NoPistons -Mazda Rx7 & Rx8 Rotary Forum

NoPistons -Mazda Rx7 & Rx8 Rotary Forum (https://www.nopistons.com/)
-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   How Do You Get Some Revvs Out Of A Rotary. (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/how-do-you-get-some-revvs-out-rotary-19187/)

Apex13B 06-21-2003 03:25 PM

you can always buy an older Cosworth HF series V8, they rev to about 17k https://www.nopistons.com/forums/pub...1047683785.gif I have one at the shop for sale, only about $45,000



you'll need a lot more oil pressure also, The rule of thumb is 10 lbs per 1000 rpm

TyresmokinRx7 06-21-2003 04:13 PM

I've hear and seen a 13B peripheral port rev to 10500 RPM, but he had spent close to $12,000 on the motor. Poor bloody motor, now that's going around fast, 175 times per sec for 6 seconds, then she https://www.nopistons.com/forums/pub...1047683517.gif

pengaru 06-21-2003 04:29 PM

conceptually the rotary is capable of quite high rpms, but I personally feel mazdas implementation is limiting, the weight of the rotors, lack of intermediate bearing support on the eccentric shaft, and choice of material for the apex seals (along with size and design) all come into play.



of course, these can all be modified, but it comes down to how much you want to spend. gururacing has the two piece eccentric shaft with intermediate housing needle bearing support, you can get lightened rotors (though they are still relatively heavy iron pieces from what I've seen, I have yet to find rotors for the 13B made entirely from scratch in lighter materials in the aftermarket world) increasing oil pressure is not very difficult, there are ceramic apex seals which are lighter and wear less than stock helping to prevent float and allowing use of uprated apex seal springs without eating up the rotor housing.



however, if you consider the fact that we do have motors with ~10lb pistons moving in a planetary motion that still rev higher than most stock reciprocating piston motors comparably priced, it is impressive... now just imagine if someone like porsche or lotus invested time and money into the design and made rotors from more ideal materials, with less attention to cost.

cryptokid 06-21-2003 09:22 PM

very good info guys.



so, 2 piece needle bearing eshaft, check.



now, wheres a good deal on some ceramic seals?



how about rotors? who makes some good lightend and balanced rotors?



i want atleast 12K rpms. i dont want to go "all out" but i want to do it for a reasonable price without sacrificing anything. (imagine doin 50mph in first gear!)



the oil pump, i can do myself. i have a good deal of expierence in machining pumps to tighter than stock clearences. when i left the vw world, i was pushing 160psi oil pressure with drilled and tapped galleys. vw as in porsche 914's anyways. (porsche 914 is basically a vw, or atleast i consider it to be)



anyone know how much judge ito charges for port work? i could probably do it myself , i have a good ammount of expierence porting vw's and motorcycles. but looking at ito's work, the man seems to take pride in what he does, and i like that. and im sure he could port my housings better than i would ever able to do, because he has expierence in rotarys, somthing i do not.



guys, i need more links. all the rotary sites i been to looking for parts only carry little bs things like plug wires and air filtera and cai's. i need the special internals already mentioned.



thanks.

motoracer47 06-22-2003 12:03 AM

whats a resonable price? https://www.nopistons.com/forums/pub...IR#>/blink.png ultimatly, the ultra-light weight rotors are about 2grand a set(only performed on new rotors), ceramic apex seals=1200-1400, the guru e-shaft=dont know for sure, but id bet at least 2grand, all the seals and gaskets=about 800-1000, if your going to be revving i would think new bearings throughout=another 300? lightweight flywheel and clutch=500 or so,balance the whole assembly=200? plus other things that im not even aware of. Im guessing for what your wanting to do 7-10,000 for the engine. oh yea, all numbers above us dollars.

cryptokid 06-22-2003 01:30 AM

bearings i can do myself. (lathe)

flywheel and clutch i can do myself (lathe) and it only costs $20 to get em dynamically balanced @ my local street and strip builder.



but how do you get 800-1000 for engine seals? jesus ******* christ on a pogostick, i could hand cut seals if its going to be that expensive.

motoracer47 06-22-2003 10:37 AM


Originally Posted by cryptokid' date='Jun 22 2003, 12:30 AM
bearings i can do myself. (lathe)

flywheel and clutch i can do myself (lathe) and it only costs $20 to get em dynamically balanced @ my local street and strip builder.



but how do you get 800-1000 for engine seals? jesus ******* christ on a pogostick, i could hand cut seals if its going to be that expensive.

[





800-1000 is the prices ive seen for complete (all rotor,and engine seals,gaskets, and such) of coarse thats retail, you might get it on ebay for about 600. Im not for sure if you would need brand new bearings, however im curious how you would manufacture bearings on a lathe? I believe they are cold rolled steel with the babbit coating? joined by a puzzle piece which is then ground down. Wouldn't cutting them on a lathe remove the babbit? How do you turn a clutch? flywheel i can see, but a clutch? have any pictures? Hand cutting seals, hmm so how i think the engine would fry in 10 minuets, but if you can pull it of, go for it! Ultimatly it sounds like your wanting to take the engine alot higher than the factory max rev rating of 8500rpm, and no matter which way you look at it, 14000rpm is gona cost money. Just like the old saying goes. horespower costs, how fast do you want to spend? https://www.nopistons.com/forums/pub...>/evildeal.gif

motoracer47 06-22-2003 10:48 AM

actually, on the seals, the various prices you will find will be for various kits, the price i quoted was for the complete kit, (almost every seal/gasket in the engine)however, it also somes with apex seals and springs which you would not need because of ceramics. https://www.nopistons.com/forums/pub...1047683664.gif

j9fd3s 06-22-2003 01:27 PM

a buddy of mine was revving his bp to 10.5, and he didnt have any trick parts, just careful assembly



mike

motoracer47 06-22-2003 01:46 PM

cool,10k is what im going to shoot for with my n/a project(though id be happy with 9500) i think crypto is wanting to get to 12-14000 rpm, just not sure if thats possible without some trick parts.


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