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I have a 2014 overland grand cherokee with approximately 174,000 miles on it. While I love the air suspension and performance, the ride quality is slowly deteriorating. On new paved roads the vehicle drives excellent, but on rough, bumpy roads I can feel every detail of the road. I've been thinking about modifying it to soften it a bit, either by the dampers or air struts, or perhaps something else entirely. Has anyone does something similar to their car, and if so, how did you like it?
 

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Discussion Starter #3
Yes haha. While the car has been loyal to me, its beginning to get old. I'm curious if changing the struts and shocks is different with an air suspension? Thank you for your feedback!

-Javier
 

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The front air strut is all one piece and would need to get changed as an assembly. The rear I think has separate shocks that can be changed by themselves. Unfortunately, the front struts aren’t cheap.
 

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I saw that haha😭 Its definitely something I want to do in the future so I appreciate the knowledge. Thanks again
 

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I don’t have first hand experience and I’m no expert, but wouldn’t an air bag fail before there’s any loss in performance? I’d think the system would be programmed to fill the bag up to X psi over and over again, even if there was a deformity in the bag, until the bag pops or the pump fails. Would it be worth the time/expense, or has anyone had experience with, taking it to the shop to have the nitrogen in the system purged and refilled fresh? I may be in left field since I don’t know the molecular properties of nitrogen and all, but if it breaks down over time to create oxygen in the closed-loop system I’d think it would feel different to you when driving. I’m thinking along the same lines as water accumulation over time in brake fluid.
 

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The Air bags/cylinders aren’t nitrogen filled. It’s an open system with a compressor. The shocks themselves are likely nitrogen filled, but that’s a whole different ballgame. That’s why I recommended replacing the shocks and struts. Not because the air bags are failing, but because the shocks are likely losing their damping ability due to age.
 

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With respect I must disagree. QuadraLift is closed loop, there is a big tank right behind the rear seats. If the compressor sucked in outside air, there would need to be a filter to replace, right?

OP I’ve provided my thoughts and I hope you find a solution. I’m hoping to get my 2015 to your mileage! As another, perhaps cost-prohibitive option, I’ve heard of retrofit kits that replace the air suspension altogether, replacing them with traditional coil overs. Normally it would hurt resale value but at 174k I’m sure you’re happy with long-term ownership.
 

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Discussion Starter #9
Yes haha I was thinking of trading it in but I enjoy the car too much. So far it's been nothing but loyal to me so i was thinking future plans for it. These are all great ideas so I thank you all. I was also thinking of replacing the air suspension but perhaps when it dies or starts showing signs of wear. So far nothing!!
 

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2014 Summit 5.7 4wd 20" tires swapped to 18", added all skid plates
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This is a bit of a read, but it corrects some misconceptions we both have about the Quadra Lift system. While it is considered a closed system and is filled with nitrogen, the compressor (which is located at the front behind the fender) does have an intake filter and desiccant pack to bring in outside air if the system runs low.
I believe are misinterpreting what the document is saying. Under no circumstances does the system bring in outside air. The pump works with high pressure nitrogen and moves it back and forth. The system is charged to around 200 psi with high pressure nitrogen. Both sides (inlet and outlet) of the pump start with 200 psi nitrogen. The pump moves it around and doesn't "know" it's got 200 psi on both inlet and outlet. It need only be capable of pumping up to about 50 psi to facilitate the movement in and out of the air bags and reservoir. The inlet filter and desiccant are only for repair purposes when the system must be discharged and recharged from a nitrogen station designed to service the system. As explained in the article the pump does not have the capacity to pump up low pressure (14.7 psi) outside air to 200 psi so there is no way it could pump outside air into the system.
 

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A closed system - because it's better
Quadra-Lift is a closed system so adjustments are much faster than other systems that must draw in or exhaust air for operation. It is the first SUV to use the latest air suspension technology utilizing a closed type design.
The closed type system does not draw in fresh air during vehicle lifting or leveling-up, or pump air out to the atmosphere during lowering or leveling down. Instead it moves stored pressurized air from the reservoir to the air springs and back again.
Since the system's compressor is working with pre-pressurized air, and not air at atmospheric pressure, the compressor can be smaller which translates into reduced power consumption and weight as well as improved NVH characteristics. Pressurized air is moved between the reservoir and the springs by way of an air supply unit (ASU). The ASU consists of an air compressor and a valve block assembly that is plumbed to the springs with a network of lines. The ASU valve block provides six color-coded pneumatic connections to the system. Four connections distribute or retrieve air from each of the air springs. One connection is the inlet from the compressor, and the last connection exhausts the system. The ASU also contains an intake / exhaust assembly with filter, onboard desiccant, a reversing valve, a temperature sensor, and a pressure sensor. It is important to note that the ASU is not designed to fill an empty system. The ASU's main function is to pressurize and move air that is already there.
Front and rear height sensors measure the distance between the body and suspension, and provide feedback to the control system to constantly monitor vehicle height. The air suspension control module (ASCM) contains the logic that controls ride height during all driving and loading conditions. The ASCM controls the ASU compressor and valve block, and is influenced by many other modules and systems. The powertrain control module (PCM), anti-lock brake system (ABS) control module, cabin compartment node (CCN), and drivetrain control module (DTCM) are all primary inputs to the ASCM.
By working with pre-pressurized air, the closed air suspension system also provides additional benefits to the customer:


  • Reduced time to change vehicle height

  • A significantly greater number of repeated lifts without lift time deterioration

  • System performance that is unaffected at higher altitudes when compared to an open type air suspension
 

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I don’t intend to get into an argument over this, but from the article: “There are times when the system will need to make up a significant amount of air. This can occur with large changes in ambient air temperature or if service has been done on the system and lost air has not been replaced.”

perhaps I’m wrong, but I interpreted this to mean that the system can take in and compress outside air if necessary (though not via normal operation). That being said, I’ve been present for the replacement of air struts in two different WK2s, and both have automatically filled the system with compressed outside air before we were able to take them to service to have the air purged and nitrogen recharged.
 

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2014 Summit 5.7 4wd 20" tires swapped to 18", added all skid plates
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I don’t intend to get into an argument over this, but from the article: “There are times when the system will need to make up a significant amount of air. This can occur with large changes in ambient air temperature or if service has been done on the system and lost air has not been replaced.”

perhaps I’m wrong, but I interpreted this to mean that the system can take in and compress outside air if necessary (though not via normal operation). That being said, I’ve been present for the replacement of air struts in two different WK2s, and both have automatically filled the system with compressed outside air before we were able to take them to service to have the air purged and nitrogen recharged.
Keep in mind that every place the word "air" is used it really means nitrogen. It is likely that the designers understood that over time even the best system is likely to lose some amount of it's charge so the design (certainly if I was the designer) would include provisions for it to have an excess of nitrogen when "fully charged". For the example you cited "the system will need to make up a significant amount of air. This can occur with large changes in ambient air temperature or if service has been done on the system and lost air has not been replaced.” I read that as meaning it "makes up" the shortage by using some of the excess capacity it's been carrying, not that it's pulling in outside air. Were that not the case someone who lived in phx and commuted to flagstaff in the winter would constantly have large temperature changes... when they were in flagstaff it would have to "make up" air due to the low temp.. then when it came down to phx the next day it would have "too much" air and would have to get rid of it. If the system really operated that way and you made many such trips you would wind up replacing all the nitrogen with air.

That's how I read it. As to your experience with replaced parts and saying it pumped itself up my question would be what makes you think it was pulling in outside air rather than just pumping some of the spare nitrogen from the reserve tank? I'm not saying you are wrong, only that it doesn't fit with how they say the system is supposed to work. I would assume any "intake" that would allow "air" to be drawn into the system would be capped off except for those rare times it was connected to a recharge machine. To have it draw in outside air you would need to remove that cap and manually or with a scan-tool open that recharge port. Admittedly I'm making assumptions here based on what mopar has published.
 

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I have a 2014 overland grand cherokee with approximately 174,000 miles on it. While I love the air suspension and performance, the ride quality is slowly deteriorating. On new paved roads the vehicle drives excellent, but on rough, bumpy roads I can feel every detail of the road. I've been thinking about modifying it to soften it a bit, either by the dampers or air struts, or perhaps something else entirely. Has anyone does something similar to their car, and if so, how did you like it?
You can replace the whole QL system from Rocky Road Off Road they make an entire replacement kit (springs, struts etc...) with everything you need and it’s Jeep. And while you’re at it take a look at the options for lifting leveling you GC. I’ve lifted 2 WK2’s a 2011 and my current 2014 limited. Get rid of that troubling QL and you’ll be happier in the long run.
 

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I have a 2014 overland grand cherokee with approximately 174,000 miles on it. While I love the air suspension and performance, the ride quality is slowly deteriorating. On new paved roads the vehicle drives excellent, but on rough, bumpy roads I can feel every detail of the road. I've been thinking about modifying it to soften it a bit, either by the dampers or air struts, or perhaps something else entirely. Has anyone does something similar to their car, and if so, how did you like it?
I have a 2013 Overland, should be the same system??
 

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I have a 2013 Overland with the air suspension. Got tired of the self-draining Jeep shocks and replaced them with Bilstein even though they’re said not to fit. Much better ride than before. Can’t tell any difference in tire wear or ride height (except higher than the blown out shocks).
 
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