Handling the Dart

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Hemispherical

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I've got a Dart with a small-block 340 that wallows about town like a beached whale. Instead I want a car that navigates the crowd like a hyperactive debutante: a nimble. tight street ride.

So before going crazy I wanted to sanity check my proposed set-up by you guys:

0.920 torsion bars
heavy-duty 1 1/4 front sway bar
rear sway bar
regular Koni shocks all round

Questions:
#1 Should I even consider 0.990 bars in combo with sway bars, or are the 0.920 overkill with the rest of the setup?
#2 Will I even notice the rear sway bars? Word seems to be that they may help counteract any tendancy to understeer? Does anybody think they're must have?
#3 Presumably the adjustable Koni shocks should be set quite stiff to match the t-bar, no?

Any other tips or suggestions? I also plan front discs and a refurbished power steering unit from FirmFeel or similar. I'm actually in Australia, so parts are a lot harder than in the States. I'm new to all this, but got the mopar bug now, and discovering my inner rrrrrevhead :) Thanks..
 
That is not a bad front set up. I am also going to use the .920 torsion bars but the.990 are too big and should only be used on hi-po race cars. the .920 bars are solo racer bars that are a great idea for the weekend autocrosser but not good for an every day thing.

I am not real keen on sway bars. Right at the present time I am figuring a way for a panhard bar or watts link in the rear with the opition of a sway bar still in. A watts link is used in hi-po race cars also due to the noise it makes sometimes when turning into a corner at very high speeds. It uses a swivel action that causes the noise. A panhard bar doesnt make the noise due to it only being like a steel rod. You mount it at one side of the axle housing then run it up as far as you can to the frame, in a diagonal of course. Both keep body roll to a min. and lateral stability to a very excellent position.

Koni shocks I have no idea about, I like to read up on shocks and the development and testing of the shock before I use it.

I am asumming (which I shouldnt at 5 41 am in the morning with out any sleep) that you mean t-bar as in traction bar. A little suggestion is if you are more worried about taking the turns then running the 1/4 mile drag then take it off. I will explain more later on that subject because something else hit me (think I am getting old). If you meant t-bar as in track bar then by all means please keep it on and send me a pic of it lol. It keeps the rear end centered under the car when lateral load (cornering) is placed on it.

Another thing is with the leaf springs always get soft comfy springs. Some people believe that a hard/stiffer leaf spring means better traction. You want the suspension to do just that, suspend! You want a nice soft spring that will take the bumps in. With a stiff leaf spring it makes the wheels hop if you hit a little hole which in turn means less traction due to the tire bouncing off the ground.

Dont know if you understand this because I dont even. Getting old and quick so I have a quick mind loss happening. Hope you get it all set up the way you want it!

Also the tires, bigger sidewalls mean more roll to it. If you want to run 15's lets say check out tire companys and find which one has a stiffer sidewall in the tire or just go to your local tire dealership. A big sidewall wants to lean and it causes not the tread to wear but the sidewall its self when you corner. Hope this all helps.
 
I aint done just yet, I forgot to mention about this one company that I will need to send you the link to. Your power steering ratio is also a cause of poor steering. It is probably the stock 22 to 1 or 20 to 1 ratio. Comparison, corvettes are 15 to 1 and yours is 20's some to 1. This company makes a longer pitman and idler arm to increase your steering response. It can lower a 15:1 raito to 12.5 or 11:1. With your power steering set up I would say it would lower it to 16 to 1 or 17 to 1. Which is about the same as most new cars of today. There I believe I am done.
 
18 years old, and "your getting old", ROTFLMAO! If your old, there are a buncha of us here who are in big trouble. :toothy7:

Hemispherical,
Pick up a copy of "How To Make Your Car Handle" By Fred Puhn, it is still available and is an outstanding source of info for helping you figure out how to set a car up to handle well. B&S dosn't quite understand what it is he was trying to explain at whatever time in the morning he typing that. (No offense my young friend, I commend you on trying)

A road car with soft suspension and a fairly large amount of wheel travel is not the ideal place to use a panhard bar, especially if the bar is not set up in a horizontal plane equall or very nearly equal to the road surface. A panhard bar causes some lateral motion that is directly proportional to the amount of wheel travel and will fight the leaf springs as the suspension moves up and down and may cause a structural failure of the bar or leaf springs and/or attachment points of same. It will also cause some very unusual handling that will not be what you would call, fun.

A Watts linkage may provide a better plan for a road car but also has it's limitations as it will require some rather LARGE brackets , the linkage MUST be horizontal or the linkage will not give the proper axle motion, and the center attachment point must be designed strong enough to take the side loads when cornering, the links also must be long enough to provide the neccesary vertical travel as the linkage tends to leave perfect geometry at the extremes of it's travel.

If you intend to attempt either of these in your vehicle it will require welding and structural design that must be of the highest quality, it is a very bad thing to have a weld or bracket failure in a high speed high load corner, can lead to your sudden demise, if ya know what I mean.

So like I said, get the book and read it a couple of times first, you won't regrett it I assure you.
 
Alright, soft suspension is a key due to what I said earlier this morning. A leaf spring that will take in the bumps is a whole lot better then a leaf spring that takes in a bump and transfer it to the whole car which in turns makes you feel like you are riding a wave.

Anyways I totally agree with Krabysniper about the Watts link. They were used alot back in the day on Trans-Am cars and Lakewood now makes bolt on ones for those Mustand boys. Unless you intend on putting your car into a full on road race with leaf springs then you dont need it. Also Watts links are not only used on leaf springs, they can also be used on 3 links and torque arm set ups.

No offense to Krabysniper at all but it seems he knows more about Watts link then panhard rods/bars. Let me give a run down on a panhard bar. Its commonly seen on most modern solid axle cars and trucks even. It is also called a lateral bar or track bar, as to why I said you should keep the t-bar if you meant t-bar as track bar. It connects to the frame on one side and to the rear axle on the other. As with any suspension tuning is the number one thing. The placement is key, and should be as long as possible and mounted horizontal to the rear axle at STATIC ride height. With out the proper placement you get what Krabysniper was talking about witht he structure failure and unusual handling. An angled panhard bar will cause the axle to move sideways when the suspension travels. Also the height at which the panhard bar is mounted it determines the rear roll center. If you mount the bar higher you got a higher rear roll center which you dont want. If you mount it lower it lowers the rear roll center giving you more side bite at the rear which TENDS to promote handling. But if you lower it to much it will cause the chassis to roll, slow down corner exit accerleration, and a number of suspension geometry problems.

Talk to Hotchkiss, FAY'S2 Suspension, Global West, Detroit Speed and Engineering, any suspension expert. They are the best people to talk to and all I am saying is what I have heard and read from some of these people plus some of the old time racers.

Also to Krabysniper, you got a PM lol.
 
Thanks guys. It's time to get schooled with Fred Puhn, and start fiddling with the old girls underside, find out what works, what doesn't : )
 
if I heard right, since mopar leaf springs have the axle forward of center and the way the leafs are stacked in that section,as well as a pinion snubber, you don't need traction bars since they act like one. DSE used to only focuses on 1st gen camaros, with staggered shocks(68-69) that have always had problems with wheel hop/axle windup, but now are going into 2nd gen camaros and 2nd gen novas. HOTCHKIS, and FAYS2 do not have anything pioneered for mopars at all. They are GM and Ford oriented, respectively. In my opinion, Richard Ehrenberg(Mopar Action Tech writer) is the guy to listen to when it comes to mopar suspension. just read into the green brick and the one lap of america as well as some of his other accomplishments. FOr GM, Hotchkis is awesome, Mopars.....not. Global West is also great for Ford and GM guys but don't have anything designed or engineered for Mopars. just my 2 cents.
 
Yes all of your statements are true. But I do see your point, I didnt mention any one that dealt with 'handling' Mopar suspensions, which is what he is looking for. His front system seemed very well planned but I just listed and described some rear suspension ideas and listed the people I know have dealt with them.

Also your 2 cents is always appericated, like everyone elses. Never hurts to post your opinions and ideas, which in this case was needed due to me overlooking they dont deal with us Mopar owners. Guess they are to worried about getting the Bowties and Ovals as good as us to make anything for us.
 
Thanks for the tips, redfastback & BnS. I picked up a copy of Puhn. It looks great, and the bookstore guy said he sold a whole heap.
I did think the longer pitman arm was neat idea, but according to the Firmfeel site, it probably wont clear any headers you have installed.
I'll have to check the existing ratio, cuz they say:
Your stock power steering ratio is 16:1, (3 1/2 turns lock to lock), with the fast ratio pitman arm your ratio is ~ 12:1, (2 3/4 turns lock to lock)
 
A bit of clarification regarding panhard bars on Mopars (or other leaf sprung cars). They are not needed nor are they desirable. The panhard bar is used to keep the axle from moving laterally under the chassis. Leaf springs locate the axle side to side just fine and any other linkage will only tend to bind things up. You will note however that a well developed panhard setup will attach to the center (of rotation) of the rear axle and sit nearly horizontal at normal ride height. Pandard bars are typically found on coil sprung rears (GM).

Now, as for other suspension mods. .990 bars are WAY too much for street use. .890's, fresh bushings, a sway bar will make for a real nice handling street car. Out back, use 6-leaf HD springs (a factory 340 car would have had these) a small sway bar and good shocks. You will be amazed at just how nice an A-Body will drive with this combo. Note with the factory leaf setup there was not much camber (arch) in the rear springs. I seem to recall discussion recently saying that more arch will improve handling and/or ride. I'd love to see scientific data to back this up. Mopar used a nearly flat spring to improve handling and reduce bumpsteer. A dead flat spring would provide the best handling, but would make the load carrying capacity essentially zero.

Score a copy of Mopar's Chassis book after reading Puhn or Adkins. All good reading.

If you are wandering all over the road, you have something seriously wrong and should fix it before driving the car again. Repairs take priority over modifications always.
 
I upgraded to the .89 bars (383-sized) on my 67 Barrracuda with a 340 and I'm pretty happy with the ride up front as a daily driver. I don't have a sway bar and it still handles fine. Maybe someday I'll upgrade to a later K-member so I can install a factory swaybar setup. All bushings and joints were replaced with rubber MOOG parts and made a huge impact in the ride and front end control. I used KYB shocks all around. I'm not carving up canyon roads so the setup works well for me. I installed XHD springs on the back and they're a little too stiff for a daily driver. I'll probably change them out next year to something softer. That's my .02, hope it helps.

Tim
 
the bottom line is how is the car going to get driven. no one type of suspension setup will cover every aspect of driving. a car setup for dragracing sucks at cornering. a car setup for autocross sucks for everyday driving. too stiff of leaf springs suck. moving springs inboard limit your cornering performance. think about how YOU drive and what you want out of it. i have the .890 bars in my 68 cuda sb w/alum heads. my buddy has the .930 bars in his 68 cuda sb w/iron heads. we both like how our cars ride.

I am not trying to knock anyones opinion here. my day job is repairing and modifying mostly gm's and some fords and some mopars, and the same rules apply. how is the car going to be driven by the owner and what do they want out of their car. so good luck to all and just research about your decision before you buy, thats all.
 
I agree with redfastback, research has never hurt a thing, why would you think there is an R&D group in every manufacturer group.
 
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