Ladder Bar pre-load issue? (video)

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forcefed86
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Ladder Bar pre-load issue? (video)

Post by forcefed86 » Mon Mar 23, 2015 4:19 pm

Put a new engine setup in my ladder chassis and I’m having some issues. I dropped the ride height a notch and added a bunch of power, different converter etc. Car previously would take a 20+lb T-brake launch, plant the tires and dead hook. With 1.3x 60’s. 8.9x car at about 160.
Now I get very little tire hit (tiny bit of squat even) and 100 feet out the car wants to kick right. Is this too little preload in the pass side bar? Also noticed under power my pass side rear is squatting pretty hard. Friend suggested I raise the spring perch on the aft coil over and try to get the car level first.

Has double adjustable summit coil overs in the back. 90/10 up front. Had it on 6 clicks for compression, 3 extension. Second hole up from the bottom on the forward ladder mounts.

Suggestions?

Here you can see it kick right 100ft out or so. It usually kicks out so bad I have to lift.

https://www.youtube.com/watch?v=jJ_Cc6K--EM

If you slow the video to .25 you can see the car actually squats...

https://www.youtube.com/watch?v=RmEpIy1tN_I

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Re: Ladder Bar pre-load issue? (video)

Post by WRIGHTWAY » Mon Mar 23, 2015 9:21 pm

Is that a biasply slick or radial? they look hard Psi?
Joe Wright
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Re: Ladder Bar pre-load issue? (video)

Post by BirdMan » Tue Mar 24, 2015 9:13 am

I like to remove the front bolt from one of the ladder bars and get the chassis sitting level with me or my weight in the drivers seat. Doing what is needed to level it up. Then adjust the loose ladder bar to fit the bolt back into it. This usually lets the car go straight the whole distance. Are you getting into the center of the tracks? Check pinion angle to driveshaft angle and change Both ladder bars equally if a change is needed.

I found on son's Falcon with 351C of 450 HP??? best of 10.54 et. and going to 412W of 700 HP??? best of 9.69 et. I lowered the front of bars one notch and tightened extension and raised the slick pressure a 1/4# at a time to keep slick from wadding up and track surface (I call it having pups!) which disturbs traction. You need someone to observe and/or record the launch to determine slippage, chassis separation, etc.

I just noticed you squat, if so I would raise the front of the bars a hole at a time until you get no separation/squat or a little separation and then try adjusting the shocks. Also the left slick grabs harder than the right on the burnout which also indicates unequal bar settings.
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John Wallace
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Re: Ladder Bar pre-load issue? (video)

Post by John Wallace » Thu Mar 26, 2015 8:57 am

How much 'up travel' do you have on the rear spring/shock?
Looks like the springs may be too stiff?

Try loosening the extension on rear shock, maybe tighten the front extension on the front shock?

Have you calculated your set up for IC, corner weights, etc?

:?:
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