Help Please! Sagging Front end, can't adjust Ride Height at all.

[72bluNblu]

Oaaaaaky lol

That is a whole lot of talking points.

By assembling the steering knuckle with no bump stop the maximum downward working angle of the LCA can be eatablished.

From there you can figure out if the bars slide in at maximum suspension travel. It's a drag car so upward suspension travel is of importance.

Five of our cars are set up this way. Same old combo - Tubular UCA, adjustable strut rod, poly LCA bushings + greasable pins, good shocks.

Interesting to hear other perspectives on something like this.

You asked for the reasoning, I gave it to you. Not my fault there's a lot of reasons to do it differently than what you've described.

Heck, I even forgot one. I've found that most of the time I'm removing the torsion bars I'm dropping the LCA's off the spindles for another reason already. So, why hook them back up to slide the bars back in and have to remove the upper bump stop (which never has to be removed for anything else) when you can just install the bars first and not touch the bump stops?

As for determining when the torsion bars become unloaded, that's easier to do with the torsion bars installed and the torsion bar adjusting bolts loose. You can determine exactly the point where the adjusters unload, which is the important part for setting your bump stop height if you're running aftermarket control arms, torsion bars, or have altered the ride height. The point at which the adjuster unloads and the bar slides out might not necessarily be the same exact spot, and the adjuster is more important out on the street because if the adjuster comes off the lever it may not reseat in the correct spot when the suspension loads again.

Drag racing is its own special thing, drag race geometry is really easy because all you care about is launch. And all the small torsion bars used have the same hex offset (the factory offset), so there's not much variability there. When you start running larger aftermarket bars for handling the hex offset varies with the size of the bar, and you actually care about camber gain curves, roll centers, etc, etc so modifying the ride height and setting the bump stops up around the new suspension travel is paramount. Because the larger torsion bars don't twist as much, you really have to pay attention to where the adjusters unload because the range of travel where the bars are loaded is much smaller than on a lighter bar that twists a lot.

To add, I seem to remember there being an aftermarket torsion bar that was manufactured with the wrong “clock” that would cause this for some people.

That was PST’s 1.03 bars and was fixed years ago.
I remember because I was waiting for the fixed bars before I ordered mine.

The PST 1.03's originally had a zero offset on the hex ends. It's not really "wrong", but a bar of that size with zero offset doesn't allow the car to be set at factory ride height. It worked for people that were lowering their car an inch or more, but those that wanted to maintain the factory ride height couldn't do it so PST changed the offset on the bars.

I don't recall what PST changed the offset to, I know the factory A-body bars have a 30° hex offset built in. Meanwhile, the 1.12" Firm Feel torsion bars I have in my car only have a 7° offset, and their 1.18" bars are 0°.

 

[SGaringer]

Do you have any pictures of the rear suspension?

I'll get a picture today for you! I really appreciate all the help! I got the new torsion bars last night, so I plan to install this weekend. I will provide all an update after that, hopefully I am on the right track, but we'll keeping working on it until it's back to its winning form! I want to get this corrected as I have mor upgrades coming for this season!

 

[MopaR&D]

All mentioned above is right on, one other question. What are your plans for this car? If drag racing you are going the wrong way in Torsion bars. 1.03 will not transfer the weight well. Most use /6 bars or lighter.

I'm assuming with a 505 BB, beefed chassis and fatty tires that car is running at least in the 10-second range (??) in the 1/4. I forget which ET range it is exactly but definitely by the 10s you actually want the torsion bars stiffer as trying to maximize weight transfer isn't as important and making the front end easier to lift at launch can cause other problems. I remember reading that in the MP chassis manual.

 

[Best of 3]

I've been an alignment mechanic for decades. It's amazing how much settings change during a run. Even a 200lb. driver can change toe & camber substantially. The mopars seemed to be the toughest. Ride height may cause pull but not likely. I would check for things like idler arm, lower control bushings, or other looseness.

 

[92b]

Let me preface this by saying I don't have any drag race experience. So these these thoughts are coming from someone not in their lane.
The op stated that the car puts the front tires in the air on launch. When the front tires are in the air, my thought is at this time they have little influence on the direction of the car. Things like front end alignment, loose or worn front end components would just be along for the ride until the tires touch back down.
The rear tires would be what are steering the car. I think the traction difference between the lr and rr tires is what primarily would steer the car right or left.
I think if you have a car that launches straight and then lower the ride height somewhere on one corner of the car ( which will affect the ride heights on the other three corners) it will affect the weight distribution on all four tires. This in turn changes the tire load between lr and rr tire and tire load affects traction which affects steer at the back of the car.
Changing from a 150 pound driver to a 250 pound driver also changes the tire load between the lr and rr tires if the driver is positioned on the left side of the car.

 

[Swinger 340]

All mentioned above is right on, one other question. What are your plans for this car? If drag racing you are going the wrong way in Torsion bars. 1.03 will not transfer the weight well. Most use /6 bars or lighter.

I always heard 6cl bars on SB and SB bars on BB, for weight transfer to rear wheels.

 

[Newbomb Turk]

Let me preface this by saying I don't have any drag race experience. So these these thoughts are coming from someone not in their lane.
The op stated that the car puts the front tires in the air on launch. When the front tires are in the air, my thought is at this time they have little influence on the direction of the car. Things like front end alignment, loose or worn front end components would just be along for the ride until the tires touch back down.
The rear tires would be what are steering the car. I think the traction difference between the lr and rr tires is what primarily would steer the car right or left.
I think if you have a car that launches straight and then lower the ride height somewhere on one corner of the car ( which will affect the ride heights on the other three corners) it will affect the weight distribution on all four tires. This in turn changes the tire load between lr and rr tire and tire load affects traction which affects steer at the back of the car.
Changing from a 150 pound driver to a 250 pound driver also changes the tire load between the lr and rr tires if the driver is positioned on the left side of the car.

Yup. All of it. Yep.

 

[Best of 3]

Let me preface this by saying I don't have any drag race experience. So these these thoughts are coming from someone not in their lane.
The op stated that the car puts the front tires in the air on launch. When the front tires are in the air, my thought is at this time they have little influence on the direction of the car. Things like front end alignment, loose or worn front end components would just be along for the ride until the tires touch back down.
The rear tires would be what are steering the car. I think the traction difference between the lr and rr tires is what primarily would steer the car right or left.
I think if you have a car that launches straight and then lower the ride height somewhere on one corner of the car ( which will affect the ride heights on the other three corners) it will affect the weight distribution on all four tires. This in turn changes the tire load between lr and rr tire and tire load affects traction which affects steer at the back of the car.
Changing from a 150 pound driver to a 250 pound driver also changes the tire load between the lr and rr tires if the driver is positioned on the left side of the car.

I understand were your from however a pro drag racer does not want the front tires to leave the ground. The car can't be controlled/steered by the rear wheels, too many variables. I've aligned many race cars. Lot's of experimentation. Best results was driver in seat & simulated a realistic ride height raise during acceleration.

 

[71GSSDemon]

I always heard 6cl bars on SB and SB bars on BB, for weight transfer to rear wheels.

In talking with some super stock racers from back in the day, they used /6 and even the thinner ones from DC. A few even lathe turned those thinner.

 

[LocuMob]

In talking with some super stock racers from back in the day, they used /6 and even the thinner ones from DC. A few even lathe turned those thinner.

/6 with air or 318 w/o air bars is what I read were used on the Hemi cars.

 

[SGaringer]

Well, I did install the new 1.03 PST bars and it definitely made a difference. The sag is gone! It will be a few months before I can test the effectiveness of this upgrade but I will continue to upgrade other areas. I want to put new tie rods in (the current isn't bad, but the boot is torn) and a mid plate.

 

[jos51700]

Double check your T-bar adjusters, too. Chrysler had fine thread and course thread, and they're slightly different lengths. I noticed it when built my car. I have no idea if the donor car had been apart before or if Chrysler built it that way.