Joined: 04 Jun 2006
Location: Gaithersburg MD
Brief history of supsension evolution on Dart
(Sat Jul 17, 2010 5:47 am)
|For those of you out there who have just purchased an old Mopar A body car, or are thinking of upgrading the suspension of an existing one, I hope this summary of my experience will be of some benefit. Just know that there is a world of improvement available within the realm of stock, and then more with some modest upgrades. But there you must be careful. All that glitters is not gold.
I bought this car in 1993 from an old lady who drove to church on Sundays. Really. And it was a rolling death trap. It has taught me much over the years through practical application, and I thought it would be useful to share the evolution with others. I hope my wheel widths re accurate. This is from memeory, and that is not so hot these days, as we know.
Stock Set Up
The car came stock with 13" wheels which I think were 4" wide, and 9" drum brakes, and no anti-sway bar. It had 165x75 radial tires, but the spare was the original bias ply tire. This car was scary to drive. You never knew which way it would pull when you hit the brakes, and it took for ever to stop, with very high pedal effort. And when you went to change lanes on the highway it didn't stop changing lanes when you thought it would. You had to actively steer it back to where you wanted to go, and then it over corrected and went back where you came from. Does this sound familiar?
The very first upgrade was to put 14" x4.5" wheels on it and to try and increase the caster to improve the on center feel. I ended up with 185-75 tires. In order to get more caster I had to install Problem Solver upper control arm bushings. I got 2 degrees of caster out of it, and a great deal of peace of mind. The car was no longer a white knuckle experience to drive.
The next upgrade was a front sway bar. I put an Addco bar on, which had very poor front mounts that would bend and break off when you hit speed bumps. I had them welded on, and then the K member broke, which I replaced when I put the new engine in about 5 years ago now. The sway bar mounts n the LCA were poor. They mounted to the shock bolt, and no matter how you fashioned things, it would strike something in some attitude of the steering, either full up,or full down, or turn in, or turn out. I would adjust things, modify brackets etc. , and it was always poor. That thing lies right in there next to the front strut for the LCA and that was part of the constriction and problem. But, the car handled much, much better.
BBP and Disk Brakes
The next upgrade was to go to BBP wheels with disk brakes. I have had several iterations of these. The current ones came off of a 74 Sebring. The rear I first put in was an 8 1/4 from a 74 360 Duster with limited slip. That eventually went into my '70 360 Dart, and I put in another 8 1/4 from another car.At this time I upgraded to heavy duty rear springs with an extra long leaf installed in the number 2 spot to keep it from sagging again.
Later I replaced the entire front end set up complete with pittmans, drag link, tie rod adjusting sleeves, and steering box. This eliminated the play that had gotten into the box, (which was beyond adjusting out), and stiffened things more.
At that time I picked up a set of used 15x6.5" Mopar Ralley wheels from a guy on Mopart.com At that time I put 205 60 15 Michlins all the way around. Of course I rebuilt the front end entirely at this time with all new bushings. By this time this car was driving and handling like a "modern" car, but it had a funny attitude still. It would turn into a left hand corner differently than a right hand one. It was not a performance car, but it was fine on the road. Also, the front sway bar banged every once in awhile, and I would have to re-weld the front sway bar mounting tabs. But you did not fear for your life driving it.
Squaring the alignment.
One day when my wife was following me home in her car she told me she could see the left front wheel hanging out in the lane further than the left rear. I thought it was just the wider track, but decided to take it to an alignment shop and check it out. Sure enough, the car was not square. WE calculated I needed to move the left rear spring mount box rearward 1/4". So, I cut a piece of 1/4" steel and drilled the holes in the right place, loosened the box and stuck this shim in there. Upon realignment everything is fine,and the car drove better.
Cop Car Wheels
When I restored my '70 Dart, I put the rallys on that car, and bought a set of cop car rallys and put them on the '69. That was the first set of 15x7's I had on the car. I also put a rear sway bar on it. These wheels were, to me, perfection. The car handled absolutely predicatably, with balanced steering. It stopped well, and turned on a dime with no real body roll to speak of. It was close to sports car handling when compared to its first self.
Improved sway bar mounting.
I discovered one of the sway bar companies designed the chassis mount as a flat piece that bolted to the bottom of the K member, and did not stick down where it could get bashed by road debris and speedbumps. This works much better, and the company was willing to sell me just the mount. I wish I could remember who the dealer was for sure, but I think it was Just Suspensions. I then decided to fix the LCA mount once and for all. I took the tab that Addco supplied, and had it welded to the LCA just inboard of the big rivet that holds the two halfs of the LCA together. This has proven to work out well. The bar no longer bangs on anything in any position of suspension travel.
Dakota Pick Up alloys.
These were a major step backwards, because the back space was wrong. The 3.72 back space looked cool, but changed the handling for the worse. If I had had any integrity I would have taken them off and sold them, and put the cop car wheels back on. But vanity got the better of me. They looked cool. So, I left them. This was the first change that didi not yield substantial improvement. From there on, the changes that I made, which were good, mind you, were attempts to fix what the Dakota wheels did. The most distrubing thing is a strong tendency to oversteer suddenly, and a lessened tendency to return to center when leaving a tight turn. The on the road on center feel was fine, it was just coming off of interstate exits and such that it seemed kind of funky. Lou talked me into removing the rear sway bar. This improved the oversteer somewhat, but I felt I lost something at the same time. I really enjoyed the "on rails" feel it had before with the cop car wheels and the rear sway bar. It had been a hoot to drive around town.
Tubular UCA and solid LCA struts.
These improved the braking substantially. I was surprised by that. It eliminated the movement in the steering knuckle that would effect braking timing and effectiveness. It rode harder, but not terribly. I suspect the rigidity of the front end was one reason the wheel was destroyed so utterly when I hit the "mystery whatever" this week. And, I also suspect the alloy wheel, being much softer than anything else in the front end at this point, became sacrificial, and saved everything else from damage,(hopefully).
Edelbrock IAS socks are not the last word in shocks, but are a substantial improvement over any stock shock. The car handled more stably and rode better.
At this point, Lou told me about a company in Colorado that sold kits for the Mopar rears for adding disk brakes. I did this, and am very happy with them. However, I wish I had included their emergency brake feature. I elected to get rid of it, since I never use it, but have wished it were there many times since. I may add it back later.
Now that I am replacing the wheels with the proper, stock back spacing, I expect this car to handle better than ever. If I did not damage anything in the suspension when I hit what ever I hit, I am glad to be rid of the Dakota wheels. I just wish I had the sense to get rid of them long ago. Do you see any patterns here for me? Those Dakota wheels played the same role in my suspension evolution as the Accel ECU did with the EFI. And, I kept beating on an unworkable combo out of the silly reluctance to feel like I was losing money. It is the same. I hope I learned something. I will get back to this thread when the new wheels are on it, and let you know how things went.
I may upgrade the car further later, with bigger tires and wheels, but for now, I just want to get back to the magic I thought was there with the cop car wheels. I have had a few opportunities to put larger Mustang wheels and tires on this car, but the restricted back fender space is a real limitation to what will fit. And in each case decided the wheels which were available would not go in there. When I restored the car, I bypassed the opportunity then to cut these rear wheel wells open so bigger tires would fit. I thought about it, and decided against it. It is what it is now. I don't want to paint the car again yet. We will see what the future brings.
A REAL professional is someone who knows when to hit it with a bigger hammer.