AHC vs Live suspension

[jayfrem]

Hi there

My brother LC 100 we re running 285 75 16 on stock suspension. It s a 1999 that came with AHC suspension.

When it was bought ( used) suspension was jumpy as water was added accidentally with AHC by previous owner.

We have had our fair share of AHC problems manly blown accumulators. Now all is good but front AHC shocks needs replacement.

I am thinking to ditch out AHC and for an OME mild lift. Truck rarely goes off roading.

How will OME lift ride compared to AHC ?
Will truck be more unstable on road at high speed and winy roads ?
An LC 100 is no race car but currently it s pretty stable for its size .

Is AHC suspension hard to take out ? Do we have to ditch all the hydro lines ?




FJ cruiser 2009 Stock
Jeep LJ Rubicon on 36"

 

[TeCKis300]

The easy cheap solution would be to swap the system out with an OME setup.

That said, if the truck had high end remote reservoir bypass shocks, would you have any remorse dumping that? The AHC system is more sophisticated than just about any suspension out there. And like coilovers, take a bit more maintenance (though it lasts waaay longer than any aftermarket suspension). If you don't mind losing capability for simplicity/cost, then it's an easy choice.

 

[jayfrem]

Will ride quality and road stability be worse once AHC is ditched ?

You mentioned AHC lasts longer than any other suspension....how is that ?

When pumps and other starts to fail it costs an arm and a leg.

Jay


FJ cruiser 2009 Stock
Jeep LJ Rubicon on 36"

 

[brosama]

We have had our fair share of AHC problems

That'd be enough for me. I plan on riding out my AHC as long as possible but won't hesitate to swap a normal lift on when it's time. I prefer the simplicity.

From what I've gathered, most setups won't be as nice as the AHC, but you can fine tune to get something fairly comfortable. Any lift or non-stock tire size inherently carry an instability factor. Keeping it mild will help keep that number down. Driving habits also play a large role there.

WRT to AHC removal you really only have to remove a few parts to get a regular lift functional. Beyond that it's a matter of preference.
https://forum.ih8mud.com/threads/ahc-removal-time-any-tips-tricks.761387/
https://forum.ih8mud.com/threads/introducing-my-dirty-little-diva.389885/page-8

 

[dfrelich]

I've been little unsatisfied with my AHC for last two years. I took my truck to lexus and they said one of the globe went bad so I replaced it earlier in the summer. Not quite there. But then... all it took was a techstream and mini-vci, I'm in love with my truck again.

Before anyone start to take out AHC. Give $35 a chance. I wish I did.

 

[jayfrem]

I've been little unsatisfied with my AHC for last two years. I took my truck to lexus and they said one of the globe went bad so I replaced it earlier in the summer. Not quite there. But then... all it took was a techstream and mini-vci, I'm in love with my truck again.

Before anyone start to take out AHC. Give $35 a chance. I wish I did.

By globe you mean the hydraulic accumulator ($400) ?


FJ cruiser 2009 Stock
Jeep LJ Rubicon on 36"

 

[SWUtah]

My AHC started acting up, looked at cost to fix and long term expense to maintain the old AHC. Decided at 120k miles to take my Hundy from where I lived at that time in Las Vegas and have the pro's at Slee in Colorado take out the AHC and install the 2" lift OME suspension. Love the look love the ride, much better then the AHC ride. I've driven the new OME suspension over the rocky's and from Las Vegas to Texas. Runs smooth and straight with a solid truck feel. I know I have saved thousands $$$ getting rid of the AHC suspension. Some members love to work on their AHC and buy after market shocks, etc. if you are not doing it yourself with the AHC and have to use a dealership or shop you are in fr a lot of expense and frustration. JMHO

 

[TeCKis300]

Will ride quality and road stability be worse once AHC is ditched ?

Ride quality and road stability encompass a lot of conditions. Overall, yes the AHC system will absolutely be more stable and performant as it's an active system capable of adjusting and varying to different conditions. Any other system can be tuned to excel and even better AHC, but always for a more narrow set of use cases, typically at the compromise of other use cases. The dynamic nature and the ability to optimize for varying conditions is the strength of AHC, at the detriment of cost and complexity. Reliability is not one of the inherent trade-offs given the many examples of people with working systems into the 200k miles range. Most problems that come up on the boards are due to people trying to modify the system without truly understanding how it works.

You mentioned AHC lasts longer than any other suspension....how is that ?

Aftermarket coilovers are notorious for failing or lasting only 10, 20, 30k miles before needing a rebuild. Sure, they sound fancy and all, but they're not typically validated to last the service intervals that OEMs require. Or they rely on the early adopters as their testers. No joke. In the grand scheme of things, I would gladly pay for AHC than any shiney aftermarket marketing speal.

I'm comparing AHC to more advanced suspension systems. A basic shock like OME's should last a long time.

When pumps and other starts to fail it costs an arm and a leg.

Yup, and that's the true trade-off. It's not innately unreliable as mentioned earlier (unlike range rovers systems). And like all suspensions, it's a wear item and has service intervals.

 

[dfrelich]

By globe you mean the hydraulic accumulator ($400) ?


FJ cruiser 2009 Stock
Jeep LJ Rubicon on 36"

Yes that's correct. These can be bought 1/4 the price off amanayam (an oversea vendor).

 

[Wilsil]

I've been little unsatisfied with my AHC for last two years. I took my truck to lexus and they said one of the globe went bad so I replaced it earlier in the summer. Not quite there. But then... all it took was a techstream and mini-vci, I'm in love with my truck again.

Before anyone start to take out AHC. Give $35 a chance. I wish I did.

What did techstream tell you?

 

[Junglejack]

Hello Jayfrem,
Sadly the water being added to the system (truly horrible) all but makes it a fait accompli that the AHC must be scrapped if following conventional wisdom.
Personally, I love the idea of trying to save the AHC as it is a kickass solution for all but the most demanding of applications.
Best,
J

 

[dfrelich]

The techstream indicated that my torsion was out of spec. It was 4.9 for the front which had meant that the torsion bars were over cranked. A couple of weeks ago, I cranked up the torsion when I found that the 30 mm bolts were outside the spec. (read post #9 of that thread... https://forum.ih8mud.com/threads/adjusting-torsion-bar-with-ahc-questions.677799/#post-9261286)

When I over cranked, I had improvement with the way the suspension handled but I felt it was springy at some point. More noticeable when loaded with passengers and luggages. I did not have techstream at that time.

Now that I got my techstream. I connected to the system and determined that TB were over cranked. I went under the rig with 30 mm socket and cheater bar. Turned about 2 turns CCW. Lowered and raised the rig and recheck. It got closer to the spec, and then did additional turn and half. Brought me right to 7.0 for the front and 6.9 for the rear. Spec calls for 6.9 (+/- .5) Basically I did 3 turns and half.

Drove it around for few days and then I reconnected to the system. I'm still within the spec, and handles beautifully. Road bumps are much more muted.

Now that the truck was outside both ends of the spec. I can vouch that when you're outside, you will feel road bumps either ways.

- When you're under cranked, it feels like the shocks were storing too much pressure and try to snap wheels back to the road. Thus road feels like it's rough.

- When you're over cranked, the truck felt much smoother with the road. But it felt springy when going over tracks or some swells. Almost felt like top-heavy. Also with certain bumps or rail tracks, the wheel really snaps back hard.

FYI -- Mr Paddo (Steve) was big help. We agreed that the TB needs to support ⅓ of the weight of truck to operate efficiently.

For what it is all worth... it took 15 minutes to bring my truck to spec, and I was wearing clean clothes at that time.

 

[TeCKis300]

^Nice. A great progression of learning that helps explain how adjustments affect the AHC system, and that for it to be most effective, has to be within it's design specs.

I find it curious that some people suggest their 3rd party suspension to feel better/smoother than AHC. In my opinion, it must be that they are referring to their last known experience with AHC out of spec or failing. Toyota/Lexus has incredibly high internal standards relative to aftermarket stuff. A properly setup and working AHC system gives an incredibly buttery and smooth ride that just can't be matched with a standard suspension.

 

[CappyKD]

I love my AHC system. In the event of complete failure I will replace it, otherwise, I will maintain it. Just got my Tech stream working and need to dial my system in. Which AHC setting do you adjust to, the low up to n pressures or N to H pressures?

 

[dfrelich]

^Nice. A great progression of learning that helps explain how adjustments affect the AHC system, and that for it to be most effective, has to be within it's design specs.

I find it curious that some people suggest their 3rd party suspension to feel better/smoother than AHC. In my opinion, it must be that they are referring to their last known experience with AHC out of spec or failing. Toyota/Lexus has incredibly high internal standards relative to aftermarket stuff. A properly setup and working AHC system gives an incredibly buttery and smooth ride that just can't be matched with a standard suspension.

I concur. To be fair, techstream were non-existence not too long ago for average DIY-ers. I started to read about techstream about a year ago and I know many were hesitant to get the cable and software. Not easy to install, etc. But now days, it appears to be so easy to install on your windows. There are more support out there for many to feel confident.

 

[dfrelich]

I love my AHC system. In the event of complete failure I will replace it, otherwise, I will maintain it. Just got my Tech stream working and need to dial my system in. Which AHC setting do you adjust to, the low up to n pressures or N to H pressures?

Go low height and then connect your tech stream and start reading before raising your rig back to normal height. Your reading will be ready within few seconds after returning to the height.

 

[CappyKD]

Go low height and then connect your tech stream and start reading before raising your rig back to normal height. Your reading will be ready within few seconds after returning to the height.

Thanks!

 

[jayfrem]

Where to get techstream from ?


FJ cruiser 2009 Stock
Jeep LJ Rubicon on 36"

 

[CappyKD]

Where to get techstream from ?


FJ cruiser 2009 Stock
Jeep LJ Rubicon on 36"

ebay or amazon

 

[Hayes]

On-road, my OME medium equipped truck rides much like the "sport" setting before I removed the AHC.