8.8 swap
does the same loss apply to up and down offset too?
Any time the direction of power is shifted there is a loss. Question is how much?
So I did a little google searching about drivetrain power losses.
Fairly useful article here:
http://www.modified.com/tech/modp-1005-drivetrain-power-loss/viewall.html
Basic points:
There's a rule of thumb that says you should expect 15% power loss in the drivetrain. Likely it's somewhat higher, but varies a lot. Higher for automatic trans over manual, higher for 4wd, lower for fwd.
The diff is the biggest source of loss, due to transferring power 90 degrees. Expected loss for the typical hypoid gear set is 6-10%.
The tranny is expected to generate 0.5 to 1% power loss.
Getting to the point, d-shaft loss is expected to be 0.5 -1%.
Common sense says the 15 hp per degree angle loss is just silly. A u-joint absorbing 15 hp will be transferring the energy to heat. I think 15 hp would make it red hot in short order. Likely the comment came from gross misapplication of the 15% rule of thumb.
Bottom line, loss from u-joint angle should be minor and likely will affect u-joint life more than anything.
Other points of interest I ran across:
Stronger diffs typically have higher losses - example the Ford 9" uses deeper gear mesh for more contact, higher strength but more friction. Likely minor.
Engine driven fans can consume 15-20 hp! I think I'll look into the electric fan option.
