First off, lets consider this a rough draft! I want this thread to become the go to source that the other X-Frame thread should have been. The overall idea was great, but there are 7 pages so far of many unanswered ?'s, and unorganized answers littered throughout the thread. The goal here is to update the original post with the most important info, suppliers, parts needed, links, part numbers, etc.. I am currently planning the air suspension on my 2-Door '64 Impala, and I want this thread to become what I had hoped to find during my searching, that I was never able to find. As this thread takes off, all the info I gather, will be organized into this original post, and what I put in it will also be molded by your feedback and input...The car that is inspiring me to make this thread:
The front X-Frame Impala suspension needs little modification to be converted to air. The main thing that you will have to decide is if you want to run shocks or not. Many people do not, but I will, and will be documenting what additional stuff is needed to add shocks to the front. This is only a concern on the front as the factory shocks run through the factory springs, leaving no place for the shock to go once the bag is installed. This is not as big of a procedure to relocate the shocks as you might expect, and can be done for under $100 complete (Assuming you are doing the work yourself of course).
-Front Shock Relocation-
I have already done this portion of my conversion, and it was very simple. I purchased the $39 kit from www.BCFabrication.com. From my research, I have found that the specs of the Monroe Shocks with part number #32267 seem to be right inline with the measurements I took from my installed kit. I will be buying these shocks, and will update with how well the fitment was. Some vendors are selling rebadged shocks that are nothing more than a basic Monroe shock or similar, but are often carrying a price tag in upwards of $100, when you can get them for $50. The brackets have a locating hole that matches a hole in the frame, so it is hard to mess up. You can actually use the lower shock stud from the kit as a centering tool as it is the same diameter as the hole! Minor trimming of the inner fender well is required with this style kit. I added a few small welds to the installed bracket because I don't fully trust the tapped holes (Not much thickness there for tapping strong threads, and the welds are small enough, that they could easily be ground off in the future.
Here is a pic of the bracket kit:
Here is a pic of my installed brackets:
The lower part of the kit simply involves drilling a hole on the back of the A-Arm, and then bolting on the shock stud. I will post these measurements when I get my shocks installed and drill these holes.
EDIT: These shock relocation brackets turned out to be junk! They are simply way to thin, and flex back and forth about an inch in both direction as the suspension is pushed down when view from the engine bay! I will be coming up with a revised plan here soon. I would avoid these!
-Front Air-Bag Brackets-
These are commonly found in the price range for $90-$130. This set from Airassisted.com seams very reasonably priced at $100. The only way I have seen them cheaper is to go through Ebay, and I'll definitely pay the extra $10 to get them from a reputable company! Front kits typically look like this:
A 2600# bag is most commonly used for the front. It is recommended that you always use a good quality bag. I am definitely suggesting the use of something from "Slam Specialties" here. I am currently planning on using the SS series (7" SS). http://www.slamspecialties.com/air_springs/SS-7.pdf . I will post a link to a good vendor for these once I find one. I have looked at sponsors here, but website issues have made it difficult to find a solid link. Expect to pay $75 per bag for these. These are known for not ballooning (Expanding side to side with pressure) which is important for the front, because it will limit the amount trimming you will have to do to the front spring pocket to keep the bag from rubbing.
The rear suspension is a little simpler. You do not need to relocate the shocks because they do not run through the springs like the front. You simply need the bags you are going to use, and a bracket kit.
-Rear Air-Bag Brackets-
These are also commonly found in the price range for $90-$130. As above, I will be posting the link to Airassisted.com, as the rear kit is also $100. Rear kits typically look like this:
I am also suggesting using "Slam Specialties" SS-7's for the rear. Many people run the 2500# style bags in the rear, as you don't need to lift the weight that you do in the front (Engine weight obviously). But this will limit your up travel. The only benefit I see to the 2500# is that it will require less air volume, and have a slightly faster fill rate. This could be beneficial if you have a really small compressor.
Theoretically, the rear shocks can remain stock, as they do not interfere with the bag install, but i will post more if I find a shock that works better if the stockers do not meet reasonable travel needs.
The rear suspension of the X-frame Impalas suffer from a pretty poor design. It is sufficient for stock suspension/passenger car use, but when coupled with an adjustable height suspension whether it be airbags or hydraulics, it suffers from one major setback, the panhard bar. By design, it pulls the rear axle to the drivers side as the vehicle raises, and that added to the extreme travel of airbags/hydraulics, makes for very drastic side to side travel of the rear axle.
Ideally, you would convert to a Triangulated 4-Link with the longest links you could fit. For most, this is an unrealistic project as it would be fairly expensive to have done, and takes a good amount of design, and fabrication skill to take on and do it on your own. Luckily, there is a very simple mod out there that solves about 90% of the rear suspension design issues, and for most, is simply the most logical route to take when adding hydraulics/airbags to their X-frame Impala.
This is where the "Y-Bone" as the industry has dubbed it, comes into play. What this does is eliminate the ill effects of the panhard rod, and then transfers the duty of side to side axle control to the upper link, by replacing the upper link with a modified version that is now mounted at the chassis at 2 points instead of one, giving it the ability to control the side to side movement of the axle instead of the panhard rod, while keeping the axle centered during up/down travel.
There are 2 different designs I have seen floating around, Avoid ones that look like this:
This design puts a side to side load on the drivers side chassis mounted bushing, that that style bushing is not meant to handle, and is prone to failing prematurely. The preferred design is fixed and transmits the forces to the bushings more logically. The only exception is really the axle mounted bushing, but unless you are putting silly side loads on the axle with track days or high speed cornering you should be just fine. The best "Y-Bone" I have seen with a respectable price comes from forum member "A&W". For $230 plus shipping (Raw, not chrome), you get the best "Y-Bone" design I have seen, at a very reasonable price!
His contact info is here: http://www.layitlow.com/forums/9139-a-and-w.html
Nothing too special about this, pretty much just have to make sure you have enough ports to hook up what you need too, and it is highly advised that you get a DOT approved tank (Especially for you guys running higher pressures!). If you are going to be doing a full FBSS set-up (As most will be), at least 7 ports is recommendable (4 for the individual bags, a pressure switch, compressor input, and a general output for air tools is always nice!). If you will be running more than one compressor, additional ports will be needed obviously.
A FBSS system will require 8 one-way valves. If you just want separate front and rear control, 4 one-way valves will suffice. I will post more on this as the thread develops. Your valve size will depend on your speed requirements.
Word of advice, if this is your first Air-Ride install, get the biggest compressor you can afford, or run duals. I see too many new guys running one small compressor, and it can be very frustrating (I did it myself). I will personally be documenting the install of an EDC (Engine Driven Compressor, in my case a converted Sanden A/C compressor) in this thread. It is more labor intensive, but offers more air than you can expect from an electric compressor, with less noise. Unless you have some fabrication skills, or know someone who does, it is probably going to be much less of a headache to run an electric compressor(s).
At a minimum, run DOT approved plastic airline, with all metal fittings. If you are looking for a bullet-proof system, it is highly suggested to run hydraulic lines. Your line size will depend on your speed requirements.
More to come! This is a rough start to this thread and will get refined with new research, info from you, etc. Thanks for stopping by!
-Looking to add a link to a solid vendor for the "Y-Bone". If anyone has a good link, please let me know. I am trying to only post links to reputable vendors, so the links stay good, and continue to be a reliable source. I am trying to avoid things like "Jimbo on the forums makes 'em" for example.
-Let me know if there is any other things that should really be in the original post. I made a basic outline, and have been adding info based on my research for my own project.
-Quick Product Links From Article-
-Slam Specialties SS Bags - Airassisted.com - $75
-Front Bag Brackets - Airassisted.com - $100
-Rear Bag Brackets - Airassisted.com - $100
-Front Shock relocation Kit - BCFab.com - $39