What does it mean for an RX8 to be rotory powered?

[boyRacer]

Rotaries have a lot of potential... Mazda was the only japanese manufacturer to win the 24 Hours of Lemans... with a rotary too. It's just not practical to invest R&D in a rotary when the tried and proven piston is already available. I'm hoping there is another RX7 in the works...

 

[Howard]

Originally posted by: Tetsuo
It has a rotary engine. Not a conventional inline one

Inline is a reciprocating-piston engine configuration. Apples vs oranges.

 

[Howard]

Originally posted by: Eli

Originally posted by: FreshPrince
Ok, got done reading that article...looks like it's less efficient than conventional piston engine. Why did Mazda go with this engine?

I think you've got that backwards.

It is much more efficient than a piston engine. Read how a conventional 4-cycle auto engine works, then read about 2-cycle engines, then read the rotary articles again.

No, it's not. Rotaries have more surface area per "gas expansion", therefore more heat is lost, and rotaries (almost by design) have low compression ratios.

 

[Howard]

Rotaries do, however, have much higher power densities. I wish F1 would switch to turbo rotaries for a year or something.

 

[boyRacer]

Originally posted by: Howard
Rotaries do, however, have much higher power densities. I wish F1 would switch to turbo rotaries for a year or something.

lol... that would make Enzo Ferrari turn in his grave.

 

[Slammy1]

I used to have a '79 Mazda RX-7. It was so light one time I got stuck in the snow I was able to lift the front end and move it onto the road. 70cc (2X35cc) engine, but I took it up to 120. Course, started to do bad things like shoot flames out the exhaust pipe but that's a story for another telling. The Stanley Syeamer was a rotary engine, so they've been around as long as the internal combustion engine I suppose.

 

[BadgerFan]

Rotaries aren't in many cars for the same reason we don't use large chainsaw engines. While they are compact and powerful, they tend to be fuel in-efficient, noisy, and are heavy polluters. They also burn lots of oil. Now before any of you nazis jump on me I realize this is over simplified, but for a layman, I think it is a good answer.

 

[Vic]

Originally posted by: Goosemaster
Anyone have any video of it besides the commercial and the website.?

The triangle(rotor) also has a gear/cog infront of it right that contrains its range of motion, right?

Everytime someones discusses this thing, I can't help but question the amount of friction this thing is creating.

The gear/cog is actually inside the rotor, in a sun-and-planet like configuration. The inner gearing of the rotor has twice as many teeth as the crankshaft gear (making the engine a 4-stroke)...

Ah... there are pics on this page (scroll down a little).

Lots of good info on that site too.

 

[BadgerFan]

Originally posted by: Slammy1
I used to have a '79 Mazda RX-7. It was so light one time I got stuck in the snow I was able to lift the front end and move it onto the road. 70cc (2X35cc) engine, but I took it up to 120. Course, started to do bad things like shoot flames out the exhaust pipe but that's a story for another telling. The Stanley Syeamer was a rotary engine, so they've been around as long as the internal combustion engine I suppose.

Close it was 1.2L or about 1200cc. The engine was called the 12a. I am not sure a 70cc engine could even get an RX-7 up to 20MPH hehe.

 

[boyRacer]

Originally posted by: BadgerFan
Rotaries aren't in many cars for the same reason we don't use large chainsaw engines. While they are compact and powerful, they tend to be fuel in-efficient, noisy, and are heavy polluters. They also burn lots of oil. Now before any of you nazis jump on me I realize this is over simplified, but for a layman, I think it is a good answer.

I'm not those Nazis you speak of ... and your points are true... but all because of lack of R&D.

 

[Vic]

Originally posted by: Slammy1
I used to have a '79 Mazda RX-7. It was so light one time I got stuck in the snow I was able to lift the front end and move it onto the road. 70cc (2X35cc) engine, but I took it up to 120. Course, started to do bad things like shoot flames out the exhaust pipe but that's a story for another telling. The Stanley Syeamer was a rotary engine, so they've been around as long as the internal combustion engine I suppose.

Sorry, but the '79 RX-7 had the 1.3B rotary in it. Twin rotor, 1300cc (2x650cc). Came stock with 4bbl carb and headers, nice little runner with about 160hp in 2400lbs of car but they had a habit of blowing the oil seals every 50k miles.

edit: was the 1.2a in the '79? doh, the 1.3b wasn't until 81...

 

[Slammy1]

It said 2X35cc under the hood. Still, it had an engine the size of a motorcycle, just not a dirt bike like I thought. I used to tell people it was running on a sewing machine engine.

 

[Eli]

Originally posted by: Howard

Originally posted by: Eli

Originally posted by: FreshPrince
Ok, got done reading that article...looks like it's less efficient than conventional piston engine. Why did Mazda go with this engine?

I think you've got that backwards.

It is much more efficient than a piston engine. Read how a conventional 4-cycle auto engine works, then read about 2-cycle engines, then read the rotary articles again.

No, it's not. Rotaries have more surface area per "gas expansion", therefore more heat is lost, and rotaries (almost by design) have low compression ratios.

well, as someone else said.. I guess "efficiency" is kinda subjective.

They have very high power to weight ratios, that's kinda what I was getting at.

 

[Vette73]

Originally posted by: boyRacer

Originally posted by: BadgerFan
Rotaries aren't in many cars for the same reason we don't use large chainsaw engines. While they are compact and powerful, they tend to be fuel in-efficient, noisy, and are heavy polluters. They also burn lots of oil. Now before any of you nazis jump on me I realize this is over simplified, but for a layman, I think it is a good answer.

I'm not those Nazis you speak of ... and your points are true... but all because of lack of R&D.

Sorry but that is not the reason it never really took off. GM would love to have all the money they dumped into R&D. GM use to own the right to the wankle motor, and the corvette was supposed to have a dual wankle motor at one time (4 rotors). BUT it ate gas like a hog and int eh 70's that was not a good thing.

GM was going to use it because it was cheap, light, and reliable (compared to motors of the 60's and 70's).

Mazda uses it as it lets them stand out. If the RX7 or 8 had a small 4 cyl with a turbo it would not get any where near the attention it gets.

 

[Slammy1]

I think it's appearance and cheap price were the hook. Girls used to ask for rides all the time. It was a fun little car, drove just like a go cart.

EDIT: By all the time, I meant a couple of times..

 

[SagaLore]

Originally posted by: Skoorb
In regards to better or worse I'd say that it's pretty clear that, overall, it's an inferior engine. There has been many years to research and "perfect" (within reason) the rotary engine and mazda remains the only manufacturer to put one in their consumer vehicle. In fact until the new RX8 they weren't even using rotaries for a while (since RX7 had stopped production for a while). There is obviously some novelty marketing going on with the rotary engine. A person can buy an Rx8 and know that nobody else is buying a new car with a rotary, so that's definitely an attractition. Yes, it's lighter than a conventional, but hardly any cars use them, whether you're talking about a commuter car, a race car, or a drag car. They just aren't as good, although they are not CRAP and they do still work decently and can be made at a fairly competitive price, as mazda has done with the RX8. Objectively I still think that the 350z would be a better bang for buck, but the rotary is different which makes it fairly neat.

LIAR! :|

It's just underdeveloped, that is all. The piston engine has been by far longer researched and built, way back since steam engines. The engine market still has a quite a lot of propoganda built into it - my old high school science teacher had a brother that patented a new fuel system that gave engines (back in the day) 200 miles to the gallon, but an engine company bought it off him and then shelved it permanently.

Actually no you aren't a liar. Sorry. The DKM model (RX7 rotary) wasn't Wankel's original design. He prefered the KKM model because the housing also rotated at 2/3 the speed the same direction as the rotar. His development partner forced the team to go with the stationary (DKM) model because it could be smaller without an extra housing (and spark plugs were stationary), however, the KKM had huge performance abilities and could excel speeds above 15k rpm with almost no vibration.

I also believe with today's technology and know-how, a diesel compressed gasoline injected KKM wankel would be the ultimate engine. You could do away with the cooling system and just add heatsink to the rotating housing for air cooling. You could have a series of rotor chambers with different sizes and gearing speeds to cascade the air intake compression and exhaust expansion. Like they use to do with auxiallary steam pistons to regain energy efficiency.

 

[Vette73]

Originally posted by: SagaLore

Originally posted by: Skoorb
In regards to better or worse I'd say that it's pretty clear that, overall, it's an inferior engine. There has been many years to research and "perfect" (within reason) the rotary engine and mazda remains the only manufacturer to put one in their consumer vehicle. In fact until the new RX8 they weren't even using rotaries for a while (since RX7 had stopped production for a while). There is obviously some novelty marketing going on with the rotary engine. A person can buy an Rx8 and know that nobody else is buying a new car with a rotary, so that's definitely an attractition. Yes, it's lighter than a conventional, but hardly any cars use them, whether you're talking about a commuter car, a race car, or a drag car. They just aren't as good, although they are not CRAP and they do still work decently and can be made at a fairly competitive price, as mazda has done with the RX8. Objectively I still think that the 350z would be a better bang for buck, but the rotary is different which makes it fairly neat.

LIAR! :|

It's just underdeveloped, that is all. The piston engine has been by far longer researched and built, way back since steam engines. The engine market still has a quite a lot of propoganda built into it - my old high school science teacher had a brother that patented a new fuel system that gave engines (back in the day) 200 miles to the gallon, but an engine company bought it off him and then shelved it permanently.

Actually no you aren't a liar. Sorry. The DKM model (RX7 rotary) wasn't Wankel's original design. He prefered the KKM model because the housing also rotated at 2/3 the speed the same direction as the rotar. His development partner forced the team to go with the stationary (DKM) model because it could be smaller without an extra housing (and spark plugs were stationary), however, the KKM had huge performance abilities and could excel speeds above 15k rpm with almost no vibration.

I also believe with today's technology and know-how, a diesel compressed gasoline injected KKM wankel would be the ultimate engine. You could do away with the cooling system and just add heatsink to the rotating housing for air cooling. You could have a series of rotor chambers with different sizes and gearing speeds to cascade the air intake compression and exhaust expansion. Like they use to do with auxiallary steam pistons to regain energy efficiency.

That myth is junk. You can get a copy of the patent and try it yourself, it NEVER worked. Geeze gotta love the idiots that believe anything they read or hear.

 

[SagaLore]

Originally posted by: Marlin1975

Originally posted by: boyRacer

Originally posted by: BadgerFan
Rotaries aren't in many cars for the same reason we don't use large chainsaw engines. While they are compact and powerful, they tend to be fuel in-efficient, noisy, and are heavy polluters. They also burn lots of oil. Now before any of you nazis jump on me I realize this is over simplified, but for a layman, I think it is a good answer.

I'm not those Nazis you speak of ... and your points are true... but all because of lack of R&D.

Sorry but that is not the reason it never really took off. GM would love to have all the money they dumped into R&D. GM use to own the right to the wankle motor, and the corvette was supposed to have a dual wankle motor at one time (4 rotors). BUT it ate gas like a hog and int eh 70's that was not a good thing.

GM was going to use it because it was cheap, light, and reliable (compared to motors of the 60's and 70's).

Mazda uses it as it lets them stand out. If the RX7 or 8 had a small 4 cyl with a turbo it would not get any where near the attention it gets.

What amazes me, from my research, is the fact that the initial exhaust of the rotor chamber was extremely rich with unburned gasoline. So instead of throttling the fuel intake for better efficiency, they used a superburner which added MORE gasoline to the exhaust mixture to reignite the exhaust, and by the time it left the pipe it was even cleaner than standard emissions. Now explain to me what's wrong with this picture.

 

[SagaLore]

Originally posted by: Marlin1975

Originally posted by: SagaLore

Originally posted by: Skoorb
In regards to better or worse I'd say that it's pretty clear that, overall, it's an inferior engine. There has been many years to research and "perfect" (within reason) the rotary engine and mazda remains the only manufacturer to put one in their consumer vehicle. In fact until the new RX8 they weren't even using rotaries for a while (since RX7 had stopped production for a while). There is obviously some novelty marketing going on with the rotary engine. A person can buy an Rx8 and know that nobody else is buying a new car with a rotary, so that's definitely an attractition. Yes, it's lighter than a conventional, but hardly any cars use them, whether you're talking about a commuter car, a race car, or a drag car. They just aren't as good, although they are not CRAP and they do still work decently and can be made at a fairly competitive price, as mazda has done with the RX8. Objectively I still think that the 350z would be a better bang for buck, but the rotary is different which makes it fairly neat.

LIAR! :|

It's just underdeveloped, that is all. The piston engine has been by far longer researched and built, way back since steam engines. The engine market still has a quite a lot of propoganda built into it - my old high school science teacher had a brother that patented a new fuel system that gave engines (back in the day) 200 miles to the gallon, but an engine company bought it off him and then shelved it permanently.

Actually no you aren't a liar. Sorry. The DKM model (RX7 rotary) wasn't Wankel's original design. He prefered the KKM model because the housing also rotated at 2/3 the speed the same direction as the rotar. His development partner forced the team to go with the stationary (DKM) model because it could be smaller without an extra housing (and spark plugs were stationary), however, the KKM had huge performance abilities and could excel speeds above 15k rpm with almost no vibration.

I also believe with today's technology and know-how, a diesel compressed gasoline injected KKM wankel would be the ultimate engine. You could do away with the cooling system and just add heatsink to the rotating housing for air cooling. You could have a series of rotor chambers with different sizes and gearing speeds to cascade the air intake compression and exhaust expansion. Like they use to do with auxiallary steam pistons to regain energy efficiency.

That myth is junk. You can get a copy of the patent and try it yourself, it NEVER worked. Geeze gotta love the idiots that believe anything they read or hear.

Ummm no, it is not anything you've read or heard. My physics teacher was not telling me an urban legend.

 

[SagaLore]

 

[ElFenix]

Originally posted by: SagaLore

Ummm no, it is not anything you've read or heard. My physics teacher was not telling me an urban legend.

:Q

note: there is not enough energy in a gallon of gasoline to get a car to move 200 miles

 

[boyRacer]

Originally posted by: Marlin1975

Originally posted by: boyRacer

Originally posted by: BadgerFan
Rotaries aren't in many cars for the same reason we don't use large chainsaw engines. While they are compact and powerful, they tend to be fuel in-efficient, noisy, and are heavy polluters. They also burn lots of oil. Now before any of you nazis jump on me I realize this is over simplified, but for a layman, I think it is a good answer.

I'm not those Nazis you speak of ... and your points are true... but all because of lack of R&D.

Sorry but that is not the reason it never really took off. GM would love to have all the money they dumped into R&D. GM use to own the right to the wankle motor, and the corvette was supposed to have a dual wankle motor at one time (4 rotors). BUT it ate gas like a hog and int eh 70's that was not a good thing.

GM was going to use it because it was cheap, light, and reliable (compared to motors of the 60's and 70's).

Mazda uses it as it lets them stand out. If the RX7 or 8 had a small 4 cyl with a turbo it would not get any where near the attention it gets.

...well i still think that whatever negative traits it had was from lack of development. The advances in piston engines is just incredible nowadays. If we were all using rotaries instead of piston engines from day one... id imagine those initial problems with the rotary would be nonexistant now.

 

[Eli]

Originally posted by: SagaLore

Originally posted by: Skoorb
In regards to better or worse I'd say that it's pretty clear that, overall, it's an inferior engine. There has been many years to research and "perfect" (within reason) the rotary engine and mazda remains the only manufacturer to put one in their consumer vehicle. In fact until the new RX8 they weren't even using rotaries for a while (since RX7 had stopped production for a while). There is obviously some novelty marketing going on with the rotary engine. A person can buy an Rx8 and know that nobody else is buying a new car with a rotary, so that's definitely an attractition. Yes, it's lighter than a conventional, but hardly any cars use them, whether you're talking about a commuter car, a race car, or a drag car. They just aren't as good, although they are not CRAP and they do still work decently and can be made at a fairly competitive price, as mazda has done with the RX8. Objectively I still think that the 350z would be a better bang for buck, but the rotary is different which makes it fairly neat.

LIAR! :|

It's just underdeveloped, that is all. The piston engine has been by far longer researched and built, way back since steam engines. The engine market still has a quite a lot of propoganda built into it - my old high school science teacher had a brother that patented a new fuel system that gave engines (back in the day) 200 miles to the gallon, but an engine company bought it off him and then shelved it permanently.

coughcoughhackbullsh!tcoughhackburp

Damn cough.


Anyway, You would understand why this is not possible(with todays engine technology) if you understood the fact that energy is neither created nor destroyed; it merely changes forms. Gasoline only contains a certain ammount of energy. Coincidentally, it takes a fininte, known, calculable ammount of energy to propel an object.. in this case a car, at XX miles per hour.

I suppose if you made an engine that was more thermally efficient, you could significantly improve on todays MPG numbers.. but a simple fuel delivery modification isn't going to do it.

Sorry.

 

[mAdD INDIAN]

Originally posted by: Eli

Originally posted by: SagaLore

Originally posted by: Skoorb
In regards to better or worse I'd say that it's pretty clear that, overall, it's an inferior engine. There has been many years to research and "perfect" (within reason) the rotary engine and mazda remains the only manufacturer to put one in their consumer vehicle. In fact until the new RX8 they weren't even using rotaries for a while (since RX7 had stopped production for a while). There is obviously some novelty marketing going on with the rotary engine. A person can buy an Rx8 and know that nobody else is buying a new car with a rotary, so that's definitely an attractition. Yes, it's lighter than a conventional, but hardly any cars use them, whether you're talking about a commuter car, a race car, or a drag car. They just aren't as good, although they are not CRAP and they do still work decently and can be made at a fairly competitive price, as mazda has done with the RX8. Objectively I still think that the 350z would be a better bang for buck, but the rotary is different which makes it fairly neat.

LIAR! :|

It's just underdeveloped, that is all. The piston engine has been by far longer researched and built, way back since steam engines. The engine market still has a quite a lot of propoganda built into it - my old high school science teacher had a brother that patented a new fuel system that gave engines (back in the day) 200 miles to the gallon, but an engine company bought it off him and then shelved it permanently.

coughcoughhackbullsh!tcoughhackburp

Damn cough.


Anyway, You would understand why this is not possible(with todays engine technology) if you understood the fact that energy is neither created nor destroyed; it merely changes forms. Gasoline only contains a certain ammount of energy. Coincidentally, it takes a fininte, known, calculable ammount of energy to propel an object.. in this case a car, at XX miles per hour.

I suppose if you made an engine that was more thermally efficient, you could significantly improve on todays MPG numbers.. but a simple fuel delivery modification isn't going to do it.

Sorry.

So your saying those massless pulleys and ropes that my University told me about don't really exists???

NOOOOOOOOOOOOOOOOOEEEEEEESSSSSSSS!!

 

[Vic]

Originally posted by: ElFenix

Originally posted by: SagaLore

Ummm no, it is not anything you've read or heard. My physics teacher was not telling me an urban legend.

:Q

note: there is not enough energy in a gallon of gasoline to get a car to move 200 miles

Yes, there is. But you would also have to harness all of the heat and noise energy that is lost in an inefficient IC engine - an impossibility not worth discussing.