AHC for Baja style driving (LX Question)

[HGB]

I recently went driving in a desert environment and want to know if I can use my AHC on the LX for high-speed driving with some bumps. Obviously not real Baja driving, but I’m talking about 40mph ISH. Or is that going to damage the accumulators / globes?

would you suggest putting it in comfort, medium of sport?

 

[PDoyle]

AHC is only active in high mode until you reach 18 mph I think .

 

[grinchy]

It is active all the time, and it will goto N mode above a certain speed. You can't really break a globe under most usual and unusual driving. You could bottom out your suspension just like on a normal spring suspension.

If you got a rock or stump into the ahc pipes or broke open a shock then it could fail. Not likely in most driving situations

 

[Bunga]

It still has bumpstops, and it can and will bottom on them. Some people like the Firm for the valving compression in HI. I think it is too harsh. I like a rolling impact with most bumps.

I think @18 mph drops from high to N, but N can be taller with the sensor adjustment. I was super annoyed by that at first, but now I don't notice.

Baja is tough on rigs. Dust can be nightmarish. Good lights for black cows, good tires and a dual battery.

 

[TeCKis300]

No problemo. I've run at that pace and faster many times and AHC eats it up. It's pretty deep in its capability to soak up both small and big hits with comfort and control. I think you'll find its solid at maximizing use of available suspension travel while keeping things off the bump stops. With arguably larger fluid volumes compared to even remote reservoir suspensions, to aid in heat dissipation, and extended running. I don't purposely try to jump my car and AHC is probably not designed for that, but I've yet to find the limits of the system. As with any performance scenario, less wight is more performance.

AHC has several active tricks up its sleeve for this type of running including:

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.

Tips:
1) Off-road always starts with tire pressure. I run 12-20 psi with my 33's. Lower end in sand. Higher in hard pack. Stock tired rigs with less sidewall and 20" wheels may want to be in the 18-24psi range.
2) Low range is the trick with AHC as it all works as a system. It has better low speed throttle control, more torque, more engine rpm and cooling circulation, and importantly maintains more compression travel to a higher speeds, up to 62mph (refer to diagram below).
3) May want to engage center diff lock to turn off traction control nannies and have more tail out fun if on loose stuff
4) I usually have my damper setting in the softest setting (comfort) but if I'm running hard and chasing friends in Raptors for example, I may turn the selectable damper up to enable more compression stiffness. The system adapts itself, but will take your cues if more compression control is desired.

*5) Do an AHC sensor lift and get more of everything. AHC high give you 2" more lift. Add even a mild 1" sensor lift and you're now at a 3" functional lift. Or more if you fancy to get almost 4" lift and bad suspension geometry, but I like my vehicles balanced and actually have good handling for high speeds.

 

[HGB]

No problemo. I've run at that pace and faster many times and AHC eats it up. It's pretty deep in its capability to soak up both small and big hits with comfort and control. I think you'll find its solid at maximizing use of available suspension travel while keeping things off the bump stops. With arguably larger fluid volumes compared to even remote reservoir suspensions, to aid in heat dissipation, and extended running. I don't purposely try to jump my car and AHC is probably not designed for that, but I've yet to find the limits of the system. As with any performance scenario, less wight is more performance.

AHC has several active tricks up its sleeve for this type of running including:



Tips:
1) Off-road always starts with tire pressure. I run 12-20 psi with my 33's. Lower end in sand. Higher in hard pack. Stock tired rigs with less sidewall and 20" wheels may want to be in the 18-24psi range.
2) Low range is the trick with AHC as it all works as a system. It has better low speed throttle control, more torque, more engine rpm and cooling circulation, and importantly maintains more compression travel to a higher speeds, up to 62mph (refer to diagram below).
3) May want to engage center diff lock to turn off traction control nannies and have more tail out fun if on loose stuff
4) I usually have my damper setting in the softest setting (comfort) but if I'm running hard and chasing friends in Raptors for example, I may turn the selectable damper up to enable more compression stiffness. The system adapts itself, but will take your cues if more compression control is desired.

*5) Do an AHC sensor lift and get more of everything. AHC high give you 2" more lift. Add even a mild 1" sensor lift and you're now at a 3" functional lift. Or more if you fancy to get almost 4" lift and bad suspension geometry, but I like my vehicles balanced and actually have good handling for high speeds.

View attachment 2258294

Ok, you are the MAN. This is what I needed. I'm so excited now. I was thinking about buying a different rig to do a Long Travel setup on, but this is way more practical to keep my LX that is amazing on road, especially if it'll suffice for some occasional (2-3x a month) higher speed off-road driving. I have a few questions for you-

1) Will driving in Low-range mode hurt the vehicle for long periods of time (think 20 mile stretch going 30-40mph?

2) I thought the CDL only can be engaged in wet surfaces or I would risk damaging the system. Is this not true? Can I engage it and have some fun in sand/dirt? I want to drift out of corners and do donuts of course.

3) Is there a way to override the high suspension setting to allow me to remain in H while above 18 MPH? I would love to be able to lock it in and still have the ability to drop back down to a normal height on the highway.

4) what kind of damage could I see if I'm hitting really bumpy roads quickly? Shock/strut or would it be more costly AHC components? Raptor style driving is exactly what I'm after! Thanks my friend.

 

[hickuptruck]

1 - not sure why you'd want to be in low range going 30-40mph. Would put some serious heat in your center diff, no reason to be in low range at that speed either.

2 - No. CDL is to be engaged in any low traction surface. Asphalt isn't one of them. Sand is low traction. Full time 4wd isn't a donut machine. You'll just end up understeering out of your turns, and vsc will kick in abruptly if you try to drift out of turns.

3 - No, not override exists.

4 - Go airborne, land on your bumper and rip it off. Bend your frame. Bending your radiator support if you land wrong. Blowing a shock, and riding the rest of your trip on bumpstops. Blowing an accumulator. Blowing a shock and leak out all your AHC fluid, leading to a bad ahc pump (pump is about $4000 for part alone). Airbag goes off inside. Hmm, possibilities are endless.

Stock LXs aren't Pre-runners unless you're in the middle east. To even start, rip out the AHC and spend about $4-5k on some 2.5" RR coilovers, and a uniball UCA, as a start.

 

[TeCKis300]

1) It doesn't care one bit. I've gone over 80 miles in one day in low range on more technical track and sandy washes. If anything, it helps the engine, tranny, and torque converter run cooler, especially in sand. Granted if it's a wide open smooth fire road where one can maintain 50+ mph, switch it into high range as lower gearing and added suspension travel will not be the primary need. The fact that the suspension lowers at speed for better handling and more stability is not a bad thing. There's no issue with heat in the center diff as it's always engaged and running the same relative to ground speed independent of hi/lo. The gear reduction in the transfer case happens before the diff in the planetary gear set. There's gear whine in low range from the 6-pinion planetary reduction gear, but one gets use to that off-roading. Much like straight cut gears of a race car.

2) CDL is super easy to engage and disengage at speed with a button push. It also is an easy way to turn off stability control.

3) Don't override the system. Work with it. Toyota has set it up logically based on the chart above and the transition points actually make a lot of sense when playing in the dirt and using low range as designed. An AHC sensor lift can tailor the system for more lift, while keeping all the benefits of reasonable heights for road use. I sensor lifted mine .75" which I find plenty. One could go 1.5", which is easily comparable to the common 2" statically lifted LCs suspensions that then droop with load. And then you have another 2" from AHC high for a 3.5"+ lift that statically lifted LCs rarely touch without major mods.

LX's can be anything you want. One of the things to make the suspension work even better is fat sidewall tires. 35s. Then pre-run all you'd like. Then add the front LC leveling spacer which gives another .75" of suspension travel.

 

[Madtiger]

Is this route something that you must take to go to a destination? Or this is just something you want to do for fun?

A few runs........and you’re asking for tons of rattles after the fun. LX is very well made and maybe you won’t get rattles......but why risk it especially if it is just for fun (vs. route to a destination)?

 

[RyanR]

Is this route something that you must take to go to a destination? Or this is just something you want to do for fun?

A few runs........and you’re asking for tons of rattles after the fun. LX is very well made and maybe you won’t get rattles......but why risk it especially if it is just for fun (vs. route to a destination)?

I've been flogging the hell out of my LX for years. High speed desert runs, well over 100 4 wheels off the ground scenarios and blasting down rocky tracks keeping up with side by sides and dirt bikes in the CO and UT mountains as well. Truck is still as tight and rattle free as when I got it. Same can be said of my FJ Cruiser. Beat the hell out of it for a decade and still drove like new and no rattles or squeaks.

Every JEEP I owned seemed to develop a new squeak or rattle after every outing. Just a few trips hanging with me in his 2019 Wrangle Rubicon and I can hardly stand to ride in my buddies rig as it rattles and squeaks so bad, even on road, it drives me insane.

 

[Madtiger]

I've been flogging the hell out of my LX for years. High speed desert runs, well over 100 4 wheels off the ground scenarios and blasting down rocky tracks keeping up with side by sides and dirt bikes in the CO and UT mountains as well. Truck is still as tight and rattle free as when I got it. Same can be said of my FJ Cruiser. Beat the hell out of it for a decade and still drove like new and no rattles or squeaks.

Every JEEP I owned seemed to develop a new squeak or rattle after every outing. Just a few trips hanging with me in his 2019 Wrangle Rubicon and I can hardly stand to ride in my buddies rig as it rattles and squeaks so bad, even on road, it drives me insane.

Well, my brother’s Tacoma now has a bunch of rattles from off-roading in Big Bend and washboards.

So, while LC has great build quality, i ain’t gonna test it by jumping sand dunes or Baja driving.

 

[HGB]

I've been flogging the hell out of my LX for years. High speed desert runs, well over 100 4 wheels off the ground scenarios and blasting down rocky tracks keeping up with side by sides and dirt bikes in the CO and UT mountains as well. Truck is still as tight and rattle free as when I got it. Same can be said of my FJ Cruiser. Beat the hell out of it for a decade and still drove like new and no rattles or squeaks.

Every JEEP I owned seemed to develop a new squeak or rattle after every outing. Just a few trips hanging with me in his 2019 Wrangle Rubicon and I can hardly stand to ride in my buddies rig as it rattles and squeaks so bad, even on road, it drives me insane.

Which suspension settings do you find best for this type of scenario? Sounds just like what I want to do!

 

[RyanR]

Which suspension settings do you find best for this type of scenario? Sounds just like what I want to do!

I generally find the Normal drive mode to be the best for rocky terrain. Sport is great for sandy conditions. Comfort is great for making washboards disappear at lower speeds but just doesn't work well at higher speeds for anything. Just my 2 cents.

 

[tbisaacs]

The damping is dynamic - it almost doesn’t matter off-road because the truck will adjust on the fly no matter what you have it set to. The only control you have is to turn off the leveling feature (hit the off button).

 

[pvchaitanya]

Ok, you are the MAN. This is what I needed. I'm so excited now. I was thinking about buying a different rig to do a Long Travel setup on, but this is way more practical to keep my LX that is amazing on road, especially if it'll suffice for some occasional (2-3x a month) higher speed off-road driving. I have a few questions for you-

1) Will driving in Low-range mode hurt the vehicle for long periods of time (think 20 mile stretch going 30-40mph?

2) I thought the CDL only can be engaged in wet surfaces or I would risk damaging the system. Is this not true? Can I engage it and have some fun in sand/dirt? I want to drift out of corners and do donuts of course.

3) Is there a way to override the high suspension setting to allow me to remain in H while above 18 MPH? I would love to be able to lock it in and still have the ability to drop back down to a normal height on the highway.

4) what kind of damage could I see if I'm hitting really bumpy roads quickly? Shock/strut or would it be more costly AHC components? Raptor style driving is exactly what I'm after! Thanks my friend.

3 - yes there is a way to override the system and always keep it high. Although as pointed out, its not best for your traction, handling and stability of vehicle.
If you still think you know better than the toyota engineers on this, here is how you can lock into high all time.
Here is youtube video which details this override:

I dont think the AHC will auto adjust even if its locked in high mode.

 

[DenverLX]

I have a 16' LX that is armored and pretty heavy. I have 33's and the full;l sensor lift. I was worried about the AHC when I first got this vehicle bc I wasn't impressed with it on my 100. However I have been really impressed with the AHC on the 200 (LX570). I love that it lowers for parking garages and when I give my disabled father a ride.

The truck rides pretty rough in high mode and now when Im off-roading I usually engage high when I need it and then lower it to normal if I don't.

I always use the sport setting (stiffer suspension) when driving high speed mountain passes (think I-70 in colorado) bc it has less body roll and my wife doesn't yell at me for driving too fast.

I don't drive high speed off-road so I can't comment on that. I don't think its something I would want to do seeing as I already have a lot of weight and have the AHC near its suggested limits.

Overall, I don't want to mess with anything else on the suspension. Its a complicated and expensive system and it works for my needs as is. Sensor lift and big tires are all I need.

 

[TeCKis300]

Re-visiting this thread, with video proof of its abilities.

Combined with tires which itself is a key to overall suspension performance. Adjustable with AHC damping on the fly as that changes harmonics sometimes, and tire air pressure. It'll do this for hours without complaint



A real test is putting down power while soaking up bumps. That's harder on the suspension as it needs to manage bumps to stay in contact with the surface, and deal with dynamic wheel loads. Intuition may be to use high mode, but I'm using normal height (sensor lifted 1") which an advantage here as it puts the suspension in better geometry to really put power down. You can see in this hill climb which is way steeper in person, where my buddies 600hp Raptor on 37s with top shelf everything, coudln't get up the same line. At least on the first try. It's a balance of speed to manage bumps and putting power down. AHC system does this with uncanny ability. The rattles are everything else in my car. Car is as solid as can be with nary a noise. With out stuff in the car, literally only thing I hear is the spare tire chain clanging on bigger bumps sometimes.

 

[AnyMal]

I have a 16' LX that is armored and pretty heavy. I have 33's and the full;l sensor lift. I was worried about the AHC when I first got this vehicle bc I wasn't impressed with it on my 100. However I have been really impressed with the AHC on the 200 (LX570). I love that it lowers for parking garages and when I give my disabled father a ride.

The truck rides pretty rough in high mode and now when Im off-roading I usually engage high when I need it and then lower it to normal if I don't.

I always use the sport setting (stiffer suspension) when driving high speed mountain passes (think I-70 in colorado) bc it has less body roll and my wife doesn't yell at me for driving too fast.

I don't drive high speed off-road so I can't comment on that. I don't think its something I would want to do seeing as I already have a lot of weight and have the AHC near its suggested limits.

Overall, I don't want to mess with anything else on the suspension. Its a complicated and expensive system and it works for my needs as is. Sensor lift and big tires are all I need.

I agree.

If I were you though with a lot of additional weight I would definitely look into upgrading the springs. That should put you right back in the sweet spot for AHC after your lift and clear your conscience.

We don’t have an exact measure but you could start with the additional load and add that to the (somewhat) known AHC spring set rates.

In my case it’s the opposite problem of being unladen all the time. The sensor lift puts some weight back onto the shocks and dampers by coming off the springs a bit. So with my 1” lift I’m actually more compliant than the over sprung feeling when riding empty.

The LX loves weight, it rides better that way lol.

Also for those rough roads at speed, I would stiffen AHC and drop the tires a bit let the consumables do the work.