Auto-X / Roadrace rear suspension 1969 Valiant

All out Auto-X/ RR rear suspension choices

  • XV 3-link

    Votes: 0 0.0%

  • Reilly Motorsports Street Lynx 4-link

    Votes: 3 33.3%

  • Fiberglass monoleaf w/panhard bar

    Votes: 2 22.2%

  • Something else that's not metal multi-leafs

    Votes: 1 11.1%

  • None of the above

    Votes: 3 33.3%
  • Total voters
    9
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72bluNblu said:
Yeah I don't think I'd worry too much about the spring perches with that little angle.
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Dang, I misread. Yeah, angling the perches is likely pointless. There's so much slop in a u-bolt interface as it is that it would be a non-issue for mechanical alignment. The pins take care of the the critical stuff just fine.
 
Great responses guys. So it seems that, from consensus, that spring toe in should a) be minimal to keep forward bite and b) may not be needed if using a panhard rod. However, if toe is incorporated I would want to seriously consider keeping it consistent with E-body toe angle or less. Also, keep spring boxes and sliders in-line with the toe angle.

I will reach out to AFCO and try to speak to someone in regards to 72bluNblu’s attachment. I will ask how much that applies to a left-right turn / pavement application.

The results of today’s phone calls were a good conversation with Hyperco. They couldn’t help me out on the spring rate, all they carry is a 170 pound spring and don’t do custom jobs.

He did tell me about a vendor that specializes in Vette suspensions called Vansteel. They do coils and mono leafs for various Corvette generations. Al, at Hyperco, told me Vansteel had bought a Chrysler mold from Hyperco.

I was able to talk to Eric at Vansteel and he said they couldn’t get something going on the Chrysler springs until early summer 2023 but it sounds promising. I told him that there was a growing number of enthusiasts doing or wanting to do autocross in A-body Mopars and he could possibly find some customers that were looking for custom spring rates. He did go into a little bit about how composites react a little different (faster) than spring steel. He said 120 pounds seems light to him and some of his Corvette customers are using 150 and tuning with a double adjustable shock. He says you usually go a little heavier with composites for the same application than multi-leaf steel.

He is going to email me by Wed. next week to confirm he has laid eyes on the Chrysler mold. I told him about the Hotchkis double adjustable shock offerings and some of the torsion bar sizes that are popular with performance handling Mopar A-bodies. I did not talk to him about the toe in idea or sliders. It was just a quick call and we agreed talking more in the coming weeks would likely flesh out many questions and thought. He will email me with confirmation that they still have the mold and wants me to reply with any information I can think of. He wants torsion bars sizes, wheel rates, wheel base, weights, … anything I can think of as far as vehicle dynamics.I plan to get the Valiant’s corner weights from Tom. I have found wheel rates for different torsion bars somewhere before (maybe Firm Feel?). I will also pass along the AFCO attachment to get their take on it.

Their bread and butter is autocrossing Corvettes and suspension tuning. He seemed interested in this foray into the Mopar composite leaf spring market. I welcome any information any of you can provide in regards to vehicle dynamics.

I also called Flex Form earlier in the morning and left a detailed message. I had a missed call from them this afternoon. Google maps says they’re permanently closed but the voicemail said that he listened to my message and looks forward to working with me to fill my needs.

It was a good day and have two possible vendors now. Re-looking at how the thread started I am just going to focus on this option. It has more going for it than the other options, IMO. Cheaper, lighter, faster spring action, easier to fabricate than other options, springs are possibly available right now through Flex Form, sliders available, frame boxes available, double adjustable shocks available, it’s somewhat OEM style suspension, ….. I’m just going to run this down and if Flex Form can get me a composite spring in short time that’s not a drag race leaf I will pull the trigger on the sliders, shocks, splined sway bar, and frame boxes.
 
So I did a little math too. If the Hyperco's that the E-body guys seem to prefer are 225 lb/in, and the Hotchkis E-body spring rate is 160 lb/in, then for an A-body if the traditional spring rate should be ~130 lb/in you'd be looking at 182 lb/in for the Hyperco's to maintain the ratio established by those E-body guys. And my 121 lb/in AFCO's would translate to 170 lb/in.

Also, it looks like Speedway sells the 175 lb/in Hyperco's...
Hyperco 10203 Chrysler Composite Leaf Spring, 175 Lb. Rate
 
I 've seen this too. Some differences beteen this and DSE. DSE has patented swivel links and high durometer rubber bushed ends. Important if NVH is a factor for the end user. I like the panhard bar on top of the axle if you are using a stock fuel tank. Packaging may be easier. The DSE uses a longer upper link which reduces pinion angle change but is more of a bolt in.
 
BergmanAutoCraft said:
I 've seen this too. Some differences beteen this and DSE. DSE has patented swivel links and high durometer rubber bushed ends. Important if NVH is a factor for the end user. I like the panhard bar on top of the axle if you are using a stock fuel tank. Packaging may be easier. The DSE uses a longer upper link which reduces pinion angle change but is more of a bolt in.
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Treed me! Was just going to tag you and ask about how the DSE kit compares! Which part number DSE kit are you selling? It’s a GM kit that’s being adapted right?

Great insight on that! I’m not a 4 link expert by any means, but I know that little differences in the link lengths and the angles they sit at are really important for roll centers and pinion angle changes.

A lot of that comes down to application, on a street car plenty of people are happy with triangulated 4 links like the RMS. But for a more serious autoX or road course enthusiast there’s a different level of tuning and optimization and some of those little geometry changes can be really important.

That panhard bar above the axle looks kinda slick for space considerations and a stock tank
 
The DSE kit is universal, so GM or any brand does not apply. Since the architecture of the frame rails/dimensions of all the muscle era cars are all pretty close, adapting among platforms is not difficult. Of course, everyone wants 100% bolt in......

Personally, I would be inclined to do the DSE kit on my Dart and make it more of a bolt in to potentially make a product for sale.
 
BergmanAutoCraft said:
The DSE kit is universal, so GM or any brand does not apply. Since the architecture of the frame rails/dimensions of all the muscle era cars are all pretty close, adapting among platforms is not difficult. Of course, everyone wants 100% bolt in......

Personally, I would be inclined to do the DSE kit on my Dart and make it more of a bolt in to potentially make a product for sale.
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Nice!

As a product for sale making it more bolt-in definitely makes sense, way bigger market for that. As far as optimizing geometry though would making it a bolt in deal cause some compromises?

It’s a fine line, that’s how we ended up with all the triangulated 4 link kits, mostly bolt in and all stock locations. More sales but less utility. I mean at some point with a high level of competition you’re just gonna have to fabricate your own stuff, I get that.

At the level you’re at now do you think you’re tapped out for what the leaf spring rear can do? Or is it more of a combination of performance and product development? Obviously you’re a business (and you make great stuff!) so that’s not negative, just curious about where you’d draw the line between optimizing the leaf spring suspension and moving on to something else.
 
Everything has its place. Suspension parts have become very competitve. I have also found very few people understand the differences among parts. Usually, the biggest advertisers make the most sales.
 
BergmanAutoCraft said:
Everything has its place. Suspension parts have become very competitve. I have also found very few people understand the differences among parts. Usually, the biggest advertisers make the most sales.
Click to expand...

Yep, no argument from me there!

Hell I’ve been guilty of that myself, I’ve definitely bought stuff before I really understood what I was going to get out of it. Some of those decisions worked out really well for me, I ended up with the right parts and a better understanding of how things worked in the process. Aaaannnd some of those decisions just cost me money when I replaced stuff later because it wasn’t really what I needed. Live and learn right?
 
72bluNblu said:
Which part number DSE kit are you selling?
Click to expand...
I talked to Peter the other day. He mentioned the staggered set up.

DSE_genX.jpg


This is the non-staggered.
DSE1.jpg


You can see that the staggered version has a crossmember that would probably be welded to the rear bulkhead. The non-staggered version could have those pockets welded up in the wheel well, I suppose. This is a full mini-tubbed car though so the staggered makes more sense.

One thing to note about the DSE kit is that the brackets are supposed to be slipped over an axle tube that doesn't have a flange. To put them on a tube with a flange installed you would have to cut the bracket . Not a big deal.

I have all the parts priced out for the complete composite leaf spring setup which includes the Hyperco springs, new u-bolts, Fox adj. shocks, sliders, AFCO leaf spring plates, and Clavert HD spring perches. It's in the neighborhood of $1600 w/ free shipping from Summit.
The DSE staggered X-Gen Quadralink is the same price, however, it doesn't come with coilovers so that's at least another $500 to $800 for a pair of double-adjustable coilovers so we'll say about $2400.
The Control Freak suspension is $2199. The Control Freak comes with Viking double adjustables. The link suspensions likely don't have free shipping so add a coupe more bills to each. I like the design of both link suspensions.

I just thought I would identify the costs involved with these options. I am interested in finding the right suspension so identifying cost is just what it is. I am more interested identifying the right suspension. The leaf suspension loses out over the 4-links in my opinion. I don't really care about the NVH (so much) so the Control Freak's heim joints isn't a deal killer in a race car. The question is should I be looking at the length of the links? Angle of the links? They are different between CF and DSE.

The upper and lower bars supposed to intersect at the anti-squat line for a neutral set up. I don't see how either has a way to adjust the instant center like multiple bolt holes as in drag race 4-links. Am I relying on the kit manufacturer to build the IC pont into the setup? If so the Control Freak has a 67-76 A-body specific kit so I hope they would have figured where the IC will be on the car in relation to the anti-squat line. But also, they should be keeping in mind that the A-bodies had different wheel bases. Mine is 108" so it would be different than a Dart. The DSE kit is universal so I would have the liberty of setting the IC when installing it.
 
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BergmanAutoCraft said:
The DSE kit is universal, so GM or any brand does not apply. Since the architecture of the frame rails/dimensions of all the muscle era cars are all pretty close, adapting among platforms is not difficult. Of course, everyone wants 100% bolt in......
Click to expand...

Thanks for spending time with me on the phone the other day. I have some more questions about the X-Gen.

My car is fully minitubbed. My wheels are 3-piece Forgelines and right now they are 8" so I will be getting the proper barrels to widen them. The first goal would be to see if I could run an 18x10 or 11 and still put the bars on the outboard side of the frame rail. The quarters are getting a flare so hopefully the lower parallel bars can stay wide. However, I would see if I could install the DSE lower bars in a frame rail pocket to give maximum room if the tire takes up all wheel well space.

The Control Freak suspension lower bar brackets put them in line with the frame. Neither company has brackets that have bar settings (multiple bolt holes vertically). Car wheel bases are different, as are weights. How do you set the Instant Center on the DSE kit? I have read a lot about how to set up drag 4-links and it is suggested to have the bars intersect slightly above the Squat Line, behind the Center of Gravity, for most forward bite. How would you set up a corner handling 4-link in regards to bar angle?

Control Freak is already set because their brackets are specific to each Mopar body style. I hope they did their research but even then A-bodies have different wheel base. If the IC was built in for a longer wheel base Dart and the kit was put on a shorter wheel base Valiant the IC would be lower.

I suppose with the DSE kit you can play with the installation since it is a universal kit. Without adjustment holes it would have to be spot on upon installation to nail the intersection of the IC on the Squat Line for a "neutral" or slightly "positive" set up? That would be a guess in my situation because to properly set up bars the car needs to have the corners weighed and race weight already on the car.

Drag race style 4-links get away with being installed on incomplete builds (not race weight) because they generally have all these adjustment holes in the axle and frame brackets. Pictured below you see all these adjustment holes on the Chassis Engineering drag race 4 link. Is there any adjustability in the DSE?

4link.jpg
 
Personally, I like the drag race 4-link, more adjustability, and you can get a setup off Speedway for $300. Add a watts link kit for $400 (just noticed Speedway has a kit for $100), and shocks for $600 and you're at ~$1300. I'm a cheap bastard though.

The DSE kit does come with johnny joints though, so that is plus.
 
DNasty777 said:
Personally, I like the drag race 4-link, more adjustability, and you can get a setup off Speedway for $300. Add a watts link kit for $400 (just noticed Speedway has a kit for $100), and shocks for $600 and you're at ~$1300. I'm a cheap bastard though.

The DSE kit does come with johnny joints though, so that is plus.
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I like the adjustability of those as well. I looked at buying Johnny Joints or the “Lifetime” heim joints (greasable-rebuildable) . Wow! Expensive! $116 ea.
A12076F4-8877-48E6-A5C5-C3F6A715973C.jpeg
 
A few days images to note. I’m just putting these here for my own pondering.
Valiant dimensions. Purple Valiant corner weights.
The Purple Valiant and mine will be very similar but I do have aluminum cylinder heads and a fiberglass hood. Tom did not have j-bars, mine will. Looks like my T56 is 8 lbs heavier. The roll bar will be very much the same. Battery in roughly the same place. Don't really know where any other weight differences will be.


96CDB8A4-C76E-4819-AED9-FB1A0925A0CA.jpeg


B2769EDD-5991-4C2B-B24A-5A829C092F76.jpeg
 
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This is just a representation of how I would set up a four link. Red is the anti-squat line, black is ballpark for CG, and yellow is instant center.
Of course all this is theoretical and needs real weights and measurements and equipment installed.
BBB2051D-93F7-4FF9-AA7F-80CB9D25B3C5.jpeg
 
From the DSE instructions.

Instant Center: 55.4” Forward of Rear Axle Centerline 7.7” Above Ground Level
**See Chart Below for Adjustment Information**
Lower Link Adjustment Settings
Body Bracket Position
Top Hole Middle Hole Bottom Hole
Instant Center
Height
46.1” 9.1” 55.4” 7.7” 69.2 5.5”
Instant center numbers are expressed as distance forward of rear

I’ll scan the instructions tomorrow and post. Much easier to read.
 
After guesstimating my weight savings over the Purple Valiant I plugged the weights into a calculator. Weight savings would be aluminum heads, race weight fiberglass hood, fiberglass front bumper, manual steering gear. Added nominal weight for j-bars and an Accusump on the passenger side J-bar. For the rear I would reposition the battery from the rear-right to achieve better balance.
The Purple Valiant's corner weights were: LF - 888 lbs , RF - 870 lbs. , LR - 771 , RR - 721.



Screenshot 2022-11-06 20.28.16.png


All this would be assuming no weight changes to the rear but I am leaning toward the DSE X-Gen so there will be a difference in the rear.
 
parallel 4-bar with panard bar and anti-sway bar in my silver Hemi Duster (built around 2005). IMO, once you determine what you want, the challenge is getting it to fit in our A bodies.

20220901_145647.jpg


20210524_113308.jpg


20210524_113229.jpg


DSC_0079.JPG
 
of course to do the above mods, you have to choose the "rear seat delete" option

DSC_0041.JPG
 
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