Air Suspension going on a '69 E3

[dang]

I'm finally getting back around to putting the air suspension on the E3 so I thought I'd start a separate thread for it. So far this is what I have...

1969 2800. Stock and very original.

Will be fitted with 17" Style 5 BBS wheels from an E39 5-series sport. Others run these wheels on lowered cars so I know they'll fit and the air bags are slightly smaller diameter than the stock springs so that should also help. This is a test fit. The fronts rubbed on the strut tube and will require spacers, but I think I would've preferred that anyway based on where the wheel sits.

Air system is an Air Lift Performance kit off of an '08 Lexus IS350. The rear struts almost bolt on as-is, only needing some adapter plate for the tower mounts. I'm trying to put this system on with as little modification to the chassis as possible, we'll see how that goes. The front struts need to be modified so that's where I'm starting and I'll post my hand drawings and notes, I don't have them with me right now.

Here's the air system with one rear strut sitting next to the rear air struts.

Front struts will need to be cut off and a new tube welded on to hold the threaded air strut tube. I know how to weld but I'm not a welder so I'll take my drawings and parts down to a friend who fabricates automotive and off-road builds. I want to feel confident with the suspension I'm driving around on.

 

[coupedegrace]

Cool! Maybe you should call it the Bavarian Bagger. I've never seen the parts laid out like that before. How much juice does the system require? Will the stock alternator, etc. handle it, or will you need to go with something a little more powerful?

 

[dang]

Cool! Maybe you should call it the Bavarian Bagger. I've never seen the parts laid out like that before. How much juice does the system require? Will the stock alternator, etc. handle it, or will you need to go with something a little more powerful?

It has a small compressor that you can see on the left side of the photo. It doesn't draw much and doesn't/shouldn't come on very often. Pressure settings and adjustments are made through an app on your smart phone.

 

[Mike Goble]

Whoever gave you those struts must be a helluva guy...

 

[dang]

Whoever gave you those struts must be a helluva guy...

He is! They came with the 50mm collars I need too!

 

[e30strube]

When I switched the rear end of mine to the E28 setup, I put a new set of bags on the rear. I still have the old ones and can get you a pic of it if it helps.

 

[dang]

When I switched the rear end of mine to the E28 setup, I put a new set of bags on the rear. I still have the old ones and can get you a pic of it if it helps.

I'd love to see other setups..

 

[dang]

Here's a sketch of the dimensions I'm working with. The ride height is determined by the overall height of the strut. That sounds pretty obvious, but a LOT of guys running air suspension think the airbag sets the ride height so they end up with a height they want in lieu of a good ride.

My process for determining the length of the strut tube on the modified strut was to measure the overall length of the stock strut with the car on the ground, then measured the ground clearance under the frame rails (approx. 6"), then estimated that I'd want to start with a 2" drop. This would clear the fenders and give me about 4" or so ground clearance. This is only a starting point so it may end up different in the end.

24 3/8" Stock strut length
22 3/8" Air strut length (starting point)

8 1/2" Airbag extended
4 1/2" Airbag compressed
6 1/2" Airbag midpoint that I'm starting with

The 22 3/8" strut length is a constant (until I decide I want a different ride height) so if I need to add or reduce pressure in the bag to get the desired ride (not ride height) then the strut tube is adjusted to keep the overall dimension constant, or the tube is adjusted for ride height.

Another way to look at it... If you're lowering a car by putting shorter springs on you typically put on stiffer springs. I don't know of anyone that has put on softer springs to lower a car but who knows. If you think of the airbag as the spring it does the opposite of what you want. When you lower the pressure or height of the airbag it gets softer, so to get the correct stiffness using an airbag you need to increase the air pressure, making the airbag longer, then turn the threaded strut tube down to compensate for the longer airbag.

After all that babbling I ended up needing a 12" tube welded on the strut. A friend is a fabricator so I'm having him do the important stuff.

 

[dang]

Front struts are at the fabricator getting modified so I started working on the compressor/tank/manifold assembly in the trunk and the rear struts. The rear air struts are very close to the OEM E3 struts in size and length, plus the bottom mounting sleeve is the same diameter so all I had to do was shorten the sleeve a little bit for it to fit. I made a simple adapter plate with welded bolts on the bottom plate (ignore the lousy welds) and a top plate as a washer. I mounted the air strut and everything looks great and should have plenty of clearance for the wheel and tire.

 

[dang]

A little work going on with the project but not much. I was originally going to hang the compressor/tank assembly from the strut towers in hopes of isolating the vibration more but after messing with it a bit I changed my mind and will just use a board like others do. I'm going for functionality over aesthetics so I made a metal frame to hang the manifold on and use to attach the cover on the front. I'll put some insulation behind the assembly, underneath and on the front cover and leave the sides and top open.

 

[Candia4441]

A little work going on with the project but not much. I was originally going to hang the compressor/tank assembly from the strut towers in hopes of isolating the vibration more but after messing with it a bit I changed my mind and will just use a board like others do. I'm going for functionality over aesthetics so I made a metal frame to hang the manifold on and use to attach the cover on the front. I'll put some insulation behind the assembly, underneath and on the front cover and leave the sides and top open.

View attachment 139772

View attachment 139773

It is very nice setup and it must be soft ride am I right How much is this are you selling this part or you offering to install what is the story

 

[adawil2002]

If & when I buy a Mercedes 600 SWB, I'll probably replace the problematic air suspension with something like your E3.

 

[dang]

If & when I buy a Mercedes 600 SWB, I'll probably replace the problematic air suspension with something like your E3.

View attachment 139793

Seems like there would be quite a few alternatives nowadays. A strut setup would give you a lot more control that's for sure. I've seen youtube videos showing why Land Rover air struts fail, cutting them open and looking at the design. I wonder if there's an "upgrade" to the stock setup on the 600.

 

[dang]

It is very nice setup and it must be soft ride am I right How much is this are you selling this part or you offering to install what is the story

Adjustable ride and adjustable height so you can tune it to your liking. Just having fun with my E3, that's all.

 

[teahead]

Can also get pointers from @floridabmx

 

[dang]

Can also get pointers from @floridabmx

I think I got lucky with how well these air struts are going to work on the E3. Since the air systems are fairly simple it's just a matter of how well the struts mount. I won't know for sure until I get my front spindles back from the fabricator.

 

[dang]

My fabricator friend sent me this pic this morning. Looking good...

 

[Mike Goble]

Struttin' yer stuff...

 

[dang]

Picked up the front struts this weekend and I'm very pleased. I still need to weld on the brackets for the brake lines and backing plate and put some paint on them before swapping over the hubs. I bought new bearings so I'm hoping that part goes smoothly. He used a short 3" sleeve on the bottom and plug welded for more strength (and alignment).

 

[dang]

Some progress with the suspension. Everything is installed and now working but I need to clean up the lines and finish some details before I can drive it.

*** Warning, boring content follows ***
For those not familiar, these systems come with a hard wired controller and also bluetooth to use with an app on your phone. My used system didn't have a controller so I was just going to use the app, but I couldn't get it to pair with my phone. I never got a bluetooth signal from the ECU/manifold so I decided to buy a controller. I'd rather have a hard wired controller anyway but firmware updates are done through the phone/bluetooth. I hooked up the controller and it immediately says "Firmware update needed" and was barely working. I was stuck so I contacted Air Lift Performance and they said they've had some issues in the past with Android phones not connecting. My friend came over and used his iPhone and connected right up! Yay! He did the firmware update over internet/bluetooth and now my controller works good. I still need to figure out the app thing eventually.
*** Boring content complete ***

Here's a few photos of the struts mounted. I'm making a video of the whole project and will post when I'm done...