repuguru

The question in one of the threads came up about the amount of torque a 4 rotor crank shaft must endure?
Does anyone know?
Of couse the shaft would be weaker than the 3 rotor and 2 rotor. What did Mazda do to beef this up with the 787b? What about the guy in NZ cutting the special billet shafts. Is he doing the same thing Mazda is?

Rotortuner

I will bet on the 787 they streangthened it somehow. I wonder if tehy did not have speacial ribs cast into it or something. not sure but i would kinda like to know. not sure anybody realy knows about the 787 though. not many have seen the inside. hehaaa.

cjg

David Hu$tlerhoff

don't forget the 787 is a non-turbo, it "only" makes eeh ~700 hp? something like that, i'm not sure. and you can reach that hp with a stock shaft. the only problem could be high rpm
my 2 euro-cents

95MX6

The 787B engine wasn't that high of rpm, if memory serves me corretly they set the redline @ 8,000rpm for qualifying and 7,000rpm for the 24hr race. If you apply the hp formula (hp=torque * rpm / 5252) you can see the 787B 4 rotor developed 450-550ft/lbs. I would guess they reduced the stress on the shaft by placing a bearing in the middle, since shaft flex can cause the rotors to come into contact with the housing and a 4 rotor shaft is awful long.