How much difference will it make?

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Clelan

Clelan

Inferno Red Duster
FABO Gold Member
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Martensville Sask. Can.
I kinda think I know the answer, but thinking I know usually bites me in the ***. When I set my suspension up initially I had never drag raced and did not have that in mind.
I have 1.03" torsion bars up front, 1-7/8" front sway bar, 7/8" rear sway bar and Bilstien RCD shocks. I have 002/003 Super Stock springs out back.
My drivetrain consists of a 318 with Summit K6901 cam, Performer 318/360 intake, 750 DP carb from QFT, Headers and full dual 2.5" exhaust. I run an A-500 OD auto with an 8-3/4" rear (4.10 sg).
The car is a 74 Duster, at least 3200 lbs with 275-60-15 Nitto NT555R drag radials. I tried the tires at 20 psi and at 18 psi and found no difference.
I spin off the line regardless how I launch it. I tried getting up on the converter against the foot brake as much as possible (maybe 2300), it tried 1500, I tried from idle and it always spins. 60' times from 2.2 to 2.3.
Where should I start? I am thinking shocks first. I know the rear A body length shocks are a problem with the SS springs. Do I need to ditch my sway bars and heavy torsion bars? I really like how it handles as is but out here In the prairies there are no canyon roads to speak of.
Thoughts?

Cley
20210601_111215.jpg
 
I'm no drag racer, but my gut says your rear gear at 4.10 is too much, taller tires or smaller gear.
 
I would unhook the sway bars. They will restrict suspension movement.

Note: suspension movement is what makes the Super Stock springs work
 
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Unhook the front sway bar, leave the rear. Get the front end to move as free
As possible and that might include different torsion bars and almost certainly shocks. Then get a good double adjustable rear shock, and start tuning. Take way too many notes, on every pass. Make one change at a time and compare.
 
I'm more of a autox / wannabe road race guy. So your question about the Torsion Bars is yeah my understanding the trick is you are going to want to back to the original v-8 bars or even get a set of slant 6 torsion bars if you want to drag race it. The reason being the 1.03's are thicker and keeps things planted on the front weight of the car. The slant 6 bars are thinner/smaller and will lift / shift the weight load on the back tires getting you more traction...
 
Handling mods like you have are on the opposite end of the spectrum when compared to drag racing. Leaning one way compromises the effectiveness in the other.
Not only do sway bars limit weight transfer, the torsion bars do too. Thinner bars actually store energy because they are twisted more and will "unwind" more and easily. Lots of shock options including single & double adjustables that can help control what the front and rear suspensions do. SS springs are naturally good for drag racing, but are restricted by the rest of your set-up.

Optimal hook will still take a lot of tuning. No easy answer for the street or strip because each car set-up is differnt, including engine, trans, gears, weight, etc.
 
TT5.9mag said:
Unhook the front sway bar, leave the rear. Get the front end to move as free
As possible and that might include different torsion bars and almost certainly shocks. Then get a good double adjustable rear shock, and start tuning. Take way too many notes, on every pass. Make one change at a time and compare.
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Sorry for the red X. I very rarely use the X but what you said is all wrong. Superstock springs are designed to move because they unload and plant the rear end onto the track. Restricting rear axle movement is opposite of how they work.
 
I guess I'll start with some shocks. Double adjustable are fairly expensive, maybe I'll bite the bullet!

Cley
 
89on35s said:
They just have whatever came on them when I bought them from Mopar Performance years ago.

Cley
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You can unclamp the rear of the springs and use the rear clamp on the front to free up some rear movement.

toolmanmike said:
Sorry for the red X. I very rarely use the X but what you said is all wrong. Superstick springs because they unload and plant the rear end onto the track. Restricting rear axle movement is opposite of how they work.
Click to expand...
I don’t have a problem with the red x at all as long as you explain why. The rear sway bar can be a tuning aid and on some cars helps a bunch. Maybe not on a 13 sec car but on a 7 second car it will. Also they can keep the car launching straight. Since he has it my recommendation is to make sure it doesn’t limit travel in any way and use it. Put adjustable end links on it and tune with em.
 
TT5.9mag said:
You can unclamp the rear of the springs and use the rear clamp on the front to free up some rear movement.


I don’t have a problem with the red x at all as long as you explain why. The rear sway bar can be a tuning aid and on some cars helps a bunch. Maybe not on a 13 sec car but on a 7 second car it will. Also they can keep the car launching straight. Since he has it my recommendation is to make sure it doesn’t limit travel in any way and use it. Put adjustable end links on it and tune with em.
Click to expand...
Still a NO! SHow me a drag car that hooks, with Super Stock springs, and that runs a rear sway bar.
 
TT5.9mag said:
Unhook the front sway bar, leave the rear. Get the front end to move as free
As possible and that might include different torsion bars and almost certainly shocks. Then get a good double adjustable rear shock, and start tuning. Take way too many notes, on every pass. Make one change at a time and compare.
Click to expand...
This ^^^^ I know guys that run in the 9s and like how their rear sway bar holds the car. All you need to do is disconnect one side of the front. Especially the larger ones can keep the front from rising and transferring weight.
 
Did you say 1 7/8 front sway bar ?
Isnt that really big ? I will have to go out and measure my Helwig... I thought it was closer to one inch .
 
I guess I'll do that testing. Too bad test and tune is so damn busy anymore! I believe I will start with shocks!

Cley
 
I would start by unhooking the front sway bar at the track and getting the proper length rear shocks and see what that does for you.

If you plan on making it a drag race only car then going to smaller diameter front torsion bars will help, but the time that’s costing you is pretty minimal. If you still plan on driving it on the street more than you’re drag racing I wouldn’t worry about sabotaging all your street manners for a few runs at the strip. Just depends on how you want to use the car and how much shaving a little bit of time is worth to you. I’m not saying /6 bars won’t improve your launch, they will. But they’ll also make your car handle like crap the rest of the time you’re driving it.
 
Disclaimer: I have never run drag radials. But, from what I have noticed on other's cars, drag radials do not respond significantly to pressure changes like bias slicks do, and those can run all the way down to 10- mid teens psi. Radials (someone correct me if I'm wrong) seem to like higher pressures.
Without re-engineering your whole car (which seems like a real nice setup, by the way- I would avoid changing too much), I would start by unhooking the front sway bar at the track as mentioned above, maybe loosen the t-bars a couple of turns, and get a set of dedicated wheels with slicks (personal preference, they're what I'm used to) with maybe 12-15 lbs. to start with. Just be aware that at those pressures you'll probably need to use bead screws.
Try your rear bar both ways- see what works for you.
It sounds like a real nice engine build, but it still shouldn't take a ton of work to get your 'teener to hook.
JMO.
 
RustyRatRod said:
This ^^^^ I know guys that run in the 9s and like how their rear sway bar holds the car. All you need to do is disconnect one side of the front. Especially the larger ones can keep the front from rising and transferring weight.
Click to expand...

I run a rear sway bar with SS springs but havent run it down the track yet .
Iwill let you know how it works once I do .
 
89on35s said:
I kinda think I know the answer, but thinking I know usually bites me in the ***. When I set my suspension up initially I had never drag raced and did not have that in mind.
I have 1.03" torsion bars up front, 1-7/8" front sway bar, 7/8" rear sway bar and Bilstien RCD shocks. I have 002/003 Super Stock springs out back.
My drivetrain consists of a 318 with Summit K6901 cam, Performer 318/360 intake, 750 DP carb from QFT, Headers and full dual 2.5" exhaust. I run an A-500 OD auto with an 8-3/4" rear (4.10 sg).
The car is a 74 Duster, at least 3200 lbs with 275-60-15 Nitto NT555R drag radials. I tried the tires at 20 psi and at 18 psi and found no difference.
I spin off the line regardless how I launch it. I tried getting up on the converter against the foot brake as much as possible (maybe 2300), it tried 1500, I tried from idle and it always spins. 60' times from 2.2 to 2.3.
Where should I start? I am thinking shocks first. I know the rear A body length shocks are a problem with the SS springs. Do I need to ditch my sway bars and heavy torsion bars? I really like how it handles as is but out here In the prairies there are no canyon roads to speak of.
Thoughts?

Cley
View attachment 1715870296
Click to expand...


You need to start with /6 torsion bars. You don’t make anywhere near enough power to transfer any weight with those bars.

Unless you have a shock with a ton of travel you are probably topping out the rear shocks.

You need double adjustable shocks front and rear.

That’s just to get you headed the right direction.
 
RustyRatRod said:
This ^^^^ I know guys that run in the 9s and like how their rear sway bar holds the car. All you need to do is disconnect one side of the front. Especially the larger ones can keep the front from rising and transferring weight.
Click to expand...
upload_2022-2-15_11-58-25.png


Now saying that there are some pretty serious race cars that use a race only design of sway bar. It is used if the body twists excessively. Most drag cars don't use them especially Mopars.
upload_2022-2-15_12-1-35.png


Damn X frames!
upload_2022-2-15_12-2-32.png
 
He doesn’t make enough power to need a sway bar on either end. That chassis is sound bound up its constipated. He has mismatched parts. It can’t be a corner car and perform at the drag strip. He needs to figure out what he wants to be and then make a decision on what to change because turning corners isn’t a drag race.
 
Rat Bastid said:
He doesn’t make enough power to need a sway bar on either end. That chassis is sound bound up its constipated. He has mismatched parts. It can’t be a corner car and perform at the drag strip. He needs to figure out what he wants to be and then make a decision on what to change because turning corners isn’t a drag race.
Click to expand...
This ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
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