One of the first things that we wanted to do to our 2003 "Project Altima" was give it an altitude adjustment by adding an airbag suspension and Firestone Industrial's new IntelliRide automatic electronic leveling system. However, we soon found out that no one had an airbag kit available for the Nissan Altima. So, we contacted Firestone Industrial Products (in Carmel, Indiana) to see if they could help us create a kit for the popular platform. They were eager to help and immediately called the pneumatic experts at Air Ride Technologies (in Jasper, Indiana), exclusive distributors of IntelliRide, to see if they could prototype an airbag system for us. The timing was perfect. Air Ride already wanted to develop an application for the Altima using their new AirStruts (for vehicles with a MacPherson strut suspension), so arrangements were made to transport our project car from California to Indiana.
Along with solving the obvious problems of air spring and shock placement, AirStruts offer improved alignment adjustment with slotted spindle mounting holes and eccentric bolts. This prevents the need for camber caster plates to get proper wheel alignment at your new lowered ride height. AirStruts even include new upper mounts so there is no need to take apart your old strut to re-use the OEM upper mount.
AirStruts also feature 12-position valving adjustment at the top of the strut stem--under the hood where it is accessible, not under the car. This adjustable valving means that you can go from soft for quality and cruising, all of the way to full firm for the ultimate in handling performance. The AirStrut is typically set up to deliver a 2-inch drop at ride height and up to 4 inches when deflated for parking lot profiling. Applications are available or in development for a variety of cars including Accord, Acura, Camaro, Cavalier/Sunfire, Civic, Eclipse, Focus, Golf, Impala, Jetta, Malibu, Monte Carlo, Mustang, Neon, New Beetle and now Altima.
Once the Air Ride engineering team got their hands on the car, it wasn't long before they had a "one-off" kit developed and installed. Because our project vehicle is a prototype, some of the bracketry for the suspension looks "home-made," but by the time that you read this article they will have a finished, high-tech bolt-on kit available for the Altima.
Next, the team from Firestone went to Air Ride's facility, installed the IntelliRide system and tweaked the suspension so that the driving height is approximately 1 1/2 inches lower than stock in the front and 2 inches lower in the rear. Of course, the car lifts considerably higher for getting over parking lot bumps and lays out very nicely for when it's parked at shows. It also handles very nicely at all three height positions--and all at the push of a button, no gauges to watch, no front/back switches to adjust.
Follow the photos now as we show you how easy it is to give your ride an automatic altitude adjustment thanks to Air Ride Technologies and IntelliRide.
1 The Air Ride Technologies/Firestone IntelliRide system lifts the car for cruising or lays it low for show--at the push of a single button.
2. The OEM front strut assembly, standard stuff for most front wheel drive cars. The strut is attached to the spindle by the two bolts at the bottom of the picture. Notice that the sway bar is also attached to the body of the strut.
3. The top of the OEM strut is attached to the body of the car through this three bolt mounting plate. On the Altima, we will reuse this mounting plate with a small modification to the center hole.
4. To accommodate the slightly larger AirStrut upper stud, the center hole is opened up to 5/8-inch.
5. This is a spacer plate that is placed between the OEM upper mount and the body. It acts to lower the AirStrut assembly slightly to allow clearance between the adjustor knob and the hood.
6. The modified OEM upper mount is then reinstalled with the supplied spacer and fasteners.
7. This is the AirStrut as delivered from Air Ride Technologies. As you can see, it includes the lower mount and the sway bar mount... ready for a bolt-in installation.
8. The AirStrut is bolted into the OEM upper mount and spindle. Note that the upper spindle mounting hole is slotted horizontally... a neat trick that Air Ride Technologies incorporates into all of their AirStruts so that the front end alignment can be properly set at the new lower ride height. Be sure to use the supplied eccentric spindle bolts to ease the alignment process.
9. Position the AirStrut sway bar mount to properly mate up with the OEM sway bar. Tightening the attachment bolt will clamp this mount to the AirStrut body. There are a variety of different mountings for brake hoses and such. We used tie-wraps to make sure that these items didn't interfere with suspension movement. Then, cycle the suspension through full travel to be sure that the AirStrut doesn't rub on anything at anytime!
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10. The rear suspension has a traditional coil spring and separate shock and is just as simple to "bag" as the front suspension.
11. Here's the rear air suspension system for one side. As you can see, it's very simple bolt-in stuff that has been properly engineered by Air Ride Technologies.
12. First disassemble the lower shock mount and the lower control arm from the spindle to remove the coil spring.
13. The upper air spring mount is installed into the OEM upper coil spring pocket with the supplied self-tapping screws. Orient the upper mount so that the airline hole is towards the inside of the car... it makes routing the airline much easier. Note that a notch must be cut into the side of the coil spring pocket as shown for airline access.
14. The billet aluminum lower air spring mount is placed into the lower control arm over the center hole. 15. The flat roll down plate is placed on top of the aluminum mount.
16. The supplied 3/8-inch, 16-stud and rectangle retainer plate are used to combine the air spring, roll down plate, aluminum mount, lower control arm and retainer plate into one sandwich assembly.
17. Install the elbow airline fitting and swing the lower control arm/air spring assembly into position so the air spring can be attached to the upper mount. Quarters can get the nuts started, but a wrench will be needed to tighten them. Attach the airline and you're done. Be sure to run the suspension through its travel to ensure that the air spring doesn't rub on anything at anytime.
18. Next, the IntelliRide system was installed. The height sensor components are ready for pre-assembly.
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19. The assembled height sensor is ready for installation. The three-color template can be removed after the system is installed and operating properly. One template should be saved for future system re-calibration if necessary.
20. These are the height sensor linkage components ready for installation.
21. & 22. After the height sensors were pre-assembled, a location for the lower height sensor linkage was found by measuring suspension travel at full up and down positions. Multiple locations were measured to find a place where exactly 6 inches of movement was found. In this case, the lower shock clevis was found to be the ideal location. Any suspension travel between 2 and 6 inches can be used. The rear shock had 6 inches of travel so this dimension was picked.
23. A hole was drilled and tapped in the lower shock clevis for the height sensor linkage.
24. The ball stud from the height sensor linkage was screwed into the shock clevis.
25. The sensor and template were installed in a location on the inner fender well above the height sensor linkage ball stud using the supplied hardware.
26. The height sensor linkage rod length was determined by inflating the air spring, then holding the height sensor arm in the lower green section of the template and marking the rod length. The rod was then cut to that length and the jam nuts installed.
27. The rod was threaded into place and adjusted so that the height sensor rod was in the middle of the lower green section of the template. The air suspension was deflated and the suspension lifted until it compressed its stops fully and the weight of the car corner rested on the stop. The height sensor was then checked to make sure that the height sensor arm was in the upper green section of the template. The same process was used to do the other side of the car.
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28. & 29. The same process was used to find a location of the front suspension. The suspension was articulated through its entire travel and measurements were taken to find a location that had exactly 4 inches of travel because the front shock has 4 inches of travel.
30. In this case, a bracket was fabricated that clamps on the lower suspension arm to attach the lower height sensor linkage ball stud.
31. A location above the lower height sensor linkage ball stud was found for the sensor. The sensor and template were then mounted at that location with the included hardware.
32. As was done on the rear, the height sensor linkage was shortened so that when the suspension was all the way down the height sensor arm was in the lower green section of the installation template.
33. The suspension was run through its complete articulation to make sure that the height sensor arm was within the green section of the template in both suspension extremes.
34. The valve block was mounted to the wall of the trunk and the tank was mounted in the trunk near the valve block. Then the airlines were run and the wiring harness was installed.
35. The compressor was then installed next to the tank.
36. The system air dryer was installed under the package tray in the trunk.
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37. The wiring harness connections were all made and the ECU (brain) was installed under the dash. The service switch and height selection switch will be permanently mounted when the interior changes are done.
38. The AirStruts feature a 12-position valving adjustment at the top of the strut stem to go from soft for cruising to firm for maximum performance and handling.
IntelliRide... The missing link
The missing link for a state-of-the-art air suspension, the IntelliRide electronic leveling system, was developed over the past two years by Firestone Industrial engineers and is available exclusively through Air Ride Technologies. It offers three user-programmable ride height settings at the touch of a single button.
The system is height sensor-based, not air pressure-based, so no matter how much load is placed in the vehicle, the preset ride height is always restored. The system includes the IntelliRide ECU (brain), four ride height sensors, Thomas 327 12-volt compressor, 3-gallon tank, air valve manifold, air dryer and a wiring harness with Weatherpak connectors.
Now there is no need to be concerned about getting the air pressure right when you add people, luggage, or fuel to your car... the IntelliRide automatically restores your vehicle to its preset ride height.