Rotors Magazine Lots of people (myself included) want to buy a rotary car (RX8 are really cheap right now). Make a video about what new buyers need to watch out for!
steph sek i wouldnt buy a rx8 2 much problems and they are heavy if u want to get into rotary buy a fc cheaper on parts then a fb only thing good out of a rx8 are the rotors to be honest
Oliver Zbinden glad I don't live in europe then. None of my cars would be cheap to insure and probably wouldn't be legal anyways. My 91 bmw 318 has a 2002 camaro ls1 6speed combo, hell, all three of my cars have an ls1 in them. Best thing I ever did to the rx7, more useable power under the curve, better gas mileage, and cheaper to maintain. It's a first gen rx7 so i didn't "deface" an fd twin turbo...although I would if I had one...
My personal view on this topic: 0,654L is the air a rotor can displace in one turn me thinks (the 3 gaps the rotor constantly creates in the chamber). So, a 2-rotor engine has indeed 1.3L of air volume. And since a rotary engine cannot compare to any other engine, the true volume is 0,654L per rotor since it gets this volume per turn. The 2 and 4-stroke engines have their specified volume in its combustion chamber per cylinder when the piston is in its lowest point. Tha's how the engine dispacement is done. Rotors have a constant volume that intakes, sparks and exchausts its air-fuel mixture 3 times per turn and that's why it makes so much power and is able to reach so high rpms for such low volume. And that's why it consumes so much fuel also. But Honda S2000 reaching almost 10K rpms, consumes almost the same amount of fuel as the RX8, producing almost the same power and torque. So, the size and weight of the rotary engines are the main pros helping to create 50/50 weight distribution in sports cars. No need to put those engines in family cars or GTs. These engines are the recipe for handling machines. Let's wish Mazda manages to bring them back to production sometime soon-ish using new techs (hybrid tech maybe?) to reduce emissions and consumption.
giorx5 Can a rotor handle multiple displacement like many V8s (shutting down cylinders when all aren't needed)? That would be one way to reduce emissions and fuel consumption.
joerapo that could be possible on the 3 and 4 rotor designs, depending on the ecrank's positioning for each and also having a way to lubricate the apex seals without it not flooding the rotor and exhaust with unburnt oil
Sorry, but that is not how displacement in any engine is calculated. You must use the total volume of air displaced in the same number of shaft rotations need to complete the engines firing order sequence. 2-stroke Benz-Cycle 360° 4-stroke Otto-Cycle 720° 4-stroke Wankel-KKM 1080°
.65 + .65 =1.30 which is 1.3l since one face fires and completes revolution with the second trailing. That one face .65 is half the complete cycle. The face of the second rotor literally trails it a.65 so with three rotations of the e shaft 2 rotors have fired one face at a time. And only one rotor is firing at a time. So that one face on each rotor is the only measurement you can take. Its a 1.3l no matter how many faces it has because only one face fires at a time.... again .65 +.65 gives you 1.3l period there is no argument
RR made it a diesel, but it had very low braking force, where as a diesel ic have good braking force. If the breakthrough works, it may be good for cars, but not for trucks. If they can get the fuel consumption right. In a boat-test, a 100 HP two-stroke, used 44 litres petrol, and a 4-stroke 100 hp used 28 litres, for the same work.
Im glad you explained this but its funny how this debate starts when a rotary this or that mops the floor with any piston engine after a race,im 2jz now but always been IN LOVE WITH THE BRAP!
Displacement of engine is volume of displaced air, sucked into engine, after all pistons/faces have fired, under condition of 100% volumetric efficiency. If every face of rotaty engine can displace 0.65L of air, total displacement after all 6 faces have fired is 3.9L. Engine is called 1.3 because of tax reasons. In Europe some countries have luxury cap on 2L and above. In Japan I think it is about 2.5 or 3L. For Kei cars, it is 0.66L, so they might use single rotor for Kei car. And as rotary is very rare and not very much people understand it, Mazda could say whatever they want.
Exactly. The practice of only counting 1 chamber per rotor started at NSU (first builders of the Wankel) at the suggestion of Max Bentele (visiting engineer) to avoid EU displacement taxes.
There's actual displacement and then there's "but to compare to a piston engine" displacement. a 13B engine is 1.3L period, some people bitched about it and thats where this 2.6L/3.9L non-sense comes from. Below is an explanation that I think explains both sides very well: Wankel engines can be classified by their geometric size in terms of radius (rotor center to tip distance, also the median stator radius) and depth (rotor thickness), and offset (crank throw, eccentricity, also 1/4 the difference between stator's major and minor axes). These metrics function similarly to the bore and stroke measurements of a piston engine. Displacement is 3√3radius·offset·depth, multiplied with the number of rotors (note that this only counts a single face of each rotor as the entire rotor's displacement, because with the eccentric shaft - crankshaft - spinning at three times the rate of the rotor, only one power stroke is created per output revolution, thus only one face of the rotor is actually working per "crankshaft" revolution, roughly equivalent to a 2-stroke engine of similar displacement to ONE rotor face). Nearly all Mazda production Wankel engines share a single rotor radius, 105 mm (4.1 in), with a 15 mm (0.59 in) crankshaft offset. The only engine to diverge from this formula was the rare 13A, which used a 120 mm (4.7 in) rotor radius and 17.5 mm (0.69 in) crankshaft offset.[citation needed] As Wankel engines became commonplace in motor sport events, the problem of correctly representing each engine's displacement for the purposes of competition arose. Rather than force the majority of participants (driving piston engine cars) to halve their quoted displacement (likely resulting in confusion), most racing organizations simply decided to double the quoted displacement of Wankel engines.[1] The key for comparing the displacement between the 4-cycle engine and the rotary engine is in studying the degrees of rotation for a thermodynamic cycle to occur. For a 4-cycle engine to complete every thermodynamic cycle, the engine must rotate 720° or two complete revolutions of the crankshaft. The rotary engine is different. The engine rotor rotates at 1/3 the speed of the crankshaft. On two rotor engines, front and rear rotors are 180° offset from each other. Each rotation of the engine (360°) will bring two faces through the combustion cycle (the torque input to the eccentric shaft). This said, it takes 1080° or three complete revolutions of the crankshaft to complete the entire thermodynamic cycle. Obviously, there is a disparity. How can we get a relatable number to compare to a 4-stroke engine? The best way is to study 720° of rotation of the two-rotor engine. Every 360° of rotation, two faces of the engine complete a combustion cycle. 720° will have a total of four faces completing their cycle. 40ci(654cc) per face times four faces equals 160ci or 2.6L. That's a well-reasoned number and now gives something that can be compared to other engines. In addition, since four faces passed by in the comparison, it’s like a four-cylinder engine. The 13B therefore compares well to a 2.6L 4-cylinder 4-cycle engine.[1] By using the same formula, calculating actual displacement in which 1080° is the complete thermodynamic cycle of a rotary engine and a total of six faces completing their cycle, 40ci(654cc) per face times six faces equals 3924cc, 3.9L, or 240ci, in reference to a Mazda 13B rotary engine. "Each face has a swept volume of 40ci(654cc) and there are a total of six faces. With this known, the engine displacement should be 40ci(654cc) times six to equal 240ci(3.9L)."[1]
*Unless your engine does not intake, fire or exhaust an air charge every third crank rotation then you sir just proved its a 3.9 liter in total displacement... you can't have it both ways.*
Bradley Smith my 12a not stock at all full bridge 12a monster street port running a 48 webber down draft it all depends how u drive but im always on mine 100% throttle
1.3l is correct if you look at it the way the manufacturer looks at it. Only two faces fire 🔥 per power stroke/ i.e. Turning thermal energy into kinetic energy 13b= bang bang/applied motion. 2.0l piston engine= bang bang bang bang/ applied froward motion I feel 1.3l is the the most accurate displacement description
When mazda came out with the rotary they said it's a 1.3l, now every dum ass comes up with their own theory just because a 1.3litre rotary makes too much power
+MrChayl3 *Mazda didn't come out with the Wankel engine... they bought it from the company that invented it...NSU. NSU concocted the bullshit method that was used to cheat the tax collectors in countries where registration is based on engine size... today you pay the much higher amount based on the larger true displacement.*
NUCLEAR WANKEL ENGINE But there is a way, says Mark Adams, an MIT-educated physicist and former staff member at the Lawrence Livermore National Laboratory in California. He has designed an engine that he calls an “internal” rotary engine, rather like the kind of Wankel engine that has been around since the 1950s. Instead of pistons going up and down, the engine has a rotor that rotates around a crank shaft. The rotary engine that Adams envisions looks diagrammatically very like a schematic of the rotatory engine that Mazda introduced to varying degrees of success in its cars in the 1970s. It works like this: A small amount of gasified “nanofuel,” which contains nuclear material mixed with hydrogen, is ignited by a neutron source to set up a controlled fission reaction, creating heat and propelling the rotor forward and driving the crank shaft. The fuel can be derived from the transuranic parts of spent conventional nuclear fuel or can be created separately.
All 3 faces should count towards total displacement. That being said its a 3.9L engine that you can pick up by yourself, so still a great innovation. Also makes up for the terrible MPG.
Looking at that diagram you provided (good job btw lol 👌🏼) I would say the rotary is more of a hybrid between 4 stroke and 2 stroke.. looks like it's a 3 stroke as the intake stroke is separate from the compression stroke, but then the ignition and exhaust are basically the same stroke.. pretty cool if you ask me! Can't wait to rebuild my rx8 this summer.. still runs decent with 210xxx km on it! 😝
Have had 4 rotary powerd cars in my life, love them, now I own a Honda but I'm going to start looking for another rotary powerd car, as soon as I can, love the content 👍
Here in California, the very first government agency was formed to introduce motor vehicle emissions standards in 1967, still the strictest air pollution standards in the world, Diesel fueled vehicles have always been classified as clean, low emissions vehicles and were even EXEMPT emissions regulations and the bi-annual testing program for 30 years. Yes, it is possible to observe something and still not understand what you are seeing.. especially if you are not knowledgeable on the issues.
@@doktorbimmer +SuperRage Oholic if you keep telling doktorbimmer that he will start crying. Wankel engines are intimately related to his type of schizophrenia. WANKEL ROTARY ALL THE COMPANYS WILL BE MAKING WANKEL ENGINES ONCE AGAIN
Citroen and Van Veen also experimented with Wankel, but only NSU and Mazda had Wankel commercialized. A nice thought to rotate instead of the existing up/down engines, but some bad hooks: bad compression control, bad fuel consumption and bad CO2 creation.
I believe the reason that it's 1.3L from factory as you stated is that 4 cycles happen on 1 E shaft rotation an as stated thats the amount of air expelled from 1 rotation. Equally understand that for comparison. The 2.6 makes more sense as piston takes the 2 rotations to complete the 4 cycles. But yeah people gonna hate if it's a 1.3, 2.6 or a 3.9. People always hate what they don't understand.... Loving the Cosmo BTW.
Why not compare BSFC between the rotary and some typical 1.3, 2.6 and 3.9L 4 stroke cycle engines? Obviously that doesn’t measure displacement and is meant as a measure of efficiency, but it might show where the rotary most closely resembles a 4 stroke reciprocating engine.
Having owned six first-gen RX7s (and rebuilt a few rotaries) I'm in the 2.6L camp. The crank completes three rotations for every single rotation of both rotors. Therefore, each rotor fires on two of their three faces for every two rotations of the crank (eccentric) shaft - which is the same number of rotations required to complete the full cycle of a four-stroke engine, which the rotary definitely is. Since a total of four rotor faces produce a power "stroke" during these two eccentric shaft rotations we get 4 x 0.65L = 2.6L displacement. Incidentally, that works out to two power strokes per revolution for a two-rotor engine, the same as that of a 4-cylinder piston engine. But here's where things get interesting: The duration of the power stroke in a piston engine (as the piston is forced downward from TDC to BDC) is 180 degrees of crankshaft rotation. In a rotary, the duration of the power "stroke" is 240 degrees of eccentric shaft rotation - 50% longer than that of the piston engine. This provides a longer and smoother power delivery per power cycle, and the extra 50% in degrees of power stroke length is the equivalent of having an extra two cylinders (50% of four cylinders = 2 cylinders, 4 cylinders + 2 cylinders = 6 cylinders). That fact, combined with the absence of reciprocating components, is why the rotary runs as smoothly as it does.
Many thanks for this video. I have been pondering myself how to measure the true volume of a rotary engine. As you say in a 4 stroke cycle engine there are 4 components to that cycle. Now as the 4 stroke cycle in a rotary takes place in 360 degrees as opposed to a piston engine this takes place in 720 degrees. So we also have 3 chambers per rotor so i say that a rotary is similar to a 3 piston engine per rotor. So a twin rotor is actually similar to a 6 cylinder piston engine. So in a 2 rotor engine with 6 chambers of 650cc that makes it 3900 cc . If you then add that there are 2 firings in 720 cc compared to a piston you could consider the 2 rotor to actually be 7800cc for 720 degree cycle. The other problem of a rotary compared to a piston is that in a piston the power stroke lasts 180 degrees but but in a rotary that is 90 degrees. So the work available is for a much shorter duration. The other problem is that a piston engine has a much larger Crank or lever moment so produces much more torque compared to a rotary. But will not rev a fast as a rotary. I will admit to loving rotaries but never had the balls to actually buy one. I loved the RX8 R3 that i nearly bought a few years ago.
Put a 13B on a dynamometer with an airflow meter. Run the engine at a known speed and measure the airflow. Calculate the volumetric efficiency. You can't get the same numbers saying that the engine displaces 1.3, 2.6, and 3.9 liters. Only one displacement will yield a vol eff number in the range of 100%. That would be 1.3 L. The other "displacements" would yield numbers of 50% and 33%. The key detail is that the volumetric efficiency of an internal combustion engine is defined on the basis of mass air flow through one thermodynamic cycle. This is not only a function of piston displacement, but also of valves controlling the airflow. It takes two revolutions of the the crank in a 4-stroke engine to complete one thermodynamic cycle, but only one revolution of the camshaft. That's because it's the camshaft that controls the airflow.
If we compare two crank revolutions of the piston motor to two eccentric shaft revolutions on a rotary is that not equivalent to 2.6L? Hence, why racing series and insurance companies often view the rotary as a 2.6L.
Very very interesting! Very good work. Something I have never really thought about. I am also in the camp of don't really care. The only replacement for displacement is Rotary. Rotary life
All things considered I would say you should not compare it to 4 or 2 stroke. It's a rotary! For me a 4 stroke has to have valves. Thats why i also understand why people comepare it to 2 stroke specially when it comes to sound.
Thanks for posting your videos Kenny. You are in the camp of not caring but how many liters do you think the 13B engine is? I just found your channel. Why does Mazda recommend not using synthetic oil for their rotary engines? I used to use synthetic in my 91 13b but a very experienced rotary engine mechanic at Mazda convinced me to reluctantly change to mineral oil. He kind of said I would not understand why. What do you use?
Edward Dergosits In a nut shell, they recommend not to use synthetic oil if you are still running the stock oil metering pump. The reason for this is conventional oil burns easier. The Oil Metering pump (OMP) injects oil into the rotor housing much like a fuel injector to help keep the apex seals lubricated. The OMP tends to quit working, so the most common fix is the remove the OMP all together and premix the gas using two stroke oil. Once you’ve done that you are safe for synthetic. Just our $.02!
That is the best explanation I have heard Kenny. I assume that using synthetic would cause the catalytic converter to be overloaded. I replaced the OMP two months ago. Pricey fix it was.
It's nice that Mazda placed this engine in low insurrance rate... ;-) Thanx SO much, loving fan of your worki, with crash on RX8 revolution and beloved by all family 323F from 1998 :-)
I'm reluctant to say that this notion really makes sense, even if that's how it's officially measured. I'd say that an engine's displacement is best described as the volume available for one power stroke's fuel mixture, before compression, all "cyclinders" combined. (i.e. how much mixture could ideally be burnt per power stroke, if the engine was naturally aspirated). No crankshaft revolutions in this definition.
I have compaired the 2 roter to a v6. Same number of "cylinder's" so yeah 3.9L. Except for the number of power strokes which is the same as a v8, two per one revolution. No wonder people get confused about the rotary.
Ye I had an rx 8 for 10 lovely months b 4 it blew a seal due too cat failure, am also an engineer an I agree with the 2.6 litres as if you compare too a normal in-line 4 engine 2 crank revelations is what we would measure too then using the same amount makes for a more equal comparison 👍🏼
Good video except at 4:52 he says a rotor has six faces (it has 3). The confusion comes from when the Wankel was first invented, and displacement was based on 1 revolution of the output shaft. As it takes 3 shaft revs to complete 4 strokes per face, one rev will fire only one face of each rotor, and the two rotors of a 13B provide 2 combustions per rev, ie 1.3L PER REV. To be consistent with a 4 stroke piston engine, 2 shaft revs yield 2.6L displacement.
Only problem with this video is you keep stating displacements as a fixed value. A rotary engine does not only displace 1300cc's. A Mazda 13b(A) engine displaces 1300cc's per combustion. You kept stating several times that "rotaries" have a value of 1.3 liters. This is wrong terminology, a rotary engine can come in several different sizes, just as normal piston engines come in different sizes. Yes, the mazda 13b is the most common.
Internal Combustion Engines are known being linked to low Effective Compression Ratio, these first times because of poor quality of available gasoline. If changing the plug hole to an slot as Ernie Brink proposes, reduces greatly the Exhaust Gas Temperatures, this would mean a much higher Effective Compression
Not just RX7 and RX8. The old Mazda cars are the best. Very big in drag racing and on the street. R100, RX2, RX3, RX4. You should change the title of this video.
This makes sense ... 2 rotations = 2.6L and 1 rotation = 1.3L ..... So I would be correct when saying that a 1.3L Rotory is equal to a 2.6L engine. .... air volume speaking.... yep it does make sense.... thanks for that good info ...
Exactly! It's equivalent to a 2.6L 4-cycle piston engine in terms of air volume. Notice the exact wording of this; I'm not saying that's it a 2.6L engine, merely that it's equivalent!
Each face would need to be counted as an individual cylinder. A traditional piston can only have one cycle happening at once. In a rotary, when one face is in the Ignition cycle, one face is on intake and the other is exhaust, so it can have three happening at once. Also, from ignition to complete exhaust is a half turn of the crankshaft. It is literally just a 3 cylinder engine in one object, therefore, if each face can house .65L of air, then each rotor would be equal to 1.95L, so a two rotor would be 3.9L (or a 3.9L 6 Cyl), a 3 rotor would be 5.85L (or a 5.85L 9Cyl), and a 4 rotor would be 7.8L (or a 7.8L 12 Cyl). The traditional Engine Displacement definition can literally not be applied to a rotary, even if you replace "piston" with "rotor", because you would have to basically pretend the other two faces of the rotor aren't doing anything. I propose a new definition: "Rotary engine displacement is the swept volume of all the rotors inside the rotor housings of a reciprocating engine in a single movement from Top Dead Centre (of the ignition stroke) to Bottom Dead Centre of the crankshaft times 3 (to account for the 3 faces of one rotor)."
Yes, basically, it's because the Wankel rotary engine's displacement isn't measured in the same way as a piston engine. If you measure a 6.2L LS3 the same way Mazda measured the 13b to end up with 1.3L an LS3 would be a 3.1L engine. What many people have a hard time with is keeping the ENTIRE engine, all 6 faces of the rotors on a 13b, in mind at once along with the Wankel's 3:1 ratio. During operation, because there is a 3 to 1 ratio between the rotors and the eccentric shaft or e-shaft (equivalent to the crankshaft) that means for every 1 revolution of the e-shaft the rotors turn 120 degrees (1/3 of a revolution) which is the number of rotor degrees necessary to complete one phase on each rotor face. This results in 1 intake, one compression/power, and one exhaust PER rotor (although there is overlap because the second rotor is phased or "follows" the first for balancing reasons). This means in 1 revolution of the e-shaft the entire engine's swept volume displacement is .65 * 3 faces * 2 rotors= 3.9L. The main reason, I think, for this odd way of mesuringdisplacement that Mazda used that resulted in the 1.3L rating, only counting one rotor face per rotor, is because, esp. in Japan, insuring a 1.3L sports car is much cheaper than a 3.9L sports car as well as the fact that Japan has an absurd "displacement tax" so the smaller the rated displacement of the engine the better.
Someone shoulda further developed the rotary. Think about it, a 2 rotor engine has 3 moving parts, not much friction really and you could make higher compression rotors. Oil injection with the fuel would also help a lot with wear cos the fuel goes everywhere in the intake stroke and gets spread in the housings and irons. Youre gonna say something about pollution but put a DPF on it or rather an RPF(rotary particulate filter) and youd have clean emissions. Just a thought
Kenny Mckee"5:40-5:45" some arcadic reason for?????? Mazda's reason makes perfect since if you understand how displacement is truly calculated. In this whole video, you completely forgot the basics of how displacement is calculated. Displacement is calculated by firing the measured volume of air per cylinder or chamber in a "SINGLE COMBUSTION" event and not multiple ignition events. That's why it's rated as a 1.3L. In a 4 stroke 4 cyl piston engine, you need 2 rotations of the crank to ignite 4 individual cylinders to get the full total displacement (1 spark each). In a rotary, 1 e-shaft rotation gets you 1 ignition event per chamber to ignite .65L of air each chamber times 2 (1 spark each). Your video did a pretty good job of explaining but, the key words are SINGLE IGNITION EVENT. So when comparing to a piston engine, all you have to do is compare the amount of air moved for each e-shaft rotation. That's why it's comparable to a 2.6L 4 stroke piston engine because both engines will move the same amount of air and have the same exact amount of ignitions events.
APEX SEAL LEAKS INSIDE THE ENGINE ON COMPRESSION STROKE THIS WHY YOU GET 80LBS ON A COMPRESSION CHECK THIS ENGINE IS 5 TO 1 RATIO WHEN IT LEAKS INSIDE THE ENGINE LOOKING FOR A 10 TO 1 ROTARY
1.3L makes perfect sense if you will stop bashing those of us that maintain that the rotary engine is really a two stroke. A 4 stroke engine uses a full stroke (piston at TDC to BDC) for each phase, intake, compression, power, exhaust. While a two stroke technically has all 4 phases, but each phase only takes 1/2 of a stroke. A single piston 4 stroke engine fires once every 2 revolutions, while a 2 stroke fires every revolution. A rotary engine fires every revolution making it a 2 stroke engine. Remember, a stroke is 1/2 rotation of the crankshaft, not a phase described as intake, comp, power, exhaust. In a 4 stroke engine the strokes are thus named because each phase uses a single stroke, but don't project that naming convention to the stroke. The definition of the word stroke = "noun 1. an act of hitting or striking someone or something; a blow." You description gets confusing because of your initial assumption that the rotary is a 4 stroke. If you assume that the rotary is a 2 stroke, it all works out nicely. Nothing confusing about it. And as we all know, 2 strokes make more power / displacement than a 4 stroke, simply because it fires twice as often!
Boss man says they get the 1.3 measurement from one crankshaft revolution. They measure a piston engine at two crankshaft revolutions so if they measured the 13b at two crankshaft revolutions 2.6l I believe they decided to go with the 1.3 because in Japan under 2.0 is cheaper to run..
Piston engine takes two crankshaft rotations for one oto cycle. The rotary takes 3 eccentric shaft rotations for one oto cycle, but there are 3 faces so there is one power stoke per rotor per eccentric shaft rotation! 1.3, 2.6. or 3.9? 1.3 is best for insurance purposes. Note that most racing rules had a conversion factor for rotary versus piston; 2.0 was common...
Your explanation is wrong though. "Engine displacement is the swept volume of all the pistons inside the cylinders of a reciprocating engine". Problem is, the rotary doesnt have pistons and it is not a combustion engine with reciprocating motion. The rotors are basically the "pistons" on the Wankel engine. In a four stroke, two full revolutions of the crankshaft are required for all the pistons to have fired at least once. In the Wankel engine, for each revolution of the e-shaft, two faces fire at the same time. If I go by your logic, that would mean the rotary needs 3 revolutions of the e-shaft for all the faces to fire and not one, so the bond with the 2 stroke engine kinda goes away. It is hard to really understand the displacement of a rotary, but you got it wrong. The difference lies in your example. A 4 cyl four stroke has four combustion chambers, so you need all the four pistons to fire at least once for you to know how much air got into each combustion chamber. So if two pistons fired once, the other still have to, so you can't tell the displacement until then. On a rotary, there are two combustion chambers. All six faces have 654cc. But only two of them, one per rotor, for each revolution, has a power stroke. In one of the rotors, if face number 2 let's call it, has a power stroke, face number one is the intake stroke and face number two is in the exhaust stroke. But don't misunderstand this. Even if I said the faces were on some "strokes", you shouldn't treat them as pistons. That is the tricky part. But you don't consider exactly how MUCH air the engine is taking. If by one single revolution, in the 4 cyl, only half of the maximum intake of air has gone into the engine, in the rotary, in one single revolution, the maximum air intake has already been reached, which, in the case of the 13B, is 1.3L. You just keep adding air for all the six faces as if the engine could take more than 1.3L, you're just repeating the cycle. The reason for all the power of a rotary is indeed because of how fast each power stroke succeeds one another.
*Sorry, but the Wankel KKM IS A 4-STROKE so we calculate displacement at 1080° NOT 360°* *Its not that difficult to understand... each orbiting piston(rotor) has 3 sides forming 3 combustion chamber volumes, each with a swept volume of 654cc. times the 2 housings is 6 and equaling 3,924cc.* *The other important thing that people without formal engineering experience fail to understand is that a 4 cycle Otto or Diesel engine completes its firing sequence in 720° of crankshaft rotation while the 4-cycle Wankel KKM designs required 1080° of rotation to complete its firing sequence...* *These two important and often misunderstood details are the basis of the commonly used "2X" conversion formula for accurately "comparing" the displacement of the Wankel with other designs..* *_Any questions? I would be happy to explain in more detail..._*
great info when you line up a apex in the leading plug hole you see two chambers at the same time HEAT IS NO GOOD so two keep your turbo and engine in great shape you must stop the flames that are inside the engine before it ever comes out of the housings
Maybe we should measure displacement between all engines on how much Air is displaced over 360 Degrees of rotation. I would think you need a common denominator with something they all do no matter how many strokes. Then you could measure the fuel used per 360 degrees.
A 4-stroke engine requires 720° degrees of crankshaft for all the combustion volumes to complete its firing order sequence. The commonly accepted method is 360° for 2-Stroke engines and 720° for 4-stroke engines. The Wankel is a 4-stroke engine. This is why the Mazda 13b is considered to be a 2.6 liter when comparing hp-per liter.
let say we compare one 4 stroke engine with a rotary engine with same displacement , example 1.2 litre, the 4 sroke take 2 revolution to burn out 1.2 litre airfuel- mixture but rotary engine take 3 revolution, so rotary engine burn less airfuel-mixture compare to 4 stroke engine with same engine rpm.
*All Wankel engines are 4-stroke... but require 3 revolutions. This why the 13B is considered a 2.6 liter when comparing to other 4-strokes even though the true displacement is 3.9 liters in total.*
Good educational vid, bt I count it that there is an ignition event every 120 of 360 degrees of the eccentric shaft, mayb it'd be easier to explain with a single rotor engine
Actually, there’s a combustion event every *180* degrees of e-shaft rotation. Very much like a 4 cyl. On older Rotaries that had a single dual-post (wasted spark) coil for leading ignition, you could run the engine leading only on most standalone EMSs by setting it up as a 4 cylinder 4 stroke with a single ignition output (like a distributor) and then just hook the single output to the leading coil. 4-cylinder engines have a combustion event every 180 degrees. IF you look at an actual e-shaft, the lobes are offset by 180 degrees as well.
Basically the closest way to compare doritoz to pistons is by comparing both at two crank turns, for example like he said a 13b at two turns equals roughly 2.6 litres & since four sides fire the closest comparison would be a 2.6 litre four cylinder which is why they are registered as 2.6 litres, for me that's the only measurement because the comparison is always going to be against a four stroke piston engine
the answer is in the slide show and very easy. You need to measure it from the "flywheel" perspective. One revolution of the flywheel or E-shaft = 1.3 liters of air pulled into the engine. Mazda is correct.
This makes so much more sense now. 24mpg from a 1.3L didn't make sense to me, but 2.6L is more understandable for the 24mpg figure. I think your right that the engine isn't a two cycle, but it still lubricates like one. It isn't really a true four cycle either. I'd just call it a Wankel cycle. Because Wankel stroke would be the butt of too many jokes.
One of the fundamental flaws in the Wankel design was the troublesome shape of its internal components... cylinders and spherical shapes are ideal for ensuring even and consistent thermal expansion and contraction and the clearances between the moving parts, stationary parts and most importantly the sealing parts... Like the Newcomen steam engine, one of the Wankel's major flaws is that it is required to maintain high temperatures and colder temperatures with in the same housing, high wear rates and low thermal efficiency is the end result.
When asking why a small displacement engine can make big power, it's because displacement is irrelevant. What is relevant is airflow, because an engine is an airpump. That's why the same engine with different heads, cams, etc makes different amounts of power.
Yes you are correct but NOT different amount of torque ....an NA 13B is nowhere close a 2.6L in torque let alone a 3.9 Lit. So rotary (in real life not calculations) is equivalent to 2-2.2 piston in power and torque ....... and nobody actually bothered to answer HOW is the capasity of the 0.65 lit measured..... is all the "air"/"water" one housing can include or one rotor face..... from WHAT degrees up to what degrees? .....
I clicked on this video because the heading said "The SECRET Behind Why RX7 and RX8 Rotary Engines Make SO Much Power". Not how a rotory works in difference to a piston engine, I am still none the wiser. I wish people would reference their videos appropriately!
You're correct. His method of explaining displacement is...hmmm...interesting. In a machine shop, when you get your V8 bored, the method of determining overall displacement isn't the way he explained it. It's actually much simpler: en.wikipedia.org/wiki/Engine_displacement Whereas the actual volume of the intake charge happens INDIVIDUALLY and each face is fired INDIVIDUALLY and each cycle happens INDIVIDUALLY, it then follows to measure the displacement accordingly. The video description is tantamount to saying, "Well, because a turbine engine pumps 'X' CFM of air, it's equivalent to a 70L engine in size." Hmmmmmm, no. Not at all. It's displacement is it's displacement. Period.
newscooler12316 In fact he got it completely wrong. I don't understand how people can complicate these things so much. A 13B can get a maximum of 1306cc of air, 654cc per rotor. The end. Not 2.6L, not 3.9L. Most people just don't like the idea or are just too stupid to understand.
If you listen, the answer comes in what you determine to be a piston equivalent. Many consider faces of rotors to be a 'piston'. The 'INDIVIDUALLY' argument doesn't work because each piston in a piston engine is ALSO working INDIVIDUALLY. Just like every piston is connected to the same crankshaft, every rotor is connected to the e-shaft. Effectively, what you've said for those that argue each face is a piston is that you can measure displacement of a V8 by taking the volume of 2 cylinders. To use your definition from Wikipedia: "Engine displacement is the swept volume of all the pistons inside the cylinders of a reciprocating engine in a single movement from top dead centre (TDC) to bottom dead centre (BDC)." In a single motion, all 3 faces of a rotor fire. In fact, some people go as far as to say the rotary engine is a perpetual power stroke.
What are you talking about do you have any clue how a rotary runs. A 2 rotor wil fire 3 times per one revolution of the crank shaft. Please stop miss informing people. Because one face will always be in compressed and ignited position while the other is on its exhaust stroke and intake draw. Dude you are miss informing people bad
What should we talk about next on Rotary Theory?
Please talk about the differences between 4-port, older style 6-port , and the Renesis.
Rotors Magazine Lots of people (myself included) want to buy a rotary car (RX8 are really cheap right now). Make a video about what new buyers need to watch out for!
steph sek he did look back at the older video on RX8
steph sek i wouldnt buy a rx8 2 much problems and they are heavy if u want to get into rotary buy a fc cheaper on parts then a fb only thing good out of a rx8 are the rotors to be honest
Rx8’s are not heavy lol
Torque of a 1.3L, power of a 2.6L, fuel economy of a 3.9L. Simple.
evidence.
hey bro need more help FAKE TROLL az616578.vo.msecnd.net/files/2016/08/27/6360787077700554381193066848_Internet-Troll.jpg ON ALL ROTARY SIGHTS
Torque performs like a V8 what are you tryna to say?
@@thatcornfedrx8guy372 BAHAHAHAHAHAHAHAHA....... Like a V8 he says
@@stlchucko so then tell my why modified rotarys use differentials out of torquey Pickups.
It helps to have 1.3 rather then 3.9 car when insuring your car :P
Pecetos in europe (at least where i live) you pay insurance for 2.6l 😉
negative in here it's state as 1.3l ;)
Pecetos not when it’s a twin turbo 1.3l with two seats
actually they have a bench in back with bucket seats so its a 4 seater (even tho nobody can fit in the back except maybe your dog)
Oliver Zbinden glad I don't live in europe then. None of my cars would be cheap to insure and probably wouldn't be legal anyways. My 91 bmw 318 has a 2002 camaro ls1 6speed combo, hell, all three of my cars have an ls1 in them. Best thing I ever did to the rx7, more useable power under the curve, better gas mileage, and cheaper to maintain. It's a first gen rx7 so i didn't "deface" an fd twin turbo...although I would if I had one...
well my insurance costs are pretty happy with a 1.3 L 4 door car ;P
2.6 liter
3.9L
There's a video that explains with math and physics why the 13b is 1.3 liters.
My personal view on this topic: 0,654L is the air a rotor can displace in one turn me thinks (the 3 gaps the rotor constantly creates in the chamber). So, a 2-rotor engine has indeed 1.3L of air volume. And since a rotary engine cannot compare to any other engine, the true volume is 0,654L per rotor since it gets this volume per turn. The 2 and 4-stroke engines have their specified volume in its combustion chamber per cylinder when the piston is in its lowest point. Tha's how the engine dispacement is done. Rotors have a constant volume that intakes, sparks and exchausts its air-fuel mixture 3 times per turn and that's why it makes so much power and is able to reach so high rpms for such low volume. And that's why it consumes so much fuel also. But Honda S2000 reaching almost 10K rpms, consumes almost the same amount of fuel as the RX8, producing almost the same power and torque. So, the size and weight of the rotary engines are the main pros helping to create 50/50 weight distribution in sports cars. No need to put those engines in family cars or GTs. These engines are the recipe for handling machines. Let's wish Mazda manages to bring them back to production sometime soon-ish using new techs (hybrid tech maybe?) to reduce emissions and consumption.
giorx5 Can a rotor handle multiple displacement like many V8s (shutting down cylinders when all aren't needed)? That would be one way to reduce emissions and fuel consumption.
Let's see what Mazda engineers find out in the near future to make it happen.
joerapo that could be possible on the 3 and 4 rotor designs, depending on the ecrank's positioning for each and also having a way to lubricate the apex seals without it not flooding the rotor and exhaust with unburnt oil
Sorry, but that is not how displacement in any engine is calculated. You must use the total volume of air displaced in the same number of shaft rotations need to complete the engines firing order sequence.
2-stroke Benz-Cycle 360°
4-stroke Otto-Cycle 720°
4-stroke Wankel-KKM 1080°
Derpin Bird: LOL, is there anyone on the internet you haven't started a fight with? Pathetic loser.
.65 + .65 =1.30 which is 1.3l since one face fires and completes revolution with the second trailing. That one face .65 is half the complete cycle. The face of the second rotor literally trails it a.65 so with three rotations of the e shaft 2 rotors have fired one face at a time. And only one rotor is firing at a time. So that one face on each rotor is the only measurement you can take. Its a 1.3l no matter how many faces it has because only one face fires at a time.... again .65 +.65 gives you 1.3l period there is no argument
RR made it a diesel, but it had very low braking force, where as a diesel ic have good braking force. If the breakthrough works, it may be good for cars, but not for trucks. If they can get the fuel consumption right. In a boat-test, a 100 HP two-stroke, used 44 litres petrol, and a 4-stroke 100 hp used 28 litres, for the same work.
Agreed!
Im glad you explained this but its funny how this debate starts when a rotary this or that mops the floor with any piston engine after a race,im 2jz now but always been IN LOVE WITH THE BRAP!
Displacement of engine is volume of displaced air, sucked into engine, after all pistons/faces have fired, under condition of 100% volumetric efficiency.
If every face of rotaty engine can displace 0.65L of air, total displacement after all 6 faces have fired is 3.9L.
Engine is called 1.3 because of tax reasons. In Europe some countries have luxury cap on 2L and above. In Japan I think it is about 2.5 or 3L. For Kei cars, it is 0.66L, so they might use single rotor for Kei car.
And as rotary is very rare and not very much people understand it, Mazda could say whatever they want.
Exactly. The practice of only counting 1 chamber per rotor started at NSU (first builders of the Wankel) at the suggestion of Max Bentele (visiting engineer) to avoid EU displacement taxes.
*Great comments... nice to see some educated people in the comment section...*
There's actual displacement and then there's "but to compare to a piston engine" displacement. a 13B engine is 1.3L period, some people bitched about it and thats where this 2.6L/3.9L non-sense comes from. Below is an explanation that I think explains both sides very well:
Wankel engines can be classified by their geometric size in terms of radius (rotor center to tip distance, also the median stator radius) and depth (rotor thickness), and offset (crank throw, eccentricity, also 1/4 the difference between stator's major and minor axes). These metrics function similarly to the bore and stroke measurements of a piston engine. Displacement is 3√3radius·offset·depth, multiplied with the number of rotors (note that this only counts a single face of each rotor as the entire rotor's displacement, because with the eccentric shaft - crankshaft - spinning at three times the rate of the rotor, only one power stroke is created per output revolution, thus only one face of the rotor is actually working per "crankshaft" revolution, roughly equivalent to a 2-stroke engine of similar displacement to ONE rotor face). Nearly all Mazda production Wankel engines share a single rotor radius, 105 mm (4.1 in), with a 15 mm (0.59 in) crankshaft offset. The only engine to diverge from this formula was the rare 13A, which used a 120 mm (4.7 in) rotor radius and 17.5 mm (0.69 in) crankshaft offset.[citation needed]
As Wankel engines became commonplace in motor sport events, the problem of correctly representing each engine's displacement for the purposes of competition arose. Rather than force the majority of participants (driving piston engine cars) to halve their quoted displacement (likely resulting in confusion), most racing organizations simply decided to double the quoted displacement of Wankel engines.[1]
The key for comparing the displacement between the 4-cycle engine and the rotary engine is in studying the degrees of rotation for a thermodynamic cycle to occur. For a 4-cycle engine to complete every thermodynamic cycle, the engine must rotate 720° or two complete revolutions of the crankshaft. The rotary engine is different. The engine rotor rotates at 1/3 the speed of the crankshaft. On two rotor engines, front and rear rotors are 180° offset from each other. Each rotation of the engine (360°) will bring two faces through the combustion cycle (the torque input to the eccentric shaft). This said, it takes 1080° or three complete revolutions of the crankshaft to complete the entire thermodynamic cycle. Obviously, there is a disparity. How can we get a relatable number to compare to a 4-stroke engine? The best way is to study 720° of rotation of the two-rotor engine. Every 360° of rotation, two faces of the engine complete a combustion cycle. 720° will have a total of four faces completing their cycle. 40ci(654cc) per face times four faces equals 160ci or 2.6L. That's a well-reasoned number and now gives something that can be compared to other engines. In addition, since four faces passed by in the comparison, it’s like a four-cylinder engine. The 13B therefore compares well to a 2.6L 4-cylinder 4-cycle engine.[1]
By using the same formula, calculating actual displacement in which 1080° is the complete thermodynamic cycle of a rotary engine and a total of six faces completing their cycle, 40ci(654cc) per face times six faces equals 3924cc, 3.9L, or 240ci, in reference to a Mazda 13B rotary engine. "Each face has a swept volume of 40ci(654cc) and there are a total of six faces. With this known, the engine displacement should be 40ci(654cc) times six to equal 240ci(3.9L)."[1]
Nate Rist you have way too much time on your hands 😂
TJ25 not an argument.
Nate Rist props bro you know your shit!
Yeah i dont know where he pulled the multiple displacement shit out of his ass
*Unless your engine does not intake, fire or exhaust an air charge every third crank rotation then you sir just proved its a 3.9 liter in total displacement... you can't have it both ways.*
An ancient discussion that's just as interesting now as it was way back when. Great video.
By the 3 crank rotation, the 787b had a 7.8L engine (when they said there's no replacement for displacement, they really weren't joking)
all i see is mpg comments lmao if u own a rotary the best part is filling up and adding pre mix ;) 12Agang
Jay Marley 12A mpg is not to terriable with 600km per tank running non premix regular gas
Bradley Smith my 12a not stock at all full bridge 12a monster street port running a 48 webber down draft it all depends how u drive but im always on mine 100% throttle
+Bradley Smith Well, its not too terrible until you consider the 12A makes little power and no torque.
Yeah, but you can't pre-mix an RX-8
600Km per tank??? Lies. That sounds like something that came out of a brochure for a Toyota Prius or Honda Insight.
Why do they make so much power? They rev to the moon
1.3l is correct if you look at it the way the manufacturer looks at it. Only two faces fire 🔥 per power stroke/ i.e. Turning thermal energy into kinetic energy 13b= bang bang/applied motion. 2.0l piston engine= bang bang bang bang/ applied froward motion
I feel 1.3l is the the most accurate displacement description
When mazda came out with the rotary they said it's a 1.3l, now every dum ass comes up with their own theory just because a 1.3litre rotary makes too much power
+MrChayl3 *Mazda didn't come out with the Wankel engine... they bought it from the company that invented it...NSU. NSU concocted the bullshit method that was used to cheat the tax collectors in countries where registration is based on engine size... today you pay the much higher amount based on the larger true displacement.*
NUCLEAR WANKEL ENGINE But there is a way, says Mark Adams, an MIT-educated physicist and former staff member at the Lawrence Livermore National Laboratory in California. He has designed an engine that he calls an “internal” rotary engine, rather like the kind of Wankel engine that has been around since the 1950s. Instead of pistons going up and down, the engine has a rotor that rotates around a crank shaft. The rotary engine that Adams envisions looks diagrammatically very like a schematic of the rotatory engine that Mazda introduced to varying degrees of success in its cars in the 1970s. It works like this: A small amount of gasified “nanofuel,” which contains nuclear material mixed with hydrogen, is ignited by a neutron source to set up a controlled fission reaction, creating heat and propelling the rotor forward and driving the crank shaft. The fuel can be derived from the transuranic parts of spent conventional nuclear fuel or can be created separately.
All 3 faces should count towards total displacement. That being said its a 3.9L engine that you can pick up by yourself, so still a great innovation. Also makes up for the terrible MPG.
Looking at that diagram you provided (good job btw lol 👌🏼) I would say the rotary is more of a hybrid between 4 stroke and 2 stroke.. looks like it's a 3 stroke as the intake stroke is separate from the compression stroke, but then the ignition and exhaust are basically the same stroke.. pretty cool if you ask me!
Can't wait to rebuild my rx8 this summer.. still runs decent with 210xxx km on it! 😝
doktorbimmer could you walk us through the moments you experienced when
you blew up your rotary?
His mind blew A few fuses that day and he hasn't been the same since!
He is A rotary 🌰 through and through but his 🌰 cracked!
Thanks for the vid Kenny. I am in the same boat as not caring but this is great to show people that swear it's a 2 stroke engine.
Have had 4 rotary powerd cars in my life, love them, now I own a Honda but I'm going to start looking for another rotary powerd car, as soon as I can, love the content 👍
Great video, super educational. Explained it better than I have.
I personally always say that the rotary is a 3-stroke since the Power stroke and exhaust stroke happen in the same movement.
Finally, someone understands that a 13b is 2.6 liters! Thank you! Kinda like a 2.6 liter 4 cylinder, except the 13b can rev much higher
This is awesome, I have a 13B and this was eye opening. Thanks
Here in California, the very first government agency was formed to
introduce motor vehicle emissions standards in 1967, still the strictest
air pollution standards in the world, Diesel fueled vehicles have
always been classified as clean, low emissions vehicles and were even
EXEMPT emissions regulations and the bi-annual testing program for 30
years. Yes, it is possible to observe something and still not understand
what you are seeing.. especially if you are not knowledgeable on the
issues.
ZERO TOLERANCE ON LEAKAGE
Ive had 5 rx7s in my younger days... good times
15 bitch.
+Adam Smith 15 year old little bitch maybe? Your'e not even old enough to drive yet.
I had 4 days those were the dayz
@@doktorbimmer +SuperRage Oholic if you keep telling doktorbimmer that he will start crying. Wankel engines are intimately related to his type of schizophrenia. WANKEL ROTARY ALL THE COMPANYS WILL BE MAKING WANKEL ENGINES ONCE AGAIN
definitely would be at the top of its class in displacement to power output which would be a plus in a commercial
Citroen and Van Veen also experimented with Wankel, but only NSU and
Mazda had Wankel commercialized. A nice thought to rotate instead of the
existing up/down engines, but some bad hooks: bad compression control,
bad fuel consumption and bad CO2 creation.
I believe the reason that it's 1.3L from factory as you stated is that 4 cycles happen on 1 E shaft rotation an as stated thats the amount of air expelled from 1 rotation. Equally understand that for comparison. The 2.6 makes more sense as piston takes the 2 rotations to complete the 4 cycles. But yeah people gonna hate if it's a 1.3, 2.6 or a 3.9. People always hate what they don't understand.... Loving the Cosmo BTW.
Why not compare BSFC between the rotary and some typical 1.3, 2.6 and 3.9L 4 stroke cycle engines? Obviously that doesn’t measure displacement and is meant as a measure of efficiency, but it might show where the rotary most closely resembles a 4 stroke reciprocating engine.
Having owned six first-gen RX7s (and rebuilt a few rotaries) I'm in the 2.6L camp. The crank completes three rotations for every single rotation of both rotors. Therefore, each rotor fires on two of their three faces for every two rotations of the crank (eccentric) shaft - which is the same number of rotations required to complete the full cycle of a four-stroke engine, which the rotary definitely is. Since a total of four rotor faces produce a power "stroke" during these two eccentric shaft rotations we get 4 x 0.65L = 2.6L displacement. Incidentally, that works out to two power strokes per revolution for a two-rotor engine, the same as that of a 4-cylinder piston engine. But here's where things get interesting: The duration of the power stroke in a piston engine (as the piston is forced downward from TDC to BDC) is 180 degrees of crankshaft rotation. In a rotary, the duration of the power "stroke" is 240 degrees of eccentric shaft rotation - 50% longer than that of the piston engine. This provides a longer and smoother power delivery per power cycle, and the extra 50% in degrees of power stroke length is the equivalent of having an extra two cylinders (50% of four cylinders = 2 cylinders, 4 cylinders + 2 cylinders = 6 cylinders). That fact, combined with the absence of reciprocating components, is why the rotary runs as smoothly as it does.
Many thanks for this video. I have been pondering myself how to measure the true volume of a rotary engine. As you say in a 4 stroke cycle engine there are 4 components to that cycle. Now as the 4 stroke cycle in a rotary takes place in 360 degrees as opposed to a piston engine this takes place in 720 degrees. So we also have 3 chambers per rotor so i say that a rotary is similar to a 3 piston engine per rotor. So a twin rotor is actually similar to a 6 cylinder piston engine. So in a 2 rotor engine with 6 chambers of 650cc that makes it 3900 cc . If you then add that there are 2 firings in 720 cc compared to a piston you could consider the 2 rotor to actually be 7800cc for 720 degree cycle.
The other problem of a rotary compared to a piston is that in a piston the power stroke lasts 180 degrees but but in a rotary that is 90 degrees. So the work available is for a much shorter duration. The other problem is that a piston engine has a much larger Crank or lever moment so produces much more torque compared to a rotary. But will not rev a fast as a rotary.
I will admit to loving rotaries but never had the balls to actually buy one. I loved the RX8 R3 that i nearly bought a few years ago.
Ty for that answer its always a big debate over my engine. Since i am the only rotary guy in my car club.
Dude niice video, layed out perfect. I got no words for it. Thumbs up.
The most simple way to think about a rotary, in my opinion, is just to think of it as a 3 stroke. Simple and clear.
Hi random question when it comes to assembling the rotary engine using hylomar is the red 100 better than the universal blue
So how much displacement from a 13b with 12a rotors? As you seemed to think that was possible a month ago.
Put a 13B on a dynamometer with an airflow meter. Run the engine at a known speed and measure the airflow. Calculate the volumetric efficiency. You can't get the same numbers saying that the engine displaces 1.3, 2.6, and 3.9 liters. Only one displacement will yield a vol eff number in the range of 100%. That would be 1.3 L. The other "displacements" would yield numbers of 50% and 33%.
The key detail is that the volumetric efficiency of an internal combustion engine is defined on the basis of mass air flow through one thermodynamic cycle. This is not only a function of piston displacement, but also of valves controlling the airflow. It takes two revolutions of the the crank in a 4-stroke engine to complete one thermodynamic cycle, but only one revolution of the camshaft. That's because it's the camshaft that controls the airflow.
If we compare two crank revolutions of the piston motor to two eccentric shaft revolutions on a rotary is that not equivalent to 2.6L? Hence, why racing series and insurance companies often view the rotary as a 2.6L.
Very very interesting! Very good work. Something I have never really thought about. I am also in the camp of don't really care. The only replacement for displacement is Rotary. Rotary life
That's exactly what I always thought ! Have my 13B sitting in my garage looking for a car to install it into some day, thanks bro"
All things considered I would say you should not compare it to 4 or 2 stroke. It's a rotary! For me a 4 stroke has to have valves. Thats why i also understand why people comepare it to 2 stroke specially when it comes to sound.
All Wankel KKM designs are 4-stroke...
Thanks for posting your videos Kenny. You are in the camp of not caring but how many liters do you think the 13B engine is? I just found your channel. Why does Mazda recommend not using synthetic oil for their rotary engines? I used to use synthetic in my 91 13b but a very experienced rotary engine mechanic at Mazda convinced me to reluctantly change to mineral oil. He kind of said I would not understand why. What do you use?
Edward Dergosits In a nut shell, they recommend not to use synthetic oil if you are still running the stock oil metering pump. The reason for this is conventional oil burns easier. The Oil Metering pump (OMP) injects oil into the rotor housing much like a fuel injector to help keep the apex seals lubricated. The OMP tends to quit working, so the most common fix is the remove the OMP all together and premix the gas using two stroke oil. Once you’ve done that you are safe for synthetic.
Just our $.02!
That is the best explanation I have heard Kenny. I assume that using synthetic would cause the catalytic converter to be overloaded. I replaced the OMP two months ago. Pricey fix it was.
Brap stututu
iTZz Kittens compressor surge is bad for your turbo, get a bov
Brap stututu to you too!
Man that was a great explanation. especially since I'm new to rotor engine.great job.
It's nice that Mazda placed this engine in low insurrance rate... ;-) Thanx SO much, loving fan of your worki, with crash on RX8 revolution and beloved by all family 323F from 1998 :-)
Another great video!! Keep up the great work.
Keep it coming really good vids and explanation!
I'm reluctant to say that this notion really makes sense, even if that's how it's officially measured.
I'd say that an engine's displacement is best described as the volume available for one power stroke's fuel mixture, before compression, all "cyclinders" combined. (i.e. how much mixture could ideally be burnt per power stroke, if the engine was naturally aspirated). No crankshaft revolutions in this definition.
Hi Kenny, Thanks mate finally some one has made a simple video on this topic. We'll put . Cheers.
I have compaired the 2 roter to a v6. Same number of "cylinder's" so yeah 3.9L. Except for the number of power strokes which is the same as a v8, two per one revolution. No wonder people get confused about the rotary.
Ye I had an rx 8 for 10 lovely months b 4 it blew a seal due too cat failure, am also an engineer an I agree with the 2.6 litres as if you compare too a normal in-line 4 engine 2 crank revelations is what we would measure too then using the same amount makes for a more equal comparison 👍🏼
Anyone know what the Irish brokers rate the rotary against e.g. a 2 litre petrol or just a 1.3
Good video except at 4:52 he says a rotor has six faces (it has 3). The confusion comes from when the Wankel was first invented, and displacement was based on 1 revolution of the output shaft. As it takes 3 shaft revs to complete 4 strokes per face, one rev will fire only one face of each rotor, and the two rotors of a 13B provide 2 combustions per rev, ie 1.3L PER REV. To be consistent with a 4 stroke piston engine, 2 shaft revs yield 2.6L displacement.
Only problem with this video is you keep stating displacements as a fixed value. A rotary engine does not only displace 1300cc's. A Mazda 13b(A) engine displaces 1300cc's per combustion. You kept stating several times that "rotaries" have a value of 1.3 liters. This is wrong terminology, a rotary engine can come in several different sizes, just as normal piston engines come in different sizes. Yes, the mazda 13b is the most common.
Internal Combustion Engines are known being linked to low Effective Compression Ratio, these first times because of poor quality of available gasoline. If changing the plug hole to an slot as Ernie Brink proposes, reduces greatly the Exhaust Gas Temperatures, this would mean a much higher Effective Compression
Not just RX7 and RX8. The old Mazda cars are the best. Very big in drag racing and on the street. R100, RX2, RX3, RX4. You should change the title of this video.
RX3 coupes are the best and most valueable. The most sought after.
This makes sense ... 2 rotations = 2.6L and 1 rotation = 1.3L ..... So I would be correct when saying that a 1.3L Rotory is equal to a 2.6L engine. .... air volume speaking.... yep it does make sense.... thanks for that good info ...
Exactly! It's equivalent to a 2.6L 4-cycle piston engine in terms of air volume. Notice the exact wording of this; I'm not saying that's it a 2.6L engine, merely that it's equivalent!
Each face would need to be counted as an individual cylinder.
A traditional piston can only have one cycle happening at once. In a rotary, when one face is in the Ignition cycle, one face is on intake and the other is exhaust, so it can have three happening at once. Also, from ignition to complete exhaust is a half turn of the crankshaft.
It is literally just a 3 cylinder engine in one object, therefore, if each face can house .65L of air, then each rotor would be equal to 1.95L, so a two rotor would be 3.9L (or a 3.9L 6 Cyl), a 3 rotor would be 5.85L (or a 5.85L 9Cyl), and a 4 rotor would be 7.8L (or a 7.8L 12 Cyl).
The traditional Engine Displacement definition can literally not be applied to a rotary, even if you replace "piston" with "rotor", because you would have to basically pretend the other two faces of the rotor aren't doing anything.
I propose a new definition: "Rotary engine displacement is the swept volume of all the rotors inside the rotor housings of a reciprocating engine in a single movement from Top Dead Centre (of the ignition stroke) to Bottom Dead Centre of the crankshaft times 3 (to account for the 3 faces of one rotor)."
the text in the video had me dying lol. great video as usual
Very well explained
Wouldnt the rotary be a once stroke if it had one dorrito because it's all in one cycle, thus making a 2 rotor engine a two stroke?
I agree with everything this guys says, my friends V8 use just as much gas as me.
Yes, basically, it's because the Wankel rotary engine's displacement isn't measured in the same way as a piston engine. If you measure a 6.2L LS3 the same way Mazda measured the 13b to end up with 1.3L an LS3 would be a 3.1L engine.
What many people have a hard time with is keeping the ENTIRE engine, all 6 faces of the rotors on a 13b, in mind at once along with the Wankel's 3:1 ratio. During operation, because there is a 3 to 1 ratio between the rotors and the eccentric shaft or e-shaft (equivalent to the crankshaft) that means for every 1 revolution of the e-shaft the rotors turn 120 degrees (1/3 of a revolution) which is the number of rotor degrees necessary to complete one phase on each rotor face. This results in 1 intake, one compression/power, and one exhaust PER rotor (although there is overlap because the second rotor is phased or "follows" the first for balancing reasons).
This means in 1 revolution of the e-shaft the entire engine's swept volume displacement is .65 * 3 faces * 2 rotors= 3.9L.
The main reason, I think, for this odd way of mesuringdisplacement that Mazda used that resulted in the 1.3L rating, only counting one rotor face per rotor, is because, esp. in Japan, insuring a 1.3L sports car is much cheaper than a 3.9L sports car as well as the fact that Japan has an absurd "displacement tax" so the smaller the rated displacement of the engine the better.
More videos like this please
It depends on how many rotors you have in my opinion, I would agree that each face is equivalent a cylinder...so all in all it's an awesome engine!!
Then why is it obsolete now?
evidence.
Someone shoulda further developed the rotary. Think about it, a 2 rotor engine has 3 moving parts, not much friction really and you could make higher compression rotors. Oil injection with the fuel would also help a lot with wear cos the fuel goes everywhere in the intake stroke and gets spread in the housings and irons. Youre gonna say something about pollution but put a DPF on it or rather an RPF(rotary particulate filter) and youd have clean emissions. Just a thought
Welll done man! I love these videos
Kenny Mckee"5:40-5:45" some arcadic reason for?????? Mazda's reason makes perfect since if you understand how displacement is truly calculated. In this whole video, you completely forgot the basics of how displacement is calculated. Displacement is calculated by firing the measured volume of air per cylinder or chamber in a "SINGLE COMBUSTION" event and not multiple ignition events. That's why it's rated as a 1.3L. In a 4 stroke 4 cyl piston engine, you need 2 rotations of the crank to ignite 4 individual cylinders to get the full total displacement (1 spark each). In a rotary, 1 e-shaft rotation gets you 1 ignition event per chamber to ignite .65L of air each chamber times 2 (1 spark each). Your video did a pretty good job of explaining but, the key words are SINGLE IGNITION EVENT. So when comparing to a piston engine, all you have to do is compare the amount of air moved for each e-shaft rotation. That's why it's comparable to a 2.6L 4 stroke piston engine because both engines will move the same amount of air and have the same exact amount of ignitions events.
Use the type of crank and piston ring type, which is better fuel.
APEX SEAL LEAKS INSIDE THE ENGINE ON COMPRESSION STROKE THIS WHY YOU GET 80LBS ON A COMPRESSION CHECK THIS ENGINE IS 5 TO 1 RATIO WHEN IT LEAKS INSIDE THE ENGINE LOOKING FOR A 10 TO 1 ROTARY
az616578.vo.msecnd.net/files/2016/08/27/6360787077700554381193066848_Internet-Troll.jpg
1.3L makes perfect sense if you will stop bashing those of us that maintain that the rotary engine is really a two stroke. A 4 stroke engine uses a full stroke (piston at TDC to BDC) for each phase, intake, compression, power, exhaust. While a two stroke technically has all 4 phases, but each phase only takes 1/2 of a stroke. A single piston 4 stroke engine fires once every 2 revolutions, while a 2 stroke fires every revolution. A rotary engine fires every revolution making it a 2 stroke engine.
Remember, a stroke is 1/2 rotation of the crankshaft, not a phase described as intake, comp, power, exhaust. In a 4 stroke engine the strokes are thus named because each phase uses a single stroke, but don't project that naming convention to the stroke.
The definition of the word stroke = "noun
1. an act of hitting or striking someone or something; a blow."
You description gets confusing because of your initial assumption that the rotary is a 4 stroke. If you assume that the rotary is a 2 stroke, it all works out nicely. Nothing confusing about it.
And as we all know, 2 strokes make more power / displacement than a 4 stroke, simply because it fires twice as often!
*All Wankel KKM designs are 4-stroke...*
*The Mazda 13B requires 3 shaft revolutions to complete all 4 strokes in each chamber face... 3 turns equal 3.9 liter of total air displaced.*
Hi 1st time viewer i gots a question can i drop 13b engine on a front wheel drive car?
now put a turbo on that 1.3 and cram a lot of air and a lot of fuel that would change the displacement correct
Man that was so interesting you earned a sub :)
Boss man says they get the 1.3 measurement from one crankshaft revolution. They measure a piston engine at two crankshaft revolutions so if they measured the 13b at two crankshaft revolutions 2.6l I believe they decided to go with the 1.3 because in Japan under 2.0 is cheaper to run..
Piston engine takes two crankshaft rotations for one oto cycle. The rotary takes 3 eccentric shaft rotations for one oto cycle, but there are 3 faces so there is one power stoke per rotor per eccentric shaft rotation! 1.3, 2.6. or 3.9? 1.3 is best for insurance purposes. Note that most racing rules had a conversion factor for rotary versus piston; 2.0 was common...
Your explanation is wrong though. "Engine displacement is the swept volume of all the pistons inside the cylinders of a reciprocating engine". Problem is, the rotary doesnt have pistons and it is not a combustion engine with reciprocating motion. The rotors are basically the "pistons" on the Wankel engine. In a four stroke, two full revolutions of the crankshaft are required for all the pistons to have fired at least once. In the Wankel engine, for each revolution of the e-shaft, two faces fire at the same time. If I go by your logic, that would mean the rotary needs 3 revolutions of the e-shaft for all the faces to fire and not one, so the bond with the 2 stroke engine kinda goes away. It is hard to really understand the displacement of a rotary, but you got it wrong. The difference lies in your example. A 4 cyl four stroke has four combustion chambers, so you need all the four pistons to fire at least once for you to know how much air got into each combustion chamber. So if two pistons fired once, the other still have to, so you can't tell the displacement until then. On a rotary, there are two combustion chambers. All six faces have 654cc. But only two of them, one per rotor, for each revolution, has a power stroke. In one of the rotors, if face number 2 let's call it, has a power stroke, face number one is the intake stroke and face number two is in the exhaust stroke. But don't misunderstand this. Even if I said the faces were on some "strokes", you shouldn't treat them as pistons. That is the tricky part. But you don't consider exactly how MUCH air the engine is taking. If by one single revolution, in the 4 cyl, only half of the maximum intake of air has gone into the engine, in the rotary, in one single revolution, the maximum air intake has already been reached, which, in the case of the 13B, is 1.3L. You just keep adding air for all the six faces as if the engine could take more than 1.3L, you're just repeating the cycle. The reason for all the power of a rotary is indeed because of how fast each power stroke succeeds one another.
DoubleC I’ve been waiting for so long to witness someone who actually had crunched the numbers & finally fathomed the answer!
DoubleC thanks for the input
DoubleC. Make a video and post u are accurate
3.9 liter
*Sorry, but the Wankel KKM IS A 4-STROKE so we calculate displacement at 1080° NOT 360°*
*Its not that difficult to understand... each orbiting piston(rotor) has 3 sides forming 3 combustion chamber volumes, each with a swept volume of 654cc. times the 2 housings is 6 and equaling 3,924cc.*
*The other important thing that people without formal engineering experience fail to understand is that a 4 cycle Otto or Diesel engine completes its firing sequence in 720° of crankshaft rotation while the 4-cycle Wankel KKM designs required 1080° of rotation to complete its firing sequence...*
*These two important and often misunderstood details are the basis of the commonly used "2X" conversion formula for accurately "comparing" the displacement of the Wankel with other designs..*
*_Any questions? I would be happy to explain in more detail..._*
great info when you line up a apex in the leading plug hole you see two chambers at the same time HEAT IS NO GOOD so two keep your turbo and engine in great shape you must stop the flames that are inside the engine before it ever comes out of the housings
Good explanation 👍
how much fuel does it take compared with a skyline or ford six than you will have the true measurement
Great video, makes perfect sense. 👍👍
Maybe we should measure displacement between all engines on how much Air is displaced over 360 Degrees of rotation. I would think you need a common denominator with something they all do no matter how many strokes. Then you could measure the fuel used per 360 degrees.
A 4-stroke engine requires 720° degrees of crankshaft for all the combustion volumes to complete its firing order sequence.
The commonly accepted method is 360° for 2-Stroke engines and 720° for 4-stroke engines.
The Wankel is a 4-stroke engine.
This is why the Mazda 13b is considered to be a 2.6 liter when comparing hp-per liter.
let say we compare one 4 stroke engine with a rotary engine with same displacement , example 1.2 litre, the 4 sroke take 2 revolution to burn out 1.2 litre airfuel- mixture but rotary engine take 3 revolution, so rotary engine burn less airfuel-mixture compare to 4 stroke engine with same engine rpm.
*All Wankel engines are 4-stroke... but require 3 revolutions. This why the 13B is considered a 2.6 liter when comparing to other 4-strokes even though the true displacement is 3.9 liters in total.*
Good educational vid, bt I count it that there is an ignition event every 120 of 360 degrees of the eccentric shaft, mayb it'd be easier to explain with a single rotor engine
There is an ignition event every 120 degrees, however, the full cycle is only completed on face per rotation.
Actually, there’s a combustion event every *180* degrees of e-shaft rotation. Very much like a 4 cyl. On older Rotaries that had a single dual-post (wasted spark) coil for leading ignition, you could run the engine leading only on most standalone EMSs by setting it up as a 4 cylinder 4 stroke with a single ignition output (like a distributor) and then just hook the single output to the leading coil. 4-cylinder engines have a combustion event every 180 degrees. IF you look at an actual e-shaft, the lobes are offset by 180 degrees as well.
Basically the closest way to compare doritoz to pistons is by comparing both at two crank turns, for example like he said a 13b at two turns equals roughly 2.6 litres & since four sides fire the closest comparison would be a 2.6 litre four cylinder which is why they are registered as 2.6 litres, for me that's the only measurement because the comparison is always going to be against a four stroke piston engine
the answer is in the slide show and very easy. You need to measure it from the "flywheel" perspective. One revolution of the flywheel or E-shaft = 1.3 liters of air pulled into the engine. Mazda is correct.
WRONG, it takes 1080 degrees of crankshaft rotation to complete it's firing order sequence so 3.9 liters of displacement
This makes so much more sense now. 24mpg from a 1.3L didn't make sense to me, but 2.6L is more understandable for the 24mpg figure. I think your right that the engine isn't a two cycle, but it still lubricates like one. It isn't really a true four cycle either. I'd just call it a Wankel cycle. Because Wankel stroke would be the butt of too many jokes.
Josh Bonds its a rotary because the dorito spins. Pistons stroke thats why theres seperate strokes. Back and forth vs constant rotation
+Taylor McCallum *Thank you Taylor, If we need a moron we'll call you.*
2-stroke Benz-Cycle 360° 4-stroke Otto-Cycle 720° 4-stroke Wankel-KKM 1080° *ARE YOU SURE? I THINK WE WILL CALL ON YOU* stupid
So you're saying its like an "all stroke" in a way?
2 rotor is called 13b hence it's 1.3 litre, 3 rotor is called 20b and it's considered as 2 litres. Assuming 1 rotary it's a 0.65 litre displacement.
One of the fundamental flaws in the Wankel design was the troublesome shape of its internal components... cylinders and spherical shapes are ideal for ensuring even and consistent thermal expansion and contraction and the clearances between the moving parts, stationary parts and most importantly the sealing parts... Like the Newcomen steam engine, one of the Wankel's major flaws is that it is required to maintain high temperatures and colder temperatures with in the same housing, high wear rates and low thermal efficiency is the end result.
just started what I figure will take me about 7 years to finish 3 Rotor FB
When asking why a small displacement engine can make big power, it's because displacement is irrelevant. What is relevant is airflow, because an engine is an airpump. That's why the same engine with different heads, cams, etc makes different amounts of power.
Yes you are correct but NOT different amount of torque ....an NA 13B is nowhere close a 2.6L in torque let alone a 3.9 Lit. So rotary (in real life not calculations) is equivalent to 2-2.2 piston in power and torque ....... and nobody actually bothered to answer HOW is the capasity of the 0.65 lit measured..... is all the "air"/"water" one housing can include or one rotor face..... from WHAT degrees up to what degrees? .....
I clicked on this video because the heading said "The SECRET Behind Why RX7 and RX8 Rotary Engines Make SO Much Power". Not how a rotory works in difference to a piston engine, I am still none the wiser. I wish people would reference their videos appropriately!
Well, its kinda of joke really... "SO Much power" makes me laugh!
In the uk the 13b is taxed as a 2.6 litre. In japan its a 1.3.
how do i gain more torque on a rotary wankel reciprocating engine.?
trying to figure this out myself.....so far...more compression doesn't help....only good answer is add a rotor...
.no replacement for displacement
I approve this message . Now all I need is a rx8.
Ceasar Coleman you can have mine for £800 ☺
Great video, thankyou
they just measure the volume of air and fuel that can fit in the combustion chamber its not hard to understand its a 1.3...😅
newscooler12316 there are 3 combustion chambers per rotor.
Rotors Magazine um no there are 3 faces but only one actual place where combustion happens...🤣
You're correct. His method of explaining displacement is...hmmm...interesting.
In a machine shop, when you get your V8 bored, the method of determining overall displacement isn't the way he explained it. It's actually much simpler: en.wikipedia.org/wiki/Engine_displacement
Whereas the actual volume of the intake charge happens INDIVIDUALLY and each face is fired INDIVIDUALLY and each cycle happens INDIVIDUALLY, it then follows to measure the displacement accordingly.
The video description is tantamount to saying, "Well, because a turbine engine pumps 'X' CFM of air, it's equivalent to a 70L engine in size." Hmmmmmm, no. Not at all. It's displacement is it's displacement. Period.
newscooler12316 In fact he got it completely wrong. I don't understand how people can complicate these things so much. A 13B can get a maximum of 1306cc of air, 654cc per rotor. The end. Not 2.6L, not 3.9L. Most people just don't like the idea or are just too stupid to understand.
If you listen, the answer comes in what you determine to be a piston equivalent. Many consider faces of rotors to be a 'piston'. The 'INDIVIDUALLY' argument doesn't work because each piston in a piston engine is ALSO working INDIVIDUALLY. Just like every piston is connected to the same crankshaft, every rotor is connected to the e-shaft. Effectively, what you've said for those that argue each face is a piston is that you can measure displacement of a V8 by taking the volume of 2 cylinders.
To use your definition from Wikipedia: "Engine displacement is the swept volume of all the pistons inside the cylinders of a reciprocating engine in a single movement from top dead centre (TDC) to bottom dead centre (BDC)."
In a single motion, all 3 faces of a rotor fire. In fact, some people go as far as to say the rotary engine is a perpetual power stroke.
On a 2 rotor only 1 face fires at a time. It does not fire the 2 rotor until the first is on its exhaust stroke that information is wrong
No. on a 2 rotor, 1 face per rotor fires per revolution.There are 2 rotors in a '2 Rotor'. 2 of 6 total faces fire on one revolution.
What are you talking about do you have any clue how a rotary runs. A 2 rotor wil fire 3 times per one revolution of the crank shaft. Please stop miss informing people. Because one face will always be in compressed and ignited position while the other is on its exhaust stroke and intake draw. Dude you are miss informing people bad
I have no idea how a rotary runs. Thanks for checking out my youtube channel titled 'ROTORS'.
well, now it is called 'brotors' ... so you know how things brotate
Well, over here in Belgium they are taxed like a 2.6L engine and I never knew why. I guess now I do.