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Rear suspension - Torsion Bar Setting


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Hi All. Hope everyone is staying safe, and still playing with the motors. I have a question for the suspension experts.
I have a 77 - 2.7 911 and I understand the standard rear torsion bars should be 23mm rated at 100lb, the spring plates free setting should be between 36*30' and 37 degrees as a starter for standard ride height.
My car was fitted with 25mm torsion bars which are rated at 140lb. Does anyone know or have a calculation to give me an indication of what angle to set these at or what the difference in ride height would be if the same free angle setting was used (I assume considerably higher due to the spring rate). I know the final adjustment will need to be made once things settle, but a starting point would be great. Is there any info on this forum, ddk, or pelican.
Any help would be much appreciated.
Mike.

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Probably a decent start. I put in the elephant racing calculator 2400lbs and got 28.53 degrees and 2800 gave 31.48 so 30 would probably give you a decent result

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Hi. Having set mine at the 30degrees as mentioned it just rests on the "spacer stop" both sides, I will see how it settles once the engine and gearbox are back in. 

Robos, what size torsion bar do you have and is this for standard ride height or slightly lowered? Thanks Mike

Edited by MikeS911
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I used 26mm bars on my C3. 36 degrees gave me the ground clearance of a safari racer.

Set the spring plates to mid adjustment and rotate them on the outer splines, up one tooth, that will get you close enough to put it on its wheels and send it off for a geometry check.

Also I am sure my new bars have sagged slightly since the car has been back on it's wheels, so I will need to check the heights again.

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On 13/09/2020 at 10:54, MikeS911 said:

Hi. Having set mine at the 30degrees as mentioned it just rests on the "spacer stop" both sides, I will see how it settles once the engine and gearbox are back in. 

Robos, what size torsion bar do you have and is this for standard ride height or slightly lowered? Thanks Mike

Mike as far as i know mine is all standard, pic attached showing ride height.  Not sure on torsion bar size but its an 85 3.210E72D69-618D-420A-BF2F-82C9777BEA14.thumb.jpeg.26e6a42f9ce59a302575d2e4175d1949.jpeg

I should add the measurement was from the top if the sill/door aperture👍

Edited by Robos911
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