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Old 03-23-2015, 03:18 PM
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Ladder bar preload issue (drag racing) with Video.

Put a new engine setup in my ladder chassis and Iím 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 60ís. 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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Old 03-23-2015, 03:30 PM
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Do you have any preload on the passenger side ladder bar?

You may need to add an Anti-Roll Bar.
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Old 03-23-2015, 03:50 PM
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Quote:
Originally Posted by ericnova72 View Post
Do you have any preload on the passenger side ladder bar?

You may need to add an Anti-Roll Bar.
Set it up neutral. (slip fit FWD pass. ladder bolt with me in it).

Planted tires and launched straight originally, I’m sure a roll bar would help but I would like to try and dial it in without if possible. Already have a jungle gym under there. Hoping its a matter of adjustment. Guessing I got the CG all out of wack when I messed with ride height.


-thanks!

Last edited by ForceFed86; 03-23-2015 at 03:57 PM.
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Old 03-23-2015, 04:07 PM
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Pull the passenger side front ladder bar eye bolt, crank rear adjuster to lower front of ladder bar 1/4-1/2", then use a jack to push front of ladder bar eye back up enough to reinstall bolt.

This will preload the passenger side putting more weight on that tire.
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Old 03-23-2015, 04:18 PM
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I should have mentioned, it has an adjustable lower link. (pass side) I was assuming I could adjust this with the forward eye bolt installed? I have ZERO experience with a ladder bar setup. Just read a little. Wanted to add some preload to it at the track but I couldn’t break the jam nuts loose on the lower link adjuster.
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Old 03-23-2015, 04:25 PM
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That would work if you have the double adjuster lower bar type ladder bar.
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Old 03-23-2015, 06:15 PM
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I almost looks like your front brakes are dragging. The LF stops rotating a few times when it's barely off the ground, if the RF is still on the track and dragging it could be pulling you that way.
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Old 03-24-2015, 11:09 AM
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I almost looks like your front brakes are dragging. The LF stops rotating a few times when it's barely off the ground, if the RF is still on the track and dragging it could be pulling you that way.
Someone pointed out the dragging wheel thing yesterday. I completely missed that!
I did jack up the front end lsat night. Both brakes do drag a hair. But I donít see a way around this. New pads, discs, and new springs that hold pads apart etc. Donítí think this a huge issue but Iíll see if I can adjust the caliper in or out a hair to make this better. The car always picked up the pass side wheel pretty good and the wheel stopped. Car still tracked straight and kept the back wheels planted square.

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Old 03-26-2015, 02:57 PM
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From what I’ve recently read it looks like there are 2 issues.
1.) The initial hit/squat.
2.) Turning after the launch.

The way the car was built the upper 2 ladder mounts are not accessible. So I'm up as high as I can go on the FWD ladder mount. Hope the hooking right is just a pre-load issue. Looking back at the changes I made over the past 2 years I have a theory...

First I had issues with the front tires sitting too far outboard and contacting the fenders under hard braking. So raised the nose a good 1.5” with some slip-on coil overs. Then I went to a smaller 28” tire and lowered the rear shock mounts a good 1.5”. The wheel wells are huge and I liked the look of a more “tucked wheel”.

It’s my understanding that all those changes raise CG, lessening the hit on the tires. Very similar to lowering the ladder bar mounts.

To try and fix this I raised the shock perch's back to the original heights then re-centered and leveled the rearend.

The new front wheel setup sits farther inboard, so I dropped the coil overs as low as they would go. Another 1”+ I’d guess.

Mounted a cheapo cam and hope to get decent video of the actual suspension movement.

Next TNT at the track is April 11th... Fingers crossed.


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