pinion angle change

[jerome]

I had originally planned for a 3link that had a shorter third link, but I really don't have any packaging issues or a specific reason to make it shorter, and I figure a single crossmember would be easier than two.



So, here's my question. How should the pinion angle change in bump and droop?
1. no change relative to ground
2. no change relative to driveshaft
3. tilt up
4. tilt down

are most of the third links that people make, just shorter because of packaging? or is it because the want the pinion to tilt down under bump and tilt up under droop?

everything I have read about pinion angle says that it is NOT a tuning factor for acceleration and you won't find extra tenths by changing it. however, I haven't been able to find what the ideal change or lack thereof should be. I have heard a rough guideline for the correct pinion angle change as the third link is 2/3 the length of the other two. But, I would rather just make the 3rd link the same length to make it simpler to construct. Any disadvantages?

Thanks,
Jerome