rob_fed

Here is my take on making my airmatic driver adjustable front and rear system.

• forum research
• wateproofed micro rc servos
• custom links between the servos and height sensors
• cabin ashtray mounted servo controls
• many hours of testing via bench, off car and on car
• proof of concept

Front and rear links can be easily replaced with the stock ones. Everything bolts in using the existing holes and mounting locations.


Front servo assembly:

Bench testing:
Front servo install testing:

Front link disassemble:


Front link servo installed:


Rear system:

Stock link:


Rear servo link assembly:


Control panel:

Ashtray mounted: L-to-R function
Front height/Rear height/Exhaust open/Exhaust close




Front height range:

High:


Low:




Low outside:



11/02/13 - More views



Lowest setting side view: Note: Front tires rub when turned, cannot drive safely at this setting


Highest setting side view: Note: "raise" switch in "off" mode


Rear wheel at the lowest:


Note: Sensor arm cannot be moved any lower with the rear servo due to the end limit of the servo itself. But the sensor arm still has a little more to go.

corkshoppe

awsome, when can i buy the system.

tusabes

Wow
Will you be selling kits for us to do this ? How much ?
And how many hours to install ?

rob_fed

Oh no ... Selling was not my original intent.

corkshoppe

ok, so ill take it for free, but i will include a big tip! this is freaking awsome, you can buy you a 2014 with the money you'll make, if not how about i test it on my car for you!

rocko

Make one for an ABC and I'll tip generously too.. Lol! ;p

ibeforreal

Rob,
I don't know what you do for a living but I'm sure you can make a ton of money on this idea. You better talk to Skylaw about getting your design copyrighted.

rob_fed

Thanks everyone you all are too kind!!! This was just an idea that I wanted to prove to myself and to show that it worked. There is some fine tuning I could or need to do, but I don't think it is production worthy without additional tweaks. My day job is an integrated circuit designer.

corkshoppe

your brain is sick. if you dont intend to sell it maybe a complete parts list and info would be awsome, post on youtube of the car moving. this truly is an awsome mod.

tusabes

Rob fed we have all been waiting for something like this !!

Even if you don't want to make kits to sell , a parts list and instructions would be greatly appreciated

I think we would be happy to tip you for it

rob_fed

I was going to edit the original posting to include this parts list and assembly notes. But after some time, the original no longer can be edited.


Parts I used:

Threaded 4-40 push rod from any hobby store for RC vehicle use:


RC airplane Dubro brand clevis' 4-40 size:


Home Depot epoxy putty found in the plumbing department:


Small steel L-brackets from the Home Depot hardware departement:


Ebay - Micro RC servos -> search for mg90:


Note: These are not waterproof, you must fill the gear case with grease and coat the servo with PlasticDip Spray coating to insulate everything. You can find out how to do this if you search for "waterproof servos" on YouTube.

Ebay - Ordered 2 Esky servo testers for control units:


Misc:

1/4" hardward bolts and nuts (what I had at home) metric equivalents would be better.

Wire - I used 22-2 alarm wire found at the Home Depot to hook up the servos to the servo testers. You will need to cut and splice wires to complete the hook up. 22-2 alarm wire has 2 conductors and 1 metal shield wire. I used the shield as the ground connection.


Assembly tips:

Close up of one front servo assembly, you have to use epoxy putty to mount the L-bracket to the servo. I used some small galvanized wire to secure the L-bracket as a safety connection.


The rear assembly is more complicated, it took many times jacking the car up/down and crawling to get everything to mount correctly without binding when the servos move back and forth. Here the details...

Rear servo assembly:



Hopefully these additional pictures and notes will help anyone wanting to duplicated my process. The assemblies work and I can adjust the front and back when ever I want whether moving or standing still.


But there there is room for improvement:

The front control uses the full swing of the servo. I set the servo contol arm for more downward movement to get the car as low as possible at the lowest limit. But at this setting, the front tires will rub if you turn the steering wheel.

The rear control has been modified to only use about 2/3 of the rotation of the control knob. This is because the servo control arm swing is too wide or the arc too long. If you set it at the highest position, the rear raised way too high. I limited the control knob as not to over inflate the rear springs. The lowest position is not as low as the front can go, but is drivable. Probably best to leave it this way.

Also, I chose to mount the servos this way so that height sensors still react when the car is loaded or unloaded. You could probably just hook the servos up to the height sensors and not worry about the control arms. But you would lose some of the original functionality.

The speed control lowering still works, but if the system is set too low to begin with, you may run into issues when the car automatically lowers itself at highway speeds.

One other point, from my very low setting to the highest setting if I move the both knobs to the high position, the system will give you a dash error indicating the car is too low. The airmatic pump cannot react quickly enough to prevent the error. The error will clear itself as the car raises up to the upper control position. It is self tester for the system.

Anyone wanted to try this out does at their own risk. Your airmatic system should be in good working order before you experiment. Wear and tear on the airmatic system will increase along with possibly tire wear pattern issues if you drive too low all of the time.

I am open to questions and could even entertain helping build some of the small parts, but this would have to happen after further individual discussion.

rob_fed

Since this whole thing was a big personal experiment, There are other hardware pieces that could be substituted to be more durable. There are many other ways to accomplish the same thing.

* You can go to the dealer and have the airmatic control box reprogrammed to a new ride height.
* You can just by adjustable sensor control arms and set them to your desired height and be done with everything.
* If you want an electronic solution you can buy a Renntech lowering module kit
* You may be able to hook into the stock height sensors and piggy back some hardwire connections to change the voltages sensed by the airmatic control box to adjust the ride height.

I chose this way since it exploits the stock height sensors without introducing additional electrical connections to the stock system. And it is reversible by just removing the servo/arm units and replacing with the stock height control arms.

tusabes

The existing solutions (lowering links , washers etc) dont allow for in car adjustability , thats why your setup is awesone

and i think the renntech module is $1000+ and doesnt drop the car as much as your system. How much is the total parts cost for all that stuff ?

rob_fed

For what I made I have less than $150 in parts, but many hours were spent experimenting with each piece.

The Renntech device is probably the best way to adjust the suspension as you do not have to modify any of the mechanical components of the Airmatic system. The hi/lo ranges of the Renntech kits are to protect you and them. I don't think they would want to sell you something that will over inflate the air springs and on the other side, allow you to lower you car so much that it is not drive-able.

shardul

iTrader: (1)

Fantastic!

silverjimm

Very Awesome!!!

rob_fed

Auto manufacturers go to great lengths to get vehicle control ergonomics to work properly. Adding some controls in the ashtray is go for hiding, but sometimes hard to use. Moving the small knobs to position them has been a little challenging.

For a visual aid I added two voltmeters connected to the servo adjuster potentiometers to indicate position. This way can glance to see the numbers, still not the best but better than before.

S600Keith

WTH is wrong with you? This is certainly a no-brainer money maker. You could sell the parts kit with instructions for about $500 EASY!! Maybe more...

Why would you not want to take advantage of this? With that expertise you have you could certainly make something for any of the pneumatic or hydraulic systems offered by MB and other makes also.

Are you nuts!!

tusabes

And if something goes wrong his customers will complain , chargeback , or worse ... Sue him.

That's why he isn't interested in going into business

corkshoppe

ill sign a waver!

rob_fed

You captured my worst fears of trying to sell something like this. The whole setup needs to be be simplified. I am still experimenting

S600Keith

Yeah. I had not thought about that. In our over-litigious society someone will surely sue over something that is completely not Rob's fault. I can see it now. Someone will lower their car so much that it is rubbing the tires while they drive. They will sue Rob for new tires because his lowering kit made the car rub the tires.

Touche sir.

tusabes

If being sued for new tires was the worst issue that wouldn't be so bad ....It's when they rubs the tire, they blow out , and a serious accident occurs. That's the risk .

corkshoppe

ok, then get a pattent, go on shark tank find some investors, hell ill put some in!

dagentooboy

I am also an electronics designer. I work in aircraft on some control systems like this. I am thinking about trying something similar on my GL320. I have had great luck with a bluetooth 4.0 chip on some other projects and I was wondering...

would something like this need a controller in the car or would it be enough to pull up an app on your phone and change the ride height or would it be preferable to have controls in the cabin?

Is there any resistance to the sensors or do they move freely?

I was thinking a weatherproof linear actuator like we use on aircraft would be a lot more reliable (yes it would cost more) but it is rigid at a single position and you have to command movement. Most of them have a RVDT or something to read the position that would be really handy to verify that all 4 actuators were in the right position.

I think the linear actuators would provide a lot better reliability.