What would it take to get like 11 or 12 thousand rpm out of a na s4,5 13b. best i can tell all i need is 3 window berings oil pump and some serius ports to flow at that rpm. just wondering if it is posible to do it or if anyone else has done it.

 

why would you want to run that high of rpm? cause that is abuse to the engine and you dont need to go that high of an rmp anyways.

 

you would need some very serious ports to get that rpm. i know a lot of people like the idea of a rotary because of it's ability to rev, but that's kind of ridiculous for anything less than a full-on racecar setup. And you'd need to build the entire engine, this wouldn't be a do-it-on-the-cheap type of project.

 

Oiling system has to addressed as you stated, the ports have to be able to flow enough as you stated and the harde$t hurdle to overcome is e-shaft flex.

The old way to address e-shaft flex was to lighten the rotors to minimize e-shaft flex and machine the rotors narrower so when the e-shaft does flex they don't hit the housings as well as make the bearings sloppy clearance at the ends so the e-shaft doesn't seize to the bearing there when it flexes.

Still not very reliable over 9,000rpm, but known to go to 12,000rpm for a while...

The new way is to lighten the assembly and make a 2 piece e-shaft w/ a bearing added in the intermediate housing to help reduce flex. Guru Motorsports of Australia makes a kit for this.

The highest I have read w/ this kit is 14,000rpm- don't know for how long ...(remember even a stock engine can do that on a missed shift and has a chance of surviving).

 

Apex seal wear goes up exponentially with RPM.

Why bother? If you like high RPM, buy a new 600cc sportbike, it'll be cheaper in the long run, and the short run too.

 

Good point on the apex seal wear! Also an increase of abnormal rotor housing wear!

The old school way of dealing with this is to use carbon/aluminum apex seals which are light and low friction, but wear quickly and are fragile (can't withstand detonation).

The new way of dealing with this is to use ceramic apex seals which are also light and low friction and in addition wear extremely well and are fairly robust (can withstand some detonation).

I think that us individuals trying to push the performance envelope of the rotary in any way is great as Mazda is really watching and taking notes.

RX-8 has some of our racer tricks build right into its Renisis along with Mazda's own new tricks in order to raise its redline and make more power.

If we keep pushing the envelope perhaps someday Mazda will build a center bearing production 13B...

 

A clutch/flywheel designed for that RPM as well.

-S-

 

scatter shield or ballistic blanket to prevent death? (of the driver, not of the engine)

 

LanceC,

The faster and faster an engine spins, the lesser and lesser time it has to inhale air.

B

 

The RX-8 eshaft is machined with taper in the journals to accomodate the shaft flexing so there is no need to run a larger bearing clearance with it, atleast for what the RX-8 limits are I'm sure if you actually built an engine cranking 10k+ you would want to machine another .0001-.0002" of taper into the end of each journal. At lower rpm though this would increase the load on the part of each bearing closest to the rotor.

This is not to say it is the best way to solve the problem, the support bearing is probably the best that can be done. Also flexing of the excentric shaft consumes power, you may gain 1-5 hp or so by using the 2 piece shaft with larger gains at higher engine stresses.