Torsion bars for stock suspension rebuild

-
R

Rocket

FABO Gold Member
FABO Gold Member
Joined
Apr 22, 2005
Messages
2,995
Reaction score
962
Location
CT
I am rebuilding my 69 Barrracuda front suspension and have noticed that most of the advertised torsion bars (Mopar Performance, Just Suspension, ...) are selling replacement bars that are thicker in diameter that the originals. Most are 0.92. Has anyone had experience with the thicker bars? Is the ride to firm? What shocks work best with the new bars? I am rebuilding the suspension to stock as a week-end curise and show car.

Thanks
 
The.920's will be stiffer, I would stay with the original bars unless you want a firmer ride. Not knowing what is in your 69 cuda engine and suspension wise i would guess you have .870 bars and those are available. I have .890 bars (heavy duty suspension) in my 67 with KYB gas shocks and a aftermarket antiswaybar and the ride is very firm. If you are trying to keep to the stock ride use Monroe or Gabriel gas shocks. mancini racing (www.maniciniracing.com) has the .870,.890 and .920 bars for $140.
 
Sorry about forgetting the engine info. The car is a 340 4 speed Formula S.
 
Go for the .890's and a swaybar, that will make for a good street car.
 
I just pulled a pair of bars from a '69 383 dart (.89). I was going to take them to our local swap in the spring but if your interested you can send me an email [email protected].
 
JLP - Define "very firm":bounce:

I'm planning a complete suspension overhaul on my 75 Dart Sport, and I want to give it much improved handling for the street, without turning it into a haywagon ride. It's originally a 318 car (no sway) and I am looking at doing a total rebuild with either .92 or .89 bars. I'm thinking the .89 set should hold up the front end very well with just a smallblock in it. Any thoughts?

Also what brand of sway bar do you have? I'm looking at Hellwig and Addco. I like the Firm Feels, but they are more of a race bar, and this is a street car (read:waste of money).
 
Very little suspension travel, almost no leaning in the corners. I have Quickor 1.25" front and 3/4" rear, probably more than is needed for the street but damn it handles like a slot car. Either Hellwig or Addco bars are fine. do you plan on doing a rear bar. If you do and buy a 1 1/8" for the front only get a 5/8" for the rear or you will have tire lift in tight corners. The .890's should be just fine, gives a firmer ride then stock and let you keep you teeth. Shocks make a big difference also, I am using the KYB's and love them. I have been running them on my A bodies for years. I also have poly bushings every where. My car was built to handle.
 
When I rebuilt the suspension (and did the disk brake swap) in my 68 Barracuda I still had the \6 in it. Because I was planning a small block swap I went up one size from the small block heavy duty bar (.870) to the big block .890 bar. Even with the slant 6 the .890 bar still road well and made a dramatic improvement in the handling. Now with the small block in the car I did not detect any degradation in the handling.

BTW the car has the heavy duty 6 leaf springs in the back, KYB Gas-A-Just shocks and no sway bars. I have asked Santa for sway bars for X-mas and I will also be going to power steering with a Firm Feel quick ratio box.
 
Thanx for the info guys..

I don't understand the tire lift though. Isn't that whole point of sway bars, keeping tires planted by distributing weight more evenly? Or is it a matter of the rear sway not having ENOUGH give if it's too big?

I already put HD leafs in the back with poly rear bushings and KYBs. The ride is an "experience" to say the least. The front wallows, plows and wanders thanks to everything being worn out, but the back is solid....a VERY odd feeling.....

KYBs are also going in the front, and I'm removing my power steering in favor of a manual box. I'm sticking to rubber bushings. I hear alot of complaints that it transfers a lot of vibration & shock through the car.
 
Sway bars tie the two sides of the car together so the suspension can't move independantly of each other. When you turn into a corner the outside supension compresses and the inside wants to un load i.e., body roll. The sway bar will resist the tendancy of the inside to un load and the body to roll.

Your car now has a lot of understeer, that is it wants to plow in a corner to the out side of the turn. Adding a front swaybar reduces the understeer. One that is to big will actually cause the car to go into an oversteer condition or the tendancy for the back end to spin out. Adding a rear bar tends to push the car back towards an understeer condition.

Why do you want to go to manual steering? My Barracuda has manual steering and when it had a \6 it was manageable but now with the 360 it's a bear at slow speeds plus it takes so much input that it will never be quick through transition type maneuvers. I have all the parts to swap to power this winter. I am rebuildding the steering box with Firm Feel's quick ratio guts so I will have a car that steers like a new car with decent feedback and minmimal turns lock to lock.

FWIW, I rebuilt my front end with polygraphite bushings every where but the lower control arms. I got no appreciable improvement in the handling, no noticeable increase in harshness/vibration but within a couple of months the front end started squeaking like an old bed spring. I switch back to rubber when I swapped in the 360.
 
Various reasons on the steering: The power box (well, pump) is WAY to powerful.....I don't like being able to drive with 1 finger!!!
Did Mopar make a different pump that would allow me to get increased resistance?

plus it takes so much input that it will never be quick through transition type maneuvers
Click to expand...

Are you implying the range of motion necessary? or the amount of force (strength) needed to move it? I thought the base gear ratio was the same?

My power unit has a bit of slop in it, but it does react pretty quick, so it's good in that respect. I wouldn't mind keeping it if I can increase the feedback/resistance.

I have some time in my dads '70 340 Swinger with no power options, and I liked it. I am use to driving M35 & M109 military cargo trucks with no power steering..so this is no big deal.....

I already have a new (?) manual box in the garage, but I'm sure I can get my $$ out of it if I stay with a power unit.
 
The reason I am rebuilding my box with a Firm Feel fast ratio internals is to get the feel a modern power steering system has.

Parking lot manuvering is a real chore with manual steering. A speed the effort to steer is not bad but it requires so much motion of the wheel you just can't move it fast enough for quick transition manuevers. There is a fast ratio manual box or a long pitman arm to spped up the steering but that will only make the parking lot manuevers that much more of a chore.
 
dgc333 said:
Your car now has a lot of understeer, that is it wants to plow in a corner to the out side of the turn. Adding a front swaybar reduces the understeer. One that is to big will actually cause the car to go into an oversteer condition or the tendancy for the back end to spin out. Adding a rear bar tends to push the car back towards an understeer condition.
Click to expand...
This is backwards. Adding a front bar, or increasing the stiffness of a front bar increases understeer. Adding a rear bar, or increasing the stiffness of a rear bar increases oversteer. Don't take my word for it... SCCA handling chart

My advice, get a good book (or three) on automotive suspension and handling. Don't guess at what parts to use. Just like building a good engine, the parts used must work together in order to acheive the desired results.

superdart, in your case I would get the .890 T bars and rebuild the rest of the front end. Get the best adjustable shocks you can afford. And then do some tuning and see how the car handles. If you still have too much body lean, go for the sway bars. But size them according to your oversteer/understeer requirements. Typically on a street car you want a slight amount of understeer that transitions to oversteer when more power is applied.
 
Gee Greg!
That page is contradictory. It states increasing front roll stiffness will increase understeer or it will decrease understeer, see the quote from the page.

"Front roll resistance increases, increasing understeer or decreasing oversteer. May also reduce camber change, allowing better tire contact patch compliance with the road surface, reducing understeer."

My experience has been putting a sway bar on a car that doesn't have one is that will decrease understeer likely for the reason in the second sentance of the quote.
 
dgc333 said:
Gee Greg!
That page is contradictory. It states increasing front roll stiffness will increase understeer or it will decrease understeer, see the quote from the page.

"Front roll resistance increases, increasing understeer or decreasing oversteer. May also reduce camber change, allowing better tire contact patch compliance with the road surface, reducing understeer."

My experience has been putting a sway bar on a car that doesn't have one is that will decrease understeer likely for the reason in the second sentance of the quote.
Click to expand...
It is the reduction of camber change that 'may' reduce understeer. This is completely dependant on the cars front suspension geometry. If the outside tire in a turn folds over onto the sidewall, then of course it's going to push. The swar bar can eliminate some of that tendancy because it lessens the up/down travel of the front wheels thereby reducing the camber change. However, the purpose of the sway bar is to control weight transfer, not front tire camber.
 
Well you can learn something new every day! :)

I had always believed that increasing the front roll stiffness reduced understeer.
 
Having the rear bar stiffer then the front causes the inside rear tire to lift in a tight corner under hard acceleration. I have had this happen. Replaced bar one more matched to the front bar and that solved the problem. The way mine is setup now they were purchased as a matched set for my application.
 
Well, I already have the .89 bars on order from the dealer. Should be here in a few days.

Now I am wondering if I should bother with the manual box?? I need to decide before I buy the steering column adapter. Also, Firm Feels states the log pitman arms do not play well with headers (I have comp headers..so that's out).
 
My suggestion is to talk to a good alignment shop about what you want out of your car and the options you are comtemplating. An excellent book by Tom Condran called,"Performance Handling For Classic Mopars," is still available @ A.C.M.E Mail Order
PO Box 282612
San Francisco, CA. 94128-2612
Met him @ the Spring Round-Up in Seattle in '99, read the book, and then mulled ideas over w/Mike and Jerry at Burien Frame. NO regrets, no complaints :salut:
 
You must log in or register to reply here.
-

Back
Top