After you add up leafs, bushings, sliders, relocation boxes, ect you may be a lot closer to a 4 link than you realize.
ANY AUTOCROSS RACERS
- Thread starter loganscuda
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Sorry, I've been MIA with work and school and my Dart being done. I run the full Hotchkis setup (including leaf springs). They're decent springs, but IMO are a little too soft and allow for a lot of travel and sag with people/tools in the car. One of my friends competitively ran a '67 Valiant. It wasn't anything too special. 360 crate engine making 280 hp, 4 speed OD, full Hotchkis setup, 4-point cage, but he had 2-3 inch body flares allowing him to have 315/30/18's on all 4 corners. He had to add helper springs to his rear leafs because of body flex. He won that year and destroyed everyone. The most successful Mopars are A-bodies with with stock geometry (no tubular k-frames, coilovers, or 4-links) suspensions.
As for my racing input and the feel of the car, I haven't autocrossed the car much this past year as I've been finding issues here and there taking me away from autocross events and I suck as a driver (not enough experience). I've done 2-3 autocrosses and half a race day at Willow Springs.
As for my racing input and the feel of the car, I haven't autocrossed the car much this past year as I've been finding issues here and there taking me away from autocross events and I suck as a driver (not enough experience). I've done 2-3 autocrosses and half a race day at Willow Springs.
loganscuda
This/These
Can't get video to load sorry it was pretty good. I took my son with me on the track it was like the Duke boys running from Boss Hog. He was laughing and haulering all Five races.
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No workie.
69wacuda
Handling, and a 500ci engine.... All in good time!
Wanted to get some of your guys opinions that use these cars in more of a performance fashion. I recently received my car back from the alignment shop and seems to be setup wrong compared to my own research. It is my understanding that you want the LCA to be parallel with the ground. This is how I got it back and it's already at ride height.
Thanks in advance.
Thanks in advance.
A stock LCA will look somewhat parallel to ground when reducing ride height below stock specs.
Can't go by that with an aftermarket LCA. Look how differently it is shaped, and its not 3" tall.
If both the lower ball joint is stock (and it looks it) and the torsion bar/LCA bushing attachment, you can still measure ride height the factory way.
Can't go by that with an aftermarket LCA. Look how differently it is shaped, and its not 3" tall.
If both the lower ball joint is stock (and it looks it) and the torsion bar/LCA bushing attachment, you can still measure ride height the factory way.
Mattax has it right, the construction of the QA1 arms make it look like they’re at a different angle than they really are. But they still use the factory lower ball joint and still have the same torsion bar socket/lever so you can check the right height the same way as factory. What you're looking for is the ball joint and the torsion bar lever to be at the same, or close to the same height. When that happens the camber and bump steer curves are about as good as they get. And it actually looks like you're pretty close to that. The other thing is, a small difference isn't the end of the world either. What shows up on a suspension program and what you actually notice driving the car can be a little different, most folks won't notice small changes in the geometry as far as a camber curve is concerned.
Per the factory method, you should be ending up at an "A"- "B" difference close to 0 for ideal geometry with modern tires and alignment specs. A-bodies are the "V and L" line.
Your car, with a line between the bottom of the adjusting blade and the ball joint housing. It's a bit of a guess because you can't see the bottom of the adjusting blade, but, it should be pretty close. The green line should follow the bottom of the LCA (I also have QA1's, so, I know a little about their shape). The red line is horizontal, and it intersects the bottom of the ball joint and where the bottom of the adjusting blade should be. So, I think your car is pretty close. Measure per the factory instructions and see what that A-B difference is, that will tell you for sure. The other thing is, look at the UCA's. They're also pretty close to horizontal. If the car is where you want it, I'd leave it.
Per the factory method, you should be ending up at an "A"- "B" difference close to 0 for ideal geometry with modern tires and alignment specs. A-bodies are the "V and L" line.
Your car, with a line between the bottom of the adjusting blade and the ball joint housing. It's a bit of a guess because you can't see the bottom of the adjusting blade, but, it should be pretty close. The green line should follow the bottom of the LCA (I also have QA1's, so, I know a little about their shape). The red line is horizontal, and it intersects the bottom of the ball joint and where the bottom of the adjusting blade should be. So, I think your car is pretty close. Measure per the factory instructions and see what that A-B difference is, that will tell you for sure. The other thing is, look at the UCA's. They're also pretty close to horizontal. If the car is where you want it, I'd leave it.
69wacuda
Handling, and a 500ci engine.... All in good time!
Right now A is less than B which goes against the factory spec sheet you posted. I could start there. Also my car is riding really rough. I think it's bottoming out due to the fact that I only have about 3/4"-1/2" of upward LCA travel and 4" of downward travel. From what I've read about many others setups mine shouldn't ride that rough with Hotchkis leafs and 1.03 PST TB. Also, this is set with the TB adjuster all the way backed out. I have only one way of adjustment. What if I pulled the TB out, keyed the LCA up 45 degrees, and used the TB adjuster to bring the car up to ride height. This should make A greater than B, which allows for more clearance between the LCA bumpstop and the frame, while keeping the ride height the same?
Don’t worry about what the factory spec says, that’s out the window with radials and a modern alignment. You just have to worry about having enough travel.
You’re bottoming out, that’s not enough clearance. Even with my 1.12” torsion bars I need almost a full 1” of upward LCA travel. With 1.03’s you’ll need more than that.
The other thing is, I wouldn’t be surprised if your adjusting bolts are being fully unloaded and losing contact with the adjuster lever at full extension. You still have the factory upper bumpstop in there. You probably need to install a taller upper bumpstop to keep the adjusting bolt from dropping off the adjusting lever at full extension. When you lower the car that much, you have to recenter the range of travel around the new ride height.
Reclocking the torsion bars won’t change what you’re talking about. If the adjuster is all the way out, just screw it in and raise the ride height. You may be able to reclock the bars, but that won’t change the range of travel. Just the position of the adjuster. The only way to add travel to the suspension on compression is to raise the car. The ratio is like 2:1 also. If you add a 1/2” of clearance at the LCA bumpstop, you’ll raise the car almost 1”.
69wacuda
Handling, and a 500ci engine.... All in good time!
Okay. my hope with reclocking the bars is that the distances between the upper and lower bumpstops will be more equalized(recenter the range of travel). (more upward travel for the LCA and less downward travel for the UCA) This should also put the Control Arms in a more parallel-ISH configuration, instead of them both oriented upwards toward the sky. If I am way off base here, just let me know, I just want some return on the Funvestment I made, and a car that will perform and not just look pretty.
69wacuda
Handling, and a 500ci engine.... All in good time!
This might be a better picture. I'll take another look tonight and get some actual measurements and better pictures.
Nope. Re-clocking the bars does not change the position of the LCA at ride height. Your ride height is set by the angle of the LCA- it locates the lower ball joint, which locates the spindle, which locates the wheel. If you remove the torsion bars completely, that's still true. The angle of the LCA sets the ride height, and the angle of the LCA is only limited by the bumpstops/frame.
If you reclock the torsion bars, all you're doing is changing the angle of the LCA with respect to the torsion bar hexes. It does not change the range of travel of the suspension (still bump stop to bump stop), and it does not change the angle of the LCA at a given ride height. All it does is change the range of adjustment on the torsion bar adjusters. You might not be able to put the car at the ride height you want because the adjuster doesn't have enough range, but that doesn't change the angle of the LCA at the ride height you want.
Here's something else to consider-
Your LCA's are the new design for the QA1's, they have the included bump stop. Like this...
Mine are the old design. They don't have a bump stop at all. With the older design, the LCA has a shorter profile than the stock LCA's. Meaning, you actually add travel to the suspension because the LCA can go up further on compression before it hits the frame.
So what that means is that at the same ride height, my car will have more suspension travel left. You have some options if you want to address this. It looks to me like you're actually running a bump stop that's 11/16" tall, like the one's in the first picture I posted. These are those stops- Energy Suspension Bump Stops 9.9121G. If you swap them out for ones that are shorter, .375" to be exact, you will pick up some travel without raising the car. These are the stops I use, the difference is pretty obvious Energy Suspension Bump Stops 9.9132G
The other option would be to take the bump stop, and the mounting boss, completely off the LCA. The mounting boss under the bump stop on the new LCA's looks like it's at least a good 3/8" tall. Of course, that would mean modifying your brand new LCA's, which you may not want to do. But you can see the new design already has a more robust gusset than the old design that I have. Removing the bump stop mount, assuming you leave the gusset intact, shouldn't hurt the strength of the LCA. Then, you could just relocate the bump stop onto the frame. Since my QA1 LCA's didn't have bump stops, I added one to the frame stop. You can also see my modified upper bumpstop in this picture. I use one of these Energy Suspension Bump Stops 9.9136G, and I even run a spacer under that.
Here's my car, and the bumpstop I use. This isn't at ride height, it's on jack stands in this one (full extension). I thought I had one at ride height with the new LCA's but it doesn't look like I do, I'll take one later.
67autocross
A new iron curtain drawn across the 49th parallel
Did you check to see if it is bottoming out the shocks?
69wacuda
Handling, and a 500ci engine.... All in good time!
Not nearly enough travel for the shock to bottom out due to the proximity of the LCA to the frame.
GMachineDartGT
Senior Member
What size tire is up front? The suspension looks like it' way low.
69wacuda
Handling, and a 500ci engine.... All in good time!
255/40r18. 26" and change tall
GMachineDartGT
Senior Member
My advice:
Raise the ride height slightly. I ran that same tire for years but used a stock lca. I ran thinner Bump stops. The window of ride height vs. Suspension height is narrow.
What are your shock settings. T bar vs shock damping is a critical relationship. I don't think 1.03 is nearly enough in this case. My guess is this car understeers quite a bit.
Do you have a alignment specs on paper?
Feel free to PM me to discuss
69wacuda
Handling, and a 500ci engine.... All in good time!
Don't judge me to much this is my first foray into autocross. The event was a "Come Try Autocross" day, for charity. I did six runs overall and was pleasantly surprised with how my car handled. I had about 8 clicks left on my shocks and will play with that more next time. All in all it was a very fun day. I'm considering getting another set of stiffer TB but I am still undecided. I think i'll just drive it for a while and see what happens.
loganscuda
This/These
69wacuda. Nice run. What rear suspension setup do you have. Looks like it handles great in the corners. So are you hooked. Corner carving is a blast I love it. Did you have problems with fuel splashing out the filler tube.
Look like A good run to me not to mention fun!
joes68340s
Well-Known Member
69wacuda what gears are you running.
Looks fine from the video. Work on the driving skills and only make minor changes, if any, to setup. Its only realistic to focus on one thing at a time. So if there is something you really can't work around, then experiment with mechanical adjustments. But in my experience, driving is hard to improve when messing with mechanicals.
Some basic mechanicals are pretty easy to ballpark. Mark each tire with shoe polish to see how much tread - or sidewall is being worked. Then adjust tire pressure and/or alighnment as needed. Even there - sometimes a change in driving can reduce the amount the front tire may be rolling onto the sidewall.
Back didn't seem loose. Go have fun.
Damn fine job, I hope my 1st Time looks as good.
Mattax’ suggestions seem sound, looks like you could use up a little more real estate in order to retain some of your speed in a few of the corners.
A buddy of mine had other drivers do ride alongs for critique and suggestions.
Mattax’ suggestions seem sound, looks like you could use up a little more real estate in order to retain some of your speed in a few of the corners.
A buddy of mine had other drivers do ride alongs for critique and suggestions.
loganscuda
This/These
Looks awesome!
Mattax has some great advice, I don't think I'd change a ton on that car at the moment. Just drive it and get comfortable with it's capabilities. The body roll didn't look bad at all in the video's, and the car didn't seem to be understeering a bunch either. I don't think there's any reason you need to change the torsion bars right away. The 1.03's may be a little smaller than what you want for an autoX car, but that also depends a lot on your tires. And if it's just for fun it doesn't matter a whole lot. I think you're right to just run the bars for awhile and see how you like them, you can always change them later.
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