# Air Susp Newb with something in my head.



## 79RabbitDSL (Mar 26, 2003)

Hey Guys,
I have an idea I want to run by you. I am a complete newb to air suspension but have a decent amount of experience with regular suspension. 
Anyway, I am getting a Jetta Wagon (hopefully in the next few months, but maybe in as many as six). I really like how the wagons look pretty low but this will be my winter car and I will be living in the rockies starting in Jan so I need something that will be able to get through the snow. I was thinking of building a setup with small airbags acting as helper springs on a normal coilover setup. Either put the bags below or above the springs and have them completely uninflated when not in use and be able to inflate them when I need the extra height. I was also thinking of just running a tank with no compressor to save a little space and cash. I would only be using this once in a while in the winter or maybe on some bad roads so I thought I may be able to get away with just topping it off at home or the gas station with a regular compressor.
So my main questions right now are:
What happens when you deflate the bags completely? 
Will they be sitting metal on metal or will they crush the rubber in between?
Are there any low profile bags (i figure I only need a few inches of lift)?
Would just running a tank work, or would I not have enough air?
Am I crazy or could this work?


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## Grig85 (Feb 11, 2006)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

I think with big tank you can get it done without compressor, but its not gonna be very convinient. as for your bag questions I wouldn't try rinning bag over spring as there is really no point in it. waist of money IMO. just get normal bags instead of springs, they will get you high enough to ride in the winter.


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## Santi (Mar 26, 2004)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*


_Quote, originally posted by *79RabbitDSL* »_So my main questions right now are:
1.What happens when you deflate the bags completely? 
2. Will they be sitting metal on metal or will they crush the rubber in between?
3. Are there any low profile bags (i figure I only need a few inches of lift)?
4. Would just running a tank work, or would I not have enough air?
5. Am I crazy or could this work?

Lets answer ur questions first. 
1. when u deflate bags ur car goes down until shock or bags doesnt compress anymore. 
2. it'd be metal on meta
3. there is no such thing, kinda of. 
4. u wont have enough air to make it worth ur while, u'll need like a 5-7 gallon tank to be efficient. 
5. ur kinda a crazy, and it wont be worth it IMHO. 

Like Erik(grig85) said, its pointless, and if u run out of air then ur kinda SOL... also if there is a leak on the bags, then ur done.. 
Universal Air carries a set of bags that are meant to go over coilovers, but it doesnt have sizes, or how much they compress to and what not. 
but they are $399. idk, if thats for both, or jsut one. 
https://www.universalairsuspen...9a55c 








just save some money and do an actual bag install.


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## Retromini (Nov 7, 2004)

*Re: Air Susp Newb with something in my head. (Santi)*

Simply because I ran across this today....check out KW's new coilover hydraulic system. I have no idea on the applications but it sounds like exactly what you're looking for. It's meant to temporarily raise sports cars for things like speed bumps. Then you deflate and have normal coilover spring rates again.
Worth looking into at least 
http://www.kw-suspension.com/e...x.php


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## TheMarkP (Jul 24, 2002)

*Re: Air Susp Newb with something in my head. (Retromini)*

as far as the no compressor thing alot of guys use nitrogen...but u have to know where to fill up on nitrogen, but u can go months without filling up the tanks...its a minitrucker thing. ...u can get alot more nitrogen in the same space than air.


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (Santi)*


_Quote, originally posted by *Santi* »_
Lets answer ur questions first. 
1. when u deflate bags ur car goes down until shock or bags doesnt compress anymore. 
2. it'd be metal on meta
3. there is no such thing, kinda of. 
4. u wont have enough air to make it worth ur while, u'll need like a 5-7 gallon tank to be efficient. 
5. ur kinda a crazy, and it wont be worth it IMHO. 

Like Erik(grig85) said, its pointless, and if u run out of air then ur kinda SOL... also if there is a leak on the bags, then ur done.. 
Universal Air carries a set of bags that are meant to go over coilovers, but it doesnt have sizes, or how much they compress to and what not. 
but they are $399. idk, if thats for both, or jsut one. 
https://www.universalairsuspen...9a55c 








just save some money and do an actual bag install. 


1+2 Ok, my questions 1 and 2 were intended to see if it was safe to run the bags fully deflated so they are basically a non functional spacer. This wouldnt cause any damage right?
3 kinda?
4 Ok, I can fit a compressor if needed
5. I know im crazy
My reasoning for doing this is as follows. This is my first new car, and I plan on having it for at least 10 years. I do not want this car to be my project car, I already have a VR6 Swapped Harlequin and am in the market for a mk1(I hate that I have to say that now) Rabbit. I want it to look good, perform well in all my different driving situations and most importantly be reliable and last. I do not want to go full bags. I like having the standard spring/ shock setup because in my opinion it is more tunable and reliable (im sure you guys will argue with me here).
I have seen that k/w setup, thats what gave me the idea. Right now that is only available for a couple porsches and im guessing the cost will be prohibitive.


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (KraCKeD-GTI)*


_Quote, originally posted by *KraCKeD-GTI* »_as far as the no compressor thing alot of guys use nitrogen...but u have to know where to fill up on nitrogen, but u can go months without filling up the tanks...its a minitrucker thing. ...u can get alot more nitrogen in the same space than air.

Yeah, we actually did something similar on a project for work. You actually compress the nitrogen (or nitrous oxide in our case) so much that it becomes a liquid.
But I really dont want to go that far, I would rather run a compressor.


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## Capt. Obvious (Oct 23, 2006)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

Honestly, going to bags is a lifestyle decision. It's not like coilovers where you just install them, set the ride height and forget about it.
Air ride is like having children: it's a decision you have to make and be prepared to stick with. There will be trials and tribulations, ups and downs, highs and lows, but at the end of the day you need to be there for your air suspension.


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## Grig85 (Feb 11, 2006)

*Re: Air Susp Newb with something in my head. (Capt. Obvious)*


_Quote, originally posted by *Capt. Obvious* »_Honestly, going to bags is a lifestyle decision. It's not like coilovers where you just install them, set the ride height and forget about it.
Air ride is like having children: it's a decision you have to make and be prepared to stick with. There will be trials and tribulations, ups and downs, highs and lows, but at the end of the day you need to be there for your air suspension.

hahaha http://****************.com/smile/emthup.gif well said


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## gregvh (Jun 28, 2007)

*Re: Air Susp Newb with something in my head. (Grig85)*

"ups and downs, highs and lows" ... nice pal on words/ Puns


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## Grig85 (Feb 11, 2006)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*


_Quote, originally posted by *79RabbitDSL* »_
I have seen that k/w setup, thats what gave me the idea. Right now that is only available for a couple porsches and im guessing the cost will be prohibitive.

this whole idea isnt to practical, really. Going with all that trouble just so you can lower your car by a bit and as you said not so ofter. why not adjust your coilovers twice a year


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## crippled4life (Feb 19, 2006)

*Re: Air Susp Newb with something in my head. (Grig85)*


_Quote, originally posted by *Grig85* »_
this whole idea isnt to practical, really. Going with all that trouble just so you can lower your car by a bit and as you said not so ofter. why not adjust your coilovers twice a year









good point


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## gregvh (Jun 28, 2007)

*Re: Air Susp Newb with something in my head. (KraCKeD-GTI)*


_Quote, originally posted by *KraCKeD-GTI* »_as far as the no compressor thing alot of guys use nitrogen...but u have to know where to fill up on nitrogen, but u can go months without filling up the tanks...its a minitrucker thing. ...u can get alot more nitrogen in the same space than air.

I know a guy that has an s10 on bags. He is a transport truck mechanic so he had took one of those massive air tanks (at least 50 gallon) off the side of a truck and put it in his box. He fills it up about once a week and his truck looks like a fuel tanker


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (Grig85)*


_Quote, originally posted by *Grig85* »_
this whole idea isnt to practical, really. Going with all that trouble just so you can lower your car by a bit and as you said not so ofter. why not adjust your coilovers twice a year









Like I said, this is going to be my "reliable" dont want to fix or screw around with car. I want to get it at a height where it looks good and handles decent, get it aligned at that height and leave it. It will be driven 99 precent of the time on smooth roads, so why have it jacked up like 50 percent of the year?


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

So im looking at these
https://www.universalairsuspen...886c7
Probably with a set of koni coilovers with shorter springs to offset the 4" lost to the airbag. Im pretty sure those bags are the same ones as they use on their 4x4 airbag coilover setup
http://www.4wheeloffroad.com/t....html
Obviously I dont need 5 inches of lift, so if anybody knows of anything that would be a little smaller I would love to hear about it.
Thanks to everybody for giving me their opinions (although most of them aren't in favor of what I want to do)


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## Capt. Obvious (Oct 23, 2006)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

You do realize that those are just Aerosports on a big ass coilover, right?


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## Retromini (Nov 7, 2004)

*Re: Air Susp Newb with something in my head. (Capt. Obvious)*

Tanabe Air Cobra's. Another one that probably has no application for VW's...but it might help in your quest. Small bag so you don't have to shorten your springs too much. It's just a small pancake bag between the top plate and the spring hat.


































_Modified by Retromini at 10:31 AM 9-16-2008_


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (Capt. Obvious)*


_Quote, originally posted by *Capt. Obvious* »_You do realize that those are just Aerosports on a big ass coilover, right?

Yes, Which is why I stated that...
Thank you Captain Obvious


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (Retromini)*


_Quote, originally posted by *Retromini* »_Tanabe Air Cobra's. Another one that probably has no application for VW's...but it might help in your quest. Small bag so you don't have to shorten your springs too much. It's just a small pancake bag between the top plate and the spring hat.

































_Modified by Retromini at 10:31 AM 9-16-2008_

Yeah, I saw those. Thats exactly what I want to do. Any idea what bag that would be?


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## tmvw (Jan 14, 2008)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

not trying to be a negative nancy here, but what exactly are you trying to accomplish by doing this


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (tmvw)*


_Quote, originally posted by *tmvw* »_not trying to be a negative nancy here, but what exactly are you trying to accomplish by doing this
















A Car that has a good stance and handles well that can be raised so its drivable when there is a lot of snow or when the roads are bad.


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## tmvw (Jan 14, 2008)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*


_Quote, originally posted by *79RabbitDSL* »_
A Car that has a good stance and handles well that can be raised so its drivable when there is a lot of snow or when the roads are bad.

so why can't you do tradition air ride or just raise your coils when there is snow?


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (tmvw)*


_Quote, originally posted by *tmvw* »_
so why can't you do tradition air ride or just raise your coils when there is snow?

I dont want to do a traditional air ride for the reasons I listed already. I dont want to adjust coils on a daily basis and deal with alignment issues.
I really dont see why people are fighting me so much on this one. KW has a system that does the same thing on the market so obviously this makes sense to some people. There are also a bunch of cars on the market, audi allroad, land rover, etc that have adjustable height suspensions. The people who are buying these cars are shelling out extra cash for that feature so why can't I add it to my car.
I am a Mechanical Engineer with access to a shop where I can design and fabricate basically anything I need/want. Whats wrong with trying something different, What I am suggesting isn't too ridiculous, Im using a bunch of off the shelf parts for what they are designed for, with a few small changes here and there, making some pieces to integrate the parts to build a system that does what I want it to do.


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## tmvw (Jan 14, 2008)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*


_Quote, originally posted by *79RabbitDSL* »_
There are also a bunch of cars on the market, audi allroad, land rover, etc that have adjustable height suspensions. The people who are buying these cars are shelling out extra cash for that feature so why can't I add it to my car.



technically, the cars you listed have "traditional" air-ride systems. (with variations here and there, obviously)


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## Afazz (Feb 10, 2002)

*Re: Air Susp Newb with something in my head. (tmvw)*

Check out the Roberuta cup kits: http://www.topsecretjpn.com/roberuta.shtml
Keep in mind none of these solutions are cheap, in any sense of the word! The KW system would probably be $5-6k+ just to retrofit into an existing coilover kit, which you still have to buy. It's doable, and I understand your problem and concerns, but I don't think you'll find anything cheap and easy.


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## Capt. Obvious (Oct 23, 2006)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*


_Quote, originally posted by *79RabbitDSL* »_I really dont see why people are fighting me so much on this one. KW has a system that does the same thing on the market so obviously this makes sense to some people...
...I am a Mechanical Engineer with access to a shop where I can design and fabricate basically anything I need/want. 

The reason is because you want to do something with parts that don't exist/can't really be obtained. If you can get your hands on those small bags used for that JDM kit, you'll be onto something.
Since you have access to a fab shop, I recommend trying to modify a set of air cylinders (like this one) so that it is only a couple inches tall. That way, it can sit at the top of the shock with no air in it and your car will behave like a regular car, but then you can lift it up an inch or two when need be. 
Edit: and while I was typing that, somebody posted pretty much exactly what I had in mind.











_Modified by Capt. Obvious at 11:57 AM 9-16-2008_


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (Capt. Obvious)*

Yeah, I was looking at that route, Just a pancake sir cylinder on top of the current strut with some kind of a bearing built in to replace the strut bearing. That gets a little trick because of the higher loads that would have to go through the cylinder and the shortened strut length. I think putting a bag around the strut/shock is a simpler solution, but may be harder to source the needed parts.
Oh, and I never said I was trying to do this cheap. I dont mind paying a little bit for something that works and does what I need.


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## revolverapology (Jun 29, 2007)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

I really don't understand why you are so set on this or think that its any different or more reliable than a standard setup. Having a bag just sit there compressed for months while driving. then expect everything to work....You will still need valves, line, ptc connections, tank, compressor, and a controller.
Sounds like you want to do something that has all the same parts but way more money for such a little payoff. This actually sounds less reliable than a dd full fledged bag set-up.








But hey be stubborn and waste your money. Looks like that tanabe setup is the only way.
If you want to be low, you have to live the low! 
Steve


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## revolverapology (Jun 29, 2007)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

Well doing alittle research on the tanabes..might as well go burn $4000 in the corner of your house..
http://****************.com/smile/emthup.gif


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (revolverapology)*

How am I being stubborn, by trying something different? And its my money and if it does what I want how is it a waste? I want to explore something different, if I decide it is outside my budget and abilities to build something then I will drop it, until then im trying to gather as much info as possible.
As I explained before, I do not want to be slammed like everyone else seems to think I should be, I want to be lower for looks, but not give up the ability to drive my car in the winter and on crappy roads (this is my winter car after all, I have a nice Harlequin to play with when its nice out.) 
Like I have said before I design and build machines wayyy more complex than this for work and have the tools and skills to fabricate pretty much anything I need, so no, the tanabe setup is not the only way.

_Quote, originally posted by *revolverapology* »_
If you want to be low, you have to live the low! 


I dont exactly understand this quote, why do you have to live the low if you have air suspension, just hit the switch


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## revolverapology (Jun 29, 2007)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

Who says that the car has to be slammed with bags? Thats all adjustable..
You are being stubborn because you think some how that it would be more reliable..when in the real world it will be worse...and cost more..i was talking about a waste of money towards the tanabes...
And I mean no harm but being different just to be different isn't always the best thing to do for yourself....you are trying to be different on something that is already here and easy to install...and has trial and error...if you make this system have fun trying to use your car for awhile as a DD because im alnost positive that its not going to have any problems...
And really if you have all these skills why are you even asking a forum with people that have no experince to what you apperently have? Just do it! Its all talk.


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## revolverapology (Jun 29, 2007)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

also im not dissing you or your thoughts but in all seriousness there is no need to make some elaborate setup. Put some nice struts with some bags and you are done...same ride if not better than a coilover...why do you think all of the highend cars use air bag suspension? Ride quality!
But hey id love to see you try it if you can. I have experince also with fabrication with race cars and such so im always open to new stuff...


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## windsorvr (Nov 23, 2004)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*


_Quote, originally posted by *79RabbitDSL* »_
I am a Mechanical Engineer with access to a shop where I can design and fabricate basically anything I need/want. 

then get to work. i would keep it simple, just bag the car and be done.


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## ryanmiller (Apr 13, 2006)

*Re: Air Susp Newb with something in my head. (windsorvr)*

you know, if you build your system right you can just turn the key and have it at ride height..


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## UBER KUHL (May 16, 2005)

wow! a lot of hate in this thread. I actually really like the idea of the Tanabe setup. It amazes me at how people think it would be less reliable than a traditional bag setup. So what happens when your bag blows on a traditional setup? If it blows on this type of setup, you at least have your coil springs to drive on. I hope this thread stays more on topic, because I'd like to explore more into making this a reality for my car too. I've emailed a few companies about the small bags, and waiting on replies. Anyone else have any luck finding them? I'm thinking they need to be around 4" diameter, and about 2-3" inflated and pretty small compressed or uninflated.
keep this thread going though. It's a cool concept at the least.


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## michgo2003 (Jan 11, 2007)

Ressurection post...


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## 2doorV6 (Jan 29, 2003)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

cool idea, i look forward to seeing if anyone finds a solution


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (2doorV6)*

Well, I have done some work on this, mostly conceptual because I am soon to be funemployed (moving to vail to be a ski bum for a few months) and dont have the money to throw at it right now. But right now I am thinking Slam specialties RE5 bags on the front because they have internal bumpers so they will be happy when fully compressed. I will cut out a center hole and mount some plates top and bottom with o-rings which seal on the strut tube. Then I will have a short coilover spring with a springrate I like underneath. I might get some slight leakage around the o-rings but it shouldnt be a big deal. For the rears I will just do some of those load helpers which fit inside the spring. 
If anybody has a junk bag I can snag for cheap/free that would help me out a ton
Here are some pics of the basic concept


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## JB_1152 (Feb 16, 2007)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

This is really halirous, I mean, if you can do this dude go for it! But wow, not matter how many drawings you make of it, including PRO E, AutoCad,....whatever, doesn't mean it is just gonna work. 
I'm curious what you plan to do to make sure this "custom" bag you are going to make stays sealed? I don't know if you have ever held an Aerosport bag in your hands and actually looked at it, but they are a pretty complex unit. Again, if you can do it, awesome way to go, but I just wonder it that bag you plan to cut holes in isn't just gonna leak like a siv and if it does, well I guess it is a good thing you still have a spring in there
Good luck http://****************.com/smile/emthup.gif


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (JB_1152)*

Whats Hilarious? That is a real revelation, "not matter how many drawings you make of it, including PRO E, AutoCad,....whatever, doesn't mean it is just gonna work" Wow, I really though it would because it works in Solidworks. You have just taught me more than my entire education. Who should I make the $150,000 check out to???
The model was just to illustrate my concept to one of my engineer friends who is also a v-dub head, or maybe he is a v-dub head who is also an engineer. Either way, it took me about 20 mins to do and is still just a concept, it will need a lot more thought and detailing before I am ready to start cutting. I figured that I'd throw the pictures up when someone expressed an intrest in the idea and brought the thread back up. I in no way shape or form meant to imply that this is what I will end up with or that it would work, I apologize for the misunderstanding.
Back on topic, The aerosport bag is more complex than what I am doing. I believe they have a couple internal sleeves that must seal on one another. I am sealing on a polished rod, its a dynamic seal so will take some simple calculations and the correct gland design in my adapter plate. nothing crazy at all. Depending on how everything sits I may have to add bushings to keep all the axis aligned, this adds a little cost and some size but it is still basic stuff.
From here on forward can we try to act like our mothers taught us, "if you don't have anything nice to say don't say anything at all" 
If you think this is stupid and wont work then dont post, if you have something constructive and useful to say then lets hear it.
I have no doubt that I can make this work, its just a matter of resources (time and money) Like I have said before I routinely design and build stuff way more complex than this for work
Thanks for your comments and hopefully less negativity in the future


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## Afazz (Feb 10, 2002)

*Re: Air Susp Newb with something in my head. (79RabbitDSL)*

Unless their policy has changed in the last year or so, Universal Air will crimp their bellows onto upper and lower plates that you make yourself. When I was considering this, Universal Air said it would only cost the same as a standard airbag - $80. They will give you the necessary dimensions to make your plates so the bag seals. Last I saw, that's how Bagyard bags are made. Make an upper bag plate; Make a lower bag plate; press in some bronze bearings; add some o-rings or lip seals; crimp on the bags; Done. I don't see why people are making such a huge deal out of this idea








Here are the different bellows they offer:
https://www.universalairsuspen...c8820
My concerns are 1) the spring rate of two springs in series, while the bag is extended, since an airbag is very soft 2) the sealing capabilities of a high-speed dynamic seal in an air (i.e. nonlubricating) volume.


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## 79RabbitDSL (Mar 26, 2003)

*Re: Air Susp Newb with something in my head. (Afazz)*


_Quote, originally posted by *Afazz* »_Unless their policy has changed in the last year or so, Universal Air will crimp their bellows onto upper and lower plates that you make yourself. 

Very interesting information. I was planning on using the slam specialties because of the built in bumper, but if I can incorporate a bumper into my own mounting plates that would be way better. Ill have to look into this more. Thanks for the info

_Quote, originally posted by *Afazz* »_Make an upper bag plate; Make a lower bag plate; press in some bronze bearings; add some o-rings or lip seals; crimp on the bags; Done. I don't see why people are making such a huge deal out of this idea








. 

I agree, its all simple stuff that has been done millions of times.

_Quote, originally posted by *Afazz* »_My concerns are 1) the spring rate of two springs in series, while the bag is extended, since an airbag is very soft 2) the sealing capabilities of a high-speed dynamic seal in an air (i.e. nonlubricating) volume. 

1) It will be interesting to see how the springrate ends up. Im not too concerned it will be too soft, I will be raised above stock height anyway so there will be little risk of bottoming out because the combined springrate is too soft. It may make handling a little funny, but I dont plan on being inflated while going at speeds much more than 30 so it shouldn't pose a huge safety issue.
2)Yeah, i am sure there will be some inherent leakage around the lower o-ring (or lip seal or whatever) I will just have to spec something that can deal with the high speeds and minimize the leakage.
Thanks for your ideas/comments


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## fastgermancar (May 4, 2005)

watching


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## MacBeth_SK (Aug 25, 2008)

*Re: (fastgermancar)*

i did not read everything but in austria is a company that manufactures such airrid systems.

http://www.h-o-t.at/hotprodukt....html


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## Banned wagon (Mar 3, 2004)

*Re: (MacBeth_SK)*

This is a great idea! watching


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