Why Do Rotaries Suck?

[RICE RACING]

I like this thread but the bloke coming in here personally attacking sydneykid is quite pathetic; we like rotary engines here, this is just an education class on what capacity they actually are and whether they are 2 cycle or 4 cycle ect.

Ive learned heaps! now to summarise so far:

-13b is a 3.9litre engine which is why they can make big power numbers and spool up a large turbine - any dispute there?

-13b, each rotor spins at 3000rpm; spins a 1:3 gear so its 9000rpm, hence the lowered torque levels until u hit higher rpms.

-They are fragile just like our piston engines but make up for it by being light n small; good for drag racing and fits in any small spaceframe like car

is that right?

now can we drop the 13b engine and concentrate on the 12a, as it only has one rotor and is probably easy to compare than 2 rotors.

So people don't get confused:

The 13B measuring in the 4 stroke time scale is a 2.616lt motor, that is all most people like on this site would want to know "how does it compare to my Datsun" ? < that is your answer.

The rotary engine as a racing motor for its size is the most durable and long lasting for its power to size relationship... proven fact over many racing classes. The reason for this is the the secret in how slow the rotor turns to do its cycle and how much area there is for various load bearing parts be they bearings or seals or combustion faces they are a super reliable racing engine and no other motor for its capacity can match it in power output or use of stock parts to obtain these various levels of power be it in drag racing or circuit.

Cost & simplicity wise you will never ever beat a 13B engine compared to any other 2.6lt 4 stroke engine. *remember the time scale*

[RICE RACING]

But a rotor has 3 faces, you can't look at one face in isolation. We don't look at one cylinder in a 4 cylinder piston engine in isolation, so why should we ignore ther other 2 sides of a rotor?

That's cycle position of the eccentric shaft, not the cycle position of the rotor, which is after all the pumping medium.

No there not, you don't doube a 2 stoke engines capacity, or halve a 4 strokes capacity depending on crankhaft degrees of rotation. Their capacity is defined as how much they pump for a complete cycle of their pumping media, ie; their pistons. But when we get to rotaries, Mazda (and it would seem you) expect us to divide the amount they actually pump by 3. I completely fail to see the logic in that.

This is the basis of our dissagreement, you want to use eccentric shaft revolutions to influence capacity measurement and I see no logic in that. It flies in direct contravention of every other pumping (capacity) measurement of every other type of engine.

That, by the way, isn't the question I asked. I'm guessing that you didn't asnswer the question because you don't like the answer. In the persuit of truth, let me repeat the question "2. if you rotate 1 x 13B rotor 360 degrees how much air does it pump?"

Cheers

Gary

I can't help you if you don't understand how every internal combustion engine principle works. You need to re read over my posts.

[ylwgtr2]

I like this thread but the bloke coming in here personally attacking sydneykid is quite pathetic; we like rotary engines here, this is just an education class on what capacity they actually are and whether they are 2 cycle or 4 cycle ect.

Ive learned heaps! now to summarise so far:

-13b is a 3.9litre engine which is why they can make big power numbers and spool up a large turbine - any dispute there?

-13b, each rotor spins at 3000rpm; spins a 1:3 gear so its 9000rpm, hence the lowered torque levels until u hit higher rpms.

-They are fragile just like our piston engines but make up for it by being light n small; good for drag racing and fits in any small spaceframe like car

is that right?

now can we drop the 13b engine and concentrate on the 12a, as it only has one rotor and is probably easy to compare than 2 rotors.

ive never seen a 12a with one rotor

[GTR-32U]

Far from it, its me knowing you are an idiot for your delusional ranting baseless posts on a topic you obviously know very little about

See its comments like this that irritate me. Why insult the guy for ? He isnt an idiot. what he has done is bring forward a logical discussion of the engines true capacity- Something which is obviously in doubt. So far Gary's and your ( up until this point ) points have been great and educational.I dont recall gary heaping any insults onto the engine. And for the record I happen to think Rotaries are a great engine...More so suited to track work than say a daily work hack, But the fact is something " More " must be happening to be able to drink much more fuel than an equivalent 1.3 litre, Make obscenely high horsepower levels compared to an equivalent 1.3 And be able to support such a large Turbocharger relatively lag free compared to an equivalent 1.3 .....Fact is Rotors are a great engine- misunderstood by many however

[bigmikespec]

on the other hand....hands up who likes tits???(providing your hands free at the moment)

One hand is typing the other one is wacking myself off because I have a degree in Mech. Eng... and I am thinking about tits!

Great info though besides the personal swipes. Logically what Gary says is entirely correct... 3.9L

[Johnny]

So people don't get confused:

The 13B measuring in the 4 stroke time scale is a 2.616lt motor, that is all most people like on this site would want to know "how does it compare to my Datsun" ? < that is your answer.

The rotary engine as a racing motor for its size is the most durable and long lasting for its power to size relationship... proven fact over many racing classes. The reason for this is the the secret in how slow the rotor turns to do its cycle and how much area there is for various load bearing parts be they bearings or seals or combustion faces they are a super reliable racing engine and no other motor for its capacity can match it in power output or use of stock parts to obtain these various levels of power be it in drag racing or circuit.

Cost & simplicity wise you will never ever beat a 13B engine compared to any other 2.6lt 4 stroke engine. *remember the time scale*

I dont wanna compare my engine to a rotory; different mechanics so i doubt anyone on this site is ignorant to compare a piston engine to a rotor.

I thought it wasnt four-cycle, as told many times by sydneykid; its 2-cycle repeated for a full revolution which displaces 3.9litres. My girlfirend who aint exactly a car person said instantly when i was watching youtube videos of rx7's "sounds like a chainsaw" now that jst hit me in the head as to the fact, it sounds like one cos it is a 2cycle combustion engine. WOW!

we love all engines on this site, you coming here and trying to act like mr bigshot aint impressing anyone; who are you? whats your name? whats your trade? whats your education? what do you look like?

this is the net, no1 cares as long as you post some educational information like sydneykid has. You jst post up diagrams n talk about thermodynamics: how do i know u know anything about it.

i love the 13b n 20b, every1 on here does, some dont like the sound but hey - who cares but im pretty sure no1 likes you.

ive never seen a 12a with one rotor

im sorry, did i get that wrong? 13b has 2 rotor housings and 2 rotors; the 12a? what is it? single rotor??? please educate me

[ylwgtr2]

10a,12a,13b all twin rotors with the difference in the thickness of the rotors/housings for capacity....13a engine is also twin rotor but shares the same thickness as the 10a but has a similar capacity to the 13b which they acheive by the swing of the rotor...20b is triple rotor....have a read here for the ins and outs.....rotary engine .....but hey....what would i know...i dont have a degree

Edited September 20, 2009 by ylwgtr2

[Sydneykid]

So people don't get confused:

The 13B measuring in the 4 stroke time scale is a 2.616lt motor, that is all most people like on this site would want to know "how does it compare to my Datsun" ? < that is your answer.

Well I'm confused, what's time got to do with capacity? On that basis a 5,000 rpm 2 litre engine has half the capacity of a 10,000 rpm 2 litre engine, because of the number of firings over time. Then what about a 2 litre 2 stroke engine? They have twice as many firings in the same time frame, does that mean their capacity is 4 litres?

Cost & simplicity wise you will never ever beat a 13B engine compared to any other 2.6lt 4 stroke engine. *remember the time scale*

Of course, that's because it's a 3.9 litre 2 stroke, arguably equivalent to a 6.8 litre 4 stroke. Just to compound the idiocy of it, CAMS counts them as 1.3 x 1.8 = 2.3 litres. Any wonder they do OK, despite only 3,000 rpm.

Cheers

Gary

[Sydneykid]

I can't help you if you don't understand how every internal combustion engine principle works. You need to re read over my posts.

And yet you won't help me out be answering a very simple question ""2. if you rotate 1 x 13B rotor 360 degrees how much air does it pump?"

Why is it that you don't want to answer the question, obviously you know the answer, so that's not why. Could it possibly be that the answer destroys your argument? Surely not.

Let me clear one thing, I'm not knocking rotary engines, what I am doing is simply pointing out the facts as I see them and supporting those facts with reasoned arguments. What I don't like is the Mazda lies for 40 years, that started for 100% for marketing reasons and have had repercusions ever since in motorsport. But the rotary engine itself is not the subject of that objection.

Cheers

Gary

[RICE RACING]

I dont wanna compare my engine to a rotory; different mechanics so i doubt anyone on this site is ignorant to compare a piston engine to a rotor.

I thought it wasnt four-cycle, as told many times by sydneykid; its 2-cycle repeated for a full revolution which displaces 3.9litres. My girlfirend who aint exactly a car person said instantly when i was watching youtube videos of rx7's "sounds like a chainsaw" now that jst hit me in the head as to the fact, it sounds like one cos it is a 2cycle combustion engine. WOW!

we love all engines on this site, you coming here and trying to act like mr bigshot aint impressing anyone; who are you? whats your name? whats your trade? whats your education? what do you look like?

this is the net, no1 cares as long as you post some educational information like sydneykid has. You jst post up diagrams n talk about thermodynamics: how do i know u know anything about it.

i love the 13b n 20b, every1 on here does, some dont like the sound but hey - who cares but im pretty sure no1 likes you.

im sorry, did i get that wrong? 13b has 2 rotor housings and 2 rotors; the 12a? what is it? single rotor??? please educate me

It has 4 distinct and separate stages to its cycle, it is not a 2 stroke at all.

It may sound like one as it does not have any valves to silence the exhaust pulse thus like a 2 stroke they are loud.

I am no Mr Bigshot, but I am right in what I say. It is on you and anyone else who is uneducated and opinionated to re read the posts and take it upon yourself to understand what is being shown to you *if you dont get it by now you really need to take some time to get up to speed with thermodynamics*.

Sadly if your not educated in Mechanical Engineering or are plain slow, then you will never get it, and will go on and on like most others who do on forums appealing only to those of similar intellect

You want to know my trade my back ground? get off your arse and go to my web site

Unlike most people with opinions I do this for a living and am good at it, when you can shape up to me then I will accept your critical internet forum opinion till then its nothing more than a misguided uneducated delusional rant by people who never knew much in the first place

I like ALL engines, I understand ALL engines when you or anyone else who has contributed here can say the same then I will be happy to explain more but going over and over the same basic fundamentals I typed is a waste of my time and dare say yours as well

[Streeter]

Fix the link in your sig mr thermodynamics degree man.

you obviously have experience and knowledge on the subject but the arrogance makes it hard not to hate on you LOL

[RICE RACING]

Fix the link in your sig mr thermodynamics degree man.

you obviously have experience and knowledge on the subject but the arrogance makes it hard not to hate on you LOL

I am not arrogant at all, anyone who meets me will tell you that in person, don't take the internets and a typed word as reading into someones character!

[Streeter]

^^apologies. The internet does take away alot from a conversation. Maybe it was just from my perspective.

constant referrences to degrees and assuming no one else knew what you were talking about is what made me jump to that conclusion.

[RICE RACING]

^^apologies. The internet does take away alot from a conversation. Maybe it was just from my perspective.

constant referrences to degrees and assuming no one else knew what you were talking about is what made me jump to that conclusion.

I don't even have a degree, my point is its hard to explain something of a technical nature to most if they do not understand the concepts of it all. Its like trying to do a subject without having done the prior one.... it simply makes it too hard to follow and people just cant keep up.

When I did thermodynamics the actual physics of how a rotary worked was glossed over, I learned much more from my own application of my education in the following 12 years.

[vl_turbed]

They don't suck.

It's the small minded people that don't know anything about them that give them a bad wrap. I have owned 3 and I never had a single problem with them at all and I dare say the people that bad mouth them have never even owned one.

Just like anything mechanical (and female) they can have issues when mistreated.

i share the same opinion if you havent owned one or three in this case you have no right to judges them i used to own a 1999 toyota hiace witha 13bt in it i had only minor problems with the turbo buht no problems with the engine watsoever as long as it is kept and serviced there a efn good engine

[Streeter]

be careful to assume others have no experience with them.

Ive built a fair few and mucked around with them for 6 years.

Sydney kid has built a couple of race cars (possibly including engines) aswell.

Not everyone is an 18 year old noob to rotaries here.

Edited September 20, 2009 by Streeter

[ARTZ]

now can we drop the 13b engine and concentrate on the 12a, as it only has one rotor and is probably easy to compare than 2 rotors.

You are joking right?

Edited September 20, 2009 by doozooby

[FineLine]

This same argument has been going on for the 40 odd years the rotor has been in production. laymen such as myself could be swayed by either argument. However Neither argument addresses the original question. "why do rotors suck"

The question wasnt "are rotors good for any particular application in the world of internal combustion".

The same question could be asked of any particular design of motor. They all have their strengths and weakness's. Trouble is, it wasnt. So why do rotors suck?

A. They do sound like arse, Depending on cofiguration they emit either the "wank wank" sound or they make a noise akin to a model airplane on rhoids.

B. They are not fuel efficient. If as claimed by the pro rotor team they are 1.3 or 2.6 litres or whatever the fuel efficiency is even worse than I was led to believe.

C. there is a question mark over their reliability

D. Pound for pound they do appear to lack torque to any degree. Even a briggs and Stratton can be made to look good if its propelling something light enough.

E. The rotor Fanboiz Are the rudest bunch of chuntz to ever grace these boards. Plain and steadfast arguments have been proffered by the piston brigade only to be met by personal attacks from the egg beater crowd. Some of them have offerred damn fine arguments in favor of the rotor but let their credibility fly out the window With their personal remarks.

Bring it on rotor heads but dont sully a damn good debate by attacking the man rather than the argument.

[Streeter]

This same argument has been going on for the 40 odd years the rotor has been in production. laymen such as myself could be swayed by either argument. However Neither argument addresses the original question. "why do rotors suck"

The question wasnt "are rotors good for any particular application in the world of internal combustion".

The same question could be asked of any particular design of motor. They all have their strengths and weakness's. Trouble is, it wasnt. So why do rotors suck?

A. They do sound like arse, Depending on cofiguration they emit either the "wank wank" sound or they make a noise akin to a model airplane on rhoids.

B. They are not fuel efficient. If as claimed by the pro rotor team they are 1.3 or 2.6 litres or whatever the fuel efficiency is even worse than I was led to believe.

C. there is a question mark over their reliability

D. Pound for pound they do appear to lack torque to any degree. Even a briggs and Stratton can be made to look good if its propelling something light enough.

E. The rotor Fanboiz Are the rudest bunch of chuntz to ever grace these boards. Plain and steadfast arguments have been proffered by the piston brigade only to be met by personal attacks from the egg beater crowd. Some of them have offerred damn fine arguments in favor of the rotor but let their credibility fly out the window With their personal remarks.

Bring it on rotor heads but dont sully a damn good debate by attacking the man rather than the argument.

Hrrrm

A. totally subjective. RB26s can sound ok but personally I HATE the sound of stock rb20 with an exhaust. So this point is pretty much irrelevant.

B. doesnt matter on the size its performance Vs Economy. For a daily commuter they arent as good as a piston engine. For a performance engine they can be tuned so a high output engines cruising economy is quite ok compared with other performance engines.

C.true, although keep the engine happy with temps, iginition, fuel and they are arguably better than most. So not really a good point to bring up about them sucking. Although admittedly I gave up on them cause I was sick of having something off and having an engine shit itself.

D.Torque and power are just an equation. Rotors have plenty of torque. Look at a stock 20B or 13B turbo. LOADS of torque very early on and good power, the cosmo is very heavy car!

E.Feeling you there a bit but has nothing to do with the engine.

Anyway I was finding the talk on displacement was more interesting than if the rotary is a good or bad engine. I think most are happy with the slight topic change. More random tit shots are also welcome.

[RICE RACING]

This same argument has been going on for the 40 odd years the rotor has been in production. laymen such as myself could be swayed by either argument. However Neither argument addresses the original question. "why do rotors suck"

The question wasnt "are rotors good for any particular application in the world of internal combustion".

The same question could be asked of any particular design of motor. They all have their strengths and weakness's. Trouble is, it wasnt. So why do rotors suck?

A. They do sound like arse, Depending on cofiguration they emit either the "wank wank" sound or they make a noise akin to a model airplane on rhoids.

B. They are not fuel efficient. If as claimed by the pro rotor team they are 1.3 or 2.6 litres or whatever the fuel efficiency is even worse than I was led to believe.

C. there is a question mark over their reliability

D. Pound for pound they do appear to lack torque to any degree. Even a briggs and Stratton can be made to look good if its propelling something light enough.

E. The rotor Fanboiz Are the rudest bunch of chuntz to ever grace these boards. Plain and steadfast arguments have been proffered by the piston brigade only to be met by personal attacks from the egg beater crowd. Some of them have offerred damn fine arguments in favor of the rotor but let their credibility fly out the window With their personal remarks.

Bring it on rotor heads but dont sully a damn good debate by attacking the man rather than the argument.

in your articulate reply you forgot point F...........

You are a tool