Hi,

when considering torque and HP curves,

does a rotary RPM = a normal 4-stroke RPM?

-joe

 

yup.
RPM is a measure of how quickly the output shaft spins. if you're asking "how fast do the rotors spin", then no: the rotors spin at 1/3 the speed of the output shaft. also, a single rotor'd engine will have twice as many power strokes per output shaft revolution (which is one power stroke per rev) as a 4 stroke single piston engine would (which is one power stroke per two revs)...

 

so is it still legit to compare rotary dynographs to 4-stroke dynographs? My question basically stems from the Renesis' 9k rpm limit... shoudl I be as impressed with this as I am?

 

Sure it is...why not? Power & torque are just what they are, and the crank speed is what counts.

 

absolutely... it's not as if the rotary is cheating to get those nine-thousand output shaft rpm. the torque per revolution and power at a certain rpm is directly comparable to a "regular" four stroke piston engine.

so in short yes, you should be that impressed when you see that the RENESIS is better than the Honda F20C (S2000 motor) in almost every respect: dimentionally smaller, lighter, higher redline, more peak power, more torque at every point in the rev range, flatter torque curve (no "on cam-off cam" behavior), at least competitive emissions-wise, and possibly even better on fuel consumption in a larger vehicle (by 200 lbs or so).

 

:D

 

i'd just like to admit that all of that stuff i posted i got from Buger :D he be da man.

 

Absolutely. In addition, a two-rotor rotary has two power pulses per crankshaft (eccentric shaft) revolution, just like a 4-cylinder reciprocating engine.

 

that's true, but i think because the power stroke lasts for 270degrees of output shaft rotation (the eccentric shaft or "e-shaft" for our friend ProConVert) as opposed to 180 degress for piston engines, the power strokes overlap more similarly to a six-cylinder engine than four.

to avoid confusion and explain the longer power stroke, i'll refer back to the fact that the rotor itself spins at 1/3 the speed of the e-shaft. the power stroke for the rotor itself lasts only 90 degrees of rotation, from TDC (combustion side) to BDC (expiration side), which translates into 3 e-shaft degrees for every 1 degree of rotor rotation: that equals 270 degrees of e-shaft rotation per power stroke.

 

Basically, the Renisis is a damn good ratary, and the new porting is the main reason, the longer the stroke, the more power, and as has been mentioned because of the 1 combustion per 3 revs, u save fuel , and get a higher redline and a good compression ratio which all adds up to good Hp :D

 

uhhh... i lost you after "the Renisis is a damn good ratary"...

 

sorry dude lil typo there

ROTARY ROTARY ROTARY ROTARY (a thousand times)