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Originally posted by armstrkw:
No its not a 1.3 Liter, its a 2.6 Liter. The way they calculate 1.3 is subjective. The engine is just as big as yours!!!
If you want to know more about it read sport compact car May's edition.
Do you measure your cars displacement with just the displacement of one cylinder?? Well, thats what Mazda does on its Renesis's engine.
Don't go around telling people its a 1.3 because it is clearly not.
Feel free to enlighten those of us who have failed to grasp the complete automotive authority and technical prowess of SCC.
Mazda's 1.3 Litre figure is not the measure of just one rotor, as you suggest. It is the measure of the swept combustion volume of the engine--the same approach applied (with simpler mathematics) to 2-cyle and 4-cycle reciprocating engines--and since each of the two rotors sweeps 654cc's worth of fuel-air mixture during a compression 'stroke', the math is valid.
If you have an alternate formula for rotary engine displacement that can be applied to piston engines as well, then I am certainly open to consider it. It might also be valuable to Mazda as well, since they certainly appear to have been in error for quite a while now.
B. Riley
Melbourne, FL
'01 Camry LE V6/5-spd
Was: '00 Black/Tan SVT Contour #560 - Sold 3/26/03
Before that: '95 Champ/Blue Contour GL V6 ATX
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Right, I am sorry it came out kinda wrong each of mazda's chambers is 654cc making it a 1308cc when having two chambers. However this is only counting two stroke's when all regular engines are calculated using a 4-stroke method. All I am saying is that this Renesis engine is breathing just as much as your 2.5 L. When you say its a 1.3 then you are saying it breaths like a prius engine which is clearly not the case. If thats the way you want to think about it the go right ahead!!! Just doesn't seem locical to me!!!
Canada = little France
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Originally posted by armstrkw:
Right, I am sorry it came out kinda wrong each of mazda's chambers is 654cc making it a 1308cc when having two chambers. However this is only counting two stroke's when all regular engines are calculated using a 4-stroke method. All I am saying is that this Renesis engine is breathing just as much as your 2.5 L. When you say its a 1.3 then you are saying it breaths like a prius engine which is clearly not the case. If thats the way you want to think about it the go right ahead!!! Just doesn't seem locical to me!!!
I'm not sure where or why you are including the number of cycles or 'how it breathes' in your determination of displacement. Displacement is just that - combustion chamber volume (L^3, in dimensional analysis speak). Not volume per cycle or volume per crankshaft revolution. It is not a function of crank theta or omega. It is the swept volume of each combustion chamber multiplied by the number of combustion chambers.
Indeed, 2-cycle piston engines have their displacements calculated the same way as 4-cycle versions: (pi/4)(bore^2)(stroke)(N), where N is the number of cylinders. However, their breathing (and power output) characteristics are quite different. But these characteristics are not captured by engine displacement.
B. Riley
Melbourne, FL
'01 Camry LE V6/5-spd
Was: '00 Black/Tan SVT Contour #560 - Sold 3/26/03
Before that: '95 Champ/Blue Contour GL V6 ATX
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Why would I include that?? Because people like you go around saying that the engine is a 1.3 L and never really explain why this really can't be compaired to a normal engine. All that I ask that if you are going to call it a 1.3 then explain why it doesn't behave like a 1.3 when compaired to 4 stroke engines.
Canada = little France
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does it really matter? none of us get paid the big bucks to run the mazda rotary projects....
the car looks good and goes fast....isnt that the point?
--Chris--
1999 Silver Frost SVT
#1671 of #2760
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Originally posted by armstrkw:
Why would I include that?? Because people like you go around saying that the engine is a 1.3 L and never really explain why this really can't be compaired to a normal engine.
Yeah, I 'go around' telling people it's a 1.3L, just like Mazda says. Just last Saturday, I strolled around my neighborhood--with a Mazda brochure in hand--telling everyone of its size and specific output. It really consumes my every waking thought. 
Quote:
All that I ask that if you are going to call it a 1.3 then explain why it doesn't behave like a 1.3 when compaired to 4 stroke engines.
I'm "calling it" (as if I arbitrarily picked a number ) a 1.3 Litre engine because its displacement is derived from the very definition of engine displacement. It is engineering fact. Grade school mathematics. Refer to my previous posts if you've forgotten.
If Mazda--the leading automotive developer of Wankel engines--has been using the wrong method of deriving the displacement of its engines for so many years, then perhaps you could put your expertise to work and share with us the formula that you propose should be used, and supporting reasons behind why it should deviate from the method used to calculate displacement for 4-cycle piston engines. Might be a good idea to share it with Mazda, and any 2-cycle engine makers out there also. They've probably been doing it all wrong.
B. Riley
Melbourne, FL
'01 Camry LE V6/5-spd
Was: '00 Black/Tan SVT Contour #560 - Sold 3/26/03
Before that: '95 Champ/Blue Contour GL V6 ATX
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Look dumb a$$, I said you were right the displacement is 1.3L, this is however very misleading. You should call it a 1.3L-rotary like anyone with some intelligence would call it. There is a simple matter of when you compare it to a conventional engine you can not say that it behaves like a 1.3L it is more like a 2.6 due to the face of it being a two-stroke engine.
"On a four stroke, there's only one intake stroke for every two revolutions, so from a breathing standpoint, displacement is how much combustion chamber volume gets sucked in over two revolutions. For a rotary, with one intake stroke per revolution, that means measuring two combustion chambers per rotor, not one, like Mazda says.
Each chamber in a 13B displaces 645cc, so by Mazda's two-stroke method, a 13B is 1308cc. When comparing it to a four-stroke method, which it is what we are doing when we compare it to other cars out there. One ends up with 2616cc."
My point, saying that the RX-8 has half the displacement of my 2.5L is just not correct. You are comparing apples and oranges. Though you would not be correct calling it a 2.6 L you would be a little closer.
-I am not saying that Mazda is wrong, I just think there is a better way when comparing the renesis to regular engines.
-High school math? Must have missed that in engineering
Canada = little France
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Originally posted by Blk560:
I'm not sure where or why you are including the number of cycles or 'how it breathes' in your determination of displacement. Displacement is just that - combustion chamber volume (L^3, in dimensional analysis speak). Not volume per cycle or volume per crankshaft revolution. It is not a function of crank theta or omega. It is the swept volume of each combustion chamber multiplied by the number of combustion chambers.
Indeed, 2-cycle piston engines have their displacements calculated the same way as 4-cycle versions: (pi/4)(bore^2)(stroke)(N), where N is the number of cylinders. However, their breathing (and power output) characteristics are quite different. But these characteristics are not captured by engine displacement.
...If Mazda--the leading automotive developer of Wankel engines--has been using the wrong method of deriving the displacement of its engines for so many years, then perhaps you could put your expertise to work and share with us the formula that you propose should be used, and supporting reasons behind why it should deviate from the method used to calculate displacement for 4-cycle piston engines. Might be a good idea to share it with Mazda, and any 2-cycle engine makers out there also.
So when the questions get tough, the names start flying?
Anxiously awaiting a toned response to the questions posed, particularly with respect to how you would characterize the displacement of a 2-stroke piston engine by applying the 'cycle' concepts you're trying to apply to the Wankel.
TTFN...see ya Monday (traveling for Easter).
B. Riley
Melbourne, FL
'01 Camry LE V6/5-spd
Was: '00 Black/Tan SVT Contour #560 - Sold 3/26/03
Before that: '95 Champ/Blue Contour GL V6 ATX
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I have no life
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so when i'm talking about a turbo'd engine I have to say it's 2.5L but it behaves like a 4L or 5L? Or how about the meguiar's focus, it's a 2.0L (may be bored a bit larger) but it behaves like a 20L??  get real. it's a 1.3L. yes it's a wankel and makes power differently, still it's a 1.3L.
98.5 SVT
91 Escort GT (almost sold)
96 ATX Zetec (i brake to watch you swerve)
FS: SVT rear sway bar
WTB: Very cheap beater
CEG Dragon Run - October 13-15
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Turbo is different, the displacement is still the same just more O2.
Canada = little France
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