T-bars vs Stored energy

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draginmopars

draginmopars

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Location
Shady Hills, Florida
Our 70 Dart has original /6 torsion bars
Drag car

Want to change the rate of rise, in the front
The / bars seem dead.

this winter
we are installing heim joint tubular A arms
to get smoother movement of the arm
wonder while it is apart
change the bars to New 340 bars
or a used set (340) bars

I'll get the #'s off the bars later, to see what exactly they are

guess, we really need to weigh the car, it would help

small block,alum heads, intake
727
Dana 60
 
It would be easier to control the rise of the front end with good set of adjustable shocks.....we have Comp Eliminator 3 way shocks ..which I would not call GOOD shocks...LOL

We use both tubular A arms and adjustable strut rods...front ends have a lot of weight transfer...

two of the 3 cars have /6 t bars and the 71 Dart has 318 bars which i believe are 340 bars since the car came with AC...

What rear suspension are you using?
 
70aarcuda said:
It would be easier to control the rise of the front end with good set of adjustable shocks.....we have Comp Eliminator 3 way shocks ..which I would not call GOOD shocks...LOL

We use both tubular A arms and adjustable strut rods...front ends have a lot of weight transfer...

two of the 3 cars have /6 t bars and the 71 Dart has 318 bars which i believe are 340 bars since the car came with AC...

What rear suspension are you using?
Click to expand...

4.10 Dana 60- leaf springs
et pro with 10" wheel- 5" backspace

do also have a set of 318- with A/C bars

a new combo for us
It either hooks and hops or spins

fiber glass bumper,front/rear valance and fiber hood, fiber dash, alum bumper mounts
battery in rear.

449 smalll block
airwolf heads
air gap intake
to get weigh off the front

best et
6.84
1.51 60ft
99.5 mph



Yes, we have been reading about shocks,
still can't decided which ones
We have til 2nd week of feb. to decide
 
The adjustable strut rods Tony mentioned make a real big difference on freeing up the front end for quicker rise response. While your at it you might want to consider them.
 
Yes....lightening up the front end is nice...we got the glass hood...bumper...light weight brackets...plus Strange light weigh brakes too..big difference in weight if you got the 73+ disc brakes...but still lighter than any of the other mopar brakes..

What is your intent or goals for the car?
 
OldmanRick said:
My thoughts too???

The only way I could see getting "stored energy" out of the bars would be to compress them more at rest. I'd think the larger bars would counteract that?
Click to expand...

I understand that

It's that the front has lost over a inch in height
on the right side
since the beginning of the year
I noticed this recently

I really need some scales to see what is going on

front end is All new parts except t- bars

Is why i'm thinking they need a change
 
yes...the /6 bars will storage alot more "energy" than the bigger bar...

these photo show the /6 bar...
 

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here
watch the back of the car, and the head lights behind it

the rear tires come off the ground
then have to get out of it to recover

[ame]http://vid267.photobucket.com/albums/ii313/draginmopars/white%20dart%202/009.mp4[/ame]
 
70aarcuda said:
need long shocks on the rear......
Click to expand...


we have long shock

when we first built the car, lowered it
did not check the shock travel
found out first time out and fixed it.
( marker marks are > at rest and compressed)
now have over 6" of travel

005-1-3.jpg



then added another half spring to the pack,(SS spring) to reduce spring wrap
 
Is it not moving fast enough or too fast?

340 are the wrong direction in almost every case on a drag car.

If it's moving too fast, control it with a good adjustable shock. If too slow, you need to loosen up the front.

Hook and spin is a loading and unloading situation which also may directly related to proper shock control of your suspension. Tire pressure, ride height and a bunch of stuff can be the cause. Lots of times it's in the front of the car, which you appear to be addressing.

Watched video, looks like shocks are still too short... With the rear hanging, how much extra extension do you have? If it's not at least 2" get a longer set of shocks

Tires? If drag radials, put more air in them. I run 275/60 DR's at 20-24#. People think it's crazy, cars hook hard.
 
running 17lbs of tire pressure
has a little more than 2" / springs hangin

so, what you guys are saying is I need adjustable shocks.

I light just went off,

The shocks are to stiff??
slammin the tire , like a basket ball...
 
crackedback said:
Is it not moving fast enough or too fast?

340 are the wrong direction in almost every case on a drag car.

If it's moving too fast, control it with a good adjustable shock. If too slow, you need to loosen up the front.

Hook and spin is a loading and unloading situation which also may directly related to proper shock control of your suspension. Tire pressure, ride height and a bunch of stuff can be the cause. Lots of times it's in the front of the car, which you appear to be addressing.
Click to expand...

it's a 449 stuffed into a 340

have tried different rpm's
has a 4500 converter

can change to a 3500

My thoughts were to free the movement of the upper arm
when we built it with new stock bushing, didn't like the stiffness of movement of the arm

if it matters, ?
it also has rear sliders
 
draginmopars said:
running 17lbs of tire pressure

so, what you guys are saying is I need adjustable shocks.

I light just went off,

The shocks are to stiff??
slammin the tire , like a basket ball...
Click to expand...

I think they may be a little too "loose" on the hit myself? If you have enough tire, I'd try something closer to a 50/50 setting with the current setup? Then again, this car has some serious potential so that may not be enough for the cure.
 
OldmanRick said:
I think they may be a little too "loose" on the hit myself? If you have enough tire, I'd try something closer to a 50/50 setting with the current setup? Then again, this car has some serious potential so that may not be enough for the cure.
Click to expand...


on the tire deal

we started with 245/60-15 in 2013
then 275/60-15

nov 2013 stripped the car down
move the spring in
added narrowed Dana
and gear change from 4.56 to 4.10
and 10"wheels> ET pros


Still have the same problem

Getting off the line

have tried many rpm's
from idle to 4500

different tire pressure

even timing to kill the hit

What is strange is
the very first pass
it will hook and go
after that who knows

leave at 165*
runnin E85




Thanks everyone

I don't know what direction to go> front or back

That' why I come here for help

looks like i need to buy some adjustable shocks, for one thing

Which ones ??? lol
 
So it's not coming up fast enough.

The 340 comment was about the bars. I would not put 340 bars in it.

Have you cut the upper bump stops. If the car tops out on the stops,it will essentially KILL any further transfer.

Clamp the crap out of the front segments. Take all but one clamp off the rear

17# in a drag radial on that car is WAY too low. You're killing the sidewall. The sidewall rebounding and poor shock control are likely causing a lot of the issues with the hop as well.

SS springs, rancho 9 ways, 275's at 23#... 1.43-1.45 60's
My friends Cuda goes 1.40's with 275's at 20-22# It's goes 1.34-1.36 on a slick

This car went 1.47 with 20-22# IIRC.
http://www.forabodiesonly.com/mopar/showthread.php?t=122763
 
crackedback said:
The 340 comment was about the bars. I would not put 340 bars in it.

Have you cut the upper bump stops. If the car tops out on the stops,it will essentially KILL any further transfer.

17# in a drag radial on that car is WAY too low. You're killing the sidewall. The sidewall rebounding and poor shock control are likely causing a lot of the issues with the hop as well.

SS springs, rancho 9 ways, 275's at 23#... 1.43-1.45 60's
My friends Cuda goes 1.40's with 275's at 20-22# It's goes 1.34-1.36 on a slick
Click to expand...

thanks
do have another set of / bars can swap out
I really think the passenger side bar is shot.
when we tried 20-23psi all it did was spin

we could tell by slow mo vid, watching the painted on marks on the tire

I'll get some shocks and increase the tire psi,
have to wait til feb. (track opens) :burnout:
 
you don't want to put 340 bars in your car. It will only make it worse.

your saying 6cyl bars vs stored energy?

stored energy is what helps get the front end moving up for weight transfer. the 6cyl bars will give you more stored energy than all the others except maybe the Mopar Performance drag bars.

The way that works is like this.
the 6cyl bars are smaller than the 340 bars. this makes the "spring rate" less. when you install a t bar, you are locking one end down so that it can not move in a twisting motion. this is the end in the cross member. the other end can rotate and does when you turn the adjuster bolts and let the front end down to put weight on the lower control arm. so your bar is being twisted in the same way that you would wring out a wash cloth. say you installed 340 bars and counted the number of turns it took on the adjusters to get the car to the height you wanted in the front. now, if you were to install the softer 6cyl bars it would take more turns (twisting of the bar) to get the front end to that same height. what this does is put more tension in the bar by twisting it more. that makes stored energy that is going to help the front end get a "run and go" when you nail the throttle and the weight shifts rearward.

that's a long way of explaining it, but basically you want the bar that you have to twist more to get the ride height your after.

now, it makes no difference which end of the bar is in the cross member and which end is in the front suspension. It DOES matter which side the bars are on. you may already know that, but in case you don't, here goes.
looking at the end of the bars, they will be marked with a R or a L on them. the L is the driver side and the R is the passenger side. It matters because they are "pretwisted" from the factory, and if you have them in the wrong side they will be fighting against their natural direction. this could cause an issue with weight transfer as well.

You may already know every word of this post. I'm not trying to make you out to be a dummy, just putting it out there in case you don't know these things.

For what its worth, I have a 71 dart with 408 stroker on e85 with caltracs and 29.5x9 slicks. runs low 6.80's with 1.45-1.47 60ft times. I had a similar problem to yours after going to Caltracs and mono leaf springs. I leave at 3200 rpm on a transbrake. the only things I did to fix it was using a nickels worth of air gap on top of the rear leaf spring, and tighten my rear shocks up to 7 from 4 on the extension. Hooks hard now and those sixty ft times are with a 1.76 first geared Powerglide.

hope something here helps you.
 
whitepunkonnitro said:
It-needs a pinion snubber...really, it really is that simple.
Click to expand...

Tony, I do listen to what you say

with the truck dana, there is no provision for a snubber, let alone the floor sheet metal getting beat up


back in Aug, this year

built an adjustable snubber/ 1 1/4" threaded rod
so we could go to any setting

car would still hop
even if 0 clearance to 1"

looking back now
low tire pressure (17psi) may also be a problem

ykgu.jpg


kuu.jpg




crackedback-

ordered a full set of adjustable shocks last night
found out Rancho are now made by Calvert racing
 
IMO, Pinion snubber = door stop to let a breeze in the garage. I never use them, EVER. If the rear springs are good, clamped, it's an unnecessary item, a crutch. Low 10 and hi 9 second leaf spring A body cars... no pinion snubber in sight! :) You got your own data about whether they work.

The Calvert rear shocks are good. Make darn sure there is enough extension. Try to get video from the side concentrated on your rear tire. In almost every case with leaf sprung mopars, a car hopping like yours has too short of a shock on it and it can't control the rear axle movement. This is also where the importance of clamping the crap out of your front segments.

The rate of torsion bars thing. Another visual of the concept. Two springs, each 12 inch in height. One has a 100Lb rate, another with a 50lb rate. Take 100 lbs and set it on top of each. The 50lb spring will now be at 6" height, the 100 still at 12". What reaction would each spring have if the weight was knocked off? One is going to fly from the stored energy, the other, not so much... Same with putting a higher rate bar in your drag car. You want a bar that requires a lot of preload to sustain ride height.

If you can, cut the upper and lower bumps tops 3/8", drop the front down and set the ride height so the adjuster has just enough preload to stay in place at full extension, try it there. It may be in the weeds, but it should have around 5+ inches of travel. Front end travel is your friend!

There are a lot of ways to skin a cat. It's all about finding the approach that works best for you.
 
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