Quote:
Originally Posted by Frank Lee
That sounds like so not working on the street!
Extra carrier bearings = more driveline friction; extra u-joints = more driveline friction; extra carrier bearings and u-joints AND slip joints = more driveline mass.
I went the other direction on a '74 Chev pickup. It had a 2-pc shaft, I replaced the u-joints and carrier bearing only to have vibration afterwards. Just by dumb luck I came across a 1-piece direct replacement about that time. Put it in there, things got smooth, and I never looked back.
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Compretery agree with Frank, here.
Adding rotating mass, bearings, slip-sections, and Universal/CV joints (depending on your driveline setup) will NEVER increase your FE, unless your original equipment was so far out of whack you shouldn't have been driving it.
After working for a company in Binghamton, NY, I designed a 1 piece CV shaft for FWD cars that had no bearings and would still flex under suspension loads, worked out the design w/ the engineers, and had it blueprinted. Don't care enough to apply for a patent, honestly, since I can prove intellectual property.
Maybe, some day, I'll get around and work on it. Probably not, though. It would be alot of work for minimal gain. You simply don't lose
that much energy through the CV shafts or driveshaft.
For your friend, I'm sure he found something, but I don't know if I believe 15HP from harmonic vibration. Why haven't I heard about this on every other (professional) BSF racer?