Six cylinder torsion bars with big block

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I bought brand new /6 bars for my drag race big block. I couldn't get them to hold the ride height so I swapped them for small block bars.
 
debate is good. sharing knowledge is good. experience teaches us, no doubt, some times the HARD way! LOL
remember when the factory designed these old cars, they we building a car to drive and handle on the streets/roads. ... purpose built drag cars?? the 68 hemi A was only a starting point for the pro racers.
SOooo, if your goal is 60 foot times, OR that and a car that is safe to drive on the windy roads. and have good 60 foot times, ????? like ya say, try both, and let us know what your opinion is.....
 
The xx/yy number are normally compression/rebound numbers; can;t say if these are real for this shock. Up front, the soft (low) rebound damping allows the front to rise quickly and the stiff (high) compression numbers slows the drop of the front end as you scoot down the track. The high compression number also fights diving and is probably keeping the front form dropping onto the stops. (But it is putting more load on the shock mounts.)

If you are primarily dragging, then the softer/smaller t-bars will result in better front end rise and give a bit more weight transfer to the rear. Makes all the sense in the world. If you are just dragging, then I can see how this works OK.

The stiffer rear springs will help reduce overall body roll, so that is helping you. Roll sitffness comes from ALL of the springs (both front and rear), plus any anti-sway bars front and rear. Since you are not doing any real cornering, the relatively poor distribution of roll stiffness (a lot in the rear and much less in the front) is not hurting you. On the road, it would likely be a more likley to spin out (lose the rear end) on gravel or wet, versus a car with better match of front and rear spring stiffness. But, you can make up for some of the F/R spring mismatch in cornering with a good front anti-sway bar and no rear anti-sway bar.

The larger/stiffer T-bars are NOT appropriate for all cases. Rough road handling is hurt by too stiff a spring, and moreso when the shock rates are anywhere close to properly matched to the spring rates; too stiff a spring & shock comob reduces the RATE of suspension travel and the AMOUNT of actually used travel; this reduces wheel compliance for bumpy surfaces and breaks cornering traction easily over bumpy surfaces. If the driver likes the really stiff stuff, then it is likely he/she is doing most driving on smoother surfaces. These are the reasons why offroad racing and rally cars don't use nearly as stiff a spring rate as road race, auto-x, or circle track cars.
 
I had a different problem with the /6 bars in my /6 duster ,I got up one morning and the car was leaning on the left front down ,this car only has 65000 miles garage keep for35 years with no rust. t-bar snapped in half sitting still ,replaced them with used 340 bars and couldn't believe the difference.
 
My original '69 Dart GTS 440 car had the big block bars under it, and it was no handling king, by any stretch of the imagination! I could not imagine running /6 torsion bars under that, and it was a restored, bone-stock "M"-code 440 car! At that same time, I had a stock '67 Dart GT with the 225/auto, with the stock bars. THAT, too, handled like crap until I upgraded to a set of big block bars that came extra with the 440 car. THEN, it handled like it should.

Six-cylinder bars under a big-block A-body??? No way in hell, thank you.
 
Doosterfy said:
One thing I never do is go on internet forms and call someone a dumass and/or post pictures I found on the net to further assert the name calling. It's stupid and immature to do so. I prefer to keep forums like this technical and not resort to school kid mud slinging. I have a good memory also and at some point you may be looking for info or a part that I have. I like helping people but will not help you or others like you.3
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if your going to quote me, at least make sure you interpreted right. I didn't call you a dumbass. I said your going to look back and think it to yourself, just as I did. Now put your big boy britches back on.
 
Ok this thread has me worried now did Mopar make a very sub standard front suspension that made all their cars a danger to drive? If so why were they allowed to be put on the road ! Let's look at this from a numbers poimt and I want real advice not you home grown bull **** opinion!

6 cyl bars are .830 diam / 100lb/inch rate

340 bars are .870 diam/ 120lb/inch rate

383 bars are .890 diam/ 130/inch rate

Now my bigblock is 500 lbs 25 more than the advertised weight of the 6 cyl! I am also. Running a glass pun on hood another 30 lb saving! I see no reason to run anything more than the 340 torsion bars on this car!! Any serious input and reasoning would be appreciated! This car will be street driven as if it was 1971!
 
I've been swapping 6 cyl. bars INTO all sorts of Mopars since the 70's, and would never consider any other way. Here's why.
The 6 cylinder bar has to be twisted tighter to maintain the weight of a Big Block or Hemi at normal ride height. When you hit the gas, that extra stored energy in the bar will spring the front end higher the instant torque is applied to the rear axle. The difference in traction is night and day. A lot of cars with thicker bars will bite at the hit, and then break traction right after the snubber finishes its upward movement. Getting the nose up quicker will make a seamless transition between the hit and full weight transfer.
Bottom line is that any big block A body is a handling travesty...if you want something glued to the curves build an aluminum headed SB, or even a Slant (I don't care how much horsepower you've got...a well tuned Slant will eat you alive in the curves. A BB A Body is a DRAG RACING package. Treat it as such.
 
It is another myth. I have several friends that run mid 9's and drive on the street with BB and Slant 6 Bars. You are right.... A lot of what is said on here is all BS Repeat stuff from people that don't do anything but type on their keyboard and repeat what they have heard! Sad but true. I have learned to listen to the guys that actually do the stuff not talk about it.

YB.com is best for out of the box thinking with Radical results. You can do deep searches and find just about anything from people that actually put it to the test.

If you change the bars you will slow the car down is my guess. The car will not transfer the weight as well as the 6 bars do.
 
I don't think anyone says six cyl bars don't work with a big block. Just isn't advised for a car that's is mostly a street car. The six cyl bars are good for the track but that's about it.

I've done the 440 into an abody swap numerous times. Used six cyl bars at first. Yes it ran and drove on the street. Wasn't dangerous as long as you drove it like a drag car. Mostly straight line and taking it real easy in turns.

Then I put a 383 bar in the car. What a world of difference on the street. I won't ever us six cyl bars again unless it's a pure track car.

Hell. I just did a disc brake swap on the wife's slant six dart. I added 1" bars while at it. Holy crap. The improvement was amazing. Like someone stated already. Slant six bars aren't even good on a slant six car. :)
 
I drove my BB Dart back and forth to work, when I lived in SoCal. /6 BB is for straight line applications, and works on the street. If your building a car for handling don't use them. here is a video of my old car.

[ame]http://youtu.be/Wg-z2JM6jms[/ame]
 
Thank you for the info. i am asking about Weight. Were all your big block cars heavy with cast iron parts? i am only asking because i am down to small block weight so i am thinking the 6 bars or the 340 bars will be more than enough. This is physics based on weight isnt it?
 
Ok i was able to speak to a local Mopar guy and he said To run the V8 340 bars and be done with it. The car wont do well if i have to dive it..
 
WOW!
This is one very divided thread on what people like and how they like driving there rides.
 
whitepunkonnitro said:
I've been swapping 6 cyl. bars INTO all sorts of Mopars since the 70's, and would never consider any other way. Here's why. The 6 cylinder bar has to be twisted tighter to maintain the weight of a Big Block or Hemi at normal ride height. When you hit the gas, that extra stored energy in the bar will spring the front end higher the instant torque is applied to the rear axle.
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Actually 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.
 
Fisher said:
Ok this thread has me worried now did Mopar make a very sub standard front suspension that made all their cars a danger to drive? If so why were they allowed to be put on the road ! Let's look at this from a numbers poimt and I want real advice not you home grown bull **** opinion! 6 cyl bars are .830 diam / 100lb/inch rate 340 bars are .870 diam/ 120lb/inch rate 383 bars are .890 diam/ 130/inch rate Now my bigblock is 500 lbs 25 more than the advertised weight of the 6 cyl! I am also. Running a glass pun on hood another 30 lb saving! I see no reason to run anything more than the 340 torsion bars on this car!! Any serious input and reasoning would be appreciated! This car will be street driven as if it was 1971!
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The lighter bars have to twist more to support the same amount of weight. In the world of materials science, this greater twist for a given load results in a high level of what is termed 'strain' in the material. Higher strain levels fatigues parts more and distorts them more. So, there is some truth to the lighter bars being more prone to sagging and breaking. BUT, on the other hand a T-bar is a spring like any other spring. (In fact, a coil spring is just a t-bar in a sprial shape....) Strain exists in all springs: broken leafs and coils are not at all unusual.

No, the Mopar suspension is not substandard. In fact F1 cars went to T-bars some years back! Don't sweat that part.

The selection of spring rate in any car depends on weight AND application. The use of the 1.12" diameter T-bar is for a specific handling use. The application depends on what you want. I live in the rural Appalachians, and rally is my motorsport 'fix'. I would not have any use for the 1.12" T-bar on the local roads here (very bumpy in spots, and lots of sudden camber changes that require a lot of suspension travel to maintain traction). Ditto for rally use.

So you need to look at your roads and your intended use to decide. BTW, the standards of 'good' handling have increased somewhat from 1971!
 
nm9stheham said:
The lighter bars have to twist more to support the same amount of weight. In the world of materials science, this greater twist for a given load results in a high level of what is termed 'strain' in the material. Higher strain levels fatigues parts more and distorts them more. So, there is some truth to the lighter bars being more prone to sagging and breaking. BUT, on the other hand a T-bar is a spring like any other spring. (In fact, a coil spring is just a t-bar in a sprial shape....) Strain exists in all springs: broken leafs and coils are not at all unusual.

No, the Mopar suspension is not substandard. In fact F1 cars went to T-bars some years back! Don't sweat that part.

The selection of spring rate in any car depends on weight AND application. The use of the 1.12" diameter T-bar is for a specific handling use. The application depends on what you want. I live in the rural Appalachians, and rally is my motorsport 'fix'. I would not have any use for the 1.12" T-bar on the local roads here (very bumpy in spots, and lots of sudden camber changes that require a lot of suspension travel to maintain traction). Ditto for rally use.

So you need to look at your roads and your intended use to decide. BTW, the standards of 'good' handling have increased somewhat from 1971!
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Exactly. The weight of the bigblock is now equal or less than an all steel small block so i will be going with the 340 bars. I have no dreams of this duster handling like anything other than a 71 duster. Its not a corner carver, its an old school street car with a few upgrades end of story. Spring rate on any car has always been determined by weight. I have been playing with brand x for so long, this mopar stuff is all new to me.
 
RaniDart70 said:
Too many people use bigger brakes and so called upgrades to compensate for lack of driving skill. Just know your car inside out and backwards and don't try to drive it like a Ferrari that its not and you will be fine. I have driven slant six drums in Denver traffic and I found that when you pay attention, you wont run into anything.
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Driving skill and paying attention only goes so far. You can't change the physics. Big brakes don't make up for lack of driving skill. They shorten your stopping distance. Mario Andretti can't make a 9" drum equipped car stop faster than the same car with 13" rotors. You're just on the wrong side of the math.

Maybe you've been lucky enough not to experience it yet, and maybe you'll be lucky enough to never experience it, but you can have an accident while you're driving within your cars capabilities while you're paying attention. Things can always happen that are beyond your control. And when they happen, I don't want to be in a /6 torsion bar suspended car with 9" brakes, because I want to have options.

It's a free country, and you can do what you like. But don't think for a second that any amount of driving skill can change the laws of physics. The best driver in an inadequate car can only be as good as the inadequate car, no matter how much attention he or she pays or how well they "know" their car. The better your car performs, the bigger the margin is for you to deal with the unknown. It's just that simple.
 
I have the slant bars on my cuda with 440/glide, no inner fenders, batteries in the trunk, alum heads/intake etc etc. I am putting the car on the street after being a track car for the last 20 plus years, I am sure that during that time it has sat on the bars/springs at least 98% of the time since back when new in 1967, they are old and Im sure fairly dead by now. I have put a front sway bar on mainly cause I got a good deal on it and to help stabalize the front for street and I will NOT be driving crazy on the street, too old for all that fancy road race driving. Since these bars are antiques I am going to go ahead and change them out but instead of bigger bars I am going with coil overs, not for any type performance gain but rather just because I can and will look cool.
For my type of street driving Im sure a decent shape set of slant 6 bars would be just fine.
 
nm9stheham said:
Actually 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.
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Stupidest thing I ever read. Want the facts? Read the Mopar Suspension manual.
 
I'm guessing that you've never felt the bumpers hit because you are sitting on them. That would make them feel adequate because the bars wouldn't be doing anything...
 
Jim Lusk said:
I'm guessing that you've never felt the bumpers hit because you are sitting on them. That would make them feel adequate because the bars wouldn't be doing anything...
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No, it is not sitting on the bumpers. I have seen the gap. When I first intalled the big block A-518 combo the t-bar jacking bolts were where they were with the S/6. The front end was too low. I turned the ja king bolts to raise the ride height to where I wanted it. There is without a doubt space between the bumper and control arm. Besides if I were driving around on the bumpers it would be obvious. No way I'm not going to feel that. I can't look at it now, the car is in storage over an hour's drive away but just by memory I'd say the gap is about 3/4 to 1 inch.
 
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