Rear drag shocks or?

Discussion in 'Drag Racing' started by Falcenac, Aug 9, 2022.

  1. Falcenac

    Falcenac Member

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    Any suggestions for rear adjustable shocks? I run 90/10 on the front 28 x11.50 et streets bias plys on rear (stick car) with home made slapper bars moderate 302 gets high 1.6 low 1.7 60 foot times.
    Wrinkles tire nice front lifts but as it gets up on tires the slapper bars lift back and it tends to momentarily unload rear tires.
    I need to limit body to axle separation, would need 10/90 shocks but doesn't look like they exist.
    Or maybe it's time for caltracs?
    Runs 8.03 to 8.06 in 1/8 th want to hit 7's with 302 before I go back to 351w and the unloading is definitely worse then!
     
  2. greasemonkey

    greasemonkey Burnin corn

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    When my car was running in that e.t. range I had 70/30 on the front and air shocks on the back. My car liked the Hoosier softer tire. I had the battery in the back,an iron head 302 with no accessories on the motor. And no front sway bar. It would literally hook in the rain. The leaf spring pack needs to have an extra clamp on the front and remove the rear clamp. I eventually made a bracket to install 50/50 Lakewood rear shocks.
     
    Last edited: Aug 10, 2022
  3. Falcenac

    Falcenac Member

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    I also have trunk mounted battery and presently a iron headed 302. This winter have afr headed 351w going back in again.
    Car does hook well but as car leaves slapper bars lift rear to much and unload tires, ordered caltracs today see if that helps tires of slapper bars banging anyway.
     
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  4. greasemonkey

    greasemonkey Burnin corn

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    Cal-tracs are as good as it gets with a leaf spring but my car with that setup and a 347 would 60' in the 1.40's. I always wondered if it would do better with a Cal-tracs.
     
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  5. Bronz

    Bronz Member

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    All of this is just based upon my experience as a weekend drag racer for 25 years, so take it for what it's worth. First, my understanding of the purpose of rear shocks in a drag car is simply to avoid wheel hop. That said, I don't think you want anything like a 90/10 or any type of biased shock, which in the front of the car is designed to let the car rise and transfer weight without slamming it down. In the rear I suspect you want it just to simply dampen any motion, either up or down.

    Now if the problem is that the car unloads when your slapper bars slap, then you can adjust them. You might try a little more distance, so that when the snubber hits, it's hitting with less force (since the spring absorbed more by bending more before the bar got to the point of contact) and thereby maybe it won't smack with enough force to unload the tires. Of course, sometimes less distance is what it takes because less distance probably means less shock, in other words it progressively loads and unloads. Sorta like a punch throw from one inch away will hit softer than one thrown from 2 feet away.

    Also, inspect your snubber. Having run plenty of swap market slapper bars over the years, one thing that can happen to them is the little rubber thingy can get hard with age and basically it hits like a rock, whereas if you use a newer softer one it may absorb and return the force instead of that force going to shock and unload the tires. They do sell just the snubbers.

    Any launch depends on so many factors that you just have to play with it on test and tune days. And, of course then you start from scratch when you go with the 351. Such is our sport.

    Hope it helps.
     
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  6. Falcenac

    Falcenac Member

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    Well I have swapped out slapper bars to Caltracs also changed shocks out.
    Rubber snubbed on old bars was indeed rock hard , no adjustments other than cutting snubbed.
    Tested caltracs on street totally different car, no more banging from slapper bars worth the price alone!.
    Seems when I dump clutch nose rises back now drops instead of the separation I was getting.
    Have a track day this coming Sunday will get a buddy to take a video see what's happening and see if 60 foot times improve. Will post results next week.
     
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  7. greasemonkey

    greasemonkey Burnin corn

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    Let us know how It goes
     
  8. Falcenac

    Falcenac Member

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    Rained out today ! Has not rained forever but did today, we have a rain date next Sunday so will let ya know how Caltracs work out then.
     
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  9. rickyracer

    rickyracer Member

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    Cal-Tracs will be a world of difference. also are you still running the front swaybar? If so, get rid of it for racing. If you haven't clamp your rear springs together so they don't slap around. Remember the front of the rear spring is about rear twist control, the rear supports the weight of the vehicle. Maybe a little stiffer in the front spring to control wrap up.
     
  10. Falcenac

    Falcenac Member

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    No front sway bar
     
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  11. Falcenac

    Falcenac Member

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    Tested out Caltracs on Sunday.
    Worked well car far more consistent 1.71 60 foot (racing at airport not a true strip) times much tighter 8.01 to8.06,
    Definitely more in it with some adjustments to both Caltracs and my launch.
    Swapping the 351w back in now, see what happens next season!
     
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