Sydneykid

OK, so now I have converted Rice, Smitt42 and GT-R32 to the truth that a 13B should be known as a 3.9 litre rotary engine. (Which of course is what I posted 20 pages or so back). All that's left is Birds, common over from the dark side and step into the light of knowledge, you're welcome too. So what's left in this quest...........the rotors only do 3,000 rpm................no, won that one already. That only leaves one of my points to get agreement on, the ever difficult 2 stroke/cycle. It's hard because the rotary huggers like to throw in irrelevancies to muddy up the water, or use narrow meanings of words to stop comparisons, or when I try and use different words to help them gain understanding they accuse me of changing the terminology. This is the most difficult of the 3 arguments to win, because there are so many ways for them to get out of jail Now we all know rotaries need oil in the combustion chamber like a 2 stroke/cycle engine. But that's not really enough evidence. We all know they sound like a 2 stroke, But that's not really enough evidence, but wait is it? Not in itself, but it is an indicator of something important. Every time a rotor face goes "past" the exhaust port it exhausts. Just like every time a 2 stroke/cycle piston goes "past" the exhaust port it exhausts. But in a 4 stroke it's only every second time the piston goes "past" the exhaust port it exhausts. I suppose they will pick on the generalisation of the word "past" because 4 strokes have valves so the piston doesn't go past the exhaust port it goes past the exhaust valve. Knit picking but I bet they use it to get out of jail. How about this then. Every time a rotor's combustion face goes past the spark plug it fires. Just like every time a 2 stroke/cycle piston's combustion face goes past the the spark plug it fires. But in a 4 stroke it's only every second time the piston's combustion face goes past the spark plug that it fires. That's a bit better, no confusion with what "past" means, a spark plug is spark plug. Except rotaries have 2 of those, perhaps they will use that as an escape. Surely not, that's really grasping at straws. Let's see what they come up with this time. Cheers Gary

Pardon me for having some fun at your expense. I didn't know 13B's had a crank, wow I learnt something today. I didn't know 13B's had pistons, wow I learnt 2 things today. I'm not sure that I need to know what enhale is though, I might pass on that bit of knowledge. Cheers Gary

I learn something new every day, Am I "flat out insane" to have bothered to find out that the rotors only do 3000 rpm. Or am I "flat out insane" to have bothered to educate people that the rotors only do 3000 rpm? I'm not sure how you measure insane, but I can't see how knowledge gained or passed on about how a rotary truly works is insane. Sound, you dare to use sound, in a vain attempt to discredit what I posted, when in fact sound actually supports what I said. The sound you hear is combustion, not 9000 rpm of eccentric shaft rotation but 3,000 rpm of combustion. Because that's how many rpm the combustion medium is doing. At this point a lesser person than me would loose control and insult your intelligence for being stupid enough to use an example that supports my argument. But I won't do that, I will simply say thanks for your support and for providing a perfect example of why I'm right. [ My agenda is quite simple, I am just pointing out the alternatives to Mazdas 40 years of marketing spin on rotaries, showing that there is more than one way to express a rotaries capacity, rpm and cycle process. That Mazdas is wrong, deliberately wrong in fact, that's why I call it lying. If only that were true. As I posted 10 pages or so back, equivalency is a fallacy. Cheers Gary

Show me where I said Mazda were the only ones to make rotary engines? In fact if you bothered to read what I actually wrote, you will know I specifically mentioned NSU and Norton with road going rotary engines. Like their piston competitors, the Fitchel and Sachs rotary engine (made by NSU) in the lawn mowers. the OS model aeroplane rotary engine and KM chainsaws were all rated for horsepower. I don't recall ever seeing a capacity rating for them. They competed with pistons engines purely on power, there was no attempt to sell them based on engine capacity. It certainly wasn't the main marketing thrust like Mazda did with their's. Interestingly the chain saws with rotary engines were too heavy and their sales died a quick death as a result. I do recall Yanmar having a rotary marine engine, I think it was diesel though. BTW, from what I remember the Ingersoll-Rand gas rotary is a pump not an engine and guess what? It was rated by how much it pumped. Cheers Gary

You get it as well , But it is more like 3 times what is specified by Mazda. Cheers Gary

No they are not. If they were, then a 2 stroke/cycle 1.3 litre would be a 2.6 litre Or a 2.6 litre 4 stroke would be a 1.3 litre. Nobody measures an engines capacity dividing or multiplying by the number of degrees the cranskaft rotates. Actually that's not true, Mazda does, but only for rotaries, they don't do it for their 4 stroke engines. Accurate? What's more accurate than how much the pump (the rotor) actually pumps? The eccentric shaft doesn't pump, the rotor does. Let me help you out here with some numbers, A 3.9 litre two stroke completes its Otto cycle in two distinct 'strokes' and does this in 360 degrees. Eveyrone calls it a 3.9 litre engine. A 3.9 litre four stroke completes its Otto cycle in four distinct 'strokes' and does this in 720 degrees. Everyone calls it a 3.9 litre engine. A 3.9 litre Wankel completes its Otto cycle for all rotor faces in 1080 degrees. Mazda call it a 1.3 litre engine. Now explain that to me again, because it looks to me like one rule for Mazda and another rule for everyone else. That's been my point all along. I'm just trying to ensure that eccentric shaft degrees are not used as the measure as they are irrelevant to everyone else except Mazda. Cheers Gary

Hang on, after all it's the Otto Cycle we are talking about here. If we are really trying to compare rotaries with piston engines, then using the term "strokes" just makes the comparison impossible. I don't think anyone should fall for the cop out, "hohoho a rotary engine doesn't stroke, so it can't be a 2 stroke hohoho". If you aren't truly trying to compare, then there is your get out of jail card, no strokes in rotary. I just get a bit sick of that same card being played all the time. If you are truly trying to compare, then at least substitute something that is applicable. I choose "cycles", sure it's not perfect, but it is applicable, it is logical and it can be understood by most people. If you don't like my choice for equivalency, that's fine, just pick one of your own. Anyway, I think you missed the point I was making, you found a method of equivalency in others, but not #6 and #7. So why not have a go at it? Cheers Gary

Well whatya know, there's another one who understands. Unfortunately they don't, it's 2.3 litres. Cheers Gary

There are 10 tests, a rotary is like a 2 stroke in 3 of those tests 3 8 9 But it's only like a 4 stroke in 2 tests. 3 10 To me that means it is most like a 2 stroke. But as usual the devil is in the detail. The main problem I have with the table is #6, you have called it "piston strokes". Obviously a rotary is going to fail that test, it doesn't have pistons. So you separate #6 (pistons) and #7 (rotors). Yet in #4 you use the equivalency "numer of faces per piston/rotor". Same again in #5 with "crank/eccentric revolutions", so being fair you should also use the same equivalency in #6 and combine it with #7. My suggestion for equivalency in #6 would be "number of combustion face cycles to complete combustion". In which case a rotary engine is 1, a piston 4 stroke is 2 and a piston 2 stroke is 1. Hence a rotary is the same as a 2 stroke piston engine in test #6. Cheers Gary Edited for my bad maths.

Oops, nobody's perfect, not even me, 7.8 litres it is. Pardon me if I blow it back at you. How much air does a 1.3 litre 2 stroke ingest per 360 degree revolution? Look at the crankshaft mate. Then think. Then think again. And again if you need to. 720 degrees? 1080 degrees? How much air does a 1.3 litre 4 stroke ingest per 360 degree revolution? Look at the crankshaft mate. Then think. Then think again. And again if you need to. 720 degrees? 1080 degrees? You argument relies totaly on the eccentric shaft revolutions having some effect on the actual measurement of a rotary engine's true capacity. When in no other internal combustion engine is that the case. As for why did I double the 3.9 litres,? Well you started the "doube the 2 stroke's actual capacity to get the equivalent for a 4 stroke" scenario. I was just following your lead. So you agree with me then, that doubling a 2 strokes capacity to get some equivalency is not practical? Cheers Gary

But they don't put them into fair displacement categories. A 13B should be included with 7.8 litre 4 stroke engines, that's 3.9 litres of pumping capacity times 2, because it's not a 4 stroke. This is also where the turbo sizing question becomes interesting, and supports the 7.8 litre capacity equivalence. If it wasn't 7.8 litres how could it spin a T04Z using only 3,000 rpm? What the alternative, 1.3 litres? We all know that there is no way a 1.3 litre engine is going to spin a T04Z at any rpm, let alone at 3,000 rpm. It's quite simple, an engine is an air pump and we all know how much air a rotary pumps and it sure as hell ain't 1.3 litres. My experience is exactly the opposite, ask the average Joe how big the engine in his car is and there is a good chance he will tell you straight away. Some will look at the badge on their car. In comparison ask the average Joe the power and torque outputs of his engine and he look at you blankly. Capacity is relevant to rego, insurance, road tax, for expense claims purposes the Tax Office even quotes costs to run a car by its engine capacity. Nobody outside the enthusiast uses horsepower and torque, it's all about capacity. Ask a pushrod lover what's different about an LS1 compared to an LS2, you can bet the first response you get is 5.7 versus 6.0 litres. I don't know about you but I haven't ever seen torque output badges on cars. I've been playing with rotary engines for a lot of years and I know full well that Mazda’s claim (for a 13B) of 1.3 litres, 4 stroke and 9,000 rpm is rubbish. The real world results don't support it, then when we get down and dirty with the facts we find they don't support it either. 1. does it ingest air like a 1.3 litre? No it doesn't 2. does it use fuel like a 1.3 litre? No it doesn't 3. does it spin up large turbos like a 1.3 litre? No it doesn't. That’s where I started in my quest for the truth many years ago. The real world logic just didn’t stack up, not even close, so I went searching for the facts. I completely ignored Mazdas words, actions, drawings, diagrams, visual representations etc, because they would obviously be slanted towards supporting their version. I sought out independent views, unbiased opinions, reasoned measurement and unconstrained opinion. That’s why I found Phil Irving’s published engineering papers so significant. Even more so the unbelievable lengths Mazda went to to lampoon someone who was an internal combustion engine luminary. Having done that research and my own measurements, I’m left with the conclusion that Mazda has at the very least distorted the facts for marketing reasons or at the very worst lied through their teeth. Cheers Gary

Why should I? It's blatantty wrong. OK, so over there is a 400 cc trail bike, it has CBR400 on the fuel tank and it says 400 cc on the for sale sign and it has 400 cc in the owners manual. What's the engine's pumping capacity? Obviously the answer is 400 cc's, unless someone is lying. It doesn't matter whether it's a 2 stoke or a 4 stroke, the engine is still 400 cc. Now, over there is an RX8, it has 1.3 litres on the for sale sign and it has 1.3 litres in the owners manual. What's the engine pumping capacity? Obviously the answer should be 1.3 lites, but someone is lying, it's actually 3.9 litres. It doesn't matter whether it's a 2 stoke or a 4 stroke, the engine is still a 3.9 litre . I don't see 400 cc 2 stroke trail bikes sold as "equivalent to 800 cc 4 stroke", so why should I tolerate 3.9 litres being sold as 1.3 litres? I don't, because it's simply not true. Cheers Gary

I'm not forgetting eccentric shaft revolutions, I'm deliberately ignoring them, because they are irrlevant. What determines a 2 stroke/cycle engine versus a 4 stroke/cycle engine si the actions of its combustion medium. not what something geared up from that does. I dissagree, it should be done, as it is with every other engine, on how much it pumps for one compete revolution of its combustion medium. I don't. What the hell has that got to do with the capacity of the engine? I don't double the 2 stroke's true capacity and call it a 500 cc engine, it's always 250 cc engine, end of story. Equivalency is impossible, I think MotoGP proved that, so why are you even trying? Cheers Gary

Where did I say anything about rotor tip speed, that's an irrelevant rpm related comparison and abslolutely nothing to do with capacity. Using your logic , when I see Honda quote 400cc for a 2 stroke trail bike, it's really 200cc's. I don't think so. Equivalency is a fallacy, stop trying for some equivalency, just state what it is. I'm a simple guy, I measure an engine's capacity by how much it pumps. Actually I can't be that simple, because every engine manufacturer in the world agrees with me and measure their engines' capacities by how much they pump. Except one, why should we allow an exception for one engine manufacturer? I don't think we should. Cheers Gary

You're baffled, well I can see why. Firstly you seem to think I am comparing a rotary engine to a piston engine when in fact I'm not. What I object to is illogical, unique and unsupportable ascertions about capcity, rpm and stroke/cycle type. This is where I get baffled....... What you are saying is we should call a 1.3 litre 2stroke/cycle engine a 2.6 litre. Nobody does that, a 1.3 litre engine is a 1.3 litre engine, it doesn't matter how many strokes/cycles it has. If it pumps 1.3 litres then it's a 1.3 litre engine. Look at it another way, you want to make an exception for a 3.9 litre rotary, an exception that no one else in the entire engine world does for their 2 stroke engines. Why is Mazda so special here? Why should they alone get to use maths to change their engines true pumping capacity but no one else is allowed? No wonder you're baffled. one rule for Mazda, another rule for everyone else. You hit the nail right on the head, that's the problem with those sorts of simulations, they only show what supports Mazda’s lies. It’s one of the law's cleverest applications, "tell the truth, the whole truth and nothing but the truth". Right here we have an example of telling the truth (for one side of the rotor) but not telling the whole truth (by leaving out the other 2 sides).Do some research, you will find that the general consensus in the automotive world was that it was marketing driven. I'm not confused, I know that multiple parts of the Otto cycle are happening simultaneously, most unlike a 4 stroke and most like a 2 stroke. Cheers Gary

That's a bit hair splitting isn't it? Common, "cycle" versus "combustion cycle", I don't think the meaning of what I said is lost in the narrow definitions you apply. I try and stick to common use terms and their meaning, it means the non technical readers don't switch off. Plus I type slowly and adding extra, irrelevant, words just slows me down I don't see any blurring, it's black and white to me. But a 4 stroke/cycle piston only does one at a time, while the rotor does 3 at a time. A 2 stroke/cycle rotary engine wouldn't function with only side, just like a 2 stroke piston engine without 2 sides. So it's illogical to look at one side of rotor to determin it's cycle. That's the import fact, we have to look at what all 3 sides of the rotor are doing, forget piston comparions, what's the rotor doing? The fact is it's doing multiple combustion processes all at the same time. My view remains that it's a 2 stroke/cycle rotary engine. You seem to think that I'm saying that's exactly the same as a 2 stroke/cycle piston engine, when in fact I'm not. No it's not, because it only shows what is happening to one third of the rotor. What about the other two thirds? Should we just ignore them? Cheers Gary

So do we laugh when you get your ass handed to you by a 3.9 litre Radical (there isn't any of them yet)? Or should that be a 2.6 litre Radical (there are a few of them around now)? No wait, you'll be saying it should be a 1.3 litre Radical (lots of them). Whatever, your ass will still be handed to you. What this has got to with an engine discussion I'm not so sure, but it was too good an opportunity let slip by. Cheers Gary

OK let's get a few things out of the way first. Guys tend to listen to what I say because in over 11,000 plus posts I tell it how I see it, I don't take the popular line, I don't follow the lemmings, I develop my own opinions, based on my own measurements and observations. In this case I see a 13B as being a 3.9 litre, 2 stroke rotary engine where the combustion media do 3,000 rpm. Pleased don't attribute more to that statement that what it is actually says. Secondly, don't diffuse the discussion by adhering to some narrow minded meaning for the terms used. It is a common tactic used by the blind (to the facts) rotary supporters. Silly stuff like rotors don't revolve they ellipse, give me a break, the earth revolves around the sun and it's in an elliptical motion. So calling rotor turns "revolutions" is well within the common use meaning. Another example, stroke in this reference means the same as cycle. Don't get led astray from seeking the truth just because someone says rotaries don't stroke, give me another break. In this context stroke = cycle. So, don't fall for these common tactics used to divert a rotary discussion from the truth. Next time someone tries to narrowly define what is a common use meaning, treat it for exactly what it is, a desperate attempt to stop you from seeking out the truth. Let's move on. The manufacturers of 2 stroke engines don't double their actual capacity because it fires every cycle, they simply state what it pumps in one full cycle of the combustion medium. ie; a 0.5 litre 2 stroke pump is stated as a 0.5 litres. It doesn't matter whether is does it in 360 degrees of crankshaft revolution or 720 degrees. The manufacturers of 4 stroke engines don't halve their actual capacity because it fires every second cycle, they simply state what it pumps in one full cycle of the combustion medium. ie; a 2.0 litre 4 stroke pump is stated as a 2.0 litres. It doesn't matter whether is does it in 720 degrees of crankshaft revolution or 1080 degrees. But not Mazda, oh no, they have a better idea, let's divide what it actually pumps by 3, even though we all know it pumps 3.9 litres in one full cycle ie; a 3.9 litre pump is stated as 1.3 litres. There is no hiding from that fact, you will hear all sorts of arguments about degrees of crankshaft versus eccentric shaft revolutions, 760 degree versus 1080 degrees. Ignore them, they may be true, but they are truly meaningless in determining the capacity of the engine, what it really pumps. But even then, if we use erroneously introduce eccentric shaft revolution, it's a 2.6 litre. So the 1.3 litre doesn't cut it, even with that attempt at distorting the true capacity of the engine by introducing irrelevant facts. Just because they are facts doesn't make them relevant. So in regards to engine capacity Mazda has been lying for 40 years. I would argue that they have been calling a 3.9 litre engine a 1.3 litre. The Mazda supporters would argue that it’s really 2.6 litres. The FIA currently says it's 2.3 litres, they used to say it was 2.6 litres. But it doesn’t matter, everyone agrees that Mazda lied, the only real question is by how much. Why did Mazda lie? Well the commonly accepted reason is marketing, they could sell the David versus Goliath story, 1.3 litre engine rules the world, small engine kicks butt, the little engine that could, etc etc. Look back at the marketing campaigns and it’s blatantly obvious. It wasn’t a conspiracy, it was simply convenient for marketing at the time. That’s brings us to the next lie, 2 stroke/cycle. Again the Mazda lemmings will put up the argument that a rotary engine doesn’t stroke, oh give me third break. They cycle and in one cycle they inlet, compress, combust and exhaust. What’s a cycle? Well in anyone’s language it’s when one particular point of the rotor completes one complete cycle (revolution). Wait I can hear it, hang on, rotaries don’t revolve. Give me a fourth break, they do revolve, it’s just not in a perfect circle. The fact is a 2 stroke/cycle engine does all 4 processes in one compete cycle of the combustion medium. Yes, it happens to be a piston, but that’s irrelevant when comparing combustion medium. In comparison a 4 stroke does all 4 processes in two complete cycles of the combustion medium. I really don’t see any room for argument here, other than feeble attempts at muddying the water with narrow minded definitions of common use terminology. The fact remains a rotary engine does all 4 processes in one cycle of it's combustion medium, so it’s a 2 stroke/cycle engine. Why did Mazda lie this time? Well the commonly accepted reason is again marketing, they knew full well that they couldn’t sell the concept of a 2 stroke engine in a serious car to the general public. They were well aware of the contempt that previous two stroke/cycle cars had generated. So that stigma had to be avoided, hence get the term 2 stroke/cycle right away from rotary engines. It wasn’t a conspiracy, it was simply convenient for marketing at the time. This brings us to the most contentious point, rpm. I call it a 3,000 rpm engine because the combustion medium does 3,000 cycles per minute. The Mazda followers say it’s a 9,000 rpm engine because the eccentric shaft does 9,000 cycles per minute. Obviously both are correct, the rotors do actually do 3,000 rpm while the eccentric shaft is doing 9,000 rpm. There is no point of disagreement there, what is in dispute is which is more relevant? I support my argument with the fact that the combustion medium is the more important rpm to measure. For me, it the most relevant because that’s what a rotary is, an internal combustion engine. Hence measuring the rpm of the combustion medium is somewhat more relevant that measuring the rpm of something that does nothing for the combustion process. If nothing else, what I have done with the rpm part of this discussion is provide ammunition to dispute the claim that a rotary engine is high revving. The fact is they aren’t, in every common use meaning of the term, “high revving engine”, because that terminology imparts the belief that the entire engine is high revving. When in fact the all important combustion parts of the engine are in fact low revving. Lastly let's put this diversion tact to bed, there is no conspiracy, just a bunch of Mazda lies, covering up of the truth, distortion of the facts and narrow use of terminology to prevent any meaningful discussion. Comparison with other combustion engines was avoided, or diffused with the furphy that rotaries are entirely different and no comparison is possible. The difficulty in comparison is a weapon used to cover up the truths. Forget about comparison, just look at the facts on their own. They are inescapable. BTW, if you want a conspiracy theory I'll give you one, that Alan Moffat conspired with a certain CAMS board member to allow a Sports Car (RX7) to race in a Championship for Touring Cars. Now that was a true conspiracy, but it's not relevant to this discussion. Maybe one for another day. Cheers Gary

So what? The important rpm (or cpm if you prefer) is the combustion medium, that's the rotors and they only do 3,000 rpm. After all they are what produce the horsepower and the torque. The eccentric shaft is just the same as a gearbox output shaft, it changes the ratio between the combustion medium and the wheels. You don't need to, just read what you posted, note the term cycle. Now go back an read what I posted. But a single rotor engine has 3 combustion faces, so the best you can do is compare it to a 3 combustion face piston engine. a 2 stroke one at that. Even then it's not a good comparison, but go ahead if you feel you must. But they (a 13B that is) are a 3.9L 2-stroke rotary engine with 3,000rpm on tap; 1. they pump 3.9 litres in one complete cycle of the rotors, even Rice agrees with that fact. 2. they inlet at the same time as they exhaust on opposite sides of the rotor, just like any other 2 stroke/cycle engine. Are you saying they don't? 3. the rotors only do 3,000 rpm. We all know they do, so how could you dissagre with that fact? What I didn't say and you seem to think that I did, was that "they are the same as a 3.9L 2-stroke piston engine with 3,000rpm on tap". That's not what I said, anywhere, anytime, in any post. Cheers Gary

You may need to go back and read what I actually wrote not what you think I wrote. The undeniable fact is the rotors only do 3,000 rpm, in terms of combustion (in a combustion engine) that's somewhat important. The gear up ratio of the eccentric shaft is irrelevant, I go to the original point, a rotary engine could have any multiple of 3 in its gear up ratio. Let's say 6, so the eccentric shaft would do 18,000 rpm but the rotors would only be doing 3,000 rpm. The gearing is irrelevant, the rotors are still only doinf 3,000 rpm. That’s the combustion process rpm of the engine. When the rotor supporters do a comparison they claim 9,000 rpm compared to a piston engine. But the truth is the pistons in a piston engine (again the all important combustion process) actually cycle at 9,000 cycles per minute, whereas the rotors only cycle at 3,000 cycles per minute. So it’s an important fact in any comparison that it is pointed out that 9,000 rotary rpm is not the same as 9,000 piston rpm. Of course I have no need for such comparisons, I know full well that the rotors only do 3,000 rpm, so they really are a low reving combustion engine. You would have already noted this if you had actually read what I wrote, in the context of combustion engines stroke and cycle are synonymous, check your dictionary. Sorry, when 1 cylinder in a 6 cylinder engine is combusting it's carrying the load of the other 5. Much the same as when one side of the rotor is combsuting the other 5 are being caried. I fail to see the difference. I'm not comparing, you need to read what I post more carefully. Let me spell it out for you, a 13B is a 3.9 litre, 2 stoke/cycle rotary engine with rotors that only rev to 3,000 rpm. I don't add any the comparison to that, it is what it is. Cheers Gary

Marketing Cheers Gary

For circuit racing I ask the tyre engineer what effective spring rates his tyre likes. After all that’s the point of contract with the road and optimising tyre traction is what it’s all about. In a RWD car I use that as my target front effective spring rate, then let the weight distribution of the car tell me what effective spring rate is needed in the rear. Note the term "effective spring rate" that is the actual spring rate divided by the movement ratio and then the leverage ratio. The tyre only feels the effective spring rate, it doesn't care what the actual spring rate is. For a tarmac road event, using the same tyres, I would come down in spring rate in comparison to what I would run on the track as the average road surface tends not to be as well looked after as the track. Plus we have to be aware of the possibility of rain if its a long event like Targa Tas. Somewhere between 10% and 20% lower has worked for me in the past. Cheers Gary

Yamaha specifically bought Ohlins for their motorcycle shock technology, so it's not surprising that the Ohlins branded car shocks that come out of the Yamaha factory in Japan are similae style to the Ohlins motorcycle shocks. I haven’t directly compared the Japanese Ohlins motorcycle shocks with the Swedish Ohlins we use on V8Supercars etc. But I have compared Japanese Ohlins car shocks with the Swedish Ohlins and they are totally different. Piston design, casting, valve layout, adjuster methodology, they are all different. Cheers Gary

You're both Johnny come latelies, it was the early '70's. Check out your history, 1971 Bathurst Hardie Ferodo 500 first in Class C Mazda RX2. The revival in the late 80's early 90's was due to turbo chargers and the realisation that at 3.9 litres a 13B made a good turbo engine with it's low compression ratio. Hence overcoming one the rotary engine major drawbacks, the inability to achive high compression ratios. Cheers Gary

That's what I said 20 pages back and you pulled out the insults and said I didn't know what I was talking about. Since you now agree with me on the capacity, let's move on to the 2 stroke/cycle discussion. You are still following the same Mazda lies as on the true capacity, you are looking at only one side of the rotor and saying it's a 4 stroke/cycle engine. That would be like looking at the piston crown in a 2 stroke/cycle piston engine and saying it's a 4 stroke/cycle engine. For the very same reasons it's illogical to only look at only one side of the rotor, when the undeniable fact is another side is inletting while the side you are looking at is combusting. That's a 2 stroke/cycle at work. Now the non thinking rotary supporters point at the fact that a rotor has 3 sides, which of course is true, but it's irrelevant when determining the difference between 2 stroke/cycle and 4 stroke/cycle. The fact remains that a 4 stroke/cycle engine does one of the 4 things at a time and a rotary doesn't, so it can't be a 4 stroke/cycle engine. A rotor does multiple parts of the combustion cycle at the same time, hence it's a 2 stroke/cycle engine. For the others, go back and look at what I have posted and you will find nowhere have I knocked the rotary engine itself. What I have a problem with is Mazdas 40 years of lying on capacity, rpm and 2 stroke/cycle. The engine itself is fine and I would have no objection if the truth of 3.9 litres (using a 13B example), 2 stroke and 3,000 rpm had been revealed from the start. So do rotors suck, no they don't, but Mazda does. Cheers Gary