my understanding with a rotary would be that there wouldn't actually be a redline if you could keep the fuel/air ratio good because its not like a piston engine where the valves start to float at redline and that causes major probs. If you could keep the fuel/air ratio good, couldn't a rotary keep climbing in rpms until the tranny gives out or until you max that gear out. could someone tell me why rotaries have redlines?

 

There is always going to be a limit on how many revolutions anything can take. If its spinning to fast it can't get propper oil lubrication.. the oil will just spin right off... also at some point you just stop gaining power and start to loose power.. so there is no point in going past your peak power range.

 

well, if there is no such thing as friction, then i think your idea of a rotary engine not having a redline would be valid

 

-overheating quicky
-Friction on bearings
-stationary gear start cracking at 9k
-clucth SCATTER
-belts/accessories flying off

 

Don't forget that after a while the eccentric shaft will start to flex, causing the rotors to come into contact with the housings.

 

Two words: Centrifugal force. That's why there is a redline.

 

Intake/airflow limitations.
Dre--flying off accessories LOL. Ever shatter a PS/WP/AC pump? Not a pretty sight. I also have a shattered pulley out of a domestic V8. It was poorly constructed like a lot of aftermarket parts out there. I'll try to find it in my bucket of junk.
Early centerforces use to scatter. Not sure if they fixed that problem. There was also someone here with a flywheel with lots of cracks. They are lucky that it didn't explode. Flywheels are like saws--after they cut through your floor and legs, they might hurt the public.
The oil issue is windage and aeration.
Yuck, flexing Eshafts. Rarely mentioned and a good call Josepi.

 

whats the difference between the s4 and s5 that give the s5 a 8000 redline and the s4 a conservative 7ooo redline?

 

lighter rotors for one thing!

 

stronger stationary gear I believe
lighter rotors so less strain on E-shaft.

Some other little things here and there.

 

Not too fast...the S5 turbo has a 7K redline. If you'll ever look at a stock s5 TII dyno, the turbo starts loosing effiency (i know i spelled that one wrong) around 6.5K

 

Power band and redline = two different things =P

 

Yes, but on most setup's its very close... and there is no point going to redline if the power band is over.

My motorcycle redlines at 10k, I shift at 7.8k cause thats when the Dyno said I begin to loose power... the next gear drops me right around .. 6.3, right back in my perfect power band.

Depending on the gear... results a ~9 second quarter mile.

 

no one has mentioned the limits on the apex seals and springs, themselves, yet. they will have various RPM limits (depending on material) and will simply start to break.