| He is a head configurator for a shuttle program at Boeing and specializes in materials. I asked him about this whole thing and there's a few things to note: (these are gross simplifications of what he told me) A driveshaft is so small in diameter that as a rotating object, saving a few pounds here and there is not worth paying extra money for. You will NOT gain HP from an aluminum driveshaft, over a steel one. any two-piece driveshaft is going to be MUCH stiffer than a one peice. as long as both have fresh joints. It's natural frequency will be so much higher that it will not be subject to the same possible vibrations of the one-piece unit. He thinks people claiming Hp gains are just experiencing fresher U-joints and happiness as a result of that. Perhaps some slop is removed since there's no longer a rubber donut around the center bearing. Steel is the way to go. Aluminum-- in order to have the same strength as steel has to be so thick, that--it will weigh the same as steel, once you're done making it. Steel also has a higher natural frequency than Aluminum and will tend to not get "excited" by your car's lower-frequency vibrations, from the engine, road, etc. CF--his jury was out on that one. He warned that while the CF fabric itself is strong, the glue holding it together is only so strong and must be taken into consideration. While we know intellectually, that people make them and they work, he was wondering how they bond the CF to the steel ends and make it any stronger, or even as strong as steel. Why would it be worth the weight-savings and BIG extra $$ if it's got any compromises from the strength of plain old steel? that said, I odered a PTI steel today for my NA rear-end TT car. _MWS
Crash Test Dummy(tm)
"taking it on the chin so you don't have to..." |
