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Naturally Aspirated Performance ForumDiscussion of naturally-aspirated rotary performance. No Power Adders, only pure rotary power!
From the "12A" to the "RENESIS" and beyond.
I know there was reference around somewhere about leading deep recess vs medium deep recess for rotors but I can't remember where it was and I thought I'd be a horrible tease.
Abusing work resources and using their Zeiss 3d scanner to get the internal and rotor face geometry of as many rotors as I have handy... RX-8 internals are done (well, it was dead, I wasn't shy about scanning the inside) and S3 12A and S5 NA face geometry coming next week. I'm working on foundry stuff and iron might be not too much of a stretch, in which case I have to think about new production 12A rotors but different than OEM. Thus why I was wondering about LDR vs MDR.
Anyway, I'll get some scans up when I get to it, not like this place is very active.
There's one page devoted to the subject in the Yamamoto book, is that the kind of info you're looking for? I think there's also an SAE paper floating around that covers it a little more.
If you're going to go to the trouble of making the casting molds, keep in mind LDR rotors are front and rear specific whereas with MDR only one mold needs to be made.
Thank you kindly; that's about what I remember. Part of the whole point of how I'm doing things is predicated around more low production methods than Mazda did, so I'm pretty sure I can get by with comparatively cheaper molds; put a different way, I'm not too bothered by needing side-specific features.
It's all pretty preliminary, but gotta have an end goal, right?
Printing patterns for sand for casting was the intent yeah. Trying to stretch capabilities a bit, so why not have a potentially useful project rather than something that's definitely a paperweight? I saw the 8C designs but I'm not trying to do direct injection nor fuel economy focused things.
One way to see what's inside for the scanner. Already scanned the exterior.
Wasn't finished but pretty good show of the detail even before optimization. Yeah not perfect but enough of the structure is there in the scan to build off of and fine tune with calipers
Honestly impressed it picked up the side seal grooves to that extent, considering.
Other side WIP - again some of the fine details are a pain in the butt to get on scan but good enough to get geometry from.
Probably throwing 12A rotor and S5 NA rotor on tomorrow, just for exterior stuff (mostly the combustion chamber face, honestly)
I think I saw some reference to that being done even on the older rotors... which reminds me, for all the talk of "maybe these are some kind of nodular iron they weld different than grey iron" maybe I should send a chunk of one out for composition testing while I'm at it.
I think I saw some reference to that being done even on the older rotors... which reminds me, for all the talk of "maybe these are some kind of nodular iron they weld different than grey iron" maybe I should send a chunk of one out for composition testing while I'm at it.
787B is rumored to have something different for rotor material, so you could too
787B is rumored to have something different for rotor material, so you could too
Yeah; I'm still at the "trying to figure out some of the parameters Mazda was using" stage. In an ideal world where I have room in my life to follow through on all of this, I want to do some practical lightweighting and performance optimization within the scope of "this is a cast iron rotor" as SCCA for one allows technical freedom in a lot of ways as long as the bits are still cast iron. Rough shape reverse engineering is easy, reverse engineering to fully understand design intent and production compromises is harder, and actually making physical rotors is... well, I think I can see many of the steps between here and there but remains to be seen if I can get there. If nothing else I might just put the CAD models and design notes up somewhere and try to tempt someone with a bigger checkbook, there's some foundries that do 3d printed sand cores for iron casting that'd be well suited for this sort of thing.
