Need help bad with ladder bar car.

Old 05-27-2007, 03:02 PM
  #1  
slowman
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Default Need help bad with ladder bar car.

need help guys. edvanced,mcracecar,bejuice,topsportman and anyone with some input. guys you have ten times the expertise then me with this stuff so thanks for any input. i went to the track with the just finished roadrunner and can't get it to stop tire shaking. i tried everything that i know but thats not much. i may have made it worse then better messing with stuff. the car is a 70road runner with ladder bars 32"long and afco shocks with the canisters double adjust. front to back weight is almost 50/50 spot on. cars weight is 3020#. big block with a th400 4800 stall. tires are 33x10.5w m/t drags with pressure all over the place and no luck. i'm trying to figure out how to load the video to the web but thats a whole storie in its self lol. the car seams to hit hard and 20-30ft out sever tire shake with every run. the tire shake i have had before this i was able to fix in the other cars but this one don't respond to anything.
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Old 05-27-2007, 06:11 PM
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us7race
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How wide are the ladder bars apart? I had mine close together and done the basic same thing..put them back out wide and no shake or hop of any kind..
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Old 05-27-2007, 07:05 PM
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slowman
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the car is mini tub with a 50" axle and the bars are about 36" apart with a anti roll bar.
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Old 05-27-2007, 08:48 PM
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us7race
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I will measure and see how far apart mine are tomorrow just to compare.. You don't have anything bottoming out do you? What angle are the bars at? Also how much weight is on the rearend? and What rate rear spring are you running? Also just curious how much power does the motor have?
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Old 05-28-2007, 05:32 AM
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mcracecars
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Jeff, how the heck did you get 50/50 weight distribution on a 70 road runner??? :shock:
Give us more info, hp, what time/mph you looking to run, gears, etc.
For 50/50 is the motor moved back a lot??
The thory of ladderbars is to try to pick up the front of the car transfering weight to the rear then moving forward.
My first guess it that you are trying to pick the car up too far forward of the c of g , hitting the tires too hard. The front of the bar may need to be raised.
Also what springs in the back, shock settings, it all enters into the equasion
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Old 05-28-2007, 06:25 AM
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slowman
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mc the car has the engine set back about 6" and its all aluminum i'm sitting back to. the whole front of the car is carbonfiber. had it all made from a local guy. the front suspenion is all bolt in from reily motorsports. the car is 21# heaver to the front with a 100# added to the rear bumper that gives me 3020#. the hp is 1342hp n/a with the single carb setup and 1493 with the 2 carb setup, the times i was looking for are 7.3-7.7 at around 180mph, gear is 4.56 and shift rmp is 8000-8100. if i remember right the springs were 350# but it was 6yrs ago when i started the car. the shocks are set at the middle for comp and rebound there afco's with the canisters. i was launching at 5500-5600 at first then started to go down from there. thanks for any help guys.
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Old 05-28-2007, 07:16 AM
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us7race
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350Lb Springs sound waaay too stiff..I have 130Lb springs in mine with 1068Lbs on the rear wheels..
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Old 05-28-2007, 07:30 AM
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slowman
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my bad the rears are 150# and the fronts are 350#.
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Old 05-28-2007, 03:15 PM
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us7race
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My ladder bars are about 28" apart or so. My rearend housing itself is 48.5" wide that is not including the c-clip eliminators or brakes.
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Old 05-28-2007, 03:26 PM
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slowman
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thinks guys i think i have it going the right way. i put a lower gear and changed the bar local up one hole. did about 6-7 launchs up the drive way and it will drive through it know. i'm not sure how to fine tune it but i guess it will come in time.
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