FZJ80 + 18ft Sunradrer

mycroft

New member
I recently had a baby and had to sell my 4x4 camper to build a more baby friendly model. The new owner has a build thread on here (1988 toyota + 1977 chinook). I decided to get an 1993 FZJ80 with e-lockers, rebuilt axles and rebuilt engine. I combined that with an 18ft 1986 Nissan Sunrader that had a blown engine. All in all, it came together pretty nicely despite having a slightly different wheelbase. I may put a build thread together if people are interested.

Right now I could really uses some advice on rear suspension. I cut about 600#s of metal, glass and upholstery out of the land cruiser and then added the fiberglass shell to the remaining frame. I added air bags inside the rear coil springs to help support the extra weight. The manufacturer of the bags says the bags are good for 1000#s per bag so they should increase capacity by 1 ton. Unfortunately the truck looks like it sags in the back at 35PSI which is the highest the manufacturer suggests in this application, despite other applications being capable of 100PSI per side. I'm considering swapping out the stock rear shocks for OME 2868 shocks since they are supposed to be capable of supporting an extra 600kg (1300#s). The spring rate will change from 170lbf/in to 360lbf/in. I'm looking for advice on how this might affect the rig. As you can imagine it drives like a top heavy Cadillac right now.

1) I'm wondering if taller stiffer springs will help put wt back on my front tires?
I read that stock, the front axle supports about 2750#s and the rear axle supports about 2750#s. Other guys on this forum have weighed their trail built rigs and found 3200#s on the front axle and 3480#s on the rear axle. I weighed my rig dry today (no water, food, gear, dog, baby, wife ect) and found that I weighed in at 2450#s on the front axle and 3960#s on the rear axle. It seems like the extra weight and extra overhang in the back are taking weight off the front tires which I worry will make the rig drive poorly and cause my tires to scallop.

2) I'm hoping that the stiffer springs will make the rig feel less like driving a ship. If not what else can I do to control body roll?

3) Does anyone know the stock distance between the axles and frame on an FZJ80?
Mine looks like it is low in the back but I don't know where to measure or what the measurement should be.

4) Dose anyone know that max rating of the rear axle?
I know what they are rated by the manufactures... but its obvious that they can handle a lot more, but how much?

5) Will these new springs even be stiff enough? I assume that fully loading the rig will add another 1000#s (so something like 5000#s on the rear springs) assuming that the axle can handle 5000#s.

The project still needs a good bit of work. At the top of the list is closing in the gap between the cab and the shell and cutting out the original sunrader floor so I can add 6in of extra head room by utilizing what I left of the the land cruisers floor.

Thank you for your help.
 

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redthies

Renaissance Redneck
That's a cool project! I'm sure we'd all be interested in a build thread. With the OME coils in my 80, I carried around 1000 lbs in the back, and towed a 31' Airstream that wheighed around 7,000 lbs. I wouldn't do it regularly, but it handled it fine the one time I needed it to. The rear axle is a 1 ton full floater, so as long as your tires and springs are up to it, I think you'll be fine.

And welcome to ExPo!
 

peekay

Adventurer
I think one of your fundamental problems is that you have a short wheel base vehicle, that is has quite a bit of ground clearance, and carrying lots of weight up high.

I would try firmer valved shocks, harder springs, and heavier duty tires. When I went from load range C tires to E tires, the difference was night and day in terms of stiffness. Also, have you looked into alternative airbags? I've had both Firestone and Airlift and generally, it seemed that the Firestone bags were far superior.

Finally, I would consider smaller tires. Obviously, big tires have their advantages, but unless you really need 33's (those look like 285s, or maybe even 305s?), I would consider dropping down a size or two, maybe even stock.
 

OVRLND

Adventurer, Overland Certified OC0017
This is a great project.

I have a few pictures of an HJ80/Sunrader I tried to buy a couple of years ago.
That one looked great ... Yours looks better and certainly more capable.

Good Luck. Keep us updated.
 

mycroft

New member
Glad to hear my axle should be able to carry the weight. Do you know the tongue weight of your airstream?
 

mycroft

New member
I do have air lift bags. I wondered if maybe the firestones were better, at least I know for next time. The tires are 285s and rated D. When it's time to get new tires I'll definitely switch to E rated and maybe go smaller. Will E be noticeably diffrent from D? Its just really hard to get excited about buying smaller tires... Althoug, if I had smaller tires from the beginning it would have made clearances under the camper shell much easier. As it is, my rear tire barley missed the step into the camper and on the other side I had to pull my black water tank because the spout would get torn off if the wheel traveled too high into the wheel well. Im current planning of repurposing thre grey water tank as black water, since its already larger and has no clearence issues. I might even move the tank into the spare tire cavity to move its weight closer to the axle. I plan on mounting the spare to the front to help with weight distribution
 

Ovl

New member
Rember springs support the weight and shocks controll the sway as well the sway bar. I have the Rancho 9000 with the adjustment and really like them. When I first put them on I had set them in the middle position and the truck felt much more like a boat cranking them up two steps really tighten the ride.
 

richxd87

Observer
I think you'll need to address the rear springs first if you're still on the stock coils. They aren't rated to carry anywhere near that weight and I don't think those helper bags are as effective as they can be carrying the additional ~1500lbs paired with stock springs. I use the bags in my 80 and they do great to help level out an additional 3-500lbs or maybe the tongue weight of a trailer and thats with the OME 2863J heavy springs. Take a look at the coil spring table linked below and maybe talk to Kurt at cruiseroutfitters to see which one he recommends with that much weight. Looks like you'll need to go to the OME 2868 springs with the highest spring rate but a lower free height to reduce any additional lift. After that, a talk with one of the custom shock makers to get you a shock valved for all that extra weight.

There are also options of a heavier rear sway bar to help combat your higher center of gravity and and additional weight.

http://www.cruiseroutfitters.com/tech_OME_coils.html

Either way, please post up a build thread! I'm very interested in following your progress and all the work you've done up until now.

Richard
 

mycroft

New member
I now have the 2868 springs in the rear and they made huge difference for city driving. The springs are pretty tall and don't compress much even when i am loaded with gear people dogs food and water. The air bags are no longer able to touch the top and bottom spring perches making them 100% useless. I took it for its first weekend adventure and there was some good and also some bad. On the freeway at about 70mph it starts to sway back and forth pretty bad. I had to accept that it tops out at 65 with current suspension. Off road it was a beast in the snow and mud but only if it was very flat. It is the most tip prone vehicle I have ever driven. It amplifies the tilt of the trail. For instance when my passenger side tires are about 10in higher uphill than driver side tires I noticed terrible body roll. I got out and measured the springs and the driver side springs had compressed about 1in and the passenger (uphill side) had expanded about an inch. This made the vehicle tilt at about twice the angle of the trail. I know i need new shocks so I called some shops and tried to get their advice. I was planning on buying the OME nitro sport but came across the KYB monomax and it seems like they are stiffer than the OME but I couldn't find a head to head comparison. I ordered the KYB and will put them on this week. I still plan on using an OME steering dampener as i couldn't find anything comparable. I am looking for a stiffer sway bar but cant find any commercially available. I even talked to slee and they didn't know of any heavier sway bars. All in all I'm pretty disappointed about its off road manners. After i put in the new shocks im planning on relocating the water tanks the hot water heater and anything else heavy to the lowest point possible to try to lower my center of gravity. I wish i could just cut down the springs to make them shorter and stiffer but they way they are finished on both ends makes this impossible. If any one has a suggestion for making this a more stable ride i am all ears. I might put the stiffer front shocks the OME 2850, but right now the front axle is still only loaded with stock wt, unless i break hard then mi sure the wt shifts forward.

To keep it interesting ill add some pictures. I did add a snorkel, its ridiculous given my current off road capabilities but maybe it will come in handy one day.
 

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