Too much preload on camber compensater?

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GMendoza
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Too much preload on camber compensater?

Post by GMendoza »

I just installed a CB Performance camber compensator on my '65 Ghia. It's lowered quite a bit therefore the CC has a few cm of preload. Preload was enough to raise the ride height.

Here's the current preload:
Image

Here's a pic of the ride height before:
Image

Here's current ride height:
Image

I felt that before the CC, the car could use stiffer rear torsion bars. Now with the preloaded CC, the ride feels right. Do you guys see any issues running that much preload on the CC? Or should I get the stiffer torsion bars, and unload the CC with longer straps?

Thanks in advance
'65 Ghia, '80 930, '89 928, '03.5 Esprit, '07 Vantage
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FJCamper
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Re: Too much preload on camber compensater?

Post by FJCamper »

Hi GMendoza,

What's happening is the camber compensator leaf spring is now carrying a substantional part of your rear weight, stressing both the straps and the center pivot support.

The CC wasn't designed for that, and something is going to break.

You can make the axle loop straps longer, releasing the preload. But, what we did was fabricate a metal bracket (replacing the end loops) drilled for a big U-bolt, and adjusted the preload by loosening/tightening the U-bolts nuts.

FJC
GMendoza
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Re: Too much preload on camber compensater?

Post by GMendoza »

Thanks FJC. Do you have a picture of your bracket?

Also, what size torsion bar do you recommend in the rear?
'65 Ghia, '80 930, '89 928, '03.5 Esprit, '07 Vantage
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FJCamper
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Re: Too much preload on camber compensater?

Post by FJCamper »

Hi,

You have the original pattern compensator, but it's as adaptable to the U-bolt method as the Sway-A-Way we use.


Image

Image

Image

We use standard, not stiffer, rear torsion bars. Even for road racing.

FJC
Steve Arndt
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Re: Too much preload on camber compensater?

Post by Steve Arndt »

The CB version is straight and not angled like the original and the Sway A Way.
http://www.cbperformance.com/ProductDet ... tCode=2819

I would try the angled version. But you may be out of luck running one with the suspension that low.
GMendoza
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Re: Too much preload on camber compensater?

Post by GMendoza »

Thanks guys for your suggestions. So I decided to have my straight leaf angled. Now preload is much less, ride is much better and right height is slightly lower than the straight leaf but slightly higher than no CC, exactly what I was looking for.

Angled leaf:
Image

New ride height
Image


I decided to keep the strap design. Given the different pivot points of the axles vs the CC, I was afraid the suspension would bind if the CC was clamped to the axles.
travel of axle vs CC:
Image

FJC, did clamping the CC to the tubes significantly firm up your ride?
'65 Ghia, '80 930, '89 928, '03.5 Esprit, '07 Vantage
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Piledriver
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Re: Too much preload on camber compensater?

Post by Piledriver »

Do be aware that your rear wheel bearings are lubricated by transmission gear oil.

Slammed looks cool, but you may need to do something about the wheel bearings with the axles pointed up.

I have hear some folks run the gear oil level a bit higher somehow.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
GMendoza
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Re: Too much preload on camber compensater?

Post by GMendoza »

Piledriver, thats a great suggestion! Thanks
'65 Ghia, '80 930, '89 928, '03.5 Esprit, '07 Vantage
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FJCamper
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Re: Too much preload on camber compensater?

Post by FJCamper »

Hi GMendoza,

Tightening up on the U-bolts really "tightens" up on the handling, as the leaf spring is now at work all the time. The feeling is a little like a rear sway bar. We always try and leave some play in the U-bolts because the U-bolts are trying to slide sideways a little as the axle tubes move up and down.

With stock front alighment, we get consistent understeer, and the car has to be pushed hard to bring out the tail. The smoothness at which that occurs depends on the tires.

This Ghia is being prepped next for HSR's 12 Hours of Sebring in December, which should be fun.

FJC
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petew
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Re: Too much preload on camber compensater?

Post by petew »

I did a very similar mod on my CC using bumpstops instead of the stock rubbers (one of which had a busted stud).

Image

It does stiffen the back end up a lot and make the car much more predictable.
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FJCamper
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Re: Too much preload on camber compensater?

Post by FJCamper »

Hi PeteW,

Great minds think alike!

FJC
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petew
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Re: Too much preload on camber compensater?

Post by petew »

Ummm, if you mean "he stole it off me so we think a like" then... yes! :mrgreen:
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Piledriver
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Re: Too much preload on camber compensater?

Post by Piledriver »

Old saying:
Good engineers borrow ideas.
Great Engineers STEAL.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
Ol'fogasaurus
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Re: Too much preload on camber compensater?

Post by Ol'fogasaurus »

I think that is called re-designing or re-purposing which is/maybe/should be the highest sign of flattery. Just remember: not all of the greatest designs have been thought of yet so get busy.

Lee
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