Jim Lusk
Well-Known Member
Then, if it's not diving the shocks are preventing it...
Six cylinder torsion bars with big block
- Thread starter Doosterfy
- Start date
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ssba
Well-Known Member
Drivers difference of opinion on what is a acceptable performance from their suspension is more of what seems to be argumented here to death.
I myself think you should build your car for how you want to drive it.
I am using 6 cylinder bars on two of my a-bodies for the quickness they can unload.
On another I will use a larger bar to have better control thru a turn.
I personally feel the brakes are much more of a safety issue than the springs
on our choice of classic car. I have cars from the 50s and older that are better
at stopping than our loved a-body with drum brakes.
I don't have a problem with the original poster sharing his experience and
I agree with his information. Some people are trying to over drive their cars.
When you push a car past its limits bad things happen. Plymouth Valiant
or Dodge Viper.
I myself think you should build your car for how you want to drive it.
I am using 6 cylinder bars on two of my a-bodies for the quickness they can unload.
On another I will use a larger bar to have better control thru a turn.
I personally feel the brakes are much more of a safety issue than the springs
on our choice of classic car. I have cars from the 50s and older that are better
at stopping than our loved a-body with drum brakes.
I don't have a problem with the original poster sharing his experience and
I agree with his information. Some people are trying to over drive their cars.
When you push a car past its limits bad things happen. Plymouth Valiant
or Dodge Viper.
nm9stheham
Well-Known Member
IMO, getting good info out here is what is important. Regardless of what any book says, be prepared to work with facts and laws of physics. The stored energy in any loaded spring is directly proportional to the weight put on it. If the weight is the same, the stored energy is the same. Lemme know if this does not make sense or what the issue is here. Or is the issue with the working with the 90/10 type of shocks? Again, asking not arguing; I am open to learn, RRR. Let us know what the book syas on this matter.Originally Posted by nm9sthehamActually there is no extra energy stored vs a thicker bar; stored energy is the same for both. The large upward motion from the /6 bar is caused by it having to untwist more to release the same amount of energy. The lighter bar also works better with a low rebound rate shock. Stupidest thing I ever read. Want the facts? Read the Mopar Suspension manual.
moper
Well-Known Member
Think of it this way... and I'm just sticking in numbers for degrees so don't flail me...lol
A car is 3500lbs and has a 58/42 weight bias. That means each front tire has 980lbs on it. It takes the same amount of energy to hold 980lbs. You have to twist a slant 6 bar 75° to get the bar to support that 980 lbs and you have to twist the BB bar 30°. The required preload is more, but the stored energy in ttoal is the same.
Similar to valve springs that have the same installed height but stiffer spring rates. A T bar get's it's rate from the diameter and material.
I think it all comes down to personal preference and capability. I've had my '65 sliding sideways taking an offramp at almost three times the speed limit. It's got slant 6 bars, tall stock sidewall 14" tires, no power steering, no sway bar, no fancy shocks, and drum brakes. Once it's on the bump stops the only thing is the tires anyway. I've been cut off and had to zig or zag quickly - if you're paying attention the car will do much more than you think it can. I've also driven 11" wide Goodyear slicks in the rain on my street car which has a magic all it's own...lol. I daily drive an old neon because it can handle so much better but it's designed to. None of these muscle cars really were designed for turning and stopping. I'll also say Mario Andrretti could safely stop a 9" drum car faster tham most with a muscle car and 13" rotors. Most drivers of these old cars have precious few skills at really aggressive driving and I think the feeling of more stability is worth more to them because they wouldn't ever push the car to it's limits.
Fisher
Old Guy with a Cool car.
Good Post Moper
Jim Lusk
Well-Known Member
Actually a lot of these old Mopars were built to handle. That's what the Formula S was all about...
nm9stheham
Well-Known Member
Well this has all been of great benefit to me. I had something better to think about than "Will the novacaine work?" while the dentist was drilling out two holes in my teeth this afternoon. Some more thinking while there also prompted me to go back to the books, and I found I was flat out wrong.
The energy stored in a spring is 1/2*k*x^2, where k is the spring constant, and x is the distance moved or (angle moved in the case of a T-bar). So if you cut the spring rate in half and the motion doubles as a result to hold the same weight, there is a net doubling of stored energy. (It is not intuitive, but it all works that waysince the energy stored is an integral of force over distance. THAT part I understand.)
So my apologies to whitepunkonitro, and my further thanks (in an odd way) to RRR for kicking me in the a** over it!
'splains better why the /6 springs are good for getting the front up in the air when launching.
The energy stored in a spring is 1/2*k*x^2, where k is the spring constant, and x is the distance moved or (angle moved in the case of a T-bar). So if you cut the spring rate in half and the motion doubles as a result to hold the same weight, there is a net doubling of stored energy. (It is not intuitive, but it all works that waysince the energy stored is an integral of force over distance. THAT part I understand.)
So my apologies to whitepunkonitro, and my further thanks (in an odd way) to RRR for kicking me in the a** over it!
'splains better why the /6 springs are good for getting the front up in the air when launching.
Doosterfy
Well-Known Member
Ad
I'm not actually getting a whole lot of front end rise on launch. Go to my YouTube channel and see the videos. The channel uses the same name I use on here, Doosterfy. Regardless of the amount of rise at launch, the car does not spin at all, the tires are glued to the track. It's by far the best car I have ever drag raced.
moper
Well-Known Member
Thanks for setting me straight too, RRR and nm9. That's not how I understood it either.
Fisher
Old Guy with a Cool car.
Lots of food for thought in this thread!
ir3333
Well-Known Member
oh my!
i installed new .890 bars in a 340 dart and they were oozy.
..disc brakes,sway bar and .920 torsion bars... minimum for a sm blk. A body.
sooner or later you will have to react to something unplanned.
i installed new .890 bars in a 340 dart and they were oozy.
..disc brakes,sway bar and .920 torsion bars... minimum for a sm blk. A body.
sooner or later you will have to react to something unplanned.
all I know is other morning (5 a.m.) another friggin deer steps out in front of me.... in the old 95 ram 3500 cummins.... ( fortunately NOT in the 72 slant dart, 9 in driums)..... I stand on the brakes, swerve at last minute..... corner of bumper clips her a-- in, just hair on it this time......
NOW, back to the program....................
NOW, back to the program....................
Fisher
Old Guy with a Cool car.
I think if the car needed .920 bars Chrysler engineers would of installed them from factory?
abodyjoe
Well-Known Member
40 years ago they didn't know any better. they handled great for the time.. its now 2014 and there are far better choices out there over 9" drums and slant six bars.
again.. if its a drag car then yes put 6cyl bars in it.. a street car that only sees 45mph arounds town sure you can get away with 6cyl bars. but if you really like driving the car.. take multi hour trips on the highway and stuff like that you will want bigger bars... the drive will be light years more enjoyable..
Fisher
Old Guy with a Cool car.
I agree with you.
Jim Lusk
Well-Known Member
I don't think it was so much not knowing any better, it was the expectation of the customer as well the available shocks and tires. HP Mopars got better suspension than the low perf ones, for a reason.
moper
Well-Known Member
I would agree - it had nothing to do with "knowing better". Citroen used torsion bars and unibody construction in the 30s. Chrysler introduced them in the late 50s. So it had to do with the consumer at the time who had coils sprung full-frame GMs and Fords to choose from and the torsion bar suspension was a far better, lighter, and responsive setup. Compare that to a FWD platform from the 80s that could out-handle and out-brake even the best factory torsion bar setups. Then compare the 80s FWD to a 2015 vehicle. Even the base models of anybody can handle and stop well. My GF's Santa Fe has a front sway bar larger than I can even buy for any of my Mopars and it's got progressive springs and struts that are all improvements over the old stuff. That's what the modern car freak drives every day. Jumping from something modern to a 50 year old car comes with some acceptance that they are nothing alike in capability.
famous bob
mopar misfit
hell. I can`t even spell it! read most all of the posts on this. Back in the day, I bought my first new car, a 68 form S 383 fastback in tulsa,ok. drove it around for a day and took off for the air base late sat. evening. very low miles on the car, (long post) out ran a camero ( called "the hugger " in gm`s tv adds, and also a v w thru the ozark mnts., they both faded in my mirror after I past them. the v w was fading behind me, the camero was last. later on, the mopar mech that taught me most of what I now, and myself put a 68 r.runner hemi in my 66 belvedere, we left the 318 torshion bars in it. had to raise them a little for the extra iron headed hemi. car handled normal, and worked real well on the drag strip. and like rustyratrod said, if u read the chrysler drag racing manual,
318 bars are recommended for drag racing. of course back then, every stop light was a drag race, and road manners seemed ok! ( I was 21). and there is more stored energy in a bar that is twisted more than one that is not twisted as much:the car still has those 318 bars under it today, my mech. buddy owns it.-------bob
mguner
How many is too many?
Both of these cars were origonal slant cars. Both are running 440s in these photos. Both were street driven frequently and never changed the torsion bars. They were not corner queens by any stretch but the 6 cyl bars worked well for suspension travel and weight transfer. The 6 cyl bars were at their limits and ride height could not be changed much.
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You always need to look at the intended usage. If you are drag racing, doing everything to zero in on that purpose, will put you on a trailer as it will not be cost effective to run it on the street. Same for a road race car. And anyone who does not think an experienced driver can't spank you at the track, good luck with that. A friend of mine, driving an 80's Corvette, had his clock cleaned by a guy driving a Chrysler Minivan. Another good friend was lapping Porsches with a 4th generation Mustang at Summit point. The hardest car to build is a daily driven street car. Each of us has certain criteria not necessarily the same as the next person. I love a real good handling car. I want it to start up and drive all day for 2 days straight from Stinking Maryland to South Dakota. I want to beat 90% of the cars I encounter in the corners and straight line on the street. I want decent mileage and have found that I can have all that. Formula S Barracuda's handle well, even with all the original springs, torsion bars and sway bars. All bushings, ball joints, arms, tie rod ends, and manual steering chucks are up to snuff. Let's not forget good shocks and tires. I would never consider running /6 torsion bars for what I like. If I wanted a limited street, more of a strip car, that would be a different consideration. I've seen "theoretical" arguments but in reality, experience is more worthwhile. I have a 96 ACR neon that handles amazing, but I have no "transition" when I get in the 66 Formula S or the 68 383 Formula S, except at low speed with the 16:1 manual box. Performance is not cheap, get the good stuff and build to what you want. If you find you want something different, you can always change things easily on our old cars. Most of have done that for decades.
MopaR&D
Nerd Member
This thread is entertaining really brings out the drag racers vs. the corner carvers lol. Like has been mentioned building a car for drag racing is counterproductive to having a good street car. When you are drag racing you WANT the front end to lift up as much as possible at launch so the soft bars are good. But if you like driving 80 MPH on I-70 through the Rockies you don't want the front end to move at all! I have the 1" bars in my Duster with an iron 360 and I love them but when I went to the strip it was obvious having softer springs in the front would have improved my weight transfer and launch. Would I change them out? No because I like handling MUCH more!
Dusterfly: you mentioned being used to big-block GM intermediates handling like crap compared to your /6-sprung BB A-body Mopar. Truth be told GM cars had some of the worst designed suspensions of the muscle-car era and this is outlined in a recent book I bought "How to Make Your Muscle Car Handle" by Mark Savitske. It's kinda funny the section on improving GM cars is like 3x that of the Mopar section and most of it is going into detail basically saying that you can't make a GM car handle worth sh** without getting expensive aftermarket parts like spindles and A-arms. He also says outright Mopars can be made to handle very well with minor changes. The geometry on Mopars was much better (more similar to a modern car) but from the factory they were so undersprung with tiny worthless sway bars (or none at all) so they gained a reputation for being bad handlers anyway.
Dusterfly: you mentioned being used to big-block GM intermediates handling like crap compared to your /6-sprung BB A-body Mopar. Truth be told GM cars had some of the worst designed suspensions of the muscle-car era and this is outlined in a recent book I bought "How to Make Your Muscle Car Handle" by Mark Savitske. It's kinda funny the section on improving GM cars is like 3x that of the Mopar section and most of it is going into detail basically saying that you can't make a GM car handle worth sh** without getting expensive aftermarket parts like spindles and A-arms. He also says outright Mopars can be made to handle very well with minor changes. The geometry on Mopars was much better (more similar to a modern car) but from the factory they were so undersprung with tiny worthless sway bars (or none at all) so they gained a reputation for being bad handlers anyway.
I'm not saying your car doesn't ride fine. As long as you like it, that's all that matters. However, I would not be trying to pass said advise on to others. You've done alot and spent a lot to lighten the front of your car, not everyone will or can. There's also a lot, i mean a lot of data to support going to bigger T-bars, including computer support data loggers.
Now, I will say from my experience, the slant 6 bars are fine for straight line. I've got a buddy with a 451 with indy heads stuffed into a 68 cuda, he's still running slant 6 bars, with the adjusters fully in just to get the ride heighth to be high enough to clear his factory size front tires when turning. Its a drag car only so it only sees the strip but I can say this, I've driven it around the block a few times, thing plowed the front end badly. Not enough to wreck or be unsafe but it drove like my 89 cummins 2wd with that heavy 1200lb cummins over the front wheels. Not a feeling I'd want for a car.
MopaR&D
Nerd Member
I watched a couple of your videos, indeed your car is lifting in the front just like it's supposed to with the small t-bars. Looks great, car seems to act just like you'd want it to in launch :thumblef:
-Sledgehammer-
Mopar Performance
I have a pair of /6 bars for sale if anyone interested.
the67fish
Well-Known Member
I have a ton of preload dialed into the left front just to keep it level on launch, 70% of the weight is on the front to keep lift at a minimum, travel limiters at about 2 inches, still would do wheelies with that convertor in it. A level launch with wheels on the ground would be best, if its going up its not as much going forward, slows the car down but hey, the pictures look good over the fireplace !!!
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