Making air bags work on G machine?

[BRIAN]

After going to a lot of shows and having my car passed up to evrything that had air bags and 20's I guess I am going new route on next project. Slammed and big wheels = big trophies and money.



I know nothing about air bags. I sthere anyway to determine their spring weight at the different levels? I know it would have to be set at certain dedicated driving level to reach optimum handling. That and the side to side issue from what I understand has been addressed with the new computer set ups.

Question is how does one determine the rate on the bags? Is there such a thing?

[Travis B]

I don't know if there is a determined rate i'm sure air ride tech has that info.....but in a sense the rate is adjustable! Lets say a 2600 series bag dual convoluted stlye for the front of your car! install hieght is 5-5.5in
compressed is 3in and max hieght is 8in! So at that 5-5.5 height range you can play with the air pressure lets say 5-10psi and change the spring rate! Mounting location is also a factor on how the bag reacts....Air bags can be made to handle!

Call [email protected] tell him
Kenny Davis hot rods sent you!

I am building a 64 chevelle right now that will be on air....I think it should handle pretty well, we'll see

[cad]

I was talking to a friend last nite with a 1970 Nova that is riding on air bags, front and rear, with 18s and 20s.
He said that his car handles awesome, and the ride is phenomenal.
Unfortunately, I dont know any of the specs at this time.
Click here for a pic...

[MuscleRodz]

I asked Tony a bunch of questions about that and although they have not got it to an exact science it is working. They are basically using a smaller bag and blowing it up to its travel limit. Then they are adjusting "spring rate" by adding or removing pressure and not changing ride height with the bag at its limit. This is the only way to seperate ride height from spring rate that I can see with air. The trick to this is making sure the shock travel is not at its limit with the bag inflated. It must still have a few inches of travel to operate. Then just dial the shock firmness up and go racing. This is what I got from our conversation and I am not sure it is exact but what I remember how it worked in theory.

Mike

[cad]

Another friend that I was talking to last nite said it is critical that independent air supply lines are installed (ie, a 4 corner system), or you will have an unsafe ride, due to "air bounce" between the 2 sides.
Plus, the monitor for air pressure at each corner should be observed at all times, therefore, he recommended to NOT hide the controller.

[Travis B]

Another friend that I was talking to last nite said it is critical that independent air supply lines are installed (ie, a 4 corner system), or you will have an unsafe ride, due to "air bounce" between the 2 sides.
Plus, the monitor for air pressure at each corner should be observed at all times, therefore, he recommended to NOT hide the controller.

4way is a must....the ride pro-e kit is what we put on just about everything!

[BRIAN]

I will make some calls but I feel the above answers are what I am going to get. Are there that many size bags where the rates in a bag at it's limits can be swapped out for say one at 90%, 75%, etc?
What about simply putting it in a spring tester at varying pressures but at the same height ?

[ViperBlue68]

I was talking to a friend last nite with a 1970 Nova that is riding on air bags, front and rear, with 18s and 20s.
He said that his car handles awesome, and the ride is phenomenal.
Unfortunately, I dont know any of the specs at this time.
Click here for a pic...

Thats a sweet looking nova I've thought about bags but i'd be nervous about ripping a bag and the car goin down at high speed....have had hydraulics when I was younger and blew a cylinder liftin while i was on the road doin 45 not a good thing to say the least...

[Travis B]

Thats a sweet looking nova I've thought about bags but i'd be nervous about ripping a bag and the car goin down at high speed....have had hydraulics when I was younger and blew a cylinder liftin while i was on the road doin 45 not a good thing to say the least...

The only way you would hurt a bag is if
1.you to much pressure in the bag
2.If it was set up improperly and it was rubbing on itself or something!

Other than that Semi's use them for thousands upon thousands of miles

[Travis B]

I will make some calls but I feel the above answers are what I am going to get. Are there that many size bags where the rates in a bag at it's limits can be swapped out for say one at 90%, 75%, etc?
What about simply putting it in a spring tester at varying pressures but at the same height ?

There are several different bags for various app's
air ride lists a bunch of them in there catalog and i'm sure they have some more!

[Beige]

Thats a sweet looking nova I've thought about bags but i'd be nervous about ripping a bag and the car goin down at high speed....have had hydraulics when I was younger and blew a cylinder liftin while i was on the road doin 45 not a good thing to say the least...

The front spring on my aunts Windstar broke and put a hole in the tire. Luckily it was parked at the time but if it wasn't... I'd take an airbag blowing out over that.

[Steve Chryssos]

There are several different bags for various app's
air ride lists a bunch of them in there catalog and i'm sure they have some more!

Yeah, but I don't see how one can convert the data on their site to match traditional metal springs??

[Steve Chryssos]

For example I know my coil-overs, at ride height have a 13.875" eye to eye length. And I know I have about 950lbs over each front wheel.

I would imagine that if i wanted to install air rides on my car, I would need to know my car's corner weights, installed length at ride height, motion ratios, etc. Stuff like that. Then, I'd wanna to know how to convert the steel spring rates in my car now over to psi. I suppose you'd want close to max psi at that static ride height for a handling car? Then, at what rate does the psi increase as you approach bump? Is it linear like my coil springs? What should I do about sway bars? Stiffer than normal?

Inquiring minds wanna know.
/Steevo

[Travis B]

For example I know my coil-overs, at ride height have a 13.875" eye to eye length. And I know I have about 950lbs over each front wheel.

I would imagine that if i wanted to install air rides on my car, I would need to know my car's corner weights, installed length at ride height, motion ratios, etc. Stuff like that. Then, I'd wanna to know how to convert the steel spring rates in my car now over to psi. I suppose you'd want close to max psi at that static ride height for a handling car? Then, at what rate does the psi increase as you approach bump? Is it linear like my coil springs? What should I do about sway bars? Stiffer than normal?

Inquiring minds wanna know.

/Steevo

very good questions......unfortunatly I don't know the answers to, I will talk with tony and see if he can respond..I know he use to post here but haven't seen him on in awhile!

[Chevy350]

Here's something similar, and some of Tony's answers:
https://www.pro-touring.com/forum/showthread.php?t=4613

[Steve Chryssos]

Better, but not specific enough. At least I know that small pressure changes make a big difference, but that post would not get me any closer to looking at a published air spring chart and making a proper selection. I realize that I could just call and get a part number. But I'd want to know how they arrived at that part number.

Perhaps some of our suspension experts will chime in and help Brian gather data that will help him ask the right questions. And gather data as though he were shopping for metal springs. Then air ride can show us the science behind converting that data to air springs.

If we can get to that point, then the question of the air spring's progressive rate tendency comes up. Which brings us to shock and sway bar tuning with respect to air spring.

I'm just curious.

[Beige]

You could use the Ideal Gas Law to approximate the pressure changes in the bag at different ride heights. If I remember right it's inversely square to the change in volume.
However, you don't need to store all of the air in the bag, and you can use leverage to change the rate that the bag changes volume through full suspension travel. Of course, any extra stuff you add is going to rack up the cost as well.

[BRIAN]

Those are the questions I am looking to have answered.

Normally I set a car up with an approx spring rate and go up or down from there trying to not adjust the coil overs more than 1/2 inch. It is hard to make that cool look and a performance ride to work. I think most guys miss that whole idea and just crank up and down not caring about spring rates or crushing the spring..

I would be curious if anyone has simply inflated a bag to it's approriate ride height, one which would allow for the usual 2/3 compression and 1/3 rebound and see what it's rate is? I would assume this is possible. There would be a wider sweet spot I am sure but there has to be a figure somehow? They can't be usig the same bags on 4000lb and 2500lb cars?


As far as the loss in rate with the compression of the bag? I wouldn't even know where to start on that one.

Bags are here to stay and with the above info they would be easier to adapt to a car that is going to be driven hard. Even if they were low rates you could do the most horrible thing possible to most here and put larger bars to somewhat compensate?

I am off to Rhinebeck, if they are there I will ask if not I will place a call Monday for some answers.

[Mean 69]

You could use the Ideal Gas Law to approximate the pressure changes in the bag at different ride heights. If I remember right it's inversely square to the change in volume.

You could, but you have more variables than you think in this system, dynamically. PV = NRT is a pretty good place to start to try to harness this thing, but realize that in an air bag, the volume is not a constant, because the bag is deformable. At least, it'd better be!! As such, it is a bit harder to model than a rigid vessel as is typically the case for textbook examples: volume, will be a function of pressure, which affects pressure, which affects volume, and so on. It can be modelled, no doubt, but I'd bet it hasn't yet.

I'll be honest, I have never considered such a device for a springing medium in a performance application (i.e used on the track, not running to the store for more chips during half-time). I'm game for learning more about the dynamics and physics of the system, as long as responses can be explained with a reasonable technical explanation (sorry, "it feels really good just try it" is not an acceptable response, it may be true, but why???).

Most folks don't want to hear it, but the word "compromise" is probably the most important word in terms of performance suspension setups, you simply can't have it all simultaneously. Let the consumer beware.

Tech?
Mark

[Porterbuilt]

These are all questions that can be answered through scientific formulas and advanced calculations... but I am yet to find them! What I do know is that one part of me is addicted to air suspension (because of it's adjustability); and another part of me isn't satisfied unless my ride can handle like it's on rails! I have devised a solution that might be of help. I am currently building (for myself) a 57 Chevrolet Pickup that will be used to proto-type a few suspension configurations. I intend it to closely follow the pro-touring theme. I also intend it to handle well. I also intend for it to be air suspended at all four corners. Sounds like some contradicting statements. But I don't think it has to be. I will use the shockwave by air ride Technologies at all four corners. I will design and build the upper mounts to be adjustable and or accept a coil-over. That way I can either spend time "tuning" the Shockwaves by playing around with its pressures and heights, and still being able to keep the suspension geometry in check; or I will unbolt the shockwaves and bolt in the appropriate coil-overs when I want to surprise people at the track.