I am hoping one of the chassi experts can point me in a proper direction. On my pro street car I have to run staggered rear spring rates to get the car to sit level. The car has a sw rear clip in it (early mopar A body) lader bar set up. The car weighs in a 3000lbs When I ordered the kit the sold me 130lb 12" springs. Well all the suspension work has been done (10 pt cage included) set the car down and it sits lower on the dr side. I figured something had to me screwed up so I releveled the car (rechecked the the assembly platofrm to, and rechecked all my measurements and the frame is level and true. I talked with the sw tech guys and they said put a heaver spring on the dr side since all the springs do is keep the car level. So I did and pit a 150 spring onthe dr. side. well I have this spring jacked up and the car is still a little low on that side. I took the car to a body shop and had them put it on their frame machine to make cartain nothing was wrong and they said that all was ok and they thought the problem might be 1 the dr upper shock mount is approx 1/8" higher . Or 2 A front spring (torsion bar) is bad causing the car to be lower on the dr side.
if I jack everything around I can get the car to sit level and it tracks straight. I haven't gotten it to the track yet but If I heat the slicks (32X18.5) and launch the car it is biting hard enough to move the bead on the rims. ( I marked the rims and tires) and it will launch straight.
rear coilover spring rates ?
Moderator: Team
rear coilover spring rates ?
Sorry if I ask alot of questions, but you never stop learning if you ask questions
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af2
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John, all the rear springs do is hold up the rear of the car! The tire spinning on the rim is not good. I see other issues as far as different weight left to right front to rear. I see no reason to run a higher rate spring on one side accept for compensation on what is really happening.
Adam
That was the the thought here dealing with Torsion bars!
I feel the torsion is the best compared to leaf and especially coil springs!!!
If you have a lazy one you are screwed.
Adam
That was the the thought here dealing with Torsion bars!
I feel the torsion is the best compared to leaf and especially coil springs!!!
If you have a lazy one you are screwed.
Last edited by af2 on Sun Nov 25, 2007 10:45 pm, edited 1 time in total.
GURU is only a name.
Adam
Adam
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Ed-vancedEngines
Johnny,
That tech you talked with must be an idiot. I do not ever know of one circumstance in a drag race car where you need to increase the left side (Driver's) spring rate higher than the right side. That causes the car to drive to the right under hard accelleration. The fact of it still launching straight just compounds the issue.
It is true that all the rear springs do is to support the vehicle prior to launch. BUT by putting a static pre-load on the driver's tire that tire should initially
The founders and owners of S&W Race Cars is Scottt Weney and Walt Weney. That is the name Scott & Walt (S&W). Both Scott and Walt know better than what you were told. They were a father and son drag racing team years ago. Scott ran one of the first 4 link roadsters.
tHINGS YOU CAN CHECK ARE YOUR FRONT SUSPENSION. yOU MENTIONED TORSION BARS. iF THE RIGHT SIDE TORSION BAR IS STRONGER OR HAS MORE LOAD CRANKED INTO IT THAN THE LEFT SIDE IT WILL MAKE THE LEFT REAR TO BE (caps) lower. If the torsion bar bushings are in bad shape it will influence the rear. If the front lower control arm bushings are in bad shape that can also cause the car to sit on one side some. All of everything forward of the subframe needs to be checked and verified.
It is also possible you stock unibody had been tweeked before the subframe installation. That would be a tough one now to fix. It is also possible that the alignment of all of the welded parts were not in alignment with each other prior to welding. That would be a toughie to fix. It is possible that you had a pulling of components as they were being welded if not supported well and welded on a jig. That would be a toughie to fix. There have been many cars modified and welded not on a jig though when done with care that came out ok.
It is possible that the subframe assembly was not even from side to side when it was jigged up and weleded. You mentioned the upper shock bracket being higher on the left side. That should not be but should be easy to fix or to compensate for.
You can adjust your left rear spring a little higher than the right if that is necessary to level the ride ht. It is better to do the adjuting on the front of the car though.
I still think that you will find your problem solutions in the front suspension of your car.
Here is what should be normale, a little spring pre-load on the right rear and the left front.
Like I saiad, Check your torsion bars and your torsion bar bushings.
Ed
It is obvius you have some frame or chassis welding/alignment issues or problems in the front end causing what you describe. Thsoe have to be found and addressed.
That tech you talked with must be an idiot. I do not ever know of one circumstance in a drag race car where you need to increase the left side (Driver's) spring rate higher than the right side. That causes the car to drive to the right under hard accelleration. The fact of it still launching straight just compounds the issue.
It is true that all the rear springs do is to support the vehicle prior to launch. BUT by putting a static pre-load on the driver's tire that tire should initially
The founders and owners of S&W Race Cars is Scottt Weney and Walt Weney. That is the name Scott & Walt (S&W). Both Scott and Walt know better than what you were told. They were a father and son drag racing team years ago. Scott ran one of the first 4 link roadsters.
tHINGS YOU CAN CHECK ARE YOUR FRONT SUSPENSION. yOU MENTIONED TORSION BARS. iF THE RIGHT SIDE TORSION BAR IS STRONGER OR HAS MORE LOAD CRANKED INTO IT THAN THE LEFT SIDE IT WILL MAKE THE LEFT REAR TO BE (caps) lower. If the torsion bar bushings are in bad shape it will influence the rear. If the front lower control arm bushings are in bad shape that can also cause the car to sit on one side some. All of everything forward of the subframe needs to be checked and verified.
It is also possible you stock unibody had been tweeked before the subframe installation. That would be a tough one now to fix. It is also possible that the alignment of all of the welded parts were not in alignment with each other prior to welding. That would be a toughie to fix. It is possible that you had a pulling of components as they were being welded if not supported well and welded on a jig. That would be a toughie to fix. There have been many cars modified and welded not on a jig though when done with care that came out ok.
It is possible that the subframe assembly was not even from side to side when it was jigged up and weleded. You mentioned the upper shock bracket being higher on the left side. That should not be but should be easy to fix or to compensate for.
You can adjust your left rear spring a little higher than the right if that is necessary to level the ride ht. It is better to do the adjuting on the front of the car though.
I still think that you will find your problem solutions in the front suspension of your car.
Here is what should be normale, a little spring pre-load on the right rear and the left front.
Like I saiad, Check your torsion bars and your torsion bar bushings.
Ed
It is obvius you have some frame or chassis welding/alignment issues or problems in the front end causing what you describe. Thsoe have to be found and addressed.
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jmarkaudio
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I have to go with Ed on this one. If you can't adjust the coilover to the same ride height with the same spring, something else is wrong. Either the car is significantly heavier on one side, or you have something causing preloading on that side. Find the problem and fix it, it will work much better than a bandaid. Set the front frame on jacks at normal ride height (and equal) without the front wheels on. If the back is now level, the problem is in the front. If it's still off, your ladder bars may be causing the problem.
Mark Whitener
www.racingfuelsystems.com
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Good work isn't cheap and cheap work can't be good.
www.racingfuelsystems.com
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Good work isn't cheap and cheap work can't be good.
Thanks for the help,
Right now I have the car up on jackstands. I did not touch the rear suspension the rear axle is on the stands and the front stands are under the frame. The car is sitting level with the mismatched rear spring combo. My next step is set the rear of the car on the frame, instead of the axle. The see how off it looks before I remeasure.
If I am understanding correctly then the problem is in the rear suspension.
My next idea was going to be make 2 identicle solid shock bars (for lack of proper wording) and recheck everything again. I figure a good step one would be reset the rear shock mount (dr side) so both sides are matched.
Then procede to pull my hair out LOL
Right now I have the car up on jackstands. I did not touch the rear suspension the rear axle is on the stands and the front stands are under the frame. The car is sitting level with the mismatched rear spring combo. My next step is set the rear of the car on the frame, instead of the axle. The see how off it looks before I remeasure.
If I am understanding correctly then the problem is in the rear suspension.
My next idea was going to be make 2 identicle solid shock bars (for lack of proper wording) and recheck everything again. I figure a good step one would be reset the rear shock mount (dr side) so both sides are matched.
Then procede to pull my hair out LOL
Sorry if I ask alot of questions, but you never stop learning if you ask questions
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Ed-vancedEngines
Like I said. First place I would look at woukld be the front complete suspension. That means everything in the front. If you are using jack stands put them under the frme and not the axle in the rear. For a long while forget the rear suspension completely except that stupid heavy left rear spring idea.
If you haven't backed fully off of your torsion bar adjustments on both sides and then tighten them both equally, you have no way of knowing if those are not forcing the left rear down or not. Most of those cars did have the right side bar jacked a little higher becuase the engine was sitting to the right side from center. After you get the torsion bars bot fully backed off and the wheels hanging down you should be able to feel if there is any bushing slack on either side. You want no slack.
To begin with you want only enough load on the torsion bars to hold the car up the minimum ht from the ground with initially both bars adjusted equally the same.
Ed
If you haven't backed fully off of your torsion bar adjustments on both sides and then tighten them both equally, you have no way of knowing if those are not forcing the left rear down or not. Most of those cars did have the right side bar jacked a little higher becuase the engine was sitting to the right side from center. After you get the torsion bars bot fully backed off and the wheels hanging down you should be able to feel if there is any bushing slack on either side. You want no slack.
To begin with you want only enough load on the torsion bars to hold the car up the minimum ht from the ground with initially both bars adjusted equally the same.
Ed
I too believe your problem is in the front. One other thing you may want to check besides unequal torsion bar settings is damage around the mounts for the K member. A rough rail road crossing or a curb too fast can damage these areas. A very little bit goes a long way to make car uneven. In a lot of cases a less than expert frame men will miss these and just adjust torsion bars to get ride hight. A 1/4 inch here can show as a couple inches ride hight. Upper spring pockets can do the same. Before lazier measuring devices these things was very common, just for the fact that it's too hard to get accurate measurements from a datum line. Not impossible but hard.
It's always good to measure out unibody before putting in cage, tie bars or just tubbing.
It's always good to measure out unibody before putting in cage, tie bars or just tubbing.
Older I get the less I know for sure
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af2
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As Bubster and Ed said, Look at the front!!!! There is no reason the rear should be where you have them!!!!!!!!! Unless you weigh 500+ pounds!?crazycuda wrote:Thanks for the help,
Right now I have the car up on jackstands. I did not touch the rear suspension the rear axle is on the stands and the front stands are under the frame. The car is sitting level with the mismatched rear spring combo. My next step is set the rear of the car on the frame, instead of the axle. The see how off it looks before I remeasure.
If I am understanding correctly then the problem is in the rear suspension.
My next idea was going to be make 2 identicle solid shock bars (for lack of proper wording) and recheck everything again. I figure a good step one would be reset the rear shock mount (dr side) so both sides are matched.
Then procede to pull my hair out LOL
GURU is only a name.
Adam
Adam
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af2
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In my opinion you can't beat the Torsion bar as far as rebound. They are slower than a leaf spring! The coil is very fast compared.crazycuda wrote:I decided im going to change the front suspension to A frame coil setup.
Look at the whole set up before you get really confused with the coil.
I would run a torsion any day compared to a coil. I don't have the room is the only reason!
GURU is only a name.
Adam
Adam
I was re reading this and something came to mind. If you are using Mopar Super stock leaf springs and they are the same as they was back in the 60s 70s from direct connection, the right rear spring has more arch than the left rear. This was designed in preload to counteract torque effects. Back then, we just cranked up the left front torsion bar to level ride hight. This added weight to the right rear and left front and took some away from the right front and left rear. this was good. Possibly someone in the past has done this and never changed back for the coil overs. this could be as easy as a good front end alignment and bar adjust..
Older I get the less I know for sure
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Ed-vancedEngines
Bubstr,
Did you ever try using the SS Mopar Leafs with clamps plus the top 4 link bar on top of axle housing? Actually worked pretty good back then.
I may be wrong but I think a lot the Mopar SS Suspension ideas to hook on those 7 inch tires and earlier to hook on the Firestone Butylairs and the Atlas Bucrons was the ideas of our own Billy Shope, a member here when he was with Mopar as a factory engineer and part of the Ramcharger Team.
I was also doing some thinking about this problem child he has;
If the front is straight and the car still is still sitting low in that left rear corner he can sorta put a band aid on it that won't hurt anything.
With the same springs on each side see how much ride ht adjusting needs done by lifting that one corner until it is level side to side. Measure how much lowwer the top left shock mount will need to go to get it all to that height. and siply move the left top shock mounting position down to make the car level. It is possible you could have not had it all in perfect level or alighnmnet when it was weled. It is possible while it was welded something could have pulled. It is possible the subframe is not 100% too. That band-aid should make it all work right. Be sure the front is also level side to side when doing the measuring and re-welding too. Possibly just moving some holes down will do the trick, by adding additional mounting holes in the top.
Ed
Did you ever try using the SS Mopar Leafs with clamps plus the top 4 link bar on top of axle housing? Actually worked pretty good back then.
I may be wrong but I think a lot the Mopar SS Suspension ideas to hook on those 7 inch tires and earlier to hook on the Firestone Butylairs and the Atlas Bucrons was the ideas of our own Billy Shope, a member here when he was with Mopar as a factory engineer and part of the Ramcharger Team.
I was also doing some thinking about this problem child he has;
If the front is straight and the car still is still sitting low in that left rear corner he can sorta put a band aid on it that won't hurt anything.
With the same springs on each side see how much ride ht adjusting needs done by lifting that one corner until it is level side to side. Measure how much lowwer the top left shock mount will need to go to get it all to that height. and siply move the left top shock mounting position down to make the car level. It is possible you could have not had it all in perfect level or alighnmnet when it was weled. It is possible while it was welded something could have pulled. It is possible the subframe is not 100% too. That band-aid should make it all work right. Be sure the front is also level side to side when doing the measuring and re-welding too. Possibly just moving some holes down will do the trick, by adding additional mounting holes in the top.
Ed
Haven't thought about Atlas Bucrons for ages. Get them at the Standard Oil Gas stations and they where gum balls. I think they where softer than the M/H slick. We used to run them on the flat head and six cylinder modified races. I've gotten better wear out of Hoosiers soft tire.
We used the adjustable pinion snubber with the clamped springs. It worked very well. We ran the same basic engine in a B/Gas and the new pro Stock and even with the change of stacked injection to two 4 barrels and 4 link to leaf it only lost from 9,90s to 10,00s on 11inch tire. I think some was due to engine setback difference and arro between Challenger and Duster.
Yes the cause for this problem is a mystery. I think a good frame measuring would be on the top of my list. You can't fix it right if you don't know what's wrong. I mean a good accurate measure including upper spring mounts. That means leveling chassis and isolating suspension. (Off the wheels.) These kind of things can trick even a good frame man. Having been around the block with torsion bar suspensions, that is the main suspect. They where good suspension, a little heavy but good. Guys that didn't work with them got lost because ride hight was adjustable and coil springs wasn't, in stock form.
We used the adjustable pinion snubber with the clamped springs. It worked very well. We ran the same basic engine in a B/Gas and the new pro Stock and even with the change of stacked injection to two 4 barrels and 4 link to leaf it only lost from 9,90s to 10,00s on 11inch tire. I think some was due to engine setback difference and arro between Challenger and Duster.
Yes the cause for this problem is a mystery. I think a good frame measuring would be on the top of my list. You can't fix it right if you don't know what's wrong. I mean a good accurate measure including upper spring mounts. That means leveling chassis and isolating suspension. (Off the wheels.) These kind of things can trick even a good frame man. Having been around the block with torsion bar suspensions, that is the main suspect. They where good suspension, a little heavy but good. Guys that didn't work with them got lost because ride hight was adjustable and coil springs wasn't, in stock form.
Older I get the less I know for sure