2nd Gen INFINITI QX56/QX80 Build

leeleatherwood

Active member
After having the airbags and rear king shocks installed and put some miles on them, including a trip from San Jose, CA to Washington state, I have some feedback on this setup.

The current modifications:
King Y62 Patrol shocks with Remote Res and Adjuster.
Firestone Coil-Rite airbags
PRG 2" Coil Spacers
OEM Coil Springs
Removed factory Air Shocks. (replaced by the Kings)



For anyone not too familiar with the Nissan IRS suspension used in the 1st and 2nd Gen Armada's and QX56's/QX80's (Maybe R51 Pathfinders too), they use 2 different "springs" to support the weight of the vehicle. In this case, the majority of the weight is supported by the coil spring, and the remainder, but still large amount, is supported by the air spring inside the Air Shock.

The rear suspension also has 2 control arms. The coil spring sitting inside of a bucket on the rear control arm, with the air shock being connected to the front control arm.

If the air shock is removed, and replaced by a typical shock, something must be done to support the load that the air shock was supporting. If you do not, the suspension will squat all the way down. Even though the coil spring is supporting a majority of the weight, it is still not even close enough to support the vehicle by itself.


There are 3 solutions to this issue:
1) Replace the coil spring with higher springrate which is capable of supporting the vehicles weight.
2) Install airbags to use as helper springs.
3) Do both.



In my current setup, I have installed the Firestone Coil-Rite airbags to use as helper springs for the OEM coils. This "works", but it is not ideal.

The factory air ride pump does not seem to have an issue operating at the pressure required for the Firestone airbags to lift the vehicle to proper height. On the other hand, the air bags have a MUCH larger volume than the factory air shocks. It seems Nissan has programmed the air ride system to turn off the air pump after a set period of time, this is probably so that the pump doesnt burn itself out incase there is an air leak or something. So, in order to get the air bags to fill up, you will need to turn the vehicle on, let the pump run, turn it off, and repeat the process a few times. Because the air ride system "leaks down" over time, like almost any other air system, after sitting for a while you will need to perform this "air up" procedure. Not a big deal, but obviously not ideal. Alternatively you could install a switch to turn the pump on manually whenever required, I will do this myself when I get time.

The larger problem with this setup, is that In-Coil airbags are literally balloons, super thick balloons. Because of this, and because of the fact that they support so much of the load, in certain parts of the road like long whooping rises and dips it feels like the rear end is riding on one of those giant bouncy exercise balls. Not ideal.

The bad thing about using air as a spring, is that they are not linear, they are progressive. When you compress a gas (air in our case), the pressure increases as the volume decreases, and to make it worse, its non-linear. The more you compress it, the higher the "spring rate" will be. This makes it very hard to tune around, and very hard for a shock to control.

Normally, when these airbags are used, they are used as helper springs. As in they help the main springs, but the main springs are still capable of supporting the vast majority of the load. In this scenario, the "balloon effect" while still present, is far less pronounced for at least two reasons, 1) The airbag is simply supporting less load. 2) The main coil actually helps to control the air bag and "balance" the spring rate more evenly.

In our case, the coil springs (main springs) are not able to support the load, and since they are such a low springrate to begin with, you lose the ability for the main spring to help "balance" the spring rate. This leads to a very pronounced balloon effect.



From the beginning, I knew about this potential problem and I ordered some Dobinsons Y62 Patrol Medium Duty springs, they simply have not arrived from Australia yet. They should be here in a month or two last time I checked.

I believe the increased springrate will resolve the balloon effect in the rear end, I still plan on using the Airbags to adjust the ride height when the load changes.
 
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leeleatherwood

Active member
My battery is not doing that great, and since I will be taking a trip to Death Valley soon I should replace it. I also want to run an electric blanket during the nights to keep warm, so a deep cycle would be good.

I am not ready to do the drawer system and "house" electrical setup so I will run the inverter off the starting battery for this trip. I will also have one of those jump boosters just incase.

The battery should be here tomorrow, its a 65 group size so a bit larger than the stock 34 group size. I measured and it should fit, fingers crossed :p The Odyssey is good for 400 cycles down to 80% discharge, so they work great as a starting battery and deep cycle.

1576885799041.png
 

Deshet

Adventurer
I am getting a q80 in the future are you saying that they all have a rear elocker?

It will be a family ride for the foreseeable future but it will get passed down to me eventually. I will probably get a 2015 or 2016. Any chances either have the better front axle.

Thanks
 

DzlToy

Explorer
Kudos for choosing something out of the mainstream and using an Odyssey battery instead of a junky, Chinese, over-hyped Optima.

Not being a Nissan owner in more than 20 years, I was surprised to see that an R180 was the OEM's choice for the IFS on large trucks and SUVs. I guess this is proof, as if any was needed, that these vehicles are, for the most part, Mall Finders, and will never see anything that will tax that diff.

Cheers
 

leeleatherwood

Active member
I am getting a q80 in the future are you saying that they all have a rear elocker?

It will be a family ride for the foreseeable future but it will get passed down to me eventually. I will probably get a 2015 or 2016. Any chances either have the better front axle.

Thanks
No American versions come with Rear Locker.
 

Deshet

Adventurer
reading through this thread confused me a lot. I was under the impression that Q80 was an upgraded Armada which is based on the Nissan Patrol. But it sounds the Q80 has a smaller/weaker diffs then the Armada and Titan. It seems crazy that the Q80 has Pathfinder axles. I have never owned Nissan Products and am leaning towards the Q80 due to better pricing compared to the Landcruiser with similar miles. I also expect better fuel mileage with selectable 4wd.

Thanks,
 

leeleatherwood

Active member
reading through this thread confused me a lot. I was under the impression that Q80 was an upgraded Armada which is based on the Nissan Patrol. But it sounds the Q80 has a smaller/weaker diffs then the Armada and Titan. It seems crazy that the Q80 has Pathfinder axles. I have never owned Nissan Products and am leaning towards the Q80 due to better pricing compared to the Landcruiser with similar miles. I also expect better fuel mileage with selectable 4wd.

Thanks,
You have to remember that there are now 2 Generations.

Gen 1 QX56 is 2004 - 2010
Gen 1 Armada is 2004 - 2016

Gen 2 QX56/QX80 is 2011+
Gen 2 Armada is 2017+

The Gen 2's have weaker front differential than Gen 1's. (R180 vs M205)

With that being said, you can easily install the Gen 1 front differential into the Gen 2, its super easy bolt in. In my opinion, I would not let this sway your decision if you are considering the QX80 for off-roading.
 

Deshet

Adventurer
Thanks for the information. I haven't heard of many faults with Nissan's lately. I remember issues with the oil coolers in the early to mid-2000's Xterra's and pathfinders; the early titans had issues with burning oil. Do these have any specific issues common to specific years?

Thanks
 

leeleatherwood

Active member
Thanks for the information. I haven't heard of many faults with Nissan's lately. I remember issues with the oil coolers in the early to mid-2000's Xterra's and pathfinders; the early titans had issues with burning oil. Do these have any specific issues common to specific years?

Thanks
I haven't heard anything concrete. I think I remember seeing something about noisy timing chain guides but I don't think it was a systematic problem. If that were the case, it probably would have been the early years and probably resolved by the time the QX80 came out.
 
PetitFrereArmada was selling his Stedi Type-X Pro lights. I bought them from him.
Still need to wire them up, but ran out of daylight.





I really dig the way the lights turned out for you. So, I was bored and decided to add some more lights to my rig just because. Now I have to keep this rig until atleast 250,000 miles before I can think of getting rid of it.

Here are a few pics or you can click on my link to see more of the pics on my thread on club Armada...

Two 8 inch led bars installed on my 2012 Infiniti QX56






 
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Installed the battery. Could have actually fit a batter about 1.5" longer and 2" taller with ease.

That is cool to see you have a larger battery than stock size. Based on what you said here, is there another larger battery that can fit here? Is the battery more heavy duty than this one you have installed?

Now that I have these auxiliary lights installed on my QX and they all work directly from my battery, I figure I need to start looking for a more heavy duty battery before I drain my current oem battery that was installed brand new 3 years ago. It may be coming to the end of its life soon, though I cannot tell yet as it seems to be performing flawlessly so far. But I am sure I will need to upgrade soon and I would like to make the sacrifice to buy the most powerful heavy duty one that can fit in the battery tray on our cars.

Do you know of any battery that is more powerful than this that you just installed that would fit on our QX? I may be interested in looking into maybe buying one some day down the road.
 
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