Frame or chassis options for A bodies

[67autocross]

I would respectfully like to point out the whole purpose of this thread is about what type of chassis or kits are avalible to improve handling, as the OP is wanting to build a "track car" and he was under the false assumption that a replacement chassis was needed. And i think it is about 100% clear to anyone reading these posts, the FASTEST track/roadrace/auto X cars are torsion bar/leaf equipped. Oh, and the guy who got outran by a 4 door B body is the same member who told us all how much faster his duster was once ditching all the factory parts and installing aftermarket stuff front and rear. Sucks to be him.

I like how you started the post with the word respectfully and ended it by slagging off another member and his car, classy.

 

[67autocross]

You're the second guy to endorse those SPC arms. They look cool and all, but they're quite a bit more expensive and they don't even come with ball joints so that's an extra expense.

I don't see too much difference between the Reilly and Hotkiss arms other than price. Their design are quite similar, also there isn't too much negative comments over Reilly Motorsports quality. That's something I factored into the equation.

The funny thing is, Hotkiss is like 10 minutes away from me. They have great stuff, but pretty pricey.

I've heard of proforged, but they're made overseas in Taiwan. That might not mean much since I hear Moog is being made overseas as well. Bummer. Moog might be better priced. I'll have to compare.

The tie rod sleeves are probably not critical, but for 50 bucks it doesn't make a huge dent in the budget and I need tie rods anyway since mine are worn and the boots are busted. Might as well go big while I'm at it.

Many have stated how much they have liked their Firm Feel torsion bars. I know they're more expensive than PST's, but that may be one area where I might splurge a little. Maybe they can work with me on the price if I purchase more parts from them.

Blu seems to like the Fox shocks too. The first time I heard of either Bilstein or Fox is in the desert racing scene. I a set of Bilstein 5100's on my Ford Ranger (a total of 6 shocks actually) that had mid-level Camburg race suspension on it. It wasn't long travel, but it was enough to take a beating in the desert. It was amazing how it handled on and off-road. I miss that truck. I sold it. Anyway.... I have been a Bilstein fan ever since.

As for rear springs, that will be later down the line. I haven't decided on rear sway bar yet. I guess I'll have to see how it handles after I do the front end.

Thanks for the advice and tips. I appreciate it! It's good to hear first hand experience. You and Blu have some nice cars!



It may seem like this thread went off on a wild tangent, but it's awesome that so many suspension options have been discussed. Nice to know that when it comes to Mopar suspension, the aftermarket is alive and hopefully doing well.

As far as torsion/leaves are concerned, I figure it's better to keep it simple. Although, if I had the cash I'd get an Alterkation kit and drop a Gen III Hemi in my Duster. ;)

One thing that I have noticed, some of the torsion bar guys have mentioned that the ride quality "is not so bad" or "rides like new Mustang" with stiffer bars but I don't think anyone with coli-overs have mentioned what the ride quality is like on a daily basis.

I would say that ride with torsion bars over 1.10" gets fairly rough especially with a low profile tire, railway tracks and sharp bumps makes the dashboard jump that's for sure. If you run 15" wheels and tires the ride is much better. I would rank the ride and driving feeling in this order:
1. Alteration with street Lynx best ride
2. Last generation solid axle Mustang, ride not bad, the factory shocks need more damping
3. Big torsion bar a body ride is stiff but livable, the old car rattles are certainly made worse.

 

[rustycraig2003]

Why not go with a solution like a Hotchkis TVS or some similar parts.

Really no reason to go cutting the whole car up. I don't even have all the hotchkis parts and the car handles extremely well. I also have 275-35-18s on all 4's.

hey goldduster how are you,I have a question for you what size rims do you have for yr 275"s ,i have 15 in centerlines,,they are almost 10 in wide ,would 275 fit ,I d like to put 295 but not sure about opening up the tubs,,i have a 65 dart ,,thanks for any input Russell

 

[replicaracer43]

I like how you started the post with the word respectfully and ended it by slagging off another member and his car, classy.

I don't know exactly what "slagging" off is........ but I merely pointed out that in that particular instance, that member was insistent that the torsion bar/leaf setup was inferior to the coilover conversions, and that his car was much faster with the aftermarket stuff. That's what made me put the "sucks to be him" comment, as I am sure it was a humbling experience to see his argument proved incorrect in the real world.

 

[72bluNblu]

$1350 with out powder coat or $1450 with powder coat. That includes viking d/a shocks and springs, adjustable upper control arms, tubular lower control arms, adjustable strut rods, new upper ball joints, shock hoops to support factory shock towers and all the hardware needed.

I'm not here to argue or debate about which is better. I just seen everyone comparing the two but using the absolute highest price point product for the debate. You can switch to coil overs for a lot less than what was being stated with the RMS system. That is all.

You still haven't addressed everything in your cost though, everything has to be new in the front for the comparison to be accurate. Otherwise you can drop the cost of the torsion bar set up significantly.

You still need to include a steering box, so now your cost is $1,960 (w/o powdercoating). You haven't included new pitman and idler arms, tie rods, or tie rod sleeves. Now you're at $2,150. You haven't included a sway bar at all, you use the 67-72 version so with a Hellwig #5906 that's another $215, so now you're at $2,365. Oh, and lower ball joints. Now you're at $2,445.

And there are still component differences, you can get cheaper tubular UCA's than what I quoted, cheaper ball joints, etc. I should also note here that the UCA's you've included in your kit will not support a 9" wide rim. I've been there, and done that. The "U" shaped UCA design limits your rim backspacing and width, just FYI. To clear 9" wide rims you need a "V" shaped UCA.

Well, as this thread clearly shows, that's up for debate and personal opinion. My preference is the coil over. I'm not here to get sucked into the debate that will never end.

Yes, uses stock steering and spindles.

Viking makes some awesome products and they are a great company to do business with.

Yeah, that was all i was trying to point out. It is possible to convert for similar prices.

So, you lose the single largest advantage to switching to coilovers IMO, which is the rack and pinion steering. Yes, getting rid of the torsion bars makes room for headers, but there are already headers out that fit torsion bar cars for most engine combinations. Spending $1,350 to run cheap headers seems counterproductive.

You use the stock shock mount (which was never designed to support the car) to support the car. Yes, I see that you have reinforced the shock towers. Regardless of this, you're still loading the chassis in a way it was never intended to be loaded. This is fundamentally different than reinforcing the shock towers on a torsion bar car, because of the size of the loads involved. On a torsion bar car the loads on the shock mounts are just from the shock, not the entire weight of the car and all of the suspension loads.

You have used the stock suspension geometry to run coilovers. This is not ideal for the coilovers. Other conversions use MII geometry, which was at least designed for the coilover type set up.

Is the rear of the LCA unsupported? If it is, that's a problem. The strut rods were designed to prevent fore/aft movement only, they do not control the rear of the LCA. Same for the pivot pin and mount, it was not designed to be unsupported on the back side. The torsion bar significantly restricts movement of the LCA in the vertical plane, and carries load as well.

This is why I used the RMS system as my comparison. Like the factory suspension set up, it was designed to be all inclusive, mounting the coilovers to it's own mounting points which allows the coilover size, angle, and compression lengths to be tailored to the suspension geometry. It also takes the load from the coilovers and places it back onto the K member. While it still changes the direction of the load compared to the torsion bars, it at least loads the K member instead of the shock mounts. The RMS is a track proven design, and while I have certainly suggested that it's probably not any faster than a torsion bar/leaf suspension, I definitely think it has some advantages that are worthwhile depending on the application and use of the car.

Simply converting to coilovers is not the point of the discussion here. The discussion concerns the handling capabilities of coilover conversions and the torsion bar/leaf spring set up. Sure, your system is cheaper and gets rid of the torsion bars. But there's no information on how it will perform when used in a handling application, or what it's longevity will be when used on the street. That information is out there for the RMS and torsion bar systems, and the HDK for that matter. Your system is different enough from all of those systems that you can't assume it will perform the same as any of them.

I'm not here to bash your conversion. Every conversion has its pros and cons, that is absolutely true. Even modifying the "stock" system with larger torsion bars has consequences that must be addressed. But it has been done and it's advantages and disadvantages have been demonstrated on the track. Same for the RMS, and I think the RMS system is more capable than the Hot Rod article suggests. But as far as it being better/faster, I still think that's a complete toss up. It's down to owner/driver preference.

The point has always been that you don't need a full chassis replacement to compete on the track. You don't even need a full coilover conversion. If you want one and can afford it, more power to you. But you don't need it.

 

[JoesEdge]

I'm not here to bash your conversion. Every conversion has its pros and cons, that is absolutely true. Even modifying the "stock" system with larger torsion bars has consequences that must be addressed. But it has been done and it's advantages and disadvantages have been demonstrated on the track. Same for the RMS, and I think the RMS system is more capable than the Hot Rod article suggests. But as far as it being better/faster, I still think that's a complete toss up. It's down to owner/driver preference.

What are the consequences that need to be addressed?

I only ask because I just wanted to make sure I knew what I was getting into. Thanks!

 

[Woods74]

^It helps to weld up the brackets that hold the torsion bar at the cross-member, they can crack out..

 

[72bluNblu]

What are the consequences that need to be addressed?

I only ask because I just wanted to make sure I knew what I was getting into. Thanks!

The torsion bar sockets and LCA pivot pin mounts should both be gusseted. I wouldn't say it's mandatory, and it's not a problem unique to larger torsion bars. I've seen torsion bar sockets that have torn out of the crossmember, same for the LCA pivot mounts in the K member, with just the stock suspension components. Some of that is because these are 40+ year old cars that are prone to rust, some of it is because the quality of the welds from the factory varied quite widely. Some cars wouldn't need anything, others might not hold up to the increased loads.

I've run my Challenger with 1.12" torsion bars for almost 8 years and probably some 60k miles without reinforcing anything in the chassis. Not the K member, not the torsion bar sockets, no subframe connectors, no torque boxes, nothing. I run it with 275/40/17's on all 4 corners, the 1.12" Firm Feel torsion bars and Mopar XHD springs in the back. And it has rust holes in the floor. Now I wouldn't suggest doing the same, there's definitely some chassis flex (ok, a lot of chassis flex) that comes along with that combination. But the only parts I've actually broken were aftermarket parts I've put on the car (CAP tubular LCA's).

You also asked about the Bergman AutoCraft SPC UCA's. There's a couple reasons I bought them. One, the fact that they're double adjustable. Meaning, you can adjust the UCA's while they're bolted in place on the car. It's just a nice thing to have, especially if you want to fine tune your alignment. The other is that they use delrin bushings and not Heim joints. I completely wore out a couple of the heims on the Hotchkis UCA's on my Challenger in under 7k miles. Yes, my car gets used in all weather conditions and on the street, and Hotchkis very graciously replaced my heims at no charge and included their new heim boots that I did not originally run. That said, I doubt the new heims even with the boots will last 10k miles. And since the Hotchkis UCA's aren't double adjustable, that means multiple installs and adjustments to reset the alignment when the heims are changed. I don't like heims on the UCA's for that reason. Strut rods are a different story, they don't see anywhere near the same amount of load.

At any rate, other than a wider range of adjustability, you don't NEED the SPC arms. I have magnumforce non-adjustable, bushed, tubular UCA's on my Duster right now, they work fine and will get you to the modern alignment specs you should have with modern radial tires. The BAC SPC UCA's are just really nice, and the adjustability is great if you intend to make adjustments frequently (like changing your alignment for certain tracks, tires, etc.). The magnumforce UCA's will be reused on my Dart, which isn't going to be set up as aggressively as my Duster is.

 

[goldduster318]

You're the second guy to endorse those SPC arms. They look cool and all, but they're quite a bit more expensive and they don't even come with ball joints so that's an extra expense.

I don't see too much difference between the Reilly and Hotchkis arms other than price. Their design are quite similar, also there isn't too much negative comments over Reilly Motorsports quality. That's something I factored into the equation.

The Hotchkis ones are kind of a unique design, they are not really just a stock tubular UCA, they have the ball joint relocated a bit. Supposedly this helps the geometry. The car handles good with them and so far so good on them holding up. The RMS ones look like stock geometry tubular arms to me. I have no issue with RMS quality as I have his strut rods on my car and we just put them on my friend's 71 Demon last weekend too.

The SPC are nice as they can be adjusted on the car as 72blunblu mentioned. I actually had to go back and remove my hotchkis and put the rod ends NOT where they were in the kit to get the caster I wanted. I would not have had to do that with the SPC ones. I did do the alignment at home in my garage with some somewhat budget tools, but it turned out perfect. I also have some concern about the longevity of the rod ends, so the delrin bushings will work better in that regard. Upper ball joints are $18/side so not the biggest deal. I basically stole a set of hotchkis ones where someone ordered the wrong part and just needed them gone so that's what the car got.

I've heard of proforged, but they're made overseas in Taiwan. That might not mean much since I hear Moog is being made overseas as well. Bummer. Moog might be better priced. I'll have to compare.

If you can get the USA moogs, fine. If they are the overseas ones...I think they are China. I read a topic about some NIB moog lowers for this application having loose balls in them from day one in the Moparts handling forum - Rylispro IIRC...tracks an E-body. Pretty scary stuff. Usually Taiwan stuff is relatively good quality anymore, I'd certainly trust it over anywhere else in Asia that's not Japan or South Korean made. I have some quite good quality tools made there as well. So I wouldn't be that afraid of them.

One thing that I have noticed, some of the torsion bar guys have mentioned that the ride quality "is not so bad" or "rides like new Mustang" with stiffer bars but I don't think anyone with coli-overs have mentioned what the ride quality is like on a daily basis.

Yes, that is my feedback too. It actually rides better with the 18's than the 15's on the same suspension as well. Ride is not bad at all, and the roads suck in MI. My pickup is a lot worse.

hey goldduster how are you,I have a question for you what size rims do you have for yr 275"s ,i have 15 in centerlines,,they are almost 10 in wide ,would 275 fit ,I d like to put 295 but not sure about opening up the tubs,,i have a 65 dart ,,thanks for any input Russell

They are 18x9 +35 offset. But a Duster probably has significantly more clearance than a 65 dart in the wheelwells. You won't be able to do it in 15's. The 18's are needed to go over the tie rod so it doesn't rub.

 

[67autocross]

What are the consequences that need to be addressed?

I only ask because I just wanted to make sure I knew what I was getting into. Thanks!

I would advise that larger bars can have clearance issues with the headers, I don't think you will have any issues if you stay under 1.10" but above that they can be tight.
If you are buying used bars watch out for the clocking of the hex heads as they are all over the map and some can be a pain to get the correct ride height with.
I would also replace the ride height adjuster bolts at the same time as you install stiffer bars as they may be more prone to stripping with stiffer suspension.
If you really start lowering the car with a factory front end you start running out of suspension travel, on bad bumps it will bottom hard on the bump stops.
I would say if you are not racing the car go with the PST 1.03 bars or maybe Firm Feel 1.06s, they should give you about the new Mustang ride quality that gets tossed about.

 

[HemiDenny]

I love ALL the honest input.....especially from the guys that have already ...been there, done that.

I look up to anyone that can bulldog one of our 40 - 50 year old cars around an Autocross. Sure looks like fun .....but I would crinkle every piece of sheet metal on the car, even the roof.

 

[72bluNblu]

I would advise that larger bars can have clearance issues with the headers, I don't think you will have any issues if you stay under 1.10" but above that they can be tight.
If you are buying used bars watch out for the clocking of the hex heads as they are all over the map and some can be a pain to get the correct ride height with.
I would also replace the ride height adjuster bolts at the same time as you install stiffer bars as they may be more prone to stripping with stiffer suspension.
If you really start lowering the car with a factory front end you start running out of suspension travel, on bad bumps it will bottom hard on the bump stops.
I would say if you are not racing the car go with the PST 1.03 bars or maybe Firm Feel 1.06s, they should give you about the new Mustang ride quality that gets tossed about.

Good point about the diameter of the torsion bars. I did need to put some dimples in my Doug's headers to clear the 1.12's. But that's also with a spool mount K, and it seems like they have more issues with header clearance to begin with. The earlier biscuit style mounts can also be shimmed to adjust the clearance, which is a no-can-do on the spools. The factory tolerances on these cars are such that some cars would probably be fine, others would need dimples. It's a tight spot, but it's not much different than header clearance is on these cars anyway- depends on your car and your set up. I really like the Doug's but I've come to the conclusion that the TTI shorty's are probably the best way to go for an autoX set up, more clearance for larger torsion bars and more ground clearance than the long tubes.

I've had no issues with the torsion bar adjusters stripping, even with the 1.12" bars, and I haven't bought any new adjusters. Just make sure that they're in good condition (threads not damaged) and don't adjust them with weight on the front end. If the threads look good, I can't see replacing the adjusters with new ones that were made in China, for example.

As far as lowering goes, you just have to match the amount you lower the car with the size of your torsion bars. Larger torsion bars allow less suspension travel than smaller bars, so you can lower the car and reduce the amount of available travel without problems. For example, my 1.12" torsion bars have a 300 lb/in wheel rate. That's almost 3x higher than the stock torsion bars. That means I only need about 1/3 of the available suspension travel that a car with stock torsion bars and ride height has. In my case, I replaced the stock bump stops with .375" tall polyurethane buttons, and have just under an inch of clearance to the frame at ride height. I rarely ever bottom the suspension, it takes a really big pothole and a hard hit to bottom it out. And the stock suspension would bottom in that case as well, the stock progressive bump stops get used more frequently than most people think, even at the stock ride height. Best way I've found to see how often the bumpstops are really touching is to put a small dab of grease on the bump stop and go for a drive. With the stock progressive bumpstops I would wager that most folks are on the bumpstops significantly more than one might think. With poly buttons it's pretty easy to tell when you hit the bumpstops. If you find you're hitting the bumpstops frequently, raise the ride height a little and try again. My car sits pretty low, the K frame is just a touch over 5" off the ground, the tops of the wheel openings on the front fenders are at 25".

 

[67autocross]

My car has a spool k with TTI headers , at first I tried some 1.18" bars and it looked like it was going to take a good bit of hammer time, I had some old Mopar 1.14s on hand and they touch but not enough to have to really start beating the headers. Keep in mind these are 15 year old TTIs so they may have changed them a bit by now.
Next set I buy will be the shorty ones for sure.