Torsion bar adjusters and bump stops when lowering car

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SeattleQQ1Fish

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I'm wrapping up the front end rebuild of my Barracuda with the goal of lowering it and improving handling. I'm using QA1 uppers and lowers, Hotchkis/Fox shocks and Firm Feel 1.06 bars. I set the ride height to where I think it looks pretty good, about 25.5" from the top of the fender lip to the floor.

My question is, at this ride height, the adjuster bolt/block is loose with the suspension unloaded. Is this normal? Also, there is less than half an inch between the lower bumpstop and frame on the passenger side and just slightly more on the driver side. Am I going to be bottoming out all the time?

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Does the car have an engine? Is it fully assembled and full of fluids?
 
No, the adjuster bolt/block should not be loose without sitting on LCA bumper. Shocks may be bottomed out.
 
Maximum lowness on the street is not your supreme goal.
On the street, you want to set the ride height to being in the window of minimum camber change as the suspension cycles up and down. Then control suspension movement to stay in the window for as much of the time as possible.
Typically, this window will be fattest when the LCA is about level, but actually when the LBJ is level with the Pivot pin on the other end.
To find the window, you will have to put the car on the alignment rack.

The reason for doing this is; Anytime that the camber changes, so does the toe-in.
And when the camber is different on one side than the other, the car will tend to self steer.,
And when the toe-in changes, the car tends to wander around.
Another thing that happens at very low ride-height, is that your SAI will not play nice with your scrub-radius.

If you really want to be low, you need drop-spindles.
I have aligned hundreds and hundreds of front ends, perhaps thousands; but
I have never aligned one with drop-spindles;
So IDK how that would work out for you.
 
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This is mine, same torsion bars, same shocks, but I have stock LCAs with boxing plates. The Torsion bar adjusters always have load on them even jacked up, and I probably have a lower ride height than you do. I do have softer cut stock bump stops. Somehow I think you have binding going on which is why the adjuster is loose.

You have enough spring rate, that distance to the bump stop will be fine. You don't need drop spindles on these cars. If you get enough caster in your alignment it will drive very well at this ride height.
 
Somehow I think you have binding going on which is why the adjuster is loose.

Any idea what might cause binding like that? The suspension seemed to go together pretty smoothly. Maybe I clocked the torsion bar wrong?
 
Maximum lowness on the street is not your supreme goal.
On the street, you want to set the ride height to being in the window of minimum camber change as the suspension cycles up and down. Then control suspension movement to stay in the window for as much of the time as possible.
Typically, this window will be fattest when the LCA is about level, but actually when the LBJ is level with the Pivot pin on the other end.

Question Brother A/J ( a Friends Sons Name also, AL Junior)
When You say Level, what part of the Lower Ball Joint are you referring to... I'm having issues. My Apologies if I'm stepping....
 

I think he means look at the point of rotation of the lbj and the lca pin. The approximate center of each should be on a plane that's parallel to the ground.

The lca itself resides above the lbj and intersects the lca pin. The qa1 parts are a different shape altogether due to their construction.
 
I think he means look at the point of rotation of the lbj and the lca pin. The approximate center of each should be on a plane that's parallel to the ground.

The lca itself resides above the lbj and intersects the lca pin. The qa1 parts are a different shape altogether due to their construction.
My Bad Brother, I have stock stuff... I am aware the Qa 1 have different geometry built in. I didn't consider that. I'm getting my.*** kicked in another thread... lol definitely Appreciate You! So for stock, that's a good baseline?
 
I redid my front end last winter. When I put my car back on the ground, I had the same issue. Adjusters were loose when jacked up, but the front sat high if I tightened them.

Then I rolled it back and forth about 10ft at a time and the front end settled. I put about 3/4" more preload into the adjusters before it all sat right once settled.

I'm using stock torsion bars for now though, your mileage may vary.
 
My Bad Brother, I have stock stuff... I am aware the Qa 1 have different geometry built in. I didn't consider that. I'm getting my.*** kicked in another thread... lol

LOL, no worries. The same applies to the qa1 as stock - the ball joint is under the end, but it intersects the pivot.

The center of the pivot and the ball joint are all that matter when it comes to geometry. The lca could be a giant u shape, but all it does is connect points a and b (pivot and ball joint).
 
Yessir, Mine are old... car was raced also....redid the entire front end last rainy season... need to get Her to the Alignment place..( That's a whole different ballgame, don't wanna start a Grumble Fest)
 
My question is, at this ride height, the adjuster bolt/block is loose with the suspension unloaded. Is this normal? Also, there is less than half an inch between the lower bumpstop and frame on the passenger side and just slightly more on the driver side. Am I going to be bottoming out all the time?

If the the adjuster is loose when the suspension is fully unloaded (UCA on the upper stop), based on your ride height, torsion bars and other equipment then what you have IS normal. It's not binding, it's not the shocks, and you don't need drop spindles. And no, a 1/2" from bump stop to frame is not enough with 1.06" bars, you will bottom out too often IMO.

What you need to do is run a taller upper bumpstop and a smaller lower bumpstop. You have to re-center the range of travel, making your current ride height the middle. Or as close to it as you can. The larger torsion bars don't twist as much when loaded, so, you have to make sure the range of travel and the adjustable range on the adjusters match very precisely. With smaller torsion bars this isn't an issue, they twist a lot and the adjusters always stay loaded as a result.

I had to do the same thing with my car. I run 1.12" torsion bars and just under 25" to the fender lip from the ground. With the suspension fully unloaded I only have about 1 turn on the adjusters from the point when the adjusting bolt hits the lever.

I run these upper bump stops, with an additional spacer underneath them (~3/16")
Energy Suspension 9.9136G Energy Suspension Bump Stops | Summit Racing
I run these lower bump stops
Energy Suspension 9.9132G Energy Suspension Bump Stops | Summit Racing

That gives me just under 1" from LCA to bumpstop, and I do still occasionally bottom out. Not frequently enough for it to be a problem, but often enough to know I couldn't go lower without larger torsion bars. Here's a picture of my set up...
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One thing is I see you have the new QA1 LCA's. I have the old design that did not have a built in bump stop, which is why my bump stop is on the frame horn and not on the LCA. The old style adds about 1" of suspension travel back into the system. The way they added the bump stop they reduced that a bunch. Some of that is bumpstop, which you can swap out for a thinner one. Part of that is the threaded boss for the bump stop, which you're stuck with unless you're willing to cut it off and put the bump stop on the frame horn like I did. And some of it is a larger gusset, but that's a pretty small amount and not worth messing with.

Old style
mopar-lower-control-arms-png-png.png


New style
newqa1.jpg


Best suspension geometry is where the ball joint and pivot are level, so if you're familiar with the FSM height process that would be an A-B of 0, or 1-7/8" lower than stock. That's about where my car sits, which I'm fairly confident is still a little bit lower than where you're at. Duster fenders and Dart fenders put the wheel lip in the same place vertically, not entirely sure about Barracuda fenders. But based on what I know about the QA1 LCA's with the new bumpstops, if you've got a 1/2" with everything the way it is now you're about a 1/2" higher than me with the old QA1 LCA's. So maximum drop on the street shouldn't be the goal, but as it turns out you're still above ideal if you're lowering for best geometry.

Drop spindles on these cars are a bad idea anyway. They add bump steer for one, which isn't great. The other thing is, they don't actually give you travel back. That's the idea of using them, you lower the car without losing suspension travel. The problem is, you just run out of space somewhere else. On my car, with the old QA1 LCA's and the ~1" additional travel they give, when my LCA is on the bumpstop the spindle is only 13" from the bottom of the inner fenderwell. Meaning, with a 26" tall tire and the suspension bottomed out the tire would hit the inner fender. Out of travel. My 275/35/18's are 25.6" tall, so it won't actually hit, but I'm at the limit. A 2" drop spindle instead of the earlier QA1 LCA would mean I'd get the same 1" of useable travel, and then spinning parts would hit stationary parts and things would go bad. Basically I'd have added more bump steer to get travel I can't use anyway.
 
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