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how to make a pickup launch?

Discussion in 'Other Rides' started by Jonny-K5, Dec 15, 2004.

  1. Jonny-K5

    Jonny-K5 1/2 ton status

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    whats the best way to set up a rear leaf sprung suspension for drag racing launches? vehicle is a longbed pickup lowered w/ 4" leaf springs.. how can i get the rear end to lift up under take off instead of squatting. i was planning on a rear sway bar and a pair of slapper bars, is there something else i should i consider? will the slapper bars plant the rear end like i want? or just prevent axle wrap.
     
  2. 3 on the tree

    3 on the tree 1/2 ton status

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    an adjustable pinion snubber would allow you to fine tune the cars launch by adjusting how much the axle rotates before hitting the snubber. Mopar guys been doing this for years.
     
  3. Jonny-K5

    Jonny-K5 1/2 ton status

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    i've thought about a pinion snubber, but doesnt that just prevent axlewrap?
    i want the rear end to lift up instead of twist and squat. i know this can be done with proper geometry in a 4 link, but i dont know if there are any tricks with a leaf sprung vehicle.
     
  4. 3 on the tree

    3 on the tree 1/2 ton status

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    The axle snubber will actually raise the rear endup. The nose of the axle pushes UP against the crossmember and raises the rear of the vehicle. I know it sounds ass backwards, buts its been working for a lot of years.
     
  5. Thunder

    Thunder 3/4 ton status

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    Why do you want your rear end to lift up when you launch?

    Your rear should squat in a good launch the more the better.. You need the all weight transfer you can get to the rear wheels for more traction. Lifting the rear and Transfering weight to the front will slow down your 1/4 mile times. Yull just end up burning rubber while the other guy blows you away. Don't bother with a sway bar its usless weight on the drag strip. Add some good adjustable traction bars. Also putting higher rate springs in the front will help.
     
  6. Jonny-K5

    Jonny-K5 1/2 ton status

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    i guess im not explaining it right. what im trying to do is get the suspension to push the rear tires down under load, which in turn lifts the body up a little. i know i've read several articles about this in hotrod mags. its been a couple years since i was into racing so i've forgotten some of the info.

    in a perfect launch, you'll have maximum weight transfer to the rear, but instead of the rear end squatting and twisting, its pushing down onto the track making better use of that weight.

    a sway bar is not useless weight on the strip. when you launch, the axle naturally twists pushing one tire down more than the other, sway bar helps balance this force to both tires.
     
  7. sled_dog

    sled_dog 1 ton status

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    quite true. In fact squatting is lost energy. Its your power lifting the car and throwing the weight back on a soft suspension. And a soft suspension will axle wrap.
     
  8. Thunder

    Thunder 3/4 ton status

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    All I can do is repeat my self. Get a Good set of traction bars. They will do what you want them to. They stop axle wrap, transfer the energy to the tires, solidly attach the axle to the frame. The end result is a faster launch.
    I guess I should of been more clear also But I thought you were tring to transfer weight forward to stop the squat.
    Traction bars dont really allow the rear to squat on the tires they will provide some lift while putting max weight to the rear.
    These:http://www.calvertracing.com/info/info.htm
    Work good on trucks
    Also some guys run those Rancho torque bars with good results but they are pretty long. The price is right tho.
     
  9. 99firehawk

    99firehawk 1/2 ton status

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    you could start with a 4x4 and launch in 4hi witch drag radials on all 4 corners.
     
  10. bigblock44k5

    bigblock44k5 1/2 ton status

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    Put some 90/10 shocks in the front first of all. Then get traction bars out back as previously stated. They will help alot, and you can also adjust them to try and get posi if you dont actually have one. Also transfer the battery to the bed if you can. Im sure you know the best way to set this up is with a 4-link.
     
  11. Cmoe

    Cmoe 1/2 ton status

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    twist and squat=axlewrap
     

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