RX8 E-shaft vs 13B-RE/REW shaft

[joff]

Originally Posted by REVIT93RX7

You're just missing the point. But I think what we need here is more data.

I agree more data is always good, but I think Glen has a very unique and valuable perspective here -- he actually broke one and followed up with Mazda to understand why and found something very interesting about tempering that has not been brought up before and should not be forgotten.

The facts I didn't know that I've gathered from this thread:
1) RX8 e-shaft is cheaper than RX7 one
2) RX8 e-shaft is lighter.
3) RX8 e-shaft was designed for a car that makes much less torque than the RX7 ever made.
4) Mazda does not temper the RX8 e-shaft, but does on the RX7 one.
5) An RX8 e-shaft has been broken by a prominant engine builder.
6) Tempering, as an extra step in manufacturing, inevitably adds cost.

Fact #5 proves that whatever was the particular failure mode experienced in Glen's build, in that particular instance the RX8 e-shaft was the weakest link.

Fact #6 brings into question the presumption that the RX8 eshaft is cheaper because its newer, as being cheaper because its cheaper to build actually makes more sense when it comes down to it IMHO.

Wikipedia has this to say about the process characteristics of tempering. Apologize if everybody already knows this, I personally did not:

1) Improves ductility and toughness
2) Reduces cracking
3) Improves machinability
4) Increases impact resistance
5) Improves malleability

#4 seems especially like something that might be good for anything inside an internal combustion engine.