S8 Air suspension build
 

Hello all,

I've been working on an air build since June. By working on the build, I mean I've been waiting on a company called BagYard from Austria to build a bolt-on kit for me. They continue to drag their feet, so I'm done waiting. Here's what I'm doing then.

I already have my management, compressors, tank, etc. I'm using twin Viar 444c compressors, a 5 gallon aluminium tank, and a management system called Accuair E-Level. E-Level uses height sensors to determine height instead on bag pressure. This negates the need to have additional gauges in the interior, only a touchpad controller is found. Another benefit is that when weight is added to the car the suspension automatically compensates and levels the car to the desired height. The system has three preset heights and also allows for full up or full down at the press of a button, or one could change heights on each corner as desired. The system uses a four corner, eight valve manifold. Lines are 3/8 inch, but with this manifold height adjustment won't be jerky or unwieldy. Here is info on the management:

http://www.stanceworks.com/2011/06/accuair-2/
http://www.stanceworks.com/2011/05/accuair-clubman-1/

And the manufacturer:

http://www.stanceworks.com/2011/02/accuair/

Now, I had planned on using a bolt-on kit, but BagYard has ridiculous wait times, though their product is top notch. They are also the only bolt-on setup available. An American company called Air Lift has released a universal system though that allows for welding to the body of the strut in order to mount correctly. Here is info on that strut:

http://bagriders.com/modlab/products...AL-STRUTS.html


I'll be using a bellow bag setup, and probably a dampening adjustable strut to set ride comfort. For the rears I'll be using a double-bellow bag by Slam Specialties called the SS-5. I'll have to build a set of "cups" or bag mounts for the rear. I'll use either a bilstein shock or the stock S8 unit.

I'm building a false floor and mounts for management, etc. in the spare tire well. I'll be having one of the armrests modified to hold the touchpad eventually, will sit flush with the top of the armrest.

The one thing I need to know is the stock S8 front strut dimensions, IE compressed height and extendended length. If anyone has some struts out of the car that would be SOOO helpful.

I'll post more info and photos in the AM. I hope to have the build complete in the next 1.5-2 weeks.

Oh, also, once I have complete info and photographs, might we add this to the upgrade sticky?

What an interesting project. That compressor that they use in their system, well I have a very similar 12v compressor I use for inflating tyres. What interests me is the Stanceworks system used two high output compressors yet Audi, Mercedes, Range Rover etc only use one and I have often thought the compressor was the weakest link in the system

I will take a picture of my tyre inflator later and post up

Here is the Stanceworks
http://cdn.stanceworks.com/wp-conten...ount-Pic-1.jpg

We certainly will! +++

New struts ordered. Fronts will have roughly 5 inches of travel. Rears much more.

Rear bags arrived, I started building bag brackets today. There are no off-the-shelf options for the D2 as of right now, though a gent named Drew Dorbritz sells a set that is fairly universal for VW/Audi applications. I've taken his design and tweaked it to be better suited to our cars. His design:

http://i631.photobucket.com/albums/u...4/IMG_0835.jpg


Here, the bags:

http://i631.photobucket.com/albums/u...4/IMG_0842.jpg
http://i631.photobucket.com/albums/u...4/IMG_0844.jpg
http://i631.photobucket.com/albums/u...4/IMG_0843.jpg

These bags are the Slam Specialties SS-5. They are 5.5 inches diameter and fully inflated are 8.6 inches tall, while when emptied they are only 2.7 inches in height. They take up to 250 PSI (driving expect to be around 40). The double bellow design is a bit more robust than a sleeve bag. The fittings are for 3/8" line, and are push-on.

The brackets are fairly complex. First we'll discuss the lower mount and how it'll fit over the peg on the control arm. I'm using pipe as a base. It is Schedule 80 (1/4" wall thickness) with an inner diameter of 1 7/8". I cut to 1 1/8" length which is just tall enough to clear the peg while also allowing a mounting bolt for the bag to pass. Here is the lower "pipe" for the lower mount:

http://i631.photobucket.com/albums/u...4/IMG_0857.jpg
http://i631.photobucket.com/albums/u...4/IMG_0856.jpg

And the "peg":

http://i631.photobucket.com/albums/u...4/IMG_0847.jpg
http://i631.photobucket.com/albums/u...4/IMG_0846.jpg

I notched it to fit over a key of sorts that is found on the peg on the control arm. This allows it to sit flat, prevents turning or twisting, and keeps the base exactly centered. I may add some material around the base as a "foot" of sorts but it isn't necessary.

The bags are the same size on both the top and bottom mounting plate. Therefore I cut four identical bases (two for top and two for bottom, or one for each side on both top and bottom) for the mounting brackets. To do that I marked a sheet of 1/4"hardened steel I had in the same diameter as the base of the bags. I then marked center and punched it. After hitting the center with the punch we used a bit and drilled the center:

http://i631.photobucket.com/albums/u...4/IMG_0848.jpg

Then we cut the sheet off close to the marking and placed it on this rig we devised:

http://i631.photobucket.com/albums/u...4/IMG_0849.jpg

That's a couple 2x4 pieces of wood with the drill bit run into it. Once that was together we slid some washers over the drill bit and then placed the at present square piece of steel onto it. The table we were using has a vice on it so we placed a cutting torch into the vice and fired it up. Then, with the torch set to cut we spun the steel plate on the wood/washers/drill bit to get a circular "pad" to mount the bags onto.

http://i631.photobucket.com/albums/u...4/IMG_0853.jpg
http://i631.photobucket.com/albums/u...4/IMG_0852.jpg
http://i631.photobucket.com/albums/u...4/IMG_0851.jpg
http://i631.photobucket.com/albums/u...4/IMG_0850.jpg
http://i631.photobucket.com/albums/u...4/IMG_0837.jpg
http://i631.photobucket.com/albums/u...4/IMG_0838.jpg

That process gave a circle but it had a lot of waste and slag so we chucked a grinder into the vice and cleaned them up:

http://i631.photobucket.com/albums/u...4/IMG_0841.jpg
http://i631.photobucket.com/albums/u...4/IMG_0839.jpg

You get something like this:

http://i631.photobucket.com/albums/u...4/IMG_0854.jpg

I gave these plates to my grandfather, who has a machine shop. He'll be cutting a notch to allow the air fitting to pass and drilling the holes for mounting bolts. The bottom plate will only be able to have one bolt to mount but has three holes so I'll be welding guide pins for two of the three bolt holes. The top gets two bolts into it and those won't be an issue.

The top mount slides over this:

http://i631.photobucket.com/albums/u...4/IMG_0845.jpg

I'm using 3 inch inner diameter Schedule 80 (1/4" wall thickness) here. Cut to 2 inches it slides over perfectly and allows room for the air-line fitting. I may also build a "foot" for the top as well. Unnecessary but a bit wider distribution of weight isn't a bad thing. I'll also be drilling the mount there and passing a stud into the car with a nut and washer on the back to keep everything firmly mounted. I'll update tomorrow with more.

Front struts will be here Tuesday- that's when the real work gets done.

:rockin:

Nice work dude..+++

Loving your work. +++

Well, the plates are punched and cut, so here they are:

http://i631.photobucket.com/albums/u...4/IMG_0867.jpg

In the meantime I decided to build my trunk setup. I cut out a piece of medium density fibreboard first to fit the spare tire well. I then carpeted both sides in an effort to quiet it and to make it somewhat attractive:

http://i631.photobucket.com/albums/u...4/IMG_0858.jpg

Note that the center bore is cut at an angle to match the taper of the spare tire well.

Now I'm placing everything where the spare would normally be in order to keep most of the setup hidden. The tank will be partially visible in the trunk. I initially placed everything like this:

http://i631.photobucket.com/albums/u...4/IMG_0863.jpg
http://i631.photobucket.com/albums/u...4/IMG_0862.jpg

Now that looked good but I realized that it would require running air lines directly into the dual exhaust I'm building. That's no good. I settled on this:

http://i631.photobucket.com/albums/u...4/IMG_0864.jpg

Before everyone asks about all the wiring run all over the place, I'll be taping it or running it through conduit and using some sort of straps or something to keep it professional looking. But, other than grounds and power off the battery, the trunk portion is completely wired. I have to run the controller harness to the front and I have to run the level sensors, But I'll wait to have them placed to do that.

Here is the manual that includes wiring diagrams. I won't begin to think I can explain it here. I can give suggestions as to where to wire in the portions of the harness that need to go to existing wiring in the car. Page 4 in particular.

http://www.accuairsuspension.com/pro...S4-TPAD_25.pdf

Switched power (labeled IGN_12V) I ran to switched power for my amp, which itself is run from switched power on the Bose amplifier.

Headlights (labeled Headlights) I ran to the grey w/red stripe wire running to the right side tail lamp. That is on the headlight switch. It allows dimming of the controller pad when headlights illuminate.

Grounds I am grouping and running to the negative battery terminal.

I look to have the rear brackets welded tomorrow, and front struts arrive tomorrow as well. I MIGHT have the bags on tomorrow, with level sensors following. I will have the wiring more presentable tomorrow. I'll also need to build a platform to mount the tank onto. I'll paint it black for now, but I plan on having a cover sewn in the same leather as my seats (caramel).

Great work. With regard to your compressors, did you know there is an OEM Audi D2 compressor that runs off the engine? I'm away ATM but when I get by I'll look it up. It was fitted to D2s with self levelling rear suspension. I don't know the specs but it would probably keep your tank topped up.

As far as I know self levelling rear suspension is hydraulic on D2 and runs from power steering pump.

Well, I'm unsure about any of that since we didn't get that over here, but I wouldn't want anything else running off the engines. These are pretty standard compressors for this sort of setup. They fill the tank very quickly.

Front struts are here so I hope to fab and install them today. I think I'll have the rear mounts done and the bags in as well.

Pretty sure the D2 rear suspension was hydraulic.. There are power steering pumps with additional outputs for it.

I don't know why car manufacturers can't make the compressor run off the engine the same as trucks. I don't ever remember having a problem with air suspension in a truck with this set up and the millions of miles I drove them

Roger the hydrolics. Didn't realise that. Given that MTM ran a Supercharger of the front of the engine there is plenty of opportunity to run a compressor. I have an article somewhere where a guy converted an A/C compressor to air. I'll dig it out when I get home.
I've added this to the sticky. +++

Don't have time to post the full write-up right now, but here's it on the ground. I'm pulling out the bags again and modifying them to go lower...

https://sphotos-a.xx.fbcdn.net/hphot...26919759_n.jpg
https://sphotos-b.xx.fbcdn.net/hphot...00422292_n.jpg

lower?

It looks too low as is, and desperately shows the need for spacers or wider wheels too

That's the beauty of it, I can raise it 6.5 inches from there by pressing a button.

Clearly this isn't how it will sit when finished, I have wheels and tires for it, but why would I mount them while still doing body work and the like?

Haven't forgotten you all, but I've been so busy with getting the car ready for a show of late I haven't had time to post updates. Assured they will be coming.

Impressive, most impressive (to paraphrase Darth Vader) :)

Might be a little to much to late now. But i am happy to say that i have helped Universal Air in California make a bolt on kit for the D2. Haven't instaled it yet so it's not available on there webstore yet. But it will be as far as i know +++