Spectre6000's Crazy Idea Thread #2: Variable Suspension

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spectre6000

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I know for a fact this is not a new idea, but I can't find where it's been done on a 4Runner anywhere. Suspension height is a crucial aspect of a viable off highway vehicle, but is a liability to a daily driver. Moving the center of gravity higher affects handling and aerodynamic drag. We find ourselves having to strike a compromise between lower, better handling, economical suspension or a high clearance, high center of gravity, low efficiency suspension. It's pretty common in higher end sportier vehicles these days to have adjustable suspension height via airbags (mainly for speed bumps though). I want to know if anyone has tried to install a system of some sort on their 4Runner that allows it to ride at stock height as a DD and at some predefined (or infinitely variable) degree of lift. It seems like it would be a fairly straightforward modification with significant benefit, so why is it not done?
 
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tried to install a system of some sort on their 4Runner that allows it to ride at stock height as a DD and at some predefined (or infinitely variable) degree of lift.
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What is a "variable suspension" in specific terms?
 
Because its not straightforward and it would be really complicated to get everything to work properly. Plus anytime you change the height of your truck, your alignment also changes.
 
Generally it's an airbag system that inflates/deflates to alter ride height. Typically it's used for high end sports cars so they can get over speed bumps and such. Lately I've seen it implemented in some higher end SUVs to accomplish exactly the sort of ends I'm looking to accomplish.

I imagine the easiest way to make it work would be to install some fairly stiff air bags like you would coil spacers to maintain a more or less stock ride quality. Go from zero airbag lift (roughly stock height) to 3" or so (off road ride height).

Alignment is certainly a consideration, but it seems a bit less critical in off road driving (though I may be missing something). I wonder how (or if) it's addressed in the various OEM applications. It doesn't seem like it would be really all that complicated to implement...
 
So basically you want your suspension to be like that of a Range Rover, Tourag or Q6? Where you can turn the nob and the entire vehicle either lifts or lowers?
 
Brentif said:
So basically you want your suspension to be like that of a Range Rover, Tourag or Q6? Where you can turn the nob and the entire vehicle either lifts or lowers?
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More or less. It seems like it'd be fairly easy. So much so that I expected to be able to find a kit (though that was a bust). I've never looked into air suspension systems, but in principle it doesn't seem all that complicated. Kind of like a reverse gangsta-style low rider (the cheap kind).

It might be as simple as some sort of adjustable air shock (the sort where the shock doubles as the spring).
 
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The problem with air bags or adjustable shocks is that they effectively increase your spring rate, exactly what you don't want off-road. Kills your flex.

If you were leaf-sprung, I could see some kind of mechanized adjustable shackle, maybe like a revolver when it's unfolded?

Maybe if you put an airbaggy thing on your body mounts.

Doesn't somebody make a remotely adjustable sway-bar? I think that'd be a better solution than adjustable suspension.
 
Red Green built a variable suspension car. It begins @ 7:00 minutes.:peace:

The Red Green Show Ep 228 "Go Fish" (2002 Season) - YouTube

Seriously though, I think maintaining the alignment with height changes would be the problem. You'd have to come up with something to change the length of the upper or lower control arm, or some cam system to keep the camber and toe-in consistent. A little height change moves the toe-in a long way on these 3rd gens.
 
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After a quick look-see (Phantom seems to be the best option I've found thus far), cups seem to be exactly what I had in mind. Doesn't seem to be a whole lot out there though... Bag overs might make for a decent option as well.

It also feels like there might be some compromise I'm failing to see.
 
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I have about 6" of adjustable lift on my 2nd Gen. I did this so that I can fit in a 7ft. Garage even though I am on portal axles and running 40" tires. I am probably the only non-buggy on the planet that can still do this. If I air down the tires I can get it under 6' overall height.
The only difficult part was finding the sweet spot to set up the steering and suspension geometry for street/highway driving. Now I can run down the road at 70mph all day and still have more lift if I needed it. I believe this is easier with solid axles than it would be with independent-- especially mixed on both ends as is the case with our runners.
But I don't generally need more lift. What I really love is the ability to level the rig right to left in off camber situations. Even on extreme sidehills I can generally level out and keep everyone comfortable and worry free.
 
One other advantage I didn't see discussed-- active suspension. Computer control of the bags with ride-height sensors to detect movement at each corner and the system will react fast enough to counter body roll in hard cornering at any speed. (I have had it up to 75mph) I can toss this rig into turns and the system does keep it in the realm of reasonable performance-- especially considering what it is. In quick, successive turns, the air compressor needs to run more often so I can't just do it all day long running on compressed air. I have found that I really like just running on CO2 and a 15# bottle lasts me about a day of wheeling plus the 30 or so mile trip each way to the trail head from my house. That also includes airing up the 40's before hitting the pavement.
 
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