vanillagorilla

iTrader: (1)

I wouldn't think leaf springs would deflect that much lateraly, but under the stress of a g and given the weight, it makes sense. Now I ask you this: Why not just slightly triangulate the leaf springs. Also I've seen more than a few leaf spring muscle cars sporting cal tracs or slide-a-links that autocross. I'm not sure as to the actual benefit of this other than controlling axle wrap, but they seem to get it done in the corners. At least it appears they aid in traction yet they don't hinder the cornering capabilities. Of course as long as you're on the gas the bars will be "driving" the tires into the pavement.

Does anyone know the weight distribution of our trucks? Roughly 70/30?

I would try to set up a little negative camber first. I bet that -2* would make a world of difference. As far as sway bars in the rear, I don't think you'll need very much. There's not very much weight back there and some body roll in the rear might be advantageous in order to negotiate turns. If the rear were too stiff you might get into a lot of oversteer, especially if the tires aren't up to the task. Make sure your pinion angle doesn't change much if at all (cal-tracs...?) while braking too. This will cause all sorts of issues as the leaf spring deforms and the front end dives.

I would try to get the factory suspension specs before you do anything. If some on wants to get the dimensions of the stock springs, I can calculate the spring rates. As for shock valving, just get some adjustables and have fun playing with them. I would look into fabing up some adjustable sway bars too. This would be a fun project to explore.

I wonder where you could score some factory prints or files of all the geometry?

GoldenVelvet

A sway bar can be 'tuned' with different length end links. There is no measurement for sway bar stiffens. That's why sway bars are discussed in size. Size make a huge difference, but so does shape. Then there is hollow verses solid. You cant really compare one brand vs another because there is no stiffness ratings like there is spring rates or shock valve dampening. In that since a matched set is a good bet. I have found that my truck is surprisingly neutral (in that at limit I have no over or under steer) with a 1 1/4 solid rear and stock front bar with upgraded front end links. But I have a much lighter truck then most.

The rule of thumb for setting up sway bars is go as stiff as you possibly can in the front and tune the rear to taste.

GoldenVelvet

You cant triangulate leaf springs with out adding two more links. Then you are back to a panhard that is a single link and more simple. Cal-tracks and Slide-a-link are the same basic designe. The advantage of the bars on a g-machine is they will make the rear track more consistently by eliminating any axle wrap due to the chassis squatting in a turn. Consistency=handling.

I would love to know the factory spring rate. Factory springs are progressive, both front and rear. Most aftermarket springs are linear rate. because linear is more consistent. Consistency= handling.

Keith

The rear leaf springs on my hudson are not parallel, so in effect they have a locating effect for the rear axle. Although, it does have a panhard rod too. they did darn good in the early days of nascar using that setup. Would probably work pretty good on a truck too.

On another note, I'm pretty sure there are stiffness ratings for sway bars. They are in effect a torsion spring, so why wouldn't they have a spring rate associated with them? On some fancy race cars the arms extending from the sway bar itself have multiple attaching points for the end link.

see:



from:
http://www.hotrod.com/featuredvehicles/67759/index.html

1ImperialSS

iTrader: (5)

suspension geometry and theory has to be by far one of the more up for interpretation and confusing and often misunderstood aspects of racing trucks

GoldenVelvet

Very true.

04sierra

I think the reason you are having problems finding a panhard bar for our leaf sprung trucks is that it is not going to benefit you all that much, although I do agree with Vanilla that at 1 g and our weight, there could be some benefit. My ideal suspension set up for max effort handling would be hotchkis springs on all corners along with a 2" drop spindle up front and shackles in the rear (for a 4/6) to get the center of gravity down even lower. Throw on some hotchkis sway bars and a good set of adjustable shocks on all 4 corners. Change all your bushings to urethane and get a good performance alignment (with some negative camber dialed in.) I think this set up paired with a wide, sticky set of tires would get you close to your goal, especially if you put a fuel cell between the frame rails as far back as possible.

Or if you want the maximum in adjustability, coilovers at all four corners would work to. Let us know the end result as I have always been fascinated with making a truck handle better than most sports cars, I just haven't had the time or money to experiment yet.

1ImperialSS

iTrader: (5)

time and money is what its all about with stuff like this

GoldenVelvet

This is on a Lightning; Panhard, shocks, leaf/coil springs (2/3 drop), sway bars, Cal-tracks bars.

^Before (stock) . . . . . . . . . . . . . . . . . . . . . ^After (with listed changes)

1ImperialSS

iTrader: (5)

thats some good lookin body lean on that first picture, how mmany g's does it pull? good tire, eagle f1's, my sisters trans-am has those