's and 42lbs more then the stock tire. What suspension setting do you run most of the time?

 

[Reckless]

I'd try to find an LX to test drive that is running LT tires. The squishy low profile P rate tires just ruin what is otherwise a great handling/riding machine. I kept my stock 20" wheels but went to a 34" Falken Wildpeak AT3W All Terrain and it feels so different now.

If anyone who has an LX with LT tires is driving through Chicago and would like to eat some famous Chicago Deep Dish Pizza please stop by. I want to see your LX! I also want to drive your LX!! I promise not to hit anything other than potholes and speed bumps.

FYI I have 4 different neighbors on my street with LX with stock tires.

 

[RyanR]

Your tire's are "E" rated and weigh 71 lbs each. 15lbs more then my BFG's and 42lbs more then the stock tire. What suspension setting do you run most of the time?

To be honest I adjust it constantly. It feels firm and controlled in normal mode. I use comfort whenever my wife and daughter are in the car, and for a section of highway construction on my commute where the pavement is just a mess. Sport is really too firm for me unless it's a nice smooth canyon road, then it's just awesome.

With the stock tires I ran in Sport mode nearly all of the time. Normal was Ok. Comfort mode I really only used on that section of road on my commute and only because its just straight and bumpy. With stock tires Comfort mode felt so disconnected I rarely used it.

 

[TeCKis300]

Your tire's are "E" rated and weigh 71 lbs each. 15lbs more then my BFG's and 42lbs more then the stock tire. What suspension setting do you run most of the time?

RyanR and I run the same model tire but in different sizes. I believe his is a 34.1" tire sized 275/65/20 @ 66 lbs. I run a 33.2" tire sized 305/55/20 @71 lbs.

Yes, the unsprung weight of the tire has changed dramatically. But I haven't found that it's necessary to bias my suspension setting for the difference in tire as the system adapts and handles it well. If anything, the ride is better over sharp transients in the road. The taller tire with more rubber does a bit to quell these hits where I now will just bomb over anything without worrying about low profile rubber (I never really worried as it's a 200-series after all...just less thought about it).

I likewise adjust the manual setting often. Firm is unnecessarily firm just going down the road. I do use it when it's just me, and I'm driving aggressively to pass traffic on 2-lanes, or hitting on/off ramps, or canyons. But I use full soft just as often on long relaxed road trips with the family. Normal mode is perfect for everything unless I'm looking for that extra control or comfort. When I tow, like this past weekend with crazy Santa Ana's and gusts upwards of 50mph, I had it on firm on the freeway. The extra control towing 7200lbs was greatly appreciated. Though I'll normally run Normal towing because I'm not canyon carving and the system has already pre-adapted for the load.

Back to tires...It's one of the most critical parts of the car in terms of performance, ride, and suspension. A lot can be tuned there with type and size selection alone. I didn't particularly like the stock 20s, it was a solid tire with good performance all around, and quiet on the freeway. But you could tell it was a low profile tire with the shock and texture it transmitted through. I've very much enjoyed the 305/55/20s in every scenario I've used it in, from towing, to running 20psi over washboard roads. Plenty of sidewall for offroad, yet not too much for towing stability.

18" wheels with 33" tires might be the ticket for those that don't need the lateral control and want more rubber isolation.

 

[RyanR]

Since I mounted the Falkens on the Lexus I drove it twice so I could get the rubbing all sorted out. Since then my wife won't give it back and I'm now driving a 4Runner full time lol

 

[UCrazyKid]

^^the video of the AVS system is pure gold. Thanks for posting. I had no idea how complex the AHC/AVS was and how many activities it was involved in.

 

[Andreas P]

I'd try to find an LX to test drive that is running LT tires. The squishy low profile P rate tires just ruin what is otherwise a great handling/riding machine. I kept my stock 20" wheels but went to a 34" Falken Wildpeak AT3W All Terrain and it feels so different now.

The overall diameter of the OEM wheels are too small IMO. On my LX, I changed to 33" wheels with both KO2s and Michelin Defender LTX on them and both in this size drove much better over all types of roads. The 33" size just gives the vehicle more confidence and its definitely less jarring over bad roads. The vehicle also looks more proportional with the 33s.