Rear Suspension Question..

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70Dart499

70Dart499

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OK guys here's what I've got, my 70 Dart has Super Stock springs, I currently have Lakewood Traction bars on the car, and it's not hooking very good, I have been told that I need to use a pinion snubber by several Mopar friends. My question is should i use a snubber? And if so, should I remove the Traction bars, or leave them on and add the snubber. I put the bars on, an then learned that they were not the best option, I'm new to MOPARS and I'm looking for some advice from Mopar experts. The car has a 499" low deck 400" engine with a reverse manual valve body 727 and an 8 3/4 rear end with 4:10 gears.
 
1. Remove your traction bars and toss them in the river.

2. Get a pinion snubber.

This is the system that the SS springs were designed around.
 
OK thanks, looks like I will get a snubber, do I need to do anything else to the springs?
 
Depending upon the SS springs you have, you may have to space the pinion snubber up so the air gap is correct between the snubber and the plate on the body. I used to know what the air gap was, but my old gray matter fails me now. I'm sure someone will pipe in with it now that I've mentioned it.
 
bOb shingler said:
what rear tires are you using, what pinion angle and what front and rear shocks?
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275 drag radials, competition engineering 3 way adjustable shocks rear and old loose worn out stock shocks in front, I drilled them so they are loose as possible, and I'm not real sure on the pinion angle to be honest.
 
If youn drilled the front shocks, you might as well take them off! Either way, it can create a dangerous situation at the track and on the street. That was an old school trick when little or nothing else was available for Mopars.

The cheapest OEM replacement shock will still have quite a bit of easy extension and at least a little compression resistance. But I like aftermarket shocks that have a little more resistance to compresion to help keep the front up a little longer and it also won't bottom out as easily if you hit the brakes hard at the finish line or hit a pothole. I've seen oil pans get smacked and headers are on the hit-list too!

Adding weight to the trunk area (safely & securely) can actually result in better ET's because the extra weight in an advantageous location is more than offset by better traction.

Since you have more HP and extra weight over the nose, hooking better will be more work than usual. Cal-Tracs can be a helpful option if it can get worked into the budget down the road. Tuning the carb accellerator pump circuit may also help how well the suspension works. Lean or rich spots can unload the suspension enough to encourage spin.

Buy a magnetic protracter at Home Depot to help figure out the pinion angle.
 
HotLines said:
Why did you put traction bars on the car..
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I was told by a shop that was doing some work for me that I needed them, I have since had it out with the shop owner over some bad work, he told me a pinion snubber wouldn't work and that traction bars were the way to go, I guess that's what I get for doing business with a mustang guy, LOL.
 
HotLines said:
or a Chevy guy..
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Well he does them too. He's a total idiot, had to rewire the whole car after he didn't put a fuseable link on the wires for the elec water pump. It burned up and torched every wire under the dash, If I hadn't been in the car when it happend It would have caught the car on fire. Guess if you want something done right you should do it yourself.
 
i tried that drill the shocks trick once and immediately took them off and tossed then in the trash. scary to say the least but the front end sure acts quickly.

you might want to try some of these suggestions.
3-ways on the front and if it's in the budget 12 ways are even better.
a pinion snubber isn't really needed.
changing the front spring eye bushing to aluminum.
i think pinion angle is somewhere around -7*.
move the front spring eye up 1-2".
remove the rear spring retainers.
subframe connectors are a must have
adjust the rear shocks to extend easy
once you do a burn-out do not do any dry hops, go stage.
 
Here are some facts about the B3 (Barracuda, Bracket, Budget) 67 Barracuda that was built by and raced by Dave Young, Tech Editor for Mopar Muscle Magazine. I bought the car last year from Dave. The build and track results for this car are well documented in the magazine (Dave also gave me all his time slips and log book as part of the purchase). This is what I learned from the magazine, from Dave, and from running the car:

1 - Traction is not a function of one system of the car (putting traction bars on may work if other parts of the car are prepared correctly). All of the various parts of the car must work togeather. The weakest link of the system will limit the car's traction/performance.

2 - To acheive good traction, the following changes were made to the stock Barracuda during the first phase of build:

Frame connectors and Roll Bar added to stiffen the body - Twisting of the chassis will change the loading on the rear tires and do it in a way that is not consistant

The car was initially equipped with a stroked 400 motor and therefore V8 type torsion bars were used in the front end to provide more spring strength to help lift the front end during launch. Stock front snubbers were used.

Super stock rear springs were used with an adjustable pinion snubber. There should be about 3/4 to 1 inch clearance with the weight of the car on the rear axle.

Strange double adjustable shocks were used front and rear

3 - Adjusting the car as follows:

Using 4 wheel scales, the weight on the rear wheels was set the same by adjusting the torsion bars

Run about 10-12 psi in the rear 28 x 10.5 tires (the car is not tubbed and this is the biggest tire that will fit)

Adjust the front shocks to allow the front end to come up quick (transferring weight to the rear wheels) and adjust to allow the front end to come down slowly under control.

The car weighed 2900 lbs with driver and the 451 motor was putting out about 650 HP. The first run down the 1/4 mile track was a 10.393 at 128.18 mph. With some refinement the car was able to get down into the 10.10's.

Then Dave wanted to go faster, and the car was changed again to it's current state of build, but that is another story.

Bottom line, make sure you have the total car working together. Just changing out one part of the car may not help.

Ma Snart
 

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The pinion angle should "straighten out" when leaving the line. That's why it's set nose down. The old Direct Connection book has the figure, I believe. I would think that the angle is dependent upon how stiff the springs are and, how heavy the car is.
Drilling the shocks to drain the oil is an ooooold "trick". I drilled a couple once and never used them. It became immediately obvious that they would be dangerous. As mentioned, they will have zero resistance and become ineffective. Thinking about newer shocks with nitrogen in them makes me think you could get hurt drilling them!
It's easy to over-do a Mopar suspension. A good rebuild of the front w/ a cheapie replacement shock and Super Stock springs (some apps don't even need a snubber) with a good drag shock in the rear are about all that's needed for a LOT of cars. I'm finding out that my 87 Mustang is much harder and more expensive to set up.
 
With super stock springs is the front end height important. I see alot of cars with the nose low.
 
Just a note..........if you adjust the weight on the rears with scales , remember how much buttocks is going to be occupying the left front.
Factor in driver weight.
Battery goes to the pass. rear .
Everything else is pretty much what Mr. Shingler said.
I didn't scale mine , but used the width and darkness of the stripes I would leave on the street in front of my house to try and estimate if I was unloading one side or another.
The car will hook on dirt now.
 
...............My old duster was 2700 lbs.........s/s springs and long drag shocks on the rear......90/10 shocks up front......1.36 60 ft.......kim......
 
MO... pinion snubbers are great for holding open doors to let a breeze into the garage... :)

Clamp the crap out of the spring front segments, let the rear segments loose. A well set up SS spring car does not need a snubber.

Put it all together with a bad pinion angle and it won't work, use junk shocks it may not work. Got to have stuff working in harmony. The front end is more important than the rear set up.
 
If I had to choose, I'd go with the pinion snubber. What you are trying to do with either is limit the amount the leaf springs wrap up under hard acceleration. As you accelerate the pinion will try to climb the ring gear. Obviously it cant so the energy is tranfered through the diff, down the axles & then to the wheels. The energy is then transfered back through the whole rear axle assy & it tries to twist itself free. This causes the leaf springs to twist to a point & then release causing the chassis to unload & cause spin & hop. A snubber or traction bars limit the movement of the axle housing to a point before the springs wrap up & unload. Traction bars do it at the point of the springs individually, while the snubber does it centrally at the middle of the axle housing. I'd rather do it in the center as depending on the weight transfer you may not get both traction bars working at the same rate.

Just be sure to renforce the floor area above the snubber's contact area if you have a significant amount of power or will be racing often. You will fatigue the floor otherwise & then the snubber won't work. Also set your pinion angle as previously recommended.

Absolutely ditch the idea about drilling out the shocks or using old worn out shocks! You obviously have a car you believe is worth putting a good motor in, it would be a shame to put it into the wall at the track because you were cutting costs. Get a good set of 90/10 shocks or something adjustable & be safe.
 
Lonewolf3165 said:
If I had to choose, I'd go with the pinion snubber. What you are trying to do with either is limit the amount the leaf springs wrap up under hard acceleration. As you accelerate the pinion will try to climb the ring gear. Obviously it cant so the energy is tranfered through the diff, down the axles & then to the wheels. The energy is then transfered back through the whole rear axle assy & it tries to twist itself free. This causes the leaf springs to twist to a point & then release causing the chassis to unload & cause spin & hop. A snubber or traction bars limit the movement of the axle housing to a point before the springs wrap up & unload. Traction bars do it at the point of the springs individually, while the snubber does it centrally at the middle of the axle housing. I'd rather do it in the center as depending on the weight transfer you may not get both traction bars working at the same rate.
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Lonewolf, I'm not sure, but I think you do not want a pinion snubber because when it does hit, it could unload the tires. The clamped springs (You don't want traction bars on a Mopar, even with stock springs!) provide control from the initial hit of the throttle.
 
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