Air Suspension 101
02-12-2010, 06:26 AM
#1
Air Suspension 101
I have been getting a few PMs lately asking about how Air Suspension works, so I figured I would put together a nice write up explaining the main components of an Air Suspension setup.
Firstly, you should understand the layout of the setup.
Compressors > Tank > Valves > Bags
You have Air Line running between each, and you have a management system controlling everything.
Bags:
First you have to decide which type of setup you want. You can go with a setup specifically designed for you vehicle, which would be 1pc. Air Struts. Or you can get universal bags and put them over your stock shocks or Coilovers in place of the springs.
This decision lies solely on you and how you want your system to respond. An Air Strut is specifically designed to your vehicle. The strut length and valving is all set for your car. This allows the Air Strut to have a much bigger range of travel for how much drop and lift you will get. Also, since the strut is valved to handle an air bag rather than a spring, the ride and handling is much better.
This doesn’t mean you shouldn’t consider a Bag-over-coil setup. This setup is fine, its just not custom tailored to your vehicle. This method takes a universal air bag and slips it over a coilover in place of the spring. Since the coilover is valved for a spring rather than an air bag, the handling is not as good. Although many will argue the adjustable dampening of a coilover will allow you to tweak it to handle properly. You will also have to adjust the height of the coilover to find a happy medium in drop and lift. If you plan to lay frame, you will have to set the coilover all the way down, with the possibility of having it bottom out when you dump your air.
All in all both setups are effective, but it breaks down to a matter of cost. Most people who have bag-over-coil setups plan and hope to upgrade to Air Struts down the road.
Now seeing that Coilovers for this car aren’t cheap, you can probably just spend another 3-400 more (depending on which coils) and just get Air Struts. If you were going to get more expensive coils like KWv3’s or JICs, it would be cheaper to just get the Air Struts.
Valves:
Valves are probably the most important part of your setup. You can choose between 1/4”, 3/8” or 1/2”. You can also choose between Individual Valves or a Valve Manifold.
Valves determine how fast your bags will inflate and deflate. You need 1 fill and 1 dump valve for each.
Now you can choose between running a 4 valve (2-way) system or a 8 valve (4-way) system. A 2-way system will only let you control the fronts together and the rears together. A 4-way system will give you independent control of each corner, also known as FBSS, Front-Back-Side to Side. This is recommended.
The problem with a 2-way setup is it basically connects the right side to the left side, so when you make hard turns the air can transfer from one side to the other, leaving you with considerable body roll. Having each bag connected to its own valves won’t let the air to transfer as such.
Now that you understand how many valves you need, you need to decide if you want to piece individual ones together, or get a manifold. Individual valves tend to leak after awhile; this is where a manifold reigns supreme. They are typically machined out of solid billet aluminum blocks, thus being bubble tight and never leaking. They are more money however, but worth every penny IMHO.
Air Line:
Deciding which size air line to run coincides with deciding which valve to run. How fast do you want your bags to inflate or deflate? Whichever valves you decide get the same size air line.
Firstly, you should understand the layout of the setup.
Compressors > Tank > Valves > Bags
You have Air Line running between each, and you have a management system controlling everything.
Bags:
First you have to decide which type of setup you want. You can go with a setup specifically designed for you vehicle, which would be 1pc. Air Struts. Or you can get universal bags and put them over your stock shocks or Coilovers in place of the springs.
This decision lies solely on you and how you want your system to respond. An Air Strut is specifically designed to your vehicle. The strut length and valving is all set for your car. This allows the Air Strut to have a much bigger range of travel for how much drop and lift you will get. Also, since the strut is valved to handle an air bag rather than a spring, the ride and handling is much better.
This doesn’t mean you shouldn’t consider a Bag-over-coil setup. This setup is fine, its just not custom tailored to your vehicle. This method takes a universal air bag and slips it over a coilover in place of the spring. Since the coilover is valved for a spring rather than an air bag, the handling is not as good. Although many will argue the adjustable dampening of a coilover will allow you to tweak it to handle properly. You will also have to adjust the height of the coilover to find a happy medium in drop and lift. If you plan to lay frame, you will have to set the coilover all the way down, with the possibility of having it bottom out when you dump your air.
All in all both setups are effective, but it breaks down to a matter of cost. Most people who have bag-over-coil setups plan and hope to upgrade to Air Struts down the road.
Now seeing that Coilovers for this car aren’t cheap, you can probably just spend another 3-400 more (depending on which coils) and just get Air Struts. If you were going to get more expensive coils like KWv3’s or JICs, it would be cheaper to just get the Air Struts.
Valves:
Valves are probably the most important part of your setup. You can choose between 1/4”, 3/8” or 1/2”. You can also choose between Individual Valves or a Valve Manifold.
Valves determine how fast your bags will inflate and deflate. You need 1 fill and 1 dump valve for each.
Now you can choose between running a 4 valve (2-way) system or a 8 valve (4-way) system. A 2-way system will only let you control the fronts together and the rears together. A 4-way system will give you independent control of each corner, also known as FBSS, Front-Back-Side to Side. This is recommended.
The problem with a 2-way setup is it basically connects the right side to the left side, so when you make hard turns the air can transfer from one side to the other, leaving you with considerable body roll. Having each bag connected to its own valves won’t let the air to transfer as such.
Now that you understand how many valves you need, you need to decide if you want to piece individual ones together, or get a manifold. Individual valves tend to leak after awhile; this is where a manifold reigns supreme. They are typically machined out of solid billet aluminum blocks, thus being bubble tight and never leaking. They are more money however, but worth every penny IMHO.
Air Line:
Deciding which size air line to run coincides with deciding which valve to run. How fast do you want your bags to inflate or deflate? Whichever valves you decide get the same size air line.
The following users liked this post:
duck31905 (08-30-2016)
02-12-2010, 06:27 AM
#2
Compressors:
The job of the compressor is to re-fill the tank. There are many different compressors to choose from, they are differed from each other by speed. You can run 1 compressor or 2. Obviously 2 will fill your tank faster than 1. Depending on your bag requirement and tank size, you will need to figure out what pressure settings you need to run. There are a few different options but the most common are 110-145, 135-175, 165-200. Using 110-145 as an example, this means the compressor(s) will kick on when the tank pressure falls to 110psi and will stop when it reaches 145psi.
Another thing to look at is duty cycle. If the compressor is 100% duty cycle that means it can run continuously. A 33% duty cycle means for every 15 minutes of running, it must stay off for 30 minutes. The formula is duty cycle = run time / (run time + rest time). A 50% compressor would be able to run for 30 minutes and must rest for 30 minutes. So your best bet is to get a 100% duty cycle.
Tank:
The most common size tank is 5 gallons. This will give you enough air to lift your ride from the floor to ride height without making your compressors kick on and giving you a little to play with as well.
You can go smaller if you prefer to save room or hide the tank, but your compressors will run more and will not last as long. If you were going to get a smaller tank I would recommend getting a 100% duty cycle compressor.
You can also go bigger, this is fine, but it will take longer to fill.
Youre going to need to decide how many ports you will need on your tank. This will be determined by what setup you build. You could Tee everything off into a couple ports, but its better to have each thing on its own port. Youll need either 1 or 2 for the compressors coming in. 1 or 2 going out to the valves. 1 for a pressure sensor. 1 for a sending unit or gauge line. You should have a drain port on the bottom if possible.
Management Controls:
Your biggest decision I think is your controls. You have the option between analog controls or digital controls.
Analog controls consist of a switch box (5, 7, 10 etc) and either needle gauges or digital gauges. This system will not allow you to save preset ride heights. You have to memorize what PSI you need your bags to be at to be at certain heights. You will have to run 5 1/8” air lines from your tank and valves up to where your gauges are, making the install more difficult.
Digital controllers are run entirely by an ECU. This system will connect to your valves to control them, and it will read the pressure from your tank and bags via sending units. These systems will allow you to set 3 height presets. Most also have a ride height on start feature, which will raise your car to your driving height (preset 2) after starting the vehicle. This feature can also be disabled. Many are starting to release level sensors too. These physically measure the height of the bag, rather than just going by psi.
Digital controllers are much more advanced, visually appealing and easier to install than analog systems, but they are much more costly.
For Examples of each, I have provided links to the products I have decided to go with.
• (2) Viair 400c compressors – 33% duty cycle. (I didn’t understand what duty cycle was when I purchased them; otherwise I would’ve gotten 100%)
Newmatics-Better Prices & Best Quality
• 5 gallon Aluminum tank with (7) 1/2" ports – I went with aluminum for the weight savings as well as the ability to polish it up nice.
Newmatics-Better Prices & Best Quality
• RideTech Big Red 3/8” valve manifold - I chose this manifold because its plug-n-play with the digital controller i decided to use and is 3/8".
Components / Hardware
Compressor System Components Valve Bodies 4- way Big Red airvalve - RideTech.com - Air Suspension Specialist
• RideTech RidePro e3 Digital Controller
Air Suspension Specialists | Air Ride Technologies – RideTech.com
Now get out there and LAY FRAME!
The job of the compressor is to re-fill the tank. There are many different compressors to choose from, they are differed from each other by speed. You can run 1 compressor or 2. Obviously 2 will fill your tank faster than 1. Depending on your bag requirement and tank size, you will need to figure out what pressure settings you need to run. There are a few different options but the most common are 110-145, 135-175, 165-200. Using 110-145 as an example, this means the compressor(s) will kick on when the tank pressure falls to 110psi and will stop when it reaches 145psi.
Another thing to look at is duty cycle. If the compressor is 100% duty cycle that means it can run continuously. A 33% duty cycle means for every 15 minutes of running, it must stay off for 30 minutes. The formula is duty cycle = run time / (run time + rest time). A 50% compressor would be able to run for 30 minutes and must rest for 30 minutes. So your best bet is to get a 100% duty cycle.
Tank:
The most common size tank is 5 gallons. This will give you enough air to lift your ride from the floor to ride height without making your compressors kick on and giving you a little to play with as well.
You can go smaller if you prefer to save room or hide the tank, but your compressors will run more and will not last as long. If you were going to get a smaller tank I would recommend getting a 100% duty cycle compressor.
You can also go bigger, this is fine, but it will take longer to fill.
Youre going to need to decide how many ports you will need on your tank. This will be determined by what setup you build. You could Tee everything off into a couple ports, but its better to have each thing on its own port. Youll need either 1 or 2 for the compressors coming in. 1 or 2 going out to the valves. 1 for a pressure sensor. 1 for a sending unit or gauge line. You should have a drain port on the bottom if possible.
Management Controls:
Your biggest decision I think is your controls. You have the option between analog controls or digital controls.
Analog controls consist of a switch box (5, 7, 10 etc) and either needle gauges or digital gauges. This system will not allow you to save preset ride heights. You have to memorize what PSI you need your bags to be at to be at certain heights. You will have to run 5 1/8” air lines from your tank and valves up to where your gauges are, making the install more difficult.
Digital controllers are run entirely by an ECU. This system will connect to your valves to control them, and it will read the pressure from your tank and bags via sending units. These systems will allow you to set 3 height presets. Most also have a ride height on start feature, which will raise your car to your driving height (preset 2) after starting the vehicle. This feature can also be disabled. Many are starting to release level sensors too. These physically measure the height of the bag, rather than just going by psi.
Digital controllers are much more advanced, visually appealing and easier to install than analog systems, but they are much more costly.
For Examples of each, I have provided links to the products I have decided to go with.
• (2) Viair 400c compressors – 33% duty cycle. (I didn’t understand what duty cycle was when I purchased them; otherwise I would’ve gotten 100%)
Newmatics-Better Prices & Best Quality
• 5 gallon Aluminum tank with (7) 1/2" ports – I went with aluminum for the weight savings as well as the ability to polish it up nice.
Newmatics-Better Prices & Best Quality
• RideTech Big Red 3/8” valve manifold - I chose this manifold because its plug-n-play with the digital controller i decided to use and is 3/8".
Components / Hardware
Compressor System Components Valve Bodies 4- way Big Red airvalve - RideTech.com - Air Suspension Specialist• RideTech RidePro e3 Digital Controller
Air Suspension Specialists | Air Ride Technologies – RideTech.com
Now get out there and LAY FRAME!
The following 3 users liked this post by STOOF:
02-15-2010, 04:47 PM
#5
I dont track, but i like to take curves as fast as possible lol so i plan to compare on a few i take daily and see what the difference is.
From what ive been reading, bags are just as good if not better handling then coils. Maybe not for track purposes per say, but for street use. And of course they handle better than stock lol.
Heres a good thread to read through.
VWvortex Forums: AirRide and Performance.
and a nice vid.
http://www.youtube.com/watch?v=Fn8XKR4Q9CU
Trending Topics
Thread
Thread Starter
Forum
Replies
Last Post
