Thinking of installing Polyurethane leafspring and body bushings in my 69 Camaro along with a rear sway bar.
Is it true that these bushings tend to get noisy and that I may not need to go with
a sway bar because of the lack of twist from these bushings?

If you get PST poly graphite, they WILL NOT squeak. That's why they impregnate them with the graphite. I got'em on all 4 corners and I really like them. As for the rear sway bar, don't do it unless you are doing major changes to the suspension geometry. A rear sway bar on a stock 1st gen car makes it handle worse, it causes severe oversteer. You'll notice several of the reputable suspension companies don't even make a rear sway bar for a first generation Camaro. The addition of a rear sway bar on a 1st gen car involves some major suspension geometry changes up front for it to work properly. So... leave out the rear sway bar. Get a good bar up front, good springs and shocks in the back, then add your Poly bushings and you are good to go.


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Shawn Peterson
1969 Z28, 406SB
http://www.geocities.com/corsican69

[This message has been edited by Shawn (edited 07-09-2000).]

Shaun,

Whats the deal on the rear sway bar not being needed on a first gen. Camaro. I guess I'm asking how the driving changes with one installed?

I'm going with heavier rear leaf springs, "poly" everywhere, a 3/4" rear Addco swaybar and I hope 295/50-R16's. I figure if my car "pushes", I will "power torque steer" it.

The front has about 530+ lb-in coils and a 1" addco swaybar plus the spindle extenders. Tires are going to be 225/50-R16's.

Years ago when I put the swaybars on my car, I really didn't know what I was experiencing when I drove it so I don't know the "handling" terms to describe how it drove. All I knew then was that it drove "better" then stock.

Please advise because I'm still learning.

I'm no expert, but from what I've read and what the suspension companies have told me is that it's related to the front steering geometry. The anchor point of the A-Arms is not correct, the result is that it does not keep the tire perpendicular to the road. What this happens, the tire begins to lean as the suspension is deflected further. The result is gradual loss of traction in the front. What I've been told is that a rear sway bar then forces the car into a severe over steer condition, i.e. the rear end wants to slide out in corners.

Some of the guys here have done a Guldstrand supension modification that corrects the front steering geometry. I'll let them comment on it because I do not know all of the details, but I believe it involves relocating the upper A-arm mounts among other things. With the front end worked over, I believe the addition of a rear sway bar is beneficial, but you'd have to ask them.

I followed the advice of the suspension guys and put new springs, PST bushings, and shocks on all 4 corners. In addition, good sway bar up front takes care of most of the haneling woes the car has. I'm not driving mine hard enough to justify cutting up the front end to get that last little bit of cornering ability out of it. The guys here that have done the suspension mods could talk more to the subject.

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Shawn Peterson
1969 Z28, 406SB
http://www.geocities.com/corsican69

This is from an older post of mine on this forum.

There is less need for a rear sway bar on a camaro BECAUSE...

1. The rear roll center of the Camaro leaf spring design is inherently much higher than the front which is below ground level. This transfers cornering forces at the rear at a much higher rate compared to the front. The closer the roll center height is to the center of mass (at that end of the car) the more the cornering forces are is transfered directly. (not thru the springs).

This is why the old sprint cars with cross spring suspension didn't need swaybars. The roll center is about 1 1/2" below the center of mass, or mass centroid axis.

The disadvantage of the sprint cars high roll center is, if the cornering weight transfers automatically thru the high roll center. There is nothing the springs or shocks can do to absorb bumps and keep the tires from breaking loose (cornering). The car will act like there is a HUGE sway bar on it.

2. When a Camaro leans, it is actually twisting the rear leafs, a little, it's probably twisting the bushings more than the leafs. This adds resistance to roll.

You can see this all adds up to higher roll resistance at the rear than you might normally think.
Later 80's Camaros had bigger swaybars on the rear but they have coil spring rear suspensions.
I am NOT saying you absolutely don't need a rear sway bar. If you stiffen the front enough, you will eventually cause the car to understeer and have to add a rear bar. It will take very little rear bar to balance a big front bar.

Notice that on most rear bar kits, the arms are fairly long and the diameter is usually small. The rear bar winds up making a small difference, if that difference balances an understeering car, fine. If not, it's not needed.

Guldstrand does not like adding linkage to the rear suspension, swaybar or other stuff like panhard bars. He feels it will wind up hurting rear traction.

Hope this helps.
David

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Check my web page for suspension info:
David's Homepage (http://ourworld.compuserve.com/homepages/David_Pozzi/)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

Thanks for the comeback, David. I think that since I have already installed a rear Addco 3/4" swaybar that after I get everything together I will test my car both with and without it. Its relatively easy to remove and put back on. Now that I think about it a stiffer rear spring setup should compensate for lack of a rear swaybar. Plus there's less stuff on the car to boot.

Right now, I'm not modifying the front A-Arm perch just yet since I've got the spindle extenders mounted. I will probably just do the "caster" change by just moving the one mount bolt hole in the future. pdq67

PDQ- Let us know what you find. I'm curious how it handles with and without.

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Shawn Peterson
1969 Z28, 406SB
http://www.geocities.com/corsican69

pdq,
You have to either put more shims on the rear a frame bolt or re drill both holes more to the rear to increase caster.

If you change only one upper A frame bolt height, you will only change anti-dive.
I would not recomend changing the anti-dive on a Camaro.
Lowering it would increase anti-dive.

Incidetally, I would not "double up" devices to increase neg camber gain. As on your car, I would not do the Guldstrand mod in addition to the spacers you installed.
It looks to me like the spacer adds more than enough by itself.
Do you have a measurement on how much the upper ball joint is raised?

The rear sway bar by addco has fairly long arms?
If that's the case the effective rate of the bar is somewhat low.
You can tune the rate further by swapping plastic or rubber end link bushings to stiffen or soften the rate.
Let us know how it works.
David

------------------
Check my web page for suspension info:
David's Homepage (http://ourworld.compuserve.com/homepages/David_Pozzi/)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

[This message has been edited by davidpozzi (edited 07-26-2000).]

David, I didn't know that you were a sprint car guy as well. I thought you were just into the trans am stuff. If you go sprint car races in Nor Cal, we probably crossed paths once or twice.

David,

Are you telling me that I should move both upper A-Arm bolt holes towards the rear of the car to shift caster and not just lower the hole closest the driver??

If so, can you tell me how much to move the holes horizonally to the rear to get the recommended 4-5 degrees tilt that will make the steering more self centering??

I know I asked earlier about "anti-dive" and you said not to try to modify it.

Come-back. Thanks, pdq67