Upgraded AHC suspension.. (1 Viewer)

[Mago]

Hi,

Anyone installed a suspension airbag for the LX570?

Wondering if the airbag height should be calculated at maximum lift height or at normal? i assume it should also carry load when the suspension is set to H..

If so, which make/model?

Thanks.

 

[linuxgod]

I suspect you'll have trouble with air bags with AHC.

On an LC the bags are supposed to fit in the spring and "lightly" touch the axle when you're at normal height. You inflate them when you add the rear load to get your rear height back up to (or close to) the unloaded height.

On an LX the height isn't just high, normal, and low, but there are a number of intermediate settings that AHC uses depending on speed. So even if you get the air bags set up right when parked and set to normal height, when you get onto the highway AHC will drop your height a bit and now the bags are off.

 

[TeCKis300]

I would refer to the 100-series forums as there's much more information on augmenting AHC with airbags. There's almost no one who's really done this on the 200-series, which partially goes to show how much more robust the 200-series AHC setup is. The two systems are similar enough that it should work well.

What load are you trying to handle and how are you going to use it?

I've augmented AHC to tow my 7700lb trailer with lots of people on board, with 10mm rear spring spacers. AHC never asked for it, but I did the same with my 100-series to great effect.

Most of the LX470 people use the same bags as the standard LC100 which is the Firsestone 4124 kit. LC200 fitment is the 4164 kit. I imagine the free length is approximately setup for standard height. Is your AHC sensor lifted? The use case for bags to support extra load in H mode is not as common. If you're either AHC sensor lifted, or want to support lots of load in H, you will want longer bags.

The multiple heights shouldn't be an issue, unless you're running full 35psi on longer bags, which would constrain the system from dropping the suspension lower. This would also have the effect of losing damping as the AHC system needs to be supporting part of the load. But then you always have control with how much air you're running in the bags to alleviate this issue. Most LX470s seem to run the bags in the 5-15 psi range.

 

[Mago]

Thanks all for the info.. I have around 700-800lbs extra constant weight (extra 45 gallon fuel tank, drawers full of stuff, fridge, tire carrier) and want to offset this with airbags. Sensors are at standard height.. I do a lot of offroading so need my suspension 'fresh'..

 

[TeCKis300]

Awesome setup you have there!

I personally would address this via spring spacers. The idea is to add more preload to the coil springs to offset the weight you've added. That leaves AHC handling what it did stock. And you'll still have full range of L/M/H in this way, without wondering if airbags have enough free length to support H.

Like I said, I've added 10mm spacers to my rear coils. This supported my 1800lbs of payload in one trip without issue getting into H. It also work transparently when I have no added load in my car.

For you, since you've statically added more weight to the car, I would look for perhaps 10mm front and 15mm rear spacers. I think I saw that very recently, there were front spring spacers available for our cars on Ebay.

 

[TeCKis300]

I had to do a double take there. I believe you said LX570, but the pics are of a LC? Or do you guys have AHC available on the LC platform in Egypt?

 

[Mago]

I do have an AHC equipped LC.. But I know my coils and suspension are the same as the LX's and you guys in the US only have AHC on LX so was taking a shortcut

The truck is European specs.. Imported.

 

[Mago]

Awesome setup you have there!

I personally would address this via spring spacers. The idea is to add more preload to the coil springs to offset the weight you've added. That leaves AHC handling what it did stock. And you'll still have full range of L/M/H in this way, without wondering if airbags have enough free length to support H

For you, since you've statically added more weight to the car, I would look for perhaps 10mm front and 15mm rear spacers. I think I saw that very recently, there were front spring spacers available for our cars on Ebay.

Thanks.. Wouldy you have a linky?

 

[TeCKis300]

These will work for rear. Note that 80 and 100 series springs are similar enough that you can use these spacers in the 200-series:
https://www.amazon.com/Dobinsons-Polyurethane-Spacers-Toyota-Cruiser/dp/B01MU5HNJS
15MM COIL SPRING SPACER TOYOTA LAND CRUISER 100 80 105 SERIES

Front is trickier. I've only seen these. It's unclear whether they are 20mm spacers or 20mm lift. I would think a 20mm spacer is too much unless you've done an AHC lift. Since these are polyurethane, you could probably cut them down relatively easily.
2 x Front Coil Spring Spacer For Toyota Landcruiser 200 Series - 20mm Lift Kit | eBay

 

[TeCKis300]

Looking at the pics again, most of your added load is in the rear. I thought you also had front bumper armor for some reason.

I'd probably just add the spacer to the rear for the moment and see how that goes.

EDIT: I just have to say WOW. The illusive AHC equipped LC. Unicorn at least in this part of the world.

 

[Mago]

Looking at the pics again, most of your added load is in the rear. I thought you also had front bumper armor for some reason.

I'd probably just add the spacer to the rear for the moment and see how that goes.

I would agree with you.. I only feel the load at the rear.
I'll try rear spacers and feed you back..

 

[Mago]

Well, I have good news for LX570 and LC AHC owners..

I had stock LC 100 Springs from my other truck and installed them today instead of the stock AHC Springs.. they did the job magnificently..

All Heights available on empty and full fuel tanks... Pics of the springs will follow..

 

[GordJ]

Quick question for teckis, does your truck kneel down the same with the spacers? This is one of my favourite differences between my LC and LX.

 

[TeCKis300]

@GordJ , I didn't do measurements before and after so I can't say it didn't change anything. But yes, it does seemingly kneel all the way down as far as I can tell. I've always noticed that AHC, when kneeling, seems to stop the kneel at a programmed point, rather than all the way down mechanically. As when I have a lot of load in the rear, it'll stop it at an programmed point that is the same as when it is unloaded. So I believe with some confidence that the spacer has not affected where it lowers to.

 

[Mago]

https://photos.app.goo.gl/gsjv5TqSugR6kGxS2

Left to right: Armoured AHC spring, stock AHC, LC100 stock.

 

[Mago]

I noted the right AHC spring is higher than the left one by almost 2 inches..

https://photos.app.goo.gl/SD6drMGeYLKZWy2D2

 

[TeCKis300]

That's pretty darn awesome you got it to work! An LC100 spring eh? Much like the LX470 days, where they'd take an 80-series spring for use in the 100-series LX470. So how does the 100-series spring feel for the application? About right? Over, under sprung?

Way to forge new paths for the community!

Embedding @Mago 's pics here:

Left to right: Armoured AHC spring, stock AHC, LC100 stock.

I noted the right AHC spring is higher than the left one by almost 2 inches..

 

[Mago]

So far I think they are a bit oversprung.. On a speed bump exit I feel it is going to bottom out but it doesn't.. Otherwise I have my truck back

Anyways I need to load it more and test.. This is an excellent start because now we know incrementally heavier Springs would work if those are oversprung in the future.

 

[TeCKis300]

If regards to it being oversprung...

If haven't done an AHC sensor lift, you could try lifting it that way incrementally. This would have the effect of reducing preload on the LC100 springs. And in effect, reducing the spring rate at normal ride height. Perhaps an 80-series spring might be something to try if you have availability for that.

That purple armoured AHC spring is awesome too. Another unicorn part to the US!

 

[Mago]

Thanks for this, I'll try the height adjustment if I feel tuning is required..

The purple spring is a German Eibach... Am dying to try it out.. But I know it will be too stiff with the stock shocks. It requires larger shocks, which I also have.

Saving those for if and when I decide to add more load..

I forgot to mention the oil pressure went down from 12.5 mpa to 9.5mpa while lifting..