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80 series vs. LJ78/KZJ78 articulation

Discussion in '70-Series Tech' started by GTSSportCoupe, Aug 19, 2014.

  1. GTSSportCoupe

    GTSSportCoupe

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    Not my video, but illustrates my point:



    Having wheeled my LJ78 quite a bit now, I'm struck by how limited the axle articulation is on these trucks (especially the front axle). I've got a 2" lift: OME medium springs, nitrocharger shocks, 1" spacers added to front springs, and whiteline castor correction bushings. I run 32" skinny tires.

    The 80 series has a similar suspension design to the coiled 70 series LWB. What is different about the 80 series that it has so much better articulation?

    Without completely redesigning the LJ78 suspension, is there a way to get more articulation? I've heard removing the sway bars has little effect.
     
    Last edited: Aug 19, 2014
  2. clintnz

    clintnz

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    80 series is 4 link + panhard in the rear, LJ78 is 2x radius arm + panhard isn't it?

    Only done 1 weekend of offroad since grafting the 80 series rear axle & suspension into my LJ71 but the difference is quite noticeable - the 4 link gives better articulation AND better stability, gets the power down well too.

    One way to get better flex without going too crazy might be to make up some new radius arms with spherical bearing rod ends at the chassis end, could correct your caster also. I have adapted rod ends onto the Nissan front radius arms that are now under mine which works well.

    Cheers
    Clint
     
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  3. Hulsty

    Hulsty

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    Get rid of all your polly bushes and castor correction, stock rubber will give best flex.
     
  4. GTSSportCoupe

    GTSSportCoupe

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    That is pretty cool that you put the 80 series rear setup into your LJ71. You have a thread on that somewhere? I'll have to check it out, although I can't see myself going that far.

    I do like the idea of making new radius arms with spherical bearing rod ends at the frame. Or even trying to retrofit a spherical bearing into the factory radius arm. I'm actually surprised that there is no off-the-shelf solution like this being manufactured anywhere for the Prado. Maybe in Japan? Seems like it would be a good common upgrade.

    Even before the castor correction bushings, the flex was not good. You're right that they're probably not helping any though.
     
  5. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    keep in mind that providing more flex .. you are also introducing more body roll " on road " situations .. I mean you can go johnny joints at the frame points for your radius arms, but that would be a compromise to the on road stability ..
     
  6. kbushnz

    kbushnz

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    The front sway bar really holds back the front from articulating in the Prado. I run a KZJ78 ....
    The rear also but not as bad as the front.
    Also the factory rubber bushes are better than aftermarket nolathane for flex but they still hold them back alot.
    I am playing with a bare chassis and running gear at the moment.... To test the range of flex for the new shocks I have installed I needed to remove one of the radius arm bolts at the chassis to allow it to give me the full range of movement... With it connected.... Only got about a 1/3 of its range before it started to lift the other side... Will get a bit more if it had weight on it....I dont think it would ever get full range in real life....WIll bind up before it did... The 80 rear end would be a huge advantage. But for me I have other "things" in the way so cant fit the arms....Otherwise I would be doing a swap...
    The best way to overcome a truck that doesnt articulate well.... is to fit lockers front and rear....;)
     
  7. GTSSportCoupe

    GTSSportCoupe

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    Thanks for your notes kbushnz. So where you running sway bars or have you removed them?

    I have been planning on installing an 80 series e-locker in the front of my Prado eventually; you're right, that would help a lot.

    I do find the Prado sways side to side a lot while wheeling, as the axles pull the frame up and down over obstacles. This becomes tiring and annoying on long runs. Especially when I've been along with 40's and 60's with decent flex, I can see their vehicles riding more level and stable. Would really be nice if the axles were a little looser, if only to provide a nicer ride while wheeling.
     
  8. Postoy

    Postoy

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    I read somewhere that you could pull one of the front control arm bolts and replace it with a hitch pin.This allows it to drive the same on the road, but pulling it at the trail head would free up the front end significantly... thoughts?
     
  9. GTSSportCoupe

    GTSSportCoupe

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    Interesting. I have heard of quick disconnects for the sway bars also; sounds like something similar?
     
  10. Postoy

    Postoy

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    I have also heard of people just leaving one side of the sway bars disconnected.
    If I can get some free time here soon maybe I will try the hitch pin thing and ramp the truck and see if it helps at all.

    Edit... I found this...

    https://forum.ih8mud.com/threads/hitch-pin-mod.596807/
     
  11. clintnz

    clintnz

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    My buid thread: http://www.offroadexpress.co.nz/Forums/viewtopic.php?f=18&t=2123 Axle swap starts about p9

    Not sure if the rod ends just @ chassis change much on road - it's the bigger deflections when getting flexed offroad where the rubber bushes will resist movement noticeably. Mine is actually not too bad on road now without anti roll bars, a bit stiffer springs in the back help I think, but I'm thinking of putting one in the front for better safety in 'emergency swerve' type situations.

    I've seen some offroad only 4x4's where they chop the front eye off one of the front radius arms to get better flex.

    Yep, in stock config my 71 definitely went better without the front anti-roll bar. I really didn't like the on road handling without it though so left it on. There didn't seem to be an easy way to clip it in/out.

    Cheers
    Clint
     
  12. kbushnz

    kbushnz

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    I run without front swaybar. The rear I made some disconnect up. Undo both ends and then attach one to radius arm. But latley have removed it completly. Bit wobbly on road but considering its lifted and running 35's you just drive accordingly.
     
  13. Postoy

    Postoy

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    kbuhnz - Does your truck articulate a lot better that way? I know this worked well on my old jeep (yj) but that was a leaf sprung truck.
     
  14. kbushnz

    kbushnz

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    It does make it better..Especially the front. ..Also not as tippy off road as it allows the axles to move a bit more independently of the body.
     
  15. Postoy

    Postoy

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    Good to know. Any chance you have any pictures of your trucks suspension working? Like flex shots?
     
  16. kbushnz

    kbushnz

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    Nothing recent as its in a thousand bits.....
     
  17. yotahed

    yotahed Diesel Head

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    I would check out ballisticfabrication.com. I run their poly flex joints on my truck. Flexy as heck. Greasable and rebuildable. You can buy the joints without the threaded shank and fit them in your control arms at the frame end with bit of resizing of the hole/sleeve. (I think the sizes are 2.65" and 3")And then put a hitch pin with a big safety cotter in place of one of your front most control arm bolts. Remove the pin when you go wheeling. Good compromise between an all out wheeling rig and daily driver.
     
  18. banknz

    banknz

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    may i see some picture from u side .thanks
     
  19. RMP&O

    RMP&O OCD Supporting Vendor

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    I have noticed the Prado has the shock inside the spring unlike an 80. It is almost a strut. Not sure if that causes a lack of articulation but it might. On my buddies 71 we are moving the shock outside the coil to a more traditional 80 style.

    Radius arms will never flex that great, they simply are not designed to. I would strongly suggest going to a 3-link if you want more flex.

    Cheers
     
  20. yotahed

    yotahed Diesel Head

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    I also moved the shock in behind the spring when i did my lift. did away with the pin on the bottom mount point to an eye on both ends.
     
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