Springs in a pro mod

Discussion in 'PSI Superchargers Tech Questions' started by jay70cuda, May 2, 2013.

  1. jay70cuda

    jay70cuda Well-Known Member

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    What is the best way figure out what springs what you need to use in your car. I started with 350 front and 150 rear. It sat like a 4x4 truck, now I have 250 front and 115 rear. Does this seem strange to anyone. It weighs about 2600 lbs and sits in ride height now. Am I gonna have handling issues ? Does this seem odd ? Thanks for the response
     
    #1
    jay70cuda, May 2, 2013
  2. outracer

    outracer Member

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    that is normal to me we are at the same with ours
     
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    outracer, May 3, 2013
  3. Mike Canter

    Mike Canter Top Dragster
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    I think I would go back to the original springs and make sure the springs are adjusted for the correct ride height at 50% shock travel. If not the you may need to adjust the lower shock mounting hole. I realize that there are all kinds of ways to use the weight of the car to compute the correct spring and that maybe ok for a prostock car but doesn't work the best on a blown 2600 lb PM. With 115 springs you are going to slam the wheelie bars and unload the slicks.
     
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    Mike Canter, May 3, 2013
  4. jay70cuda

    jay70cuda Well-Known Member

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    That was my next question. Even with super tight valving , I know the spring do more than just set ride height. With the 150 in the rear the shock is fully extended . With the 115 they sit more in the middle of the shock. But for every 1 inch of compression on the shock the spring rate doubles ?
     
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    jay70cuda, May 3, 2013
  5. Mike Canter

    Mike Canter Top Dragster
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    You need to adjust the shock mounting. Not sure what you mean on spring rates. Each inch of travel takes 150 lbs. So one inch travel is 150, two inch is 300, three inches 450.
     
    #5
    Mike Canter, May 3, 2013
  6. rcparker

    rcparker New Member

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    we run 140lb in a bickel car
     
    #6
    rcparker, May 3, 2013
  7. overkill69

    overkill69 Member

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    spring

    It sits like a 4x4 but you never mention the platforms/adjusters? Do you mean with them threaded all the way out?
    150 is kinda standard for the rear. On my 2600lb car with santhuffs the adjuster has about an inch of thread on the bottom showing.
    The way I look at it the lighter spring will be compressed more which will have more stored energy. I run stiff rebound valving front and rear so I don't want any extra energy to fight.
     
    #7
    overkill69, May 3, 2013
  8. shawn davis

    shawn davis Member

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    I ran 250 and 115 on a 2380 lb car, after kinda what you did
    I went with Mcamis recomendation for a legal car and same thing had a 4x4 57' chevy look
     
    #8
    shawn davis, May 6, 2013

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