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Technical Triangulated 4 link opinion

Discussion in 'The Hokey Ass Message Board' started by GreenGrenade, Feb 21, 2016.

  1. Shane Spencer
    Joined: Oct 3, 2009
    Posts: 2,157

    Shane Spencer
    Member

    Hey guys, setting up a triangulated 4 link on my friends c10. I have like 47 degrees angle between the upper links. Ive read 40 is the absolute minimum. I could shorten the links a bit to get more angle out of them, but i dont wanna go too short. Lower links will be outboard of the framerail. My other option was to set this kit up as a parallel and add a panhard. If i do that, can i still run the lowers at a longer length like a triangulated setup ? Thanks for any help. Heres a few pics, the one from the rear is a bit of an optical illusion as the framerails taper in 4 inches towards the cab. ImageUploadedByH.A.M.B.1456072839.628368.jpg ImageUploadedByH.A.M.B.1456072852.950428.jpg
     
  2. Andy
    Joined: Nov 17, 2002
    Posts: 4,477

    Andy
    Member

    I would use a heim joint on one end of each rod. Those ends I see do not allow twist.
    Make a mock up of your layout with paper or sticks. You need to check pinion angle change with suspension travel. Make the links over a side view of the pivot points and pin the joints so you can check movement.
     
  3. Shane Spencer
    Joined: Oct 3, 2009
    Posts: 2,157

    Shane Spencer
    Member

    Ive been graphing out the pinion change through the travel over the last few days, as well as playing with instant center points, anti squat percentage and roll centers. I actually managed to mock it up and get about 55 degrees between the uppers by shortening them about an inch so that looks like itll work. Heres a mockup pic, i still need to shorten the links to make room for the rod ends
     
  4. Shane Spencer
    Joined: Oct 3, 2009
    Posts: 2,157

    Shane Spencer
    Member

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  5. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 7,627

    mgtstumpy
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  6. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,231

    Hackerbilt
    Member

    Something about that layout throws me off a bit...not sure why.
    I think I would use one of those plates that bolt between the backcover/housing and angle the upper arms from the rails back to the center of the rear axle. Just seems like it will be more stable to me.
    Or go parallel with the panhard bar.
     
  7. Shane Spencer
    Joined: Oct 3, 2009
    Posts: 2,157

    Shane Spencer
    Member

    If it were a 9 inch id switch the upper links the other way round. Ive seen plenty of four links like this with a cast center section though, and those plates that bolt between the rear cover ive heard can have leaking issues
     
  8. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284

    Kerrynzl
    Member

    Butt the 2 uppers together and A frame it.
     
    Hnstray likes this.
  9. Shane Spencer
    Joined: Oct 3, 2009
    Posts: 2,157

    Shane Spencer
    Member

    Are you talking about a wishbone upper link ?
     
  10. 1946caddy
    Joined: Dec 18, 2013
    Posts: 1,501

    1946caddy
    Member
    from washington

    You would be building a three link then.
     
  11. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 906

    19Eddy30
    Member
    from VA

  12. tylercrawford
    Joined: Jan 30, 2011
    Posts: 726

    tylercrawford
    Member
    from Buford, GA
    1. S.F.C.C.

    Not sure what "too" short is . . . the OEM fox body mustang upper arms look half as long as you've got there.

    Any reason on not doing the upper arm bushings parallel with the axles? I'm definitely not a fabrication guy but I seem to recall a rep from energy suspension explaining the more desirable design of the arms in relation to the bushings.
     
  13. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284

    Kerrynzl
    Member

    Yep!
    Lotus did this on the underside of the Cortina [underside for a low roll centre height]
    pointing backwards or forwards doesn't matter except the roll centre height doesn't change if the centre is mounted on the rear end.

    3 link suspension.jpg
     
    Last edited: Feb 21, 2016
  14. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284

    Kerrynzl
    Member

    From a side view , running the upper and lowers parallel prevents dive under hard braking [or wheel hop]
    By having the uppers shorter [for obvious fitment issues] the instant centre shortens when the rear squats and lengthens [to infinity] at normal ride height.
    Having a short instant centre is the same as a short ladder bar. The pinion torque reaction has better leverage to "fight" rear squat
     
  15. Shane Spencer
    Joined: Oct 3, 2009
    Posts: 2,157

    Shane Spencer
    Member

    Tyler, from what ive read on a few tech articles here on the hamb, if you run the bushings parallel with the axle, the load on those bushing would be greater in the event that one side of the axle lifted higher than the other. Say if you ran over a large bump with only one rear tire, apparently that motion puts a ton of load on bushings setup like that. Im not a 4 link expert, but thats what i read, plus this is my buddys truck and he bought the links in a 4 link kit. Im just doing the fabrication for him
     

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