shaolinwog

I'm running a 13B n/a, running the standard rotors and stand apex seals its rare you see many upgrades for the actual rotors i was wondering if anyway has ever seen/heard of anyone to use the RX8 rotors in the old FC3S 13B engine?



any opinions/suggestions would be appreciated



Sean - in search of 10,000rpm everyday

krazy13

Haven't heard anything about using the rotors... HOWEVER I have heard of using the eccentric shaft and you can loose about a half pound. It requires modification to use it but less rotating mass is less rotating mass.

shaolinwog

hmmm not a bad idea, with anyluck it should be a bit more balanced aswell although i'm just speculating that. If fitting RX8 rotors seems an impossible task other than changing the rotor apex seals, has anyone got any other suggestions to make the 13B be able to handle this sort of high end rpm and continue to be smooth and balanced???



I have heard about porting the rotors but i'm not sure if what all the gains are from this and is this going to upset the rotors balance at high rpm??????

j9fd3s

people have tried the rx8 rotors, but they arent a bolt in deal, they need a lot of work, and dont seem to be any better than the late 9.7 rotors power wise.



best setup for an na 13b rotating assembly is;



89-91 9.7 rotors

rx8 e shaft

light flywheel/clutch combo

rx8 stationary gears



balance the whole thing, and run 100+ psi of oil pressure



the next hurdle is to actually make it have power up that high...

Kalito_Racing

I beleive Mazdatrix tried this out already, they have a writeup on their site about it. They did not find any significant differences and so recomend the 9.7 comp rotors like j9fc3s mentioned.

sen2two

you have to machine them among other things...lots of $, not big enough gain.



the compression jump isnt where the power gain is either...



its that the rotors are beveled slightly and lighter. just get the internal set up that j9 stated and before you get them balanced, have them beveled (some people call it chamfing). it opens the ports earlier and closes later (like porting up or down on the intake ports). plus, the weight drop is extreme depending on how far you go. but if you go to much, the side seals come into risk.

j9fd3s

chamfering.

NOPR

Using the RX-8 shaft with FC rotors is a bad idea. You'll still be using FC counterweights, but they'll have to be rebalanced due to the lightness of the eccentric shaft. this actually involves ADDING weight to the counterweights to compensate for the lighter e-shaft. This weight will be further away from the center of rotation than the weight from a stock FC shaft which is in the shaft itself, and the overall effect is more rotational resistance with an RX-8 shaft and proper balancing.



The RX-8 stat gears also sort of suck. They are made of lower quality material and they dont have the oil seal ring groove on them.

defprun

I need you to touch my car in the only ways you know how...sexily.

sen2two

a bit off topic, why cant we use earlier 13b rotors in the renesis? is it the side seal placement???