[Brian Oatway]

I've had ladder bars in my car for about a year. I played with shock adjustments, launch rpm and tire pressure to find a spot where the car would launch.

In order to get the car to hook I needed to set the launch rpm on my two step way down 2000rpm (4750 rpm stall) and adjust the bump on the rear shocks to full soft.

I'm thinking I need to move the front pivot on the ladder bars up one hole in order to get more hit on the tires so I can get the shocks into an adjustable range and up the launch rpms.

Any suggestions, am I on the right path?

 

[B Williams]

Any video of the car.

Gonna need to see what the tire is doing as well as the suspension before anyone can offer you a suggestion.

Would also help to know how the bars are set now, what shocks/shock settings and what tire/tire pressure.
Will

 

[Brian Oatway]

I do not have any video from outside of the car since I most always go to the track by myself but I do have a video from under the car looking at the shock/tire, it is in slow motion because I just couldn't see anything at full speed. In this video the launch rpm is at about 4000.

The ladder bar bracket has 4 holes and they are in the second hole from the bottom which gives them a very slight down angle.

Tires are 29x10.5 Hoosier

Thanks for your help

 

[dvw]

Bounces back after the hit. I tried to cure that on my car by tightening the rear compression, a bunch. Just made it worse. Turned out the rebound was so loose that the tire itself was bouncing the housing. Tightened the rear rebound 2 clicks and then added 1 click of rear compression from my original starting point. What a difference. Was even able to tighten the front way up on rebound as well. Made the car repeat 60 fts last Saturday, 6 passes 1.290-1.302 on 10.5 tires and a footbrake.
Doug

 

[B Williams]

First thing it does at the hit is squat down and half a tire rotation later bounce back up. It also doesn't wrap the tire until 2 revolutions in.

Seems initially like not enough AS and having the bar run down hill towards the front indicates that... but I see a few things that are taking away the chassis's opportunity to plant the tire.

You have alot of stored energy in your rear springs - having the spring adjuster compressing them as much as they are to get ride height indicates too soft of a rate... All that stored energy is overwhelming the shock rebound valving causing the bounce, which unloads the tire after the soft rate squatting down keeps alot of weight transfer off the tire initially.

I would first put heavier springs on the rear.... Reset your shocks to the middle of the compression and rebound settings and take another video. You still may need to raise the front of the bar or rear ride height to get more AS but until you take care of the rebound problem your going to have a hard time getting it to work right.
Will