XJ on air suspension

[Skruffy]

*All the work done here was done about three years ago, I am now now posting about it in hopes that someone else is interested in the project. When I did this project I wasn't planning on making a thread so photos are limited. I am overseas for the summer and not with the Jeep so I dont have the ability to take any additional photos until I get home*



After driving a WK2 with the quadra lift suspension I got to thinking... It sure is nice to have adjustable suspension... I like tinkering... Would it work for an XJ?

Where there is a will there is a way.


The WK2 system is of no use for an XJ other than inspiration, nobody makes an air suspension for an XJ that I am aware of. OffRoad Only's AirRock system for TJs and JKs was a good place for me to start. I called Steve, the owner of Off road only and asked him about putting this type of suspension on an XJ. He was super helpful and told me he did one XJ years ago using a modified version of his TJ kit. I didn't want to buy his entire system since the dabbling is my favorite part but some of his parts would be perfect. In particular the electronic sensors, the air springs themselves, and the upper spring mounts for the front end. The rest of it would all be my endeavor.


The first step for me was to replace the rear leaf springs with a set up for coils. After some investigating I chose the clayton's off road conversion kit. Super high quality, relatively easy to install. The downside to this kit or any like it is that it makes routing your exhaust very very difficult. Compound this with a suspension that flexes like nobodie's business and it ultimately become impossible with my setup (engine swap)to run a muffler or to reach the very rear of the vehicle. Not ideal, but acceptable.

Rear axle pulled

The crossmember section welded in

Rear axle. This is from a TJ rubicon. Been on the XJ for 8 or so years.

Cut the holes for the Clayton’s upper spring mounts.

 

[Skruffy]

I am having issues with uploading photos. Tapatalk errors. Might be a while till we see any progress on this thread.

 

[denverd1]

that sucks! very interested. restart your phone?

 

[Skruffy]

Making a bunch of measurements to ensure the correct ride height

Tacking in the spring perches and getting the driveline angle correct.

Because the vehicle can now go from somewhere around 3” of lift from factory to about 11” I had to be smart about the drive shaft angle. The air springs that I got from off-road only have a ride hight setting that I based everything off of. While I wanted to have the Jeep sit as low as possible during highway driving it can only go so low before things start to hit. The first was the rear shocks so they got completely remounted actually had to bring the upper mounts into the cargo area (sorry no pics of that). My next limit was the track bar hitting the front differential. A mod there gained me another couple inches of compression. Lastly was the front shocks hitting the bump stops. I lowered the front shock mounts and now at full compression the bumps are slammed just before the tire contacts the fender well. Perfect.
I am using radflo 10” shocks that are made for air springs. The shocks themselves are meant to be limiting for down travel which is needed to prevent the air spring from being pulled apart.

 

[Skruffy]

Other than the shock mounts being in a different location this setup would be the same as any other XJ with front and rear coil springs. Air springs are pretty easy to install since when they are empty the are flexible. Just jack up the vehicle and put them in like any other spring, only easier. I had to do a little trimming to ensure the rubber cant contact anything. Ripping a hole in one on a trail wouldn't be catastrophic but riding home on a bump stop isn't fun either.

This is when things start getting weird! I had some decisions to make about how to go about this. It would be relatively easy to just manual inflate each bag and you wouldn't really need sensors other than an air pressure gauge but what is the fun in that? I wanted to control this thing with an arduino microprocessor so that was what I did. If you aren't familiar with arduino imagine a tiny computer with no display or anything that you program with a computer. You write the code, the arduino gathers inputs from your sensors (think wires going in), processes the information, then sends signals out of the output pins (think wires going out). The outputs depend on the inputs, just like any computer. I have a bit of hobby experience with arduino from before but this project was well beyond anything I had attempted previously.



Things I needed


air tank
air compressor
in/out solenoid for each air spring
plumbing
sensors for air pressure, and position of each air spring
arduino
LCD display for the position data and air tank pressure

some sort of control panel
ungodly amount of wiring


the next couple posts will go over these items in more detail

 

[Evan03]

This is awesome

Sent from my SM-G960U using Tapatalk

 

[Skruffy]

This is awesome

Sent from my SM-G960U using Tapatalk

Thanks bud. I will continue to add some stuff over the next week or so.
Glad some people are interested.

 

[Scrubber3]

I'm on board. Not something I'll be doing but I like this content. Thanks for sharing

 

[Anak]

Very much interested!

Was holding off posting until you got your content up.

Once I see the whole thing I will probably have questions and want more pictures.

 

[Skruffy]

For the air tank:

I needed rockers and I needed air tanks so....
I used 3x5 steel tubing and made some rockers
Then sealed them up. Tapped 1/4”NPT hole for threading in my lines. Pressure tested and welded any holes. This took a bunch of tries.



My original paper thin rockers

Welded up and ready for primer

Getting ready to weld the rocker in place

Passenger side installed. I used some bondo to smooth over all the welds and then put a little black paint on

Welded and bondo'd (?) ready for paint

This is a view looking down from the driver side rear seat. I needed a safe way to get the air in and out of the tanks (where it wouldn't get smashed). I removed this little plastic thing and put my holes here, then with 90 degree fittings it made the plumbing work out well.

All in all this little bit worked out great. Now I have two giant air tanks and rockers.

 

[Skruffy]

Here is my air compressor solution. This thing is acceptable but not great for high demand. It has a 15 minute per hour duty cycle which cause me the amateur computer programer a great deal of trouble, more on that later. What is good about this is that it fits very nicely in this otherwise useless space in the back. Much later down the road during an engine swap I relocated my battery to the rear cargo area and having a nice short run of wire really made a huge difference in performance for this compressor. From 0 psi to 147psi takes about 11 minutes, used to take about 15. If I dump all the air out of my springs and have a full air tank I can completely raise the jeep about 3 times before the pressure is too low to lift it any more. Of course the compressor would come on at some point but just running off the compressor with no tanks would take several minutes to raise the vehicle.

 

[Skruffy]

This is where the madness really starts! Time to build the brains of the operation.




Here is the basic board that I used. An arduino MEGA big green thing on the top left. Next to that is a series of 8 relays. Each air spring needs two solenoids; one for air in and one for air out. At a very basic level the arduino sends 5V to the relays to close them, this in turn allows current to flow to the solenoid and opens or closes them as needed.
The little board with the two relays on it is for the air compressor. Because of the limited duty cycle I needed to control the run time with my arduino. I am not kidding when I tell you that I spent more time trying to "invent" the code to handle this duty cycle than I did installing the long arm kit. I had something that sort of worked but was very cumbersome as far as software is concerned. One of my buddies who has a Phd in computer sciences was in town and I had him take a look at my code, he chuckled, pecked away at the keyboard for a few minutes rewriting the duty cycle portion that I had. Much more elegant solution, much more stable, uses a fraction of the processing power that my code used I really should have asked him about it weeks before! Not much of a hardware problem but for a guy like me the software was a real head scratcher. If folks are interested in the software side of this project let me know. It is some real nerd stuff that will be painful for people that are not familiar with coding.

Here are all of the solenoids mounted to an unused drawer I made for my kitchen a few years back. The blue strip on the right side is the high pressure manifold. No need for a low pressure one since everything vents to atmosphere.

The next two photos here are some that I took for future reference but give you an idea of the madness. The CAT5 data cables were used to send sensor, switch, and display data.

After about a month of nights and weekends here is the final mounted product. Came out pretty slick IMHO. I have never been too terribly interested in making things look super nice. Of course I put a quick release air fitting on here too (silver pipe) because as we all know compressed air is super handy dandy.

 

[Skruffy]

Here is a link to a 2 minute video a demonstration.
https://youtu.be/UB84N1JwLXs


I don't have any more useful photos right now but when I get home in a few months I can take some if needed.

 

[Anak]

Very cool. Even a cute helper.

In what language did you program the Arduino? Varmint #1 plays with those. If it is a language he knows I will be interested in the code.

I would like to see a picture of the controller that your helper was using to raise/lower the Jeep. I am sure you must have the ability to control each corner separately. I would like to see how that is set up.

 

[Rusty_XJ]

This is where the madness really starts! Time to build the brains of the operation.




Here is the basic board that I used. An arduino MEGA big green thing on the top left. Next to that is a series of 8 relays. Each air spring needs two solenoids; one for air in and one for air out. At a very basic level the arduino send 5V to the relays to close them, this in turn allows current to flow to the solenoid and opens or closes them as needed.
The little board with the two relays on it is for the air compressor. Because of the limited duty cycle I needed to control the run time with my arduino. Not much of a hardware problem but for a guy like me the software was a real head scratcher. If folks are interested in the software side of this project let me know. It is some real nerd stuff that will be painful for people that are not familiar with coding.

Nice! Definitely interested in the coding side of things. I have been considering a similar setup. Thanks for laying this out for us.

 

[maxbraketorque]

Pretty cool setup. Besides being able to adjust for on- and off-road, it seems like this would be handy for dealing with steep inclines or declines.

What is the front and rear wheel travel?

BTW, what size tires are those?

 

[sdspearo]

Pretty cool project!
Having played around with arduino's for basic stepper motor control, I can appreciate the programming required for this.
For reference, Puma makes a good constant duty 12V compressor.
I imagine you have preset settings, e.g., "highway driving", "normal around town driving", and "entry/exit", and can control each bag/corner separately?
Would like to see some pics of the airbags.

 

[Skruffy]

Very cool. Even a cute helper.

In what language did you program the Arduino? Varmint #1 plays with those. If it is a language he knows I will be interested in the code.

I would like to see a picture of the controller that your helper was using to raise/lower the Jeep. I am sure you must have the ability to control each corner separately. I would like to see how that is set up.

Anak
Thanks bud. All of the coding was done in the Arduino software that is free to download. It is based of of C+. I would be happy to send you the code if you PM me. Just understand I don’t have any formal training in coding so it is probably pretty sloppy although it has been working great for over two years.
I’ll see if I can get my lovely wife to snap a photo of the controller.

 

[Skruffy]

Nice! Definitely interested in the coding side of things. I have been considering a similar setup. Thanks for laying this out for us.

Thanks rusty.
PM me and I’ll send you the code. It will be an arduino file so if you don’t have the arduino IDE you need to download it. It’s free!

 

[Skruffy]

Pretty cool setup. Besides being able to adjust for on- and off-road, it seems like this would be handy for dealing with steep inclines or declines.

What is the front and rear wheel travel?

BTW, what size tires are those?

I have been very happy with it. Even used it a few times on gnarly side hills to transfer weight like you mentioned. It has its limitations but also some serious advantages over regular springs.
All of the shocks are 10” so that limits downward travel. This thing flexes like nobody’s business.

Those are 35” tires.