Help, tweak or redesign air suspension, Classic Mini

[notabmw1]

ALL THE WAY DOWN


ALL THE WAY UP, and currently the height I have to drive it at!!! 4x4 mode is not cool.

Okay, I wanted to pick someone's brain that has a little bit more knowledge in this area. I just finished fabricating a one off air suspension system for my 76 Mini. Now that I proved the theory "works", originally I had it as just a Front Back setup, this week I pulled everything and installed a accuair vu4 manifold with a 2.5 gallon tank setup at 110/150, viair 275c. I can get low enough, and I can get high enough, but I can't get anywhere in between. The whole reason I upgraded to accuair was unless I was running 90psi+ the car would tip to one side and stay that way. Unless I pushed on that side of the car to "balance" it out side to side. I figured it was just because originally I had the front t'd together, and the rear t'd together.

The front consist of medium stroke Airlift Air AOS Sleeves 82114. Rear is .... Monroe Air Shocks.... now before you bust my balls, I figured if VW Bug guys could run them on there front, hell... I could run them on the back of my wagon. My car weighs in at 1350 total pounds. Front shocks are rated at 980lbs a piece @100psi, rears are roughly 550lbs each.. possibly. Again I can get low enough, and high enough, but I can't seem to get anywhere in between that is drivable. I have a gut feeling it is the rear shocks, but I figured for the money I would try it out first, it didn't work out on the front, that is why I upgraded to the Air Lift Sleeves.

Anyway, thoughts on what to look at. I may redesign the rear to run on bags, problem is I really need something with a diameter of 4" or so. Couldn't find anything on the market back then. I always loved my SS bags, but 5" is gonna take a lot of fab to fit those.


Mockup of front top mounts, I ended up narrowing the mounts so it was against the bushings.


Front Airlift Sleeves


THIS WAS ORIGINAL MOCK UP, I Trimmed 1.5" out of the legs on it for clearance!


THIS WAS ORIGINAL MOCK UP, I Trimmed 1.5" out of the legs on it for clearance! As well as moved the lower mount slightly outwards to make the shock sit at less of an angle.


Front lower mount, that mounts on top of top arm


Rear turrets I fabbed


Rear setup

[Oh Damn, it's Sam]

If I'm understanding the issue correctly, with the VU4 installed, even a very small adjustment at the switch(es) is causing the vehicle to move to the extremes of its range?

If that's the case, I'm guessing that the very small bags combined with the very lightweight vehicle are causing a small amount of air to produce large changes in ride height, and you're not able to "catch" the car at any moderate ride height. Try installing some flavor of flow control between the tank and the VU4, inch it down to just barely open, and try to make your adjustments then.

You could also drain the tank completely, and fill the tank while holding your switch(es) in the up position. You should see the car rise gently as the compressor adds air to the system and be able to "catch" the car at a desirable ride height. Again, this will confirm that the flow rate of your system should be slowed with flow controls.

[BrianMR]

Let me know when you are ready to sell this....I will be waiting

[notabmw1]

Let me know when you are ready to sell this....I will be waiting

Not sellin, ha! I sold my last Estate to my buddy and soon regretted it afterwards. Took me 3 years to get another one, and I have spent a fair amount of time on this one. Honestly it's almost where I want it, just want to do a wire tuck, fuel injection and turbo to the lil 1098.

[notabmw1]

If I'm understanding the issue correctly, with the VU4 installed, even a very small adjustment at the switch(es) is causing the vehicle to move to the extremes of its range?

I think I need to invest in a slow down and a check valve to the tank. I know I have 1 very small leak on the line running from tank to vu4. I was lucky enough to get the VU4 that back leaks through the tank. Not 1 bag, but all 4 leak back through there. I know there is no leaks anywhere else. Today I rode into work at 40 psi front, 100psi rear. Its a little bit lower, but it has a lean to it, lower obviously on the side I am on. So maybe if I can go to 35 front 85 rear. Currently it is just too fast to really fine tune, because it seems that its gonna take very small increments to get to where I would want to be visually and be able to cruise vs chewing up my tires. I still would like to redesign the rear to run on 4 or 5" diameter bags, and have a shock where it would be normally. I think it wouldn't cost much to go this route, and it would probably ride a hell of a lot better. They say you feel whatever the rear is doing, and it's freaking stiff right now!