OK if our engines turn the rotor 1/3 the speed of the output shaft, they don't have any valves to float and there is no change in inertia (piston going from up to down) WHY DO WE HAVE A REDLINE? and a relatively low one at that all things considered.
What is the weal link? Is it the computer controlling ignition? Is it injector duty cycle?

so many other things can rev higher then our cars and with less technology, and more moving parts
anyone have some light to shed on this?

 

For one, the performance of apex seals are going to be negatively impacted by very high RPM's. They will start to "float" and won't seal well.

 

Plus, there are components outside of the engine that need the revs limited. For example, at only 10k rpms, some flywheels will, *ahem*, fly apart.

 

My pops had a RX3 and he said the most he revved it to was 11k! my jaw droped when I heard him say "well it was past the numbers on the tach but I'd say it was 11 or maybe 12 grand..."

 

An aquaiuntance of mine had a secondary bridgeport on a 12A that he routinely shifted at 14,000 RPM. It would rev to 7,000 RPM like stock, and from there like there there is no tomorrow. The power would not drop off no matter where he shifted. However, the car had absolutely no top end and sometimes did not catch the powerband in 3rd gear. He used to rev this same 12A to 10,000 RPM in stock form but it didn't seem to breathe too well up there. Needless to say he blew the motor.

 

well the question still remains What is teh limiting component that makes mazda say "that 's it we can't let it rev any higher"
Flywheel.... maybe
anyone have any other thoughts.
I know shifting at hih rpms is harder on our synchros in the tranny

 

Assuming all the external stuff was strengthened or geared down accordingly, the engine will still have issues revving really high. The engine is balanced, but there are still large pieces of metal that aren't just spinning on their centers. The eccentric shaft flexes, apex seals float, you run out of air flow (the stock FD is running out way before redline, for example). The inertial loads become greater and greater and stuff starts to contact each other or breaks.

I heard an old rumor that Mazda let a 12A rev with no load as fast as it would go. The story was that it revved to 21,000 RPM and then self destructed.

For piston engines, the loads from inertia at redline are far greater than the loads from tranmitting the power produced by combustion. I don't think it is as easy to calculate for a rotary, but I am sure that there are similar forces at work.

-Max

 

Anyone know how high the 787B revs?

 

The 787B is quoted for max HP of 700 at 9000rpm. Pretty impressive for a motor with assembled crankshaft. Still, nothing beats an F1 Ferrari 3liter V-10 screaming at 18000rpm. Now that's LOUD....

 

I would like to see a custom Rotary made to hit 30k, just for ***** and giggles... never be able to stick it in a car but still cool knowing that you set a world record for RPM's

 

heh, $hits and giggles...

 

True rotary engines can rev upwards of 25k rpm. These are known as the DKM type. Mazda's rotaries are the KKM type.