First things first, I am not a professional neither are my friends. We are a bunch of car enthusiast that would rather try it ourselves then pay the premium to get it installed at a shop. With that being said lets get into this build. There is a handful of brands that make Air Suspensions for the 1990 Mazda Miata. The brands I know personally is D2, Truhart and Airtekk. Im pretty sure there is more air suspensions out there for the Miata but these specific brands were in my price range. D2 and Truhart are both sleeve type airbag and Airtekk is a bellow type air bag. The difference between the bellow and sleeve is how it looks and also the ride comfortability.
I ended up going with the Truhart Air Strut with the Vera Black Element Management. The management that I purchased is a "manual" management with a LCD Screen. It comes with a black 4 gallon air tank, black VIAIR 444c air compressor and all the necessary air fittings and hardware to complete the task. (besides extra gauge wire and connectors.)
The hardest part of the whole thing is mocking where to put the air tank and air compressor. I already had my 12 inch sub in the trunk, so some things needed to be rearranged. I ended up putting my air management in my trunk and my sub on my rear deck. In the process of moving things around a few interior components needed to come out because big guys in a small car don't work well. We took the hard top off then both seats and center console had to come out just to make enough room.
We then put the car on jack stands and started taking the wheels and suspension off. Taking the previous suspension off we used a 14mm socket for the top hat bolts and 17mm for the bottom bolt. The quickest way to take out the coil over suspension is having the coil over at its lowest point and having somebody else use their weight to step down on the break assembly to hold it down.
The difference between the coil over suspension and the Truhart Air Strut.
(Left: Rear. Right: Front.)
Now the fun part, it was time to put in the Truhart Air Strut. The air strut assembly is a lot different from the coil over besides the given "air bag" replacing the coil. The lock rings don't actually touch and lock like how coil overs. The air strut locks up by: (top locks top and bottom locks bottom) so in the middle are a bunch of threads for you to play with adjustment. Find your appropriate height adjustment you want to install them in (max low). So this is when the "freestyling" part begins, there wasn't any instructions given on how to install the air strut, having the 90 degree valve facing "out" towards the wheel or "in" towards the engine. The rears are faced "out" towards the wheels and fronts are "in" facing the engine.
There are a few ways of running the air lines, you could follow the brake lines under the chassis or drill to your interior and run it through there. The main goal for us was to drill the least into the chassis. How we routed the air lines are also "freestyled" even though there was a wiring diagram for that. The rears are following the brake lines under the chassis then "t valved" in the engine bay. The fronts go under the sub frame away from moving components then "t valved in the engine bay as well.
NOTE: when running air lines, stay away from moving components and things that get hot.
After running the air lines it was time to do the electrical part, FOLLOW the wiring diagram, no "freestyling" here. Since I was using a manual management setup, it was fairly easy to install. Take your time reading the wiring diagram, follow the instructions and you should be able to figure it out.
Here's a few beauty shots of the Miata aired down.
Am I happy with my purchase? As a complete product, NO. I don't like how the rear sits aired all the way down, it's almost the same height as if I had my coil overs on. Honestly, the main purpose of buying air bags especially for a Miata, is to lay frame. The front struts air out all the way down and tucks the wheel, I'm happy with that. The rears are not even close to tucking the wheel. Unfortunately I'll have to spend more money to get the rear control arms fabricated to lay frame. Most likely around the same time i'll reroute the rear air lines to go inside rather than under the chassis to prevent any type of lines being pinched when I lay frame.
When that process is done, I will do another write up but until now it's going to sit like this.
Special Shoutout to the following guys that helped during this process.
Josh: @jashishi2
Clay: @clay_burr
Alex: @the_white_ca5
Boody: @bo0.d_337
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