The series 4 rotors are cast in the combustion area of the rotor faces, whereas the series 5 rotors are machined in there. This is the easiest way to tell.
Brian

so which is better/stronger, casting or machining?

I like the lower CR of my S4 though.

I honestly wouldn't worry about it. Honestly, the only time you'll ever have to even consider thinking about this, is if you'll be pushing the engine to it's ragged edge, like in drag racing and pushing 30+psi, etc, etc. I wouldn't worry about which is stronger, because it's not a "problem area".

Yes the rotors are not much to care about its more the seals. but no one has yet to answer my question. does anyone know if they are stamped a-e for series or a-whatever being s4 and whatever-e being s5. Im not concerned about the strength as much the compression increase.

The series 4 had it's own set of letters of A-E that are specifically for the series 4 rotors, and the series 5 had letter stamps A-E for strictly series 5 and 6 rotors (they weigh the same). To answer your question, An "E" stamp on a series 4 rotor is not the same weight as a series 5 with an "E" stamp.

2lucky you the man. thanks alot.

Zenki rotors are the strongest.
Even the big rotary shops in Japan typically use the Zenki FC turbo 8.5:1 rotors in big boosted builds cause they don't dent as easy as the Kouki FC turbo or any of the FD rotors.

The machining allows for tighter tolerances between rotors, but it thins the rotor faces significantly.


-Ted

WOW! I just read over this entire thread and I have to simply say THANKS! I just learned so much more. This is what this forum is all about, sharing knowledge and information with others.

LONG LIVE THE "7"

Here you go guys... http://www.mazdatrix.com/r-rtrwgt.htm