« Engine Specs | Main | Offsetting 3rd link »
April 22, 2005
3rd Link Design
I removed the Herb Adams decoupled torque arm, as it had massive rear end rise under braking, was very heavy, and had a poor design with large stress concentrations (that resulted in a snapped bracket and destroyed a driveshaft).
There was some great discussion about geometry on Corner-carvers.com on the following posts:
2002 http://corner-carvers.com/forums/showthread.php?t=5322
Decoupled TA http://corner-carvers.com/forums/showthread.php?p=49371
3 link http://corner-carvers.com/forums/showthread.php?s=&threadid=2242
3 link http://corner-carvers.com/forums/showthread.php?s=&threadid=5223
EVM proto http://corner-carvers.com/forums/showthread.php?t=11730
http://www.evolutionmsport.com/evmCart/index.php?main_page=evm_pages&pag=59
EVM final http://www.evolutionmsport.com/evmCart/index.php?main_page=product_info&cPath=1&products_id=2
71 Mustang 3 link http://corner-carvers.com/forums/showthread.php?t=21114
A Sedan Camaro http://corner-carvers.com/forums/showthread.php?t=20867
Bill Mitchel SVD http://web.archive.org/web/20030622220451/http://billmitchellsvd.com/camaroproductsandservices.html
FFR pictures http://www.norcal-cobras.com/projects/3-link/index.htm
Forces depend on the acceleration of the car, and torque at the axles, which will be highest in 1st gear. Assume 800 ft-lbs engine torque to be conservative, 2.66 1st gear (T56 ratios at http://www.sallee-chevrolet.com/ChevyTransmissions/gmt56.html), 3.70 rear-end gear ratio, and 26" diameter tire.
To minimize the tension/compression forces on the 3rd link, move it higher from the axle centerline.
If the third link is located towards the passenger side, it counteracts the torque about the rear axle under acceleration. Location depends on rear axle ratio.
Thoughts to consider:
Upper arm length (usually 65% of LCA), which affects pinion angle from suspension travel. The stock LCA's are 19.5" long.
Angle, adjustable to set the anti-squat percentage
Location left/right for rear axle roll.
Posted by Z28tt at April 22, 2005 11:44 AM