Well yes and no, it depends on what load the car was designed to see. I can see how the load would increase if you say, but big stickey tires and stiff suspension. All that would do is cause the loads to shift AWAY from the suspension and into the frame. Once that happens i'm sure you'll see bigger loads back there. Then i'd do a modified design of the both and make it a fully boxed system with mofidied v components in the center (more like a torsion bridge). BUT the system is going to be STIFF and hence your ride and NVH (Noise, vibration, harshness) will suffer.
good luck
-bix

 

But, with a solid rear TRAILING axel as in the Fit, what effect is body re-enforcement going to have on rear camber?

 

Really in regular day to day life, nothing, but like i mentioned when you start to really put large stresses, i can see it controlling the amount of negtative (or positive). Weither that is good or bad, I don't know, it just depends on how Honda designed the suspension and what type of maximum loads they looked for as well as what they designed the body to do near that maximum load.
-bix

 

Do you understand the concept of a beam trailing arm suspension?

Bodyflex will have no impact on camber in the rear. The axel takes the forces, the body has the springs/struts, etc, but will not impact camber.

This is not the case in a IRS car, where this will be a factor as you point out.

You could take a torch and cut the back of the car off like a truck chassis and there would be no effect on camber as the axel is still a fixed unit that trails from its piviot with two springs.

 

If you guys are looking for a serious track car out of the Fit I would advise you to give up and get a 1988 Civic hatch or CRX. The Fit is certainly a fun car to a point, but is someone honestly going to multi-link a torsion beam rear end? I highly doubt it.

There are plenty of things already on the market to make the Fit more Fun but I think you guys are over-thinking this one.