The Ultimate Air Suspension Thread
Alright. So since I've had a few messages already about air suspension and what to do, how it works and what you should get. I decided to make a thread about it. This thread will cover most questions that people ask. I will also give you a run down as to what is needed and what is recommended.
Air suspension's quite the headache and our forum isn't quite up to date with it when it comes to air suspension since barely anyone will tell you what to do or what to get so I'll give you the run down since I've already gone through it all. Before I go on, the rule is that our cars have a different style of suspension. Our upper control arms allow us to only run a sleeve design strut, therefore most universal air suspension won't work.
Companies like D2, K Sport and Air Runners are complete plug and play kits. Basically you buy it from them, and it goes in your car and it works.
The kit itself will come with things like your air struts, compressor, tank, wiring, and management. Keep in mind, this management is the most important part. So these kits that come with it, they're not great. Almost every single car that you see with a custom trunk setup or remote control will not be from these kits.
For example, if you buy the D2 complete kit, it's a full kit. But it's manually managed (toggle switches), while K sports upgraded kit has other options with a remote and what not which is digital. These are complete kits, meaning there's less work of customization and what you see is what you get.
What should I go with?
Well this is completely up to you. How much money are you trying to spend and what do you want it to do? The first thing you want to think about is if you're going to easy way out by buying a complete kit. It's good if you're new. You'll hate it after you see the real stuff.
Once you've gotten over the complete kits from those companies I have told you about, lets start talking about the real stuff. So we'll start by deciding what kind of management system you would like. Struts don't matter, they're based on the type of cars so our car only has so many struts you can choose, and they're all realistically the same.
So management. The first option is your most basic and easy to use, manual management system, and if you want to go this route. The complete kits offer this. When we think manual, it's down to bare bone. Your next option is digital pressure based. It's good, and it'll get the job done. But it's not precise. Your best option is height sensor based, and this option is done with Accuair's E-Level Management. I'll go into depth.
Lets take D2 for example, you buy their kit. You get struts. Air compressor, air tank, wires, toggle switch, and a pressure gauge. So how do you air up and down? Well with the D2 kit, you have toggles and therefore that fills and empty's the bags. This is great and it sounds good, and for $2500 (rough estimate) it's a steal. But think about this.
You've just installed your air suspension, and you got it all set up. Your driving height is great and that's what you want it set as, so you go for an alignment at that height. Awesome. You drive out, go park, air down, and you're alignment is now off. To go back to the exact height you were at before, you would have to air up to that exact height. Now that's hard when you're just guessing it all by looks. That's manual. Simple, easy, no height sensors, no pressure sensors. It's a guessing game, and you suck at guessing.
Pressure Based Management:
So now it's onto the real stuff. Pressure based management system is the next best option. It's all digital, meaning there's a controller that's plugged into the manifold and the manifold puts out air to each strut based on the controller of how much you want.
So lets take the most popular pressure based management system out there called Airlift Autopilot V2
. This is the most popular system when it comes to air mainly because A. It's cheap, and by cheap. I mean it's cheaper than Accuair and it's more accurate than manual. and B. It's easier to install, and by easier. I mean it's the easiest to install, even easier than manual. Why? Because with manual, you instead of running one wire up to the controller. You run the air lines up to where the toggle switches are. Analog style = manual.
So how does pressure based management work? Pressure based management is exactly how it sounds. Your air struts fill up until it hits a certain PSI, the exact same way as to how your tires are filled. They fill until it hits that PSI and then that's when the air compressor filling your tires stops. So that's how your height of the vehicle is raised and lowered, by how you set your PSI. Let me give you an example. Lets say your struts are all installed and all alignment is done, you drive out. Park. Air out, and bam. Your alignment is off again, this time when you air back up. Your alignment is back to where it was before up to an estimated accuracy of 3-5% and this is all because your Autopilot V2 management system comes with a total of 8 presets. So you can have #2 preset to be your ride height which you will align at, #3 to be your raised height and #1 to be your low cruise. The other presets you can just mess around. So this is good. And the thing with the Autopilot V2 unit is there's an LCD that can tell you how much pressure is in each bag, your tank and if there's a leak. It's overall an amazing system and I'd highly recommend it. It's what I almost got. What stopped me? I'll explain.
As you have heard before, those who are anal about precision will tell you to fill your tires up to lets say 35psi on a colder day or at night when your tires haven't been ran on a lot or at all. This is because air pressure changes based on humidity and temperature. So lets say you've got everything set in the summer on a warm day and your air bags are set to ride height of 50psi. That's your ride height. Lets say in the winter, your ride height is still set at 50psi, but you're not as high as it was in the summer. Hot air expands, cold air doesn't. Chemistry people! This is why pressure based isn't as accurate and this is why I didn't go this route. If you live in the cold, you'll notice the difference. You'll also notice the difference when you're driving yourself vs when you're driving 4 other people. The pressure of your bags still sit at 50psi. That hasn't changed, but your height of the vehicle has. That means you'll need to let more air into your bags to compensate for the amount of people that are in your car. And this is why I chose height based management.
Height Based Management:
So lets start off by saying height based management is the most accurate system, most easy to use system, hardest system to install, and the most expensive system. I'm talking if you don't have at least $3500 to spend on your whole setup, don't even bother. So what's so good about height based management? Well first of all, Accuair
is the only company that I know that makes this. How does height based management work? Well it's in the name.
Accuair has designed their height based system called E-Level to work based on height sensors. Not only does your car have air struts installed, but there are also height sensors installed next to struts which are usually connected to your lower control arm and the frame of your car. This will give you the most accurate level of airing up and down. So whether it's the winter, summer, really hot one day, really cold the next, or you have a bunch of people sitting in your car. Your system will always compensate and be accurate because of those sensors. In fact, this is the exact same technology that is used in the Porsche Cayenne Twin Turbo's and the Range Rover's with air suspension.
So how does it work? Well your touchpad (remote) will have 3 presets. 1: Low/Cruise Height (Typically set at 10% of your total suspension travel) 2: Ride Height (the height you typically drive at) and 3: High/Extra Clearance (Typically set at 90% of your total suspension travel) and your all down which completely air out your bags. These settings are done automatically by the calibration that the E-Level does when you first set up your unit but all three of these presets can be adjusted just like your radio can. You manually adjust your height with the buttons beside it then you hold the number you want to set it at.
"I want the best. I'll take it." Wait a minute. Who's installing it? Because this is not your simple plug and play anymore. Now instead of running only one wire (air tube) to each strut, you're running that and the height sensor wire, and you're installing the sensor. I'll tell you, when I first did my sensor install. It took me over 3 hours just to do one. Most of the time, you need to fabricate a bracket to your lower control arm and then mount the sensor to your frame and so on. And accuair is so precise that if it's not done right, bam, broken sensor. $125 a sensor. You could easily overextend and underextend the sensor rode and snap the sensor.
If you're comfortable with the install and the price tag (roughly 2k just for the management system quoted from bag riders) then you're set. Take it.
Here's an amazing video by BagRiders that demonstrates how height based management system vs pressure based management system.
Well that covers the management system, but what about your air struts? Or your air tank size? Or your compressor? Or your air lines? Oh you thought it was simple. Hell no. Next is your Air struts, so what do you get? Well, you're not going universal because it doesn't fit and it doesn't work. As far as I remember (and some others can chime in) UAS does not make a sleeve system which will work without hitting our front upper control arms. How our air struts work is exactly how a coilover works. In fact, if you purchase the D2 or Ksport struts, you'll notice that besides the airbag, it's the exact same setup as the D2 or Ksport coilovers with springs.
So you're now you need to decide on what brand of struts you'd like to get. I don't know them all, but I'll name a few that are popular. You have a choice of D2 or Ksport. Both are the exact same design. You can get replacement bags for one another. There's no difference between the two. Or you can go Airrex or Airlift, both from what I heard are higher quality but more expensive. There are other brands, but I forgot what else. Air struts or Air coilovers will run you about $2000 give or take. These are fully adjustable struts. D2 and Ksport both have 32way adjustable dampening while the others have more or less. I don't remember. These are car specific, so unlike the management system which can go in any car. These air struts or air coils are specific to our cars. Don't get too caught up on this topic, just choose your brand and make sure the bags are not blown and the struts are not blown. Don't quote me on this but I also believe we share the same air struts as the 2004-2008 Acura TL's...
Now is your selection of air tank which will also affect your air compressor. There are many sizes, many types and many brands. Really it's up to you to decide what you want. The bigger the tank, the less your compressors will have to keep refilling. My air tank is a 5 gallon aluminum tank. Why? Because aluminum doesn't rust and 5 gallon is one of the largest tanks you can get. Steel tanks will rust and you'll have rust water if you're in a colder weather. So again, choose your shape, your size, and then aluminum or steel (you know what I would pick). Some people run two tanks. Totally up to you. You might also want to paint over it or decal it if you're planning on showing it. Mine's chrome, I however haven't decided if I want to do anything with it right now. It's up to you to find a creative idea.
In the air bagging community, there will be (from what I hear) only two brands you can choose from. VIAIR which is the most popular and Air Zenith also known as OB2 or AZ which is the best. VIAIR is the most popular because it comes in chrome and it's cheap. Now cheap doesn't mean good. VIAIR's compressors are generally smaller. They range from 380cc and up. Meaning that the smaller they are, the more time it takes to fill up and the less PSI it will cap out at. VIAIR also has a cool down time to let the air compressor cool down. Most who run VIAIR run two compressors because it fills up faster and it's reliable if one dies. Now this was my concern. Why would you be concerned about a compressor dying? The only reason would be because they're not that good. Not as good as Air Zenith.
An Air Zenith OB2 compressor is quality made, and what that means is that it's more expensive and built tougher. Usually one cost the same as two VIAIR units, or maybe more. The good thing about an AZ unit is that it's more quiet and it has a built in fan and will continuously fill your tank up to 200psi. An AZ unit is also a heavy, so most run one and that's all you really need. The time it takes to fill a 5 gallon tank with 1 AZ is the same amount of time it takes to fill a 5 gallon tank with 2 VIAIR 400cc compressors. So you choose really. I have both and I can't even decide. (although I'm leaning towards the AZ to save space and to maybe one day run 2 AZ's)
Now this is an addition to the compressor section but I'd like to take the time to talk about how important a quality check valve is, especially us Canadians. A check valve is a valve that opens to let air threw one direction only and will not go backwards. This check valve is put in between your compressor and your tank. Now Air Zenith comes with a quality check valve which is rated of up to -40 degrees celsius or fahrenheit. The VIAIR check valve comes with is a junk check valve which freezes EVERY. SINGLE. WINTER. So trust me when I say this, if you live in a climate that goes below zero or snows and you run a VIAIR compressor. Change your check valve to an SMC branded check valve which is rated to -40 and will work. You don't want your air suspension not going up when you're shovelling your driveway and late for work.
Now this is another subtopic that goes under compressor. I believe that everyone running an air suspension system should consider running water traps. A water trap traps water... simple. And you press a button, it releases the water. It's good for humid climates (like Texas... God, even your toilet paper is wet) or Canada where we have constant unstable weather temperatures. California... probably not as much. Water in lines aren't good, and when it freezes. It's game over. You should generally have one water trap per compressor and it's attached after the check valve between the compressor and the air tank. This stops the warm air which has some condensation to go into the air tank. Now that being said, you should still empty your air tank once a while just to make sure there's no liquid.
This is not so much the type of air lines (however you should be running DOT approved air lines and fittings) but more so the thickness of the airlines. There are (as per DOT approved) two sizes. 1/4 and 3/8. The choice of this will determine how fast your car raises and lowers. 1/4 gives a slower luxury lift and drop where as the 3/8 is quicker. There are also hard lines. If you've ever heard of these, they are generally solid metal tubes that are bent in order to run lines. Usually fancy for looks and made of copper or aluminum to avoid rust.
Along with air lines, you need to consider the type of fittings you want to use. The most popular is called Push to Connect, also known as PTC, which are the easiest to connect and easiest to remove and fix if there are leaks. PTC's are great and I use it all through my car. Your next option is compression fittings. Compression fittings are good because they stay solid and don't accidentally become removed but if there is a leak, tools are required.
Here is another video from BagRiders demonstrating the fill and dump of the 3/8 air lines.
and here's a video demonstrating the fill and dump of a 1/4 air line.
Well, it looks like you're all set. I've provided as much knowledge as I can and if you guys have any questions. I will definitely try and answer them. If there is something that I left out or put wrong, then let me know because I am human and I'm not perfect.
Now it's time for you to decide what you want. Take the shortcut of a complete kit by D2, Ksport or AirRunners or choose your own custom setup. (I would choose your own setup to save money and get the best). If you decide to choose your own, here's a check list of what you need.
- Manual Management (eg. 4 Way Toggle Management System)
- Pressure Based Management (eg. Airlift Autopilot V2 or V1 Management System)
- Height Based Management (eg. Accuair E-Level Management System w/ Touchpad)
- 5 Gallon and under
- Aluminum or Steel
- Finish (Chrome, Raw, Painted, Custom Decal)
- Single or Dual
- VIAIR 380cc, 400cc, 444cc, 450cc, 480cc.
- Air Zenith OB2
- If cold climate. Needed
- Air Zenith/not required
- Cold or humid climate
- SMC Water trap
- 3/8 (faster dump and rise)
- 1/4 (slower dump and rise)
Another thing. You'll also want to custom design your trunk. This is totally up to you. I have no creativity when it comes to that. I hope all this information will be enough to help you decide if you want to go air or not. It's a tough decision and it's an expensive one. If you keep your car for long, then I'd do it. If not, make sure your next car will have it since the management system can be moved over. Again, any questions. I'll try to answer. Any mistakes, call me out. It's a thread, the more you put in, the more it'll help our community, and if you're wondering. I do not work for BagRiders, but they've been so helpful and supportive so if you have more technical or pricing questions. They are who I'd direct you to.