Suspension advice

[Sublime69]

I have a 69 Dart thats in major need of some suspension upgrades. The car was originally a 6 cylinder. Now its a procharged 318. I did put disc brakes on it about 10 years ago. But they are still manual brakes. I has a warn out manual steering box. It has the original 6 cylinder torsion bars and all the original bushings under the car. It has super stock springs in the rear. ,that who knows how old they are. I have the car currently lowered in the front(torsion bar lowered) and lowering blocks in the back. I dont want to spend a crazy amount of money, so I dont want anything completely radical. I just want it to be lowered the correct way and be able to handle really well. I want to take it on a long trip this summer.

Any suggestions would be great! Thanks guys!

 

[68GTconvert]

You could get the hotchkis TVS system. It is like $1800-2000 but it does the front and rear with good components. I think it is a good value for the money.

 

[zac_F71]

Just redo the bushings with poly one's from Prothane (Energy Suspension) - leave the 6cyl torsion bars IMO, 4 new adjustable shocks, get a ADDCO or similar from sway bar, new joint's are a order away from NAPA or Oreillys, and steering box rebuild kits are available as well OR splurge and get the Flaming River box...

you could probably redo everything for $1,000-$1,200 (W/O the Flaming River box)

Hell everything could probably be bought from Summit in 1 order (That's honestly what I plan on doing for my 71 Demon)

 

[pettybludart]

Handle well?You need front and rear sway bars.Hotchkis?Also some fairly cheap Monroe gas shocks.Should keep you within budget.JMO

 

[replicaracer43]

Rebuild the front suspension, replace all worn parts, obviously that includes that worn out steering box! add something along the lines of a .990 or maybe 1" torsion bars, get rid of the super stock springs, go with a stock replacement set, like would have been on the 340 A bodys, (6 leaf type), install a front sway bar if it doesnt have one allready, and put on a GOOD set of shocks. This should cost less than an aftermarket replacement system, if you shop around..

 

[Sublime69]

Ok, now some say leave the 6 cylinder torsion bars and other say get bigger ones??? Also, what about drop spindles???

 

[mopardude318]

absolutely get rid of the slant 6 bars. thats why your car handles like complete horse manure. these car were underspung from the factory. get a set 1.0" bars. youll be happy. add a 1 1/8" tubular front sway bar, with bilstein shocks all around which really compliment the heavier torsion bars...

 

[zac_F71]

I say leave the bars cause you can make up for them being small diameter with a sway bar and adjustable shock you don't want a rock hard ride- low profile tires already aren't helping... especially in Chicago where roads aren't the best (much like MN)

 

[pauly v.100]

Nothing less than 1" bars, mine are 1.06" and I want to go bigger. x2 on the Bilsteins.
Others have found that the drop spindles run interference with the tie rod ends on deeper backspace wheels.

 

[abodyjoe]

not sure how much you want to spend.


for something simple i would probably go:

espo 6 leaf XHD springs

.920-1" torsion bars. both ride very nicely. firm but not harsh at all

front and rear sway bars (pick your brand)

use a better shock. there are a few brands out there that you can go with.

rebuild the front end with quality parts. maybe even go with the moog offset upper arm bushings.

and a quality alignment..

as far as drop spindles go thats all personal preference i guess.

 

[wjajr]

Dump the 44 year old 0.82” slant six bars they are too mushy, and the pro stock springs out back with their different rates and arch. Replace with ride height of choice six leaf springs from ESPO, and anything between 0.940” and one inch torsion bars. Rubber lower control arm and upper control arm with off-set bushings because you are using low profile tires, two piece strut rod bushings, and 1 ¼” front sway bar preferable not an Addco with their junk mounting hardware. Four Monroe gasmatic shocks will do for now.

Make sure all steering components are tight and within wear spec including the steering gear. Having all parts tight will make a huge difference in handling.

Also install sub-frame connectors, and perhaps an aftermarket lower radiator support stiffener, and torque boxes to tie the front and rear of the car together.

Keep factory ride height set per FSM procedure anything different will impact handling & ride, dial in as much plus castor possible, offset bushings help with this setting. If more castor is needed than what off set bushings can provide, look to installing tubular upper control arms, but get a set that is gusseted at the ball joint, these aftermarket parts generally can give up to 6+ degrees of castor to correct for alignment problems.

Where you are using low profile tires, keep in mind that the suspension designers of the day took into consideration the ability of a tall tire’s side wall to provide some of the cushioning to the overall design. Modern cars take out some of the ride harshness transmitted from inflexible short side walls by using huge rubber bushings, bushings that need constant replacement.

Your old suspension is not unlike the one that came with my Dart, the car was a sloppy unsafe mess that felt as if there were a big hinge connecting the rear and the front of two different cars.

I installed the suspension listed above under my /6 ‘67 ragtop except the lower radiator reinforcement with stock tire size. The Dart now handles like a modern vehicle, flat, predictable, neutral, and no harsh ride, in fact with 0.940” bars, it is softer than my ’07 300C AWD.

 

[mischiefdart]

The one part I replaced on my dart that made the biggest difference in the handling was the torsion bars. Went from /6 to .890" 340 bars and it was much better. Then put 1.03" bars in and what a difference they made. I don't feel like they ride too harsh but I have 15" tires on my car. I would say go at least .920" like Joe suggested. Stiffer leaf springs and bilstien shocks would balance the car out well. Mine has a stock '73 sway bar and k-frame with no rear bar and has little body lean on moderately hard cornering.

 

[Sublime69]

Thanks for all the advice guys!

Here is my question now: if i do upgrade the torsion bars and I keep the ride height im at now, will it still handle bad? I need to keep the same ride height. But i keep hearing that if i use drop spindles, the tie rods will interfere with my wheels.

 

[replicaracer43]

The real problem with running it that low with stock spindles, is running out of clearance on the lower controll arm bump stop.. It needs some type of bumpstop, but you could trim yours down, or replace it with a thinner one.

 

[Sublime69]

The real problem with running it that low with stock spindles, is running out of clearance on the lower controll arm bump stop.. It needs some type of bumpstop, but you could trim yours down, or replace it with a thinner one.

but will the ride quality still be bad since the bars aren't at the right tension?

 

[replicaracer43]

If you go to stiffer bars, it will help, it wont tend to over travel as bad.

 

[sireland67]

The 1.030 Hotchkis bars are machined with the hex ends in the same plane, instead of off set 30? degrees like your original bars, so they are stiffer and lower the car.

 

[Sublime69]

The 1.030 Hotchkis bars are machined with the hex ends in the same plane, instead of off set 30? degrees like your original bars, so they are stiffer and lower the car.

I looked on their website and i didnt see a body bars.

 

[sireland67]

I looked on their website and i didnt see a body bars.

I found my receipt where I bought them from summit on 9/17/11 and the part number is no longer valid on summits web site.
The number is HSS-19385 $349.95

 

[mischiefdart]

Having the car that low does not change how much twisting force there is on the torsion bar only the orientation of the control arm. I had my dart that low with the 1.03" bars and new bump stops. Not much clearance between the stops and the frame. I ended up going with new leaf springs and more standard ride height. I liked my car low but for the daily driver role I opted for more ground clearance. I like to drive hard on back country roads.

 

[72bluNblu]

but will the ride quality still be bad since the bars aren't at the right tension?

Ride height has almost NOTHING to do with the tension on the bars. The ride height is controlled by the torsion bar adjusters. If you look at how these work, they change the angle of the lower control arm with respect to the torsion bar anchor. That doesn't change the tension on the torsion bar AT ALL, the torsion bars are not twisted by the torsion bar adjusters, and the weight of the car stays the same, so the same load is on the torsion bars.

Now, if you're bottoming out because your car sits so low, then the ride height does effect your handling. Which is exactly why you should upgrade to larger torsion bars. The higher spring rate will reduce the amount of travel that your suspension uses, so you can get away with lowering the car and reducing the amount of available travel.

Joe summarized it pretty well, 1" torsion bars (or bigger!), better shocks, XHD rear springs, front and rear sway bars, and rebuild the front end (all the bushings and ball joints). I'd use offset upper control arm bushings since you're lowered so much, they'll help with getting a proper alignment. Alignment specs for modern tires should be -.25 to -.5 degrees camber, +3 to +4 caster, and around 1/8 to 1/16" toe in.

And for no reason should you keep your /6 bars. They sucked on /6 cars, they suck even worse with a V8. You can't even BEGIN to make up for them with sway bars. Lowered as much as you are now, I'm guessing that you bottom out your suspension frequently.

As far as drop spindles, you shouldn't need them. Most of the 1" bars on the market now have less offset, so you can get pretty low even with the stock spindles. And the loss of suspension travel is made up somewhat by having a stiffer spring. To really put it in the weeds the drop spindles will help keep some suspension travel, but you have to watch the backspace on your rims. Nothing new, its the same issue with having 15" wheels, with too much backspace you hit the tie rods. It just makes it an issue again for 17 and 18" rims. If you have much more than 5" of backspace on your rims, you'll want to check some clearances.

 

[Sublime69]

Ride height has almost NOTHING to do with the tension on the bars. The ride height is controlled by the torsion bar adjusters. If you look at how these work, they change the angle of the lower control arm with respect to the torsion bar anchor. That doesn't change the tension on the torsion bar AT ALL, the torsion bars are not twisted by the torsion bar adjusters, and the weight of the car stays the same, so the same load is on the torsion bars.

Now, if you're bottoming out because your car sits so low, then the ride height does effect your handling. Which is exactly why you should upgrade to larger torsion bars. The higher spring rate will reduce the amount of travel that your suspension uses, so you can get away with lowering the car and reducing the amount of available travel.

Joe summarized it pretty well, 1" torsion bars (or bigger!), better shocks, XHD rear springs, front and rear sway bars, and rebuild the front end (all the bushings and ball joints). I'd use offset upper control arm bushings since you're lowered so much, they'll help with getting a proper alignment. Alignment specs for modern tires should be -.25 to -.5 degrees camber, +3 to +4 caster, and around 1/8 to 1/16" toe in.

And for no reason should you keep your /6 bars. They sucked on /6 cars, they suck even worse with a V8. You can't even BEGIN to make up for them with sway bars. Lowered as much as you are now, I'm guessing that you bottom out your suspension frequently.

As far as drop spindles, you shouldn't need them. Most of the 1" bars on the market now have less offset, so you can get pretty low even with the stock spindles. And the loss of suspension travel is made up somewhat by having a stiffer spring. To really put it in the weeds the drop spindles will help keep some suspension travel, but you have to watch the backspace on your rims. Nothing new, its the same issue with having 15" wheels, with too much backspace you hit the tie rods. It just makes it an issue again for 17 and 18" rims. If you have much more than 5" of backspace on your rims, you'll want to check some clearances.

Great info! Thanks! Now what bars and sway bars do you recommend?

 

[72bluNblu]

Great info! Thanks! Now what bars and sway bars do you recommend?

Just Suspension sells their 1" torsion bars for around $200, I have a set in my Duster. Pretty compliant for a 1" bar, not harsh at all. I'm actually planning on going bigger.

PST sells a 1.03" torsion bar, I saw them on eBay for $220. They're also a site sponsor here. Link here

Hotchkis sells a 1.03" bar, and Firm Feel sells 1", 1.06", and 1.12" bars. But they both charge well over $300 for those.

I think either the JS or PST bars would be a great choice, both will be a HUGE improvement compared to what you have now.

As far as sway bars go, again, anything would be an improvement. I think Hotchkis makes the best bars, but they also cost about twice as much. They're tubular, so they're lighter than solid bars. Hellwig is also making tubular bars now. Addco is the least expensive, but they're solid bars. If you're not going to be autocrossing or road racing, any of those bars would be fine, even in the smaller diameters available. In the front I wouldn't worry about going big on the sway bar, even with 1" torsion bars. In the rear, if you go with XHD style 6 leafs you can go with a pretty small bar, those springs are already pretty stiff. An adjustable rear bar would be best (hotchkis, hellwig), but again, if you're not road racing, anything would be a huge improvement.

 

[replicaracer43]

Post number 5 covered the basics.....

 

[Idaho]

Here's the wheel fitment pics I mentioned by PM.

http://www.forabodiesonly.com/mopar/showthread.php?p=1969806924#post1969806924

The first pic was an accidental post but shows upper ball joint clearance with a 245/45/18.

I'm curious to hear comments about the ball joint angle in the second pic. This is on the bump stops. If guys are running with trimmed bump stops and the ball joints survive, perhaps its not an issue.