Cross weighing my 944

[zooklm1]

I am preparing to update my stock springs and torsion bars on my 86 944 turbo to 250 lb/in adjustable perch front springs and 28 mm torsion bar. I wanted to baseline the balance the before starting work on the suspension. I plan to replace all the bushings with Prekom sport bushings while I have things apart. I was able to source 4 - 1100 lb scales to perform the corner weighing. I have 3/4 full tank and put 180 lbs in the driver’s seat. The strut cartridges are new ( less than 4K miles) Koni sports with stock springs and same use Koni sport rear shocks. My weights were:
LF 816 lbs
LR 788 lbs
RF 790 lbs
RR 776 lbs

Total weight 3170 lbs (including fuel + driver weight)
Corner weight LF+RR = 50.2%, RF+LR= 49.8%
Front weight = 50.7 % Rear = 49.8%

I was a little surprised that the car is still really balanced after 40 years of use.

[cda951]

Those are great results, thanks for sharing.

For any street-driven 944 with rubber suspension bushings, as long as your ride heights are even front and rear (as measured using chassis hard points per the factory manual), there is no reason to get carried away with achieving perfectly even cross weights as espoused over the years by numerous articles that litter the interwebs (and probably made worse by LLMs/"AI").

This applies even to those who have converted to coilovers front and rear---unless the suspension is all spherical/monoball bushings and bearings. If there are factory-style bonded rubber bushings in the system, there is inherent bind---by adjusting individual corner heights to achieve ideal corner weights, one is applying unequal jacking forces on the suspension, which negates the theoretical goal of achieving even handling characteristics in left and right turns.

Real race cars achieve proper weights by first moving weight around, and then by altering jacking forces (but again, spherical bearings ensure there is minimal bind in the system).

EDIT: after replacing suspension components with OE-style bonded rubber bushings, one should "zero" the bushings and remove preload by placing the vehicle on its wheels and on blocks (or on a drive-on lift, preferably one with slip plates) and loosen all bushing through-bolts/nuts, jounce the vehicle, then re-torque fasteners. Even better if this is done with at least one sway bar link disconnected at each end. Then measure ride height, check corner weights if you want, then four-wheel alignment.

[walfreyydo]

Poly bushings should also achieve the same as spherical bushings since those are not under load like rubber bushings (has a lubed inner sleeve), but are obviously a little softer than spherical.