Another project!

So I've bought this:

It is a Viair 485C and is capable of 200psi at a flow rate of 25l/min and a 100% duty cycle.
It's also supposed to be quiet according to their website (it isn't, not compared to the standard compressor anyway).

Should be good, if I can make it fit that is:

I'll need to redesign a complete new mounting and housing for the compressor and the valve block. Fun!

Has anyone come across a 3D CAD model of the valveblock? Or even a dimensioned 2D drawing?

Watching with interest. I do think the modest duty cycle of the original coupled with the increasing quality doubts of available replacements will make Viair and similar swaps more interesting, especially if coupled with on board air. Can't help with the dimensions I am afraid, but there are an increasing number of 3D scanners out there many someone will create a model for you?

JLimmelman wrote:

Has anyone come across a 3D CAD model of the valveblock? Or even a dimensioned 2D drawing?

I have never seen a 3D CAD model or even an engineering drawing of the valve block.
The outside is a fairly simple shape, just rectangular blocks, so it should be possible to draw an approximation, to aid fitting it into a case for example.
However, the inside of the valve block is quite complex, with all the ports and internal passageways. To come up with a model showing all that detail it would have to come from official sources I think.
3D scanners are getting better all the time, so that maybe the route to get a scan of the outside of the block.

Just use a spare valve block & driver pack assembly, and make a larger EAS housing ? You can use the existing hole pattern as template for the new housing.

You might need a louder stereo to drown out the pump noise !! BTW, what's that blue thing that looks like a motor ?

Yes, I was pushing my luck hoping someone had a CAD model or drawing. I don't need the interior ports, basically just a "space claim" model around which to model the box.

I'm busy with the process of drawing sucah a model using my spare valveblock as Pete suggested. Progress so far:

I'm hoping that adding some decent sound deadening material designed into the new enclosure will help mute the noise of the compressor. We'll see!

The blue motor mounted on the left front strut tower is an ARB air compressor. Currently being used for tire inflation etc. but it is also plumbed in parallel with the EAS compressor with a one way valve. I can switch on to run when the EAS compressor runs as a backup if the EAS compressor might fail.

Is this an upgrade or to mask other faults? I’ve only run out of air when I had a leak…..

Nope, EAS works beautifully for normal use.
I had the compressor struggle to keep up on one 4x4 trail where I was cycling between standard and offroad height multiple times. Not a usual use case and I wasn't surprised.

The upgrade is so that I can use the onboard air reservoir for tyres, pressurizing a water tank etc.

Sounds like a good plan!

I do remember mine giving up on an off road trial but put it down to the leaks I discovered. Maybe I would have run out of air anyway !

The only reason I can see for changing/upgrading the compressor is if you have fitted Arnott Gen III's.

The extra 2" of lift that Gen III's give takes a lot of air. It quickly robs the tank when you put it on high. Not a problem if you are up to pressure and you go off road. One lift is fine. The problem arises when you go back on tarmac then go off road again. If the tank pressure has not built back up in time, it can't get back up.
FYI when I have bench tested rebuilt compressors with new seals, it took 6 mins or there abouts to get the accumulator from zero up to pressure. This was on the bench, not the car.
I personally like Marty's idea to fit two original type compressors. Like an installed spare with the ability to switch either one or both together.

Spent some more time modelling up the valveblock.
At last!

And next to the Viair compressor:

Would be great if I can get the compressor mounted sometime this year!

Wow !

This looks great!
Did you get it mounted I'm thinking tell us how and show us some pictures please :D
I thinking of doing the same mod sice it gives kind of a good feeling with a 100% duty compressor on board ;)
Would you mid sharing your CAD files (I'm using fusion360 but .stp .step files could also work).

Kind regards/Stefan @stockholmviews.com

Hi Stefan,

Nope, not mounted yet, the compressor is still in it's box in the corner of my office, but the project isn't dead yet either.
So the current direction is to retain the stock compressor in it's stock location, and rather mount the VIAIR nearby. This allows me to use the stock compressor (quiet) to operate from say 8-10bar and only have the VIAIR (loud) come on if the pressure drops below 8bar (values will be finalised when I start testing). I'm thinking this will give me a best of both world's scenario where in traffic, around town etc the stock compressor will handle low volume air duties like cycling between standard and highway height, and it will do so quietly. Large volume air duties like pumping tyres, lifting from access to standard will be handled by the VIAIR.

The idea above necessitates some changes to the driver pack, which I am busy redesigning anyway. I'll add control for the 2nd compressor, a pressure sensor (not just a switch, so that I can use software to adjust the limits) as well as a way to manually control the valves.
The manual valve control is something I want to add so that I can manually adjust the suspension height and lock it in that height for camping (rooftop tent).

The new VIAIR location is still being discussed, but currently it looks like it will live on the left chassis rail, forward of the left from airspring mount. Basically under the steering fluid reservoir. It'll have some heat and mud shielding around it and should be easily removable if I am any good at bracket design.

I'll email you the CAD models shortly.

PS: I have a bit of a deadline for this project now, so hopefully it'll actually get done. We are doing a desert river exploration trip early in next year, and the pneumatic system needs to be done by then so that the air lockers and vehicle levelling works as I want it.

stefan63 wrote:

Would you mid sharing your CAD files (I'm using fusion360 but .stp .step files could also work).

Kind regards/Stefan @stockholmviews.com

I tried sending you the CAD files, but it seems your email address is blocking it?
This is the response I got:
Message blocked
Your message to Stefan@stockholmviews.com has been blocked. See technical details below for more information.
The response from the remote server was:
550 5.1.1 Unknown recipient

Cheers,
Justus

JLImmelman wrote:

stefan63 wrote:

Would you mid sharing your CAD files (I'm using fusion360 but .stp .step files could also work).

Kind regards/Stefan @stockholmviews.com

I tried sending you the CAD files, but it seems your email address is blocking it?
This is the response I got:
Message blocked
Your message to Stefan@stockholmviews.com has been blocked. See technical details below for more information.
The response from the remote server was:
550 5.1.1 Unknown recipient

Cheers,
Justus

Thank you!
Try stefan63@gmail.com instead!
Your idé and project sounds nice looking forward to the folow up report when you have tested you new system.
stockholmviews.com is my website and you can find some P38 related stuff there if you find it interesting (https://www.stockholmviews.com/p38/).
I'm also working on a alternative pressure/over temp contoller based on a arduino nano some info on that can be found in my FB group https://www.facebook.com/groups/RRP38. Kind regards/Stefan

Perfect, mail sent.

I checked out your site, some interesting content there. I'll browse more at a later stage.
I don't do social media, so sadly no way for me to check out your page.

Cheers,
Justus

Time for an update. The system has been running flawlessly since March, done some trips in the vehicle including hot dry conditions and also some wet and cold too. Other than some leaking fittings initially there are no problems to report.

The compressor is mounted on the left chassis rail, just below the MAF sensor (unplugged in the pic below).
It's mounting bolts onto the chassis using existing mounting holes, and it incorporates an aluminium heatshield to "protect" it from the exhaust manifold.

This CAD image shows the setup in isolation quite nicely:

And here, fitted in the engine bay:

The compressor itself is surprisingly quiet. If it is running I can only hear it inside the vehicle at idle with the windows open. While driving I can't hear if it is running at all. It has enough oomph in conjunction with the standard air tank that it can, and has, reseated a debeaded tire.

To control the compressor, and set my mind at ease w.r.t. failing driver packs (I've replaced 2 with 2nd hand units), I decided to redesign the valve driver pack.
The scope here was to:

1. Control the new compressor intelligently, ie, only run when needed
2. Perform the standard valve driver pack functions of being an interface between the EAS Controller and the valveblock valves
3. Offer valve state (on/off) and system pressure information via CAN (J1939 based protocol)
4. Report valve or driver faults (open circuit, short circuit, driver overheat) faults via CAN
5. CAN control that allows me to override the valves, ignoring the EAS controller if desired. More on this later
6. Fit in the standard location between the valveblock and the standard compressor

Test fitting the PCB into it's 3D printed housing:

In its final location:

The new driver uses two connectors, instead of the single connector on the standard driverpack. One connector interfaces to the valveblock only and is in the standard connector location. The 2nd connector is under the compressor motor housing (unplugged in the image above) and this connector interfaces with the vehicle (power supply, EAS controller interface etc). This approach allows you to unplug the single connector and remove the valveblock assembly including the new driver pack as one part.
There is also a small circular connector visible in the image above, just below the 2nd valve from the right. This is a programming connector to flash the microcontroller in the new driver pack. It is now redundant as we have developed a CAN bootloader and we can now update the valve driver pack software via CAN.

Here you can barely see the new driverpack hiding between the valveblock and the compressor. Tight!

Currently the new valve driver pack has 3 operating modes.

Standard operation:
The valve driver interfaces between the EAS controller and valveblock as the standard unit does, with the 2nd compressor "helping" the standard compressor on occasion.
The standard compressor runs and is controlled by the EAS controller as it usually would. The 2nd compressor only runs if the EAS controller requests the standard compressor to run and the system pressure is below a set threshold and the vehicle is moving (ie. not stationary at a traffic light).
In reality in this means that the 2nd compressor only runs after a large drop in system pressure like you would have if moving from access height to standard height twice in succession. In a normal use case like highway to standard height the 2nd compressor will not be required to run and the standard compressor will do the work. The vehicle speed interlock which only allows the 2nd compressor to run if the vehicle is actually moving also means the system is as silent as it would normally be, nice!

Tire Pump Mode:
Selected via a switch in the EAS valveblock housing, near a new air supply port.
In this mode the 2nd compressor is used to maintain system pressure to allow the user to pump tyres from the standard air tank. If the engine is running while in this mode, the EAS controller will still have full control of the valveblock and the standard compressor and the standard compressor will run as required to maintain the system pressure and the 2nd compressor will supplement this, thus lightening the load on the standard compressor. If the engine is not running in this mode, then the 2nd compressor will run on it's own, doing all the work and keeping the standard air tank full.

Override Mode:
Selected via a CAN message.
In this mode the EAS controller is ignored and all valve and compressor control is done via CAN messages. Any of the valves can be switched on or off as requested, and the controller remains in this mode, thus ignoring any levelling requests from the EAS controller, until the vehicle starts to move.
I use this mode to level the vehicle when we are camping and sleeping in the rooftop tent. It is worth noting that, as standard, the EAS controller does not actually level the vehicle. What it does is ensure that each corner of the vehicle is the same height off the ground, so that if the vehicle is, for example, standing on a sideway slope with one set of doors high off the ground and the other side low to the ground it will lower the higher side until both sides are at the same height, thus allowing easier ingress into the vehicle on the high side. This leans the vehicle body over even more.
This mode works really well for our overlanding trips. We can stop, not caring how level the surface is, level the vehicle electronically, sleep well in the rooftop tent, and the next morning just drive off with the valve driver reverting back to Standard Operation as soon as the vehicle starts to move.

Offroad Mode:
No implemented, in planning.
The basics of this mode is to balance the pressure in the suspension air bags, from left to right (front to back remain isolated) while driving over uneven terrain. This will act almost like a swaybar disconnect, relieving suspension load from the side that is articulating up, and applying more downward pressure to the side articulating down, This is the theory anyway, testing will determine whether it works this way in practice. I need to develop a control interface for this mode that makes sense and is easy to use while not interfering with the drivers concentration. Time needed...