Builds Building Black Molly (2 Viewers)

[Jason London]

What's up with your snorkel?

Isn't it supposed to be attached to the A pillar instead of free floating out in space? Was this intentional, or ... ?

Just waiting until warmer weather to bend the plastic to the contours of the LX A pillar. I have the bracket and I’ll mount it when it warms up.

 

[Jason London]

• I drove it and towed with it for a combined total of around 1000 miles after fixing it this summer.

• The original plan was to use LC springs to reduce the amount of work, or weight, the AHC would have to carry. With the bumpers and all the accessories we really had no payload capacity left. So changing to LC springs would give the higher capacity of the LC and give me AHC to always have the same ride height indifferent to cargo load. We also tow a 31 foot Airstream and a 28 foot race car trailer with the LX, so I didn’t want to have the AHC limiting rear height or shutting down due to high pressures (which has happened to me a couple times) This was the easy part, working with the dynamic control of the AVS side is what became a balancing act.

• AHC (Automatic Height Control) and AVS (Adaptive Vehicle Suspension) work in conjunction and have an algorithmic mapping system for controlling valve blocks, ride height while underway, and damper valve positioning. Mapping is also mathematically weighted depending on driver selectable controls (comfort/sport switch).

• The LC springs reduce the AHC pressures at normal ride height and further reduce the rate of AHC pressure increases as the springs compress. However, what I didn’t account for was the LC springs were unable to match the amount of weight reduction as the suspension traveled. As the suspension drops, the AHC works more than it does at normal or compressed ride height. This will improve as the springs break in and get softer. What ends happening is a drop in pressure during downward travel and reduced AVS ability to dampen downward travel. This is compounded with higher unsprung weight and the stronger LC springs pushing downward travel at rates that are unexpected with the AHC system. Without computer modeling of what the AVS responses would be to different spring rates and the resulting AHC working pressures of complete suspension cycles and with different velocities, I have entered uncharted territory that could’ve made it dangerous to drive.

• I knew the risks and challenges going in, and I was okay with taking the time to try and dial it in. Since the LX had a lot of additional weight on it from the accessories, I figured that would shrink the margin of difference between the LX and LC spring rates. Thus getting me closer to original LX AHC pressures. Although the vehicle would have much higher inertial mass that would require more damping force to control vertical pendular motion. The LC springs help on the compression side and AVS can respond by reducing orifice size in the valve to increase damping under these conditions.

• As of right now I have installed the LC springs and drove it. I wanted to see if the AHC would lift the LX up a little since the accessories were compressing the LC springs some. But since they were new and all stiff they didn’t squat as much as
I hoped and there is a delta margin on when the AHC will begin adjusting vehicle height. So I changed the AHC offset to increase AHC ride height. This would set the AHC to keep the truck higher and put some pressure in the system at normal height, allowing the AVS to work (which requires positive pressure to work). I ha e done this a few times to find a happy equilibrium.

• There are other ways that the LC springs have changed the operating characteristics of the AHC and AVS. They are mostly due to the arc of the spring rates on the LC springs and how that influences AHC pressures. For example, when in normal, AHC pressures are lower than normal. however, when in height mode, pressures are higher than normal and ride gets more harsh than what you would expect. It’s not radically different, but noticeable to me. This is due to the nonlinear spring rate of LC springs. The rate drops off more rapidly at spring decompression/extension than the LX springs do. This is amplified by the higher AHC offset calibration to adjust AHC pressure and increase height.

This can be compensated for by adding vehicle weight and reducing AHC offset closer to stock, or waiting for the springs to break in and soften some, then Reducing offset closer to factory.

I hope this answers your questions and is detailed enough.

I mostly wanted to keep the AHC because we tow with it. Plus, it’s just cool to have the AHC functional in such a modified state. Being able to adjust the AVS for comfort and stiffen it up when towing does add a lot of control and is a very noticable difference in handling characteristics. I have and continue to debate changing to a conventional suspension with a lift kit.

I'd like to hear details of what went into getting the AHS working with the LC springs. Did you drive the truck much, or at all, with the stock springs and all of the new equipment installed? I am curious to know if there was an improvement in ride quality with the heavier springs, or if it was more peace of mind knowing the AHS system wasn't bearing as much of the weight?

 

[tbisaacs]

I have and continue to debate changing to a conventional suspension with a lift kit.

You’d be blazing a trail. Christo Slee did some experimentation here and was unsuccessful.

What prevents AHC removal?

 

[TeCKis300]

Hadn't visited your thread until now. Lots of good stuff here. Great work on bringing that LX back to glory.

In regards to AHC, yes, the system needs some shared load in order to provide adequate damping and suspension control. In the 100-series, people have also tried non-AHC LC springs, but this strategy doesn't work as it doesn't leave enough load to the AHC system. And it is only exacerbated at the extents of the suspension stroke as you've experienced. Getting neutral pressure right on the 100-series was easy as you could read it out through techstream. Just adjust neutral height with whatever spring to get at the optimal pressures.

You're forging new ground here for the 200-series. A strategy that have worked on the 100-series is to use 80-series springs. They have less spring rate than the 100-series and surely less than the 200-series. Airbags most definitely work also, but that's a rear solution only.

Another way is to preload the stock LX springs with spring spacers. This is a strategy almost guaranteed to work. It's preloading the coil springs to take the added load you have with armor, and leaving the rest of the system parameters intact. Polyurethane spring spacers as easy to come by for the rear. I have 10mm spacers to support mine. 20 and 30mm can easily be sourced.

I for the first time was able to find 200-series front spacers. It's hard to tell exactly how tall these are, but they say 20mm lift. Which makes me think they are 10mm spacers - 2 x Front Coil Spring Spacer For Toyota Landcruiser 200 Series - 20mm Lift Kit | eBay

If you want to get really creative, there exists in the world diesel specific AHC springs that are likely higher spring rates.

BTW, would love to hear more and trade stories on the Airstream. 30' no less! And see a pic.

 

[Jason London]

I drove it for a few days with the LC springs on it and the AHC pump disconnected. All the sensors were on and the AHC module was on. I never got any codes or dash Christmas trees. It rode like an ‘89 Cadillac Brougham, but I couldn’t get everything done at once and had to make a trip to a dealership to get AHC fluid.

You’d be blazing a trail. Christo Slee did some experimentation here and was unsuccessful.

What prevents AHC removal?

 

[Jason London]

I might look into doing something like some 80 series springs. I’ve been looking into making it a little taller, so some softer and more spaced out springs might be a happy middle for the system.

If I lift it I was going to cut the bottom of the AHC spring off and weld a sleeve over the shaft, making the assembly about 1.75” longeroverall. Then I would use the upper shock bolt bracket on the rear axle.

Hadn't visited your thread until now. Lots of good stuff here. Great work on bringing that LX back to glory.

In regards to AHC, yes, the system needs some shared load in order to provide adequate damping and suspension control. In the 100-series, people have also tried non-AHC LC springs, but this strategy doesn't work as it doesn't leave enough load to the AHC system. And it is only exacerbated at the extents of the suspension stroke as you've experienced. Getting neutral pressure right on the 100-series was easy as you could read it out through techstream. Just adjust neutral height with whatever spring to get at the optimal pressures.

You're forging new ground here for the 200-series. A strategy that have worked on the 100-series is to use 80-series springs. They have less spring rate than the 100-series and surely less than the 200-series. Airbags most definitely work also, but that's a rear solution only.

Another way is to preload the stock LX springs with spring spacers. This is a strategy almost guaranteed to work. It's preloading the coil springs to take the added load you have with armor, and leaving the rest of the system parameters intact. Polyurethane spring spacers as easy to come by for the rear. I have 10mm spacers to support mine. 20 and 30mm can easily be sourced.

I for the first time was able to find 200-series front spacers. It's hard to tell exactly how tall these are, but they say 20mm lift. Which makes me think they are 10mm spacers - 2 x Front Coil Spring Spacer For Toyota Landcruiser 200 Series - 20mm Lift Kit | eBay

If you want to get really creative, there exists in the world diesel specific AHC springs that are likely higher spring rates.

BTW, would love to hear more and trade stories on the Airstream. 30' no less! And see a pic.

 

[gentimmy]

Great build inspiration. Had no idea updated headlamps could be retrofitted to previous models...

 

[SWUtah]

I understand for the armored LC's used in Iraq they use heavy duty components designed for the heavier weigh from up armouring. You might check with these company's that build these armoured LC/LX's with the enhanced AHC/AVS. One of the members that took his through Africa had his enhanced.

 

[Jason London]

It was easy, but it’s expensive. The headlamp assemblies are pricey. Then you need a new signal harness, caps, and bulbs and ballasts.

Great build inspiration. Had no idea updated headlamps could be retrofitted to previous models...

 

[Jason London]

I think I saw some information about that. That’s definitely a consideration too.

I understand for the armored LC's used in Iraq they use heavy duty components designed for the heavier weigh from up armouring. You might check with these company's that build these armoured LC/LX's with the enhanced AHC/AVS. One of the members that took his through Africa had his enhanced.

 

[SWUtah]

I think I saw some information about that. That’s definitely a consideration too.

If you do the upgrade similar to the armored Lexus please let us know what components are enhanced, very interesting project

 

[RyanR]

•
I hope this answers your questions and is detailed enough.

Fantastic information, thank you! I had been contemplating adding a spacer to increase pre-load on stock springs, trying the 80 series cruiser springs, or exploring the option of a custom wound spring that is slightly stiffer but otherwise similar.

After hearing your feedback about how the AVS system responds, I wonder if keeping the spring rate similar but increasing coil length would be a better solution (for a custom coil), assuming it can still fully compress without binding.

 

[Jason London]

I think accumulator spheres with a higher nitrogen pressure is the ultimate solution. I’ve had some B&B units on my LX470 before, but they failed very quickly. I think they can customize the pressures for higher weight capacity.

As far as lift goes, extending the lower solid rod of the shock is the ideal method for 1 or 2 inches. I’ve got about 4K miles on it since it went up about an inch and I haven’t noticed any issues with front axle shafts or vibrations.

I’ll try something different this summer.

I’m pretty happy with things for now, it rides about as well as a Cruiser.

Fantastic information, thank you! I had been contemplating adding a spacer to increase pre-load on stock springs, trying the 80 series cruiser springs, or exploring the option of a custom wound spring that is slightly stiffer but otherwise similar.

After hearing your feedback about how the AVS system responds, I wonder if keeping the spring rate similar but increasing coil length would be a better solution (for a custom coil), assuming it can still fully compress without binding.

 

[electro992]

@Jason London did you ever get the rear lights installed? Curious if these are a direct fit.

 

[Jason London]

Not yet, but they are a direct fit.

However, if you don’t replace the rear bumper fascia, you will have a small gap between the outer tail light lower edge and the bumper. I’ve already replaced mine with the updated rear fascia to eliminate that gap.

On a side note. To get my old outers to fit with the new fascia I had to take a sawzall and cut about 1cm off the lower trim.

@Jason London did you ever get the rear lights installed? Curious if these are a direct fit.

 

[supercarrera]

What did you do with your running boards? Did you cut them off or replace them with the landcruiser panels?

 

[electro992]

Not yet, but they are a direct fit.

However, if you don’t replace the rear bumper fascia, you will have a small gap between the outer tail light lower edge and the bumper. I’ve already replaced mine with the updated rear fascia to eliminate that gap.

On a side note. To get my old outers to fit with the new fascia I had to take a sawzall and cut about 1cm off the lower trim.

I've read that the 2013 outer lights don't fit exactly ((first post) Upgraded 2009 LX tail lights to 2013 - ClubLexus - Lexus Forum Discussion) but am curious...to me it looks like the bottom of the outers lines up with the lines on the tailgate, which are the same part numbers (both upper and lower) on both trucks. Maybe the 2013 rear lights are a different shape that isn't obvious from pictures?

 

[airforce1]

would like to see pictures of how you wired your sub. Thanks!

 

[ranma21]

It was easy, but it’s expensive. The headlamp assemblies are pricey. Then you need a new signal harness, caps, and bulbs and ballasts.

Do you have to replace with 2013 front bumper cover in order to fit the HID lamp? Or it will fit in the 08-12 bumper cover?

 

[Jason London]

Bumper cover and grille,

Do you have to replace with 2013 front bumper cover in order to fit the HID lamp? Or it will fit in the 08-12 bumper cover?