The RX-7 confirmed to be in the pipeline for 2017---RX-Vision Unveil!!
01-09-14, 11:03 AM
#926
Senior Member
But still, at 3800 lb. it's only gained 400 lb. vs. 1967-69, "only" +12%, whereas the 911 has gained 800lb. minimum, +35%, nearly 3x the relative weight gain!
01-09-14, 12:15 PM
#927
if i were with mazda and had to deal with the criticism that undertook during the early renesis engines i would also have a hard time being enthusiastic about building another "lemon" of a car.
just ask the people who have been through 3 engines before even breaking 150k miles and ask them about how they feel about the car as a whole.
seeing your engines breaking after 30-50k miles would depress just about anyone. that is about how reliable the carbon seal engines were back in the late 60's/early 70's.. not exactly a step forward in reliability/durability. note this isn't an average figure but plenty of people have been dealing with sub 50k mile replacements since the cars rolled off the trucks, not after they have hit 150k miles and built with sub-standard parts.
just ask the people who have been through 3 engines before even breaking 150k miles and ask them about how they feel about the car as a whole.
seeing your engines breaking after 30-50k miles would depress just about anyone. that is about how reliable the carbon seal engines were back in the late 60's/early 70's.. not exactly a step forward in reliability/durability. note this isn't an average figure but plenty of people have been dealing with sub 50k mile replacements since the cars rolled off the trucks, not after they have hit 150k miles and built with sub-standard parts.
Last edited by RotaryEvolution; 01-09-14 at 12:18 PM.
01-09-14, 12:25 PM
#928
Looking at the "2015 Miata" spy photos inspired me to look at wheelbases.
Current NC Miata has 91.7" wheelbase.
FD RX-7 had 95.5" wheelbase (a little shorter than FC RX-7).
With a little use of a caliper and scaling off the front wheel I wouldn't be surprised if the car in the spy photos has the same wheelbase as the FD had. It looks to be ~4-6" longer wheelbase than the current Miata.
Why would Mazda add wheelbase? It makes the car more stable as it can handle weight transfer from acceleration and braking better. More power= longer wheelbase.
The Miata will share the platform with Alfa who will most likely stick a higher performance engine in and Mazda won't allow themselves to be outdone so they can either offer a higher performance Miata (Mazdaspeed) or put the rotary in.
I don't know which possibility I would be more exited by.
The RX-8 would have been an amazing and practical car with the Mazdaspeed6 or 3 MZR direct injection turbo in it.
Now if they can just somehow lose the Miata's convertible top...
Current NC Miata has 91.7" wheelbase.
FD RX-7 had 95.5" wheelbase (a little shorter than FC RX-7).
With a little use of a caliper and scaling off the front wheel I wouldn't be surprised if the car in the spy photos has the same wheelbase as the FD had. It looks to be ~4-6" longer wheelbase than the current Miata.
Why would Mazda add wheelbase? It makes the car more stable as it can handle weight transfer from acceleration and braking better. More power= longer wheelbase.
The Miata will share the platform with Alfa who will most likely stick a higher performance engine in and Mazda won't allow themselves to be outdone so they can either offer a higher performance Miata (Mazdaspeed) or put the rotary in.
I don't know which possibility I would be more exited by.
The RX-8 would have been an amazing and practical car with the Mazdaspeed6 or 3 MZR direct injection turbo in it.
Now if they can just somehow lose the Miata's convertible top...
01-09-14, 12:57 PM
#929
the all aluminum block 16X would be a nice place to transition the engines to, hopefully using a replaceable friction surface sandwiched to the end plates. cheaper than replacing the irons as a whole and cutting warranty costs down in the event of failures.
hopefully they are simply using this break for development and making sure the engine does what it is supposed to for the long term. saving 100lbs on the engine is already a step in the right direction.
if the engines wind up naturally aspirated i would love to see them come with ceramic seals, no more premature rotor housing failures resulting in compression loss. it's time for mazda to think outside the box of 40 years ago.
seeing how that engine design would cost roughly $1k more each unit(this is a lot when producing cars and where pennies translate to dollars once on the showroom floor), i can't hold my breathe.
hopefully they are simply using this break for development and making sure the engine does what it is supposed to for the long term. saving 100lbs on the engine is already a step in the right direction.
if the engines wind up naturally aspirated i would love to see them come with ceramic seals, no more premature rotor housing failures resulting in compression loss. it's time for mazda to think outside the box of 40 years ago.
seeing how that engine design would cost roughly $1k more each unit(this is a lot when producing cars and where pennies translate to dollars once on the showroom floor), i can't hold my breathe.
Last edited by RotaryEvolution; 01-09-14 at 01:04 PM.
01-09-14, 01:23 PM
#930
Racing Rotary Since 1983
iTrader: (6)
from Autoweek...
"Kia dropped another teaser shot of its GT4 Stinger, headed for the Detroit auto show next week. It's an overhead view, giving us a good look at the fender flares.
The GT4 will house a 2.0-liter turbocharged, direct injected four-cylinder, which delivers 315 hp. A close-ratio six-speed manual will send power rearward(!) to Pirelli P-Zero tires. Custom 20-inch center-lock wheels feature carbon fiber inserts.
Brembo two-piece rotors are clamped by four-piston calipers when some of that speed needs to be scrubbed. Sporty driving dynamics are provided by the independent double wishbone suspension.
We saw a few more pictures last week, and we'll see the full reveal on Monday when the GT4 Stinger debuts at the Detroit auto show."
i guess Kia can get it done... rear drive turbo 2 liter double A arm suspension...
all it needs is a rotary and a different badge...
hello mazda?
howard
Read more: Kia shows off rear-drive Stinger again before Detroit auto show - Autoweek
Follow us: @AutoweekUSA on Twitter | AutoweekUSA on Facebook
"Kia dropped another teaser shot of its GT4 Stinger, headed for the Detroit auto show next week. It's an overhead view, giving us a good look at the fender flares.
The GT4 will house a 2.0-liter turbocharged, direct injected four-cylinder, which delivers 315 hp. A close-ratio six-speed manual will send power rearward(!) to Pirelli P-Zero tires. Custom 20-inch center-lock wheels feature carbon fiber inserts.
Brembo two-piece rotors are clamped by four-piston calipers when some of that speed needs to be scrubbed. Sporty driving dynamics are provided by the independent double wishbone suspension.
We saw a few more pictures last week, and we'll see the full reveal on Monday when the GT4 Stinger debuts at the Detroit auto show."
i guess Kia can get it done... rear drive turbo 2 liter double A arm suspension...
all it needs is a rotary and a different badge...
hello mazda?
howard
Read more: Kia shows off rear-drive Stinger again before Detroit auto show - Autoweek
Follow us: @AutoweekUSA on Twitter | AutoweekUSA on Facebook
01-09-14, 01:32 PM
#931
which is just for show, as if it will ever actually see the light of day.
i never even understood the principle of building these prototype cars, aside from tax writeoffs they are simply a waste of money for something that is just a "look at what we can do if we throw more money than sense into making a single car".
look at half a decade ago, when people were teased with the furai. even though it was ugly it was just a false hope of mazda actually building a rotary supercar.
i never even understood the principle of building these prototype cars, aside from tax writeoffs they are simply a waste of money for something that is just a "look at what we can do if we throw more money than sense into making a single car".
look at half a decade ago, when people were teased with the furai. even though it was ugly it was just a false hope of mazda actually building a rotary supercar.
Last edited by RotaryEvolution; 01-09-14 at 01:35 PM.
01-09-14, 02:11 PM
#932
I recently stumbled across a rambling on reddit yesterday that I found interesting when the question was asked: If "classic" cars are so desirable/good looking, why don't they just make more like them?
For two a couple of reasons:
Styling of Cars
Because it simply isn't possible anymore, there is a lot of red tape. As well crash tests modern cars have to pass. For example in order to pass the frontal crash test of today, the front of a car must have a crumple zone - metal in the car that is designed to be crushed in a crash to absorb energy so that the force of a crash does not deform the passenger compartment and crush the occupants. This therefore limits the way cars can be styled as well as it adds a lot of weight to cars. I'll talk about weight later. As well as this, there is side crash test small overlap crash test, and crash tests for pedestrian safety. All with their own indirect sets of restrictions on styling because of the way the metal must be shaped to accommodate the shape of the crumple zones and stronger side pillars etc. You can read more about the American tests here.
There are also 1 million different little regulations different governments set on cars sold in their country. For example cars cannot car from factory as low anymore, the headlight must be a minimum height for road safety. As well as the rear hazard lights must be able to still flash if the trunk/hatch/boot of the car is open. This is so that if the car is stopped on the side of the road and the trunk is open to access a spare tire or something, drivers can still see the lights flashing.
There are many different laws in many different countries covering different subject like this one, each imposing little restrictions on styling that add up.
Sports Cars
With regards of older sports car, other than the aforementioned styling, the reason why they are so much more sought after is because they have certain qualities that modern cars lack because of changes in technology and what the modern car buyer wants.
The modern car buyer want comfort, technology, safety, ease of use, and the government wants higher emission & safety standards in every car. While sports cars of old have little to none of those qualities. Weight is a big factor here. Sport cars (generally) used to be a lot lighter because of the lack of these features. No comfort features, at the maximum you'd get air con, and a radio. Or safety, lack of airbags and crumple zones etc. That's it. Everything thing else adds weight. As well as the lack of computers, and electronic systems. Lower weight means the car handles better (can get around a corner quicker), can accelerate faster, and brake faster as well with the same power and the same brakes, because there less weight to move or slowdown.
Lower weight also helps with another factor: fun Cars that weight less feel much more fun than heavy cars because of certain handling characteristics, they turn in fast, and feel more responsive to your inputs, a lighter objects changes direction easier, people who drive "enthusiastically", notice these characteristics. A car that's fun to drive feels like it's immediately responding to you and is communicating to you though the steering and pedals which is explained bellow.
Another benefit of the lack of technology in older cars is the way the steering feels. Not all cars have this, especially brand new cars, but most cars older than 3-4 have something referred to in the auto industry called steering feel. When you turn the wheel of your car, you can feel little vibrations coming through the wheel and can tell what the front wheels are doing, and you can feel the road beneath you when driving "enthusiastically" or turning normally depending on the car. If you've driven a car with it you know what I mean, most people know what I'm talking about.
Feeling these sensations as well as the feeling of the car going over the road in a sports car with a harder ride, makes the driver feel as if s/he is connected with the car and not just there driving it from point A to B it can be quite a lot of fun.
Steering feel usually increases with speed, so the faster you go the more you feel, but with a car with good steering feel you feel more sensations at slower speeds. Older sports cars especially, this was a key focus, back in the day, to have a lot of steering feel. There was no traction & stability control, the feel of the steering wheel would tell you what the front wheels were doing as the feeling of the entire car in general would tell you the limits of the car (what's the fastest speed I can go around this corner without spinning out?)
Modern cars lack this almost totally. Modern steering systems (electric power steering) kill feel totally almost across the board, older cars have either hydraulic power steering (some cars have hydraulic power steering but with little feel), or no power steering at all which would make steering very heavy, but make the sensations coming through the wheel fantastic. It's difficult to describe, but the difference is massive, the steering feels crisp and clear you can feel the road though the wheel. (Toyota has used electric power steering in there cars exclusively for a while now, all there cars had power steering in the 90's which is why a lot of there cars are seen as very boring in the enthusiasts eyes.)
Modern cars lack most sensations because they're not necessary anymore, with stability control and traction control, unless you have no idea what you're doing you won't crash, and its almost impossible to spin out unless you're driving on ice. While you can drive fast, however it doesn't as feel fun because the feeling is too refined, it feels like you're just sitting here telling the car what to do. To get more feeling from a modern sports car, one must drive faster. Which is illegal and dangerous in different ways compared to a old car with no traction/stability control.
In fact these systems are better for an asshat who has no idea what they're doing because its much harder for them to crash, but in the process of this, it kills fun for the person who has the common sense to learn the limits of there car while driving fast.
The everyday car/driver
However for the average modern car buyer, like the one mom or dad drives to soccer practice and takes to work, modern cars are infinetly better, there much safer, and are much less harmful to the environment and people around us. They are loaded with tech and comfort features But for the enthusiastic driver, there's nothing like an older car. Think about this for a second, all points that make classic sports cars so desirable, decrease comfort, or safety, or they aren't necessary anymore because of computer systems. There aren't as many people who want to buy sports cars like that anymore, so the people who do, buy old ones.
Other reasons for desirability
Older cars are simpler to work on
Older cars are generally cool
Lots of old cars have something in explainable, something that cannot be proven on paper, the have character, they have a soul
TL,DR: "Classic" cars are much more fun to drive because they weigh much less due to safety, it isn't possible to style modern cars like classic ones due to safety.
Edit: American cars are a big exemption to the weight factor. All of there older cars were almost always significantly heavier than cars made by the competition for no real reason other than they were too lazy to care about weight. They have never made sports cars though, things like the mustang and camaro are called muscle cars: big engines, big attitude, too heavy, and crappy handling lol
For two a couple of reasons:
Styling of Cars
Because it simply isn't possible anymore, there is a lot of red tape. As well crash tests modern cars have to pass. For example in order to pass the frontal crash test of today, the front of a car must have a crumple zone - metal in the car that is designed to be crushed in a crash to absorb energy so that the force of a crash does not deform the passenger compartment and crush the occupants. This therefore limits the way cars can be styled as well as it adds a lot of weight to cars. I'll talk about weight later. As well as this, there is side crash test small overlap crash test, and crash tests for pedestrian safety. All with their own indirect sets of restrictions on styling because of the way the metal must be shaped to accommodate the shape of the crumple zones and stronger side pillars etc. You can read more about the American tests here.
There are also 1 million different little regulations different governments set on cars sold in their country. For example cars cannot car from factory as low anymore, the headlight must be a minimum height for road safety. As well as the rear hazard lights must be able to still flash if the trunk/hatch/boot of the car is open. This is so that if the car is stopped on the side of the road and the trunk is open to access a spare tire or something, drivers can still see the lights flashing.
There are many different laws in many different countries covering different subject like this one, each imposing little restrictions on styling that add up.
Sports Cars
With regards of older sports car, other than the aforementioned styling, the reason why they are so much more sought after is because they have certain qualities that modern cars lack because of changes in technology and what the modern car buyer wants.
The modern car buyer want comfort, technology, safety, ease of use, and the government wants higher emission & safety standards in every car. While sports cars of old have little to none of those qualities. Weight is a big factor here. Sport cars (generally) used to be a lot lighter because of the lack of these features. No comfort features, at the maximum you'd get air con, and a radio. Or safety, lack of airbags and crumple zones etc. That's it. Everything thing else adds weight. As well as the lack of computers, and electronic systems. Lower weight means the car handles better (can get around a corner quicker), can accelerate faster, and brake faster as well with the same power and the same brakes, because there less weight to move or slowdown.
Lower weight also helps with another factor: fun Cars that weight less feel much more fun than heavy cars because of certain handling characteristics, they turn in fast, and feel more responsive to your inputs, a lighter objects changes direction easier, people who drive "enthusiastically", notice these characteristics. A car that's fun to drive feels like it's immediately responding to you and is communicating to you though the steering and pedals which is explained bellow.
Another benefit of the lack of technology in older cars is the way the steering feels. Not all cars have this, especially brand new cars, but most cars older than 3-4 have something referred to in the auto industry called steering feel. When you turn the wheel of your car, you can feel little vibrations coming through the wheel and can tell what the front wheels are doing, and you can feel the road beneath you when driving "enthusiastically" or turning normally depending on the car. If you've driven a car with it you know what I mean, most people know what I'm talking about.
Feeling these sensations as well as the feeling of the car going over the road in a sports car with a harder ride, makes the driver feel as if s/he is connected with the car and not just there driving it from point A to B it can be quite a lot of fun.
Steering feel usually increases with speed, so the faster you go the more you feel, but with a car with good steering feel you feel more sensations at slower speeds. Older sports cars especially, this was a key focus, back in the day, to have a lot of steering feel. There was no traction & stability control, the feel of the steering wheel would tell you what the front wheels were doing as the feeling of the entire car in general would tell you the limits of the car (what's the fastest speed I can go around this corner without spinning out?)
Modern cars lack this almost totally. Modern steering systems (electric power steering) kill feel totally almost across the board, older cars have either hydraulic power steering (some cars have hydraulic power steering but with little feel), or no power steering at all which would make steering very heavy, but make the sensations coming through the wheel fantastic. It's difficult to describe, but the difference is massive, the steering feels crisp and clear you can feel the road though the wheel. (Toyota has used electric power steering in there cars exclusively for a while now, all there cars had power steering in the 90's which is why a lot of there cars are seen as very boring in the enthusiasts eyes.)
Modern cars lack most sensations because they're not necessary anymore, with stability control and traction control, unless you have no idea what you're doing you won't crash, and its almost impossible to spin out unless you're driving on ice. While you can drive fast, however it doesn't as feel fun because the feeling is too refined, it feels like you're just sitting here telling the car what to do. To get more feeling from a modern sports car, one must drive faster. Which is illegal and dangerous in different ways compared to a old car with no traction/stability control.
In fact these systems are better for an asshat who has no idea what they're doing because its much harder for them to crash, but in the process of this, it kills fun for the person who has the common sense to learn the limits of there car while driving fast.
The everyday car/driver
However for the average modern car buyer, like the one mom or dad drives to soccer practice and takes to work, modern cars are infinetly better, there much safer, and are much less harmful to the environment and people around us. They are loaded with tech and comfort features But for the enthusiastic driver, there's nothing like an older car. Think about this for a second, all points that make classic sports cars so desirable, decrease comfort, or safety, or they aren't necessary anymore because of computer systems. There aren't as many people who want to buy sports cars like that anymore, so the people who do, buy old ones.
Other reasons for desirability
Older cars are simpler to work on
Older cars are generally cool
Lots of old cars have something in explainable, something that cannot be proven on paper, the have character, they have a soul
TL,DR: "Classic" cars are much more fun to drive because they weigh much less due to safety, it isn't possible to style modern cars like classic ones due to safety.
Edit: American cars are a big exemption to the weight factor. All of there older cars were almost always significantly heavier than cars made by the competition for no real reason other than they were too lazy to care about weight. They have never made sports cars though, things like the mustang and camaro are called muscle cars: big engines, big attitude, too heavy, and crappy handling lol
01-09-14, 02:13 PM
#933
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the germans are good at making tanks! straight from wikipedia "Porsche was an important contributor to the German war effort during World War II. He was involved in the production of advanced tanks, such as the Tiger I, Tiger II, Elefant, and Panzer VIII Maus, as well as other weapon systems, such as the V-1 flying bombs"
01-09-14, 02:42 PM
#934
Full Member
Looking at the "2015 Miata" spy photos inspired me to look at wheelbases.
Current NC Miata has 91.7" wheelbase.
FD RX-7 had 95.5" wheelbase (a little shorter than FC RX-7).
With a little use of a caliper and scaling off the front wheel I wouldn't be surprised if the car in the spy photos has the same wheelbase as the FD had. It looks to be ~4-6" longer wheelbase than the current Miata.
Why would Mazda add wheelbase? It makes the car more stable as it can handle weight transfer from acceleration and braking better. More power= longer wheelbase.
The Miata will share the platform with Alfa who will most likely stick a higher performance engine in and Mazda won't allow themselves to be outdone so they can either offer a higher performance Miata (Mazdaspeed) or put the rotary in.
I don't know which possibility I would be more exited by.
The RX-8 would have been an amazing and practical car with the Mazdaspeed6 or 3 MZR direct injection turbo in it.
Now if they can just somehow lose the Miata's convertible top...
Current NC Miata has 91.7" wheelbase.
FD RX-7 had 95.5" wheelbase (a little shorter than FC RX-7).
With a little use of a caliper and scaling off the front wheel I wouldn't be surprised if the car in the spy photos has the same wheelbase as the FD had. It looks to be ~4-6" longer wheelbase than the current Miata.
Why would Mazda add wheelbase? It makes the car more stable as it can handle weight transfer from acceleration and braking better. More power= longer wheelbase.
The Miata will share the platform with Alfa who will most likely stick a higher performance engine in and Mazda won't allow themselves to be outdone so they can either offer a higher performance Miata (Mazdaspeed) or put the rotary in.
I don't know which possibility I would be more exited by.
The RX-8 would have been an amazing and practical car with the Mazdaspeed6 or 3 MZR direct injection turbo in it.
Now if they can just somehow lose the Miata's convertible top...
Agreed, that's not very precise (due to perspective distortion and the like), but unless that car is fitted with 18" wheels, it doesn't look like the wheelbase is increasing.
Andrea.
01-09-14, 03:02 PM
#935
Full Member
...
if the engines wind up naturally aspirated i would love to see them come with ceramic seals, no more premature rotor housing failures resulting in compression loss. it's time for mazda to think outside the box of 40 years ago.
seeing how that engine design would cost roughly $1k more each unit(this is a lot when producing cars and where pennies translate to dollars once on the showroom floor), i can't hold my breathe.
if the engines wind up naturally aspirated i would love to see them come with ceramic seals, no more premature rotor housing failures resulting in compression loss. it's time for mazda to think outside the box of 40 years ago.
seeing how that engine design would cost roughly $1k more each unit(this is a lot when producing cars and where pennies translate to dollars once on the showroom floor), i can't hold my breathe.
Honestly, I'd be really surprised if right now there were NO prototype 16x engines running around in Japan ranking up miles to see how they hold up.
Andrea.
01-09-14, 03:15 PM
#936
if they make 2 piece ceramics it would alleviate the temperature/compression variation issues. they obviously already have some tooling set aside for it since the 4 rotor n/a race engines used those seals, but i suppose they could have simply been handmade one offs due to the low numbers they had to make them in. in the end they already proved that they work in n/a engines reliably and provided an even higher rev range than ever previously seen aside from carbon which isn't a durable material for long term use.
in fact, assuming they can maintain properly low detonation cycles from occurring through a more proper knock system the engines could outlast any previous rotary engine design and even be more reliable than piston engine counterparts, closer to diesel engines. as of now the rotor housing and apex seal wear is still the largest contributor to dying rotaries than anything else and a simple swap of seals could virtually eliminate that.
in the aftermarket world we only see single piece ceramic seals, which give low initial compression until the engine is warmed up to operating temp.
in fact, assuming they can maintain properly low detonation cycles from occurring through a more proper knock system the engines could outlast any previous rotary engine design and even be more reliable than piston engine counterparts, closer to diesel engines. as of now the rotor housing and apex seal wear is still the largest contributor to dying rotaries than anything else and a simple swap of seals could virtually eliminate that.
in the aftermarket world we only see single piece ceramic seals, which give low initial compression until the engine is warmed up to operating temp.
Last edited by RotaryEvolution; 01-09-14 at 03:25 PM.
01-09-14, 05:21 PM
#937
I did a little calculation based on that pic. The wheel rims are 95 pixels across, while the wheelbase (wheel center to wheel center) comes out at 501 pixels. If we assume 16" rims, that computes to 84.4" wheelbase, whereas if we assume 17" rims, then that equates to 89.6".
Interesting, I just measured again on my monitor.
Assuming it is 17" wheel like the current Miata and so has an 18" diameter at the edge of the wheel lip I came up with 95.7".
1.04" wheel = 18"
5.53" wheelbase= 95.7"
Interesting, I just measured again on my monitor.
Assuming it is 17" wheel like the current Miata and so has an 18" diameter at the edge of the wheel lip I came up with 95.7".
1.04" wheel = 18"
5.53" wheelbase= 95.7"
01-09-14, 05:36 PM
#938
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Join Date: Jul 2002
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I did a Photoshop overlay of the test mule and the NC, printed the picture and measured the percentage difference, then used the percentage to calculate the Spy wheel base.
My calculation came out to be a 7% increase in wheel base, thus making the Spy car 6.5 inches longer.
My calculation came out to be a 7% increase in wheel base, thus making the Spy car 6.5 inches longer.
01-09-14, 06:13 PM
#939
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and what is the wheelbase of an NC miata?
01-09-14, 06:32 PM
#940
if they make 2 piece ceramics it would alleviate the temperature/compression variation issues. they obviously already have some tooling set aside for it since the 4 rotor n/a race engines used those seals, but i suppose they could have simply been handmade one offs due to the low numbers they had to make them in. in the end they already proved that they work in n/a engines reliably and provided an even higher rev range than ever previously seen aside from carbon which isn't a durable material for long term use.
in fact, assuming they can maintain properly low detonation cycles from occurring through a more proper knock system the engines could outlast any previous rotary engine design and even be more reliable than piston engine counterparts, closer to diesel engines. as of now the rotor housing and apex seal wear is still the largest contributor to dying rotaries than anything else and a simple swap of seals could virtually eliminate that.
in the aftermarket world we only see single piece ceramic seals, which give low initial compression until the engine is warmed up to operating temp.
in fact, assuming they can maintain properly low detonation cycles from occurring through a more proper knock system the engines could outlast any previous rotary engine design and even be more reliable than piston engine counterparts, closer to diesel engines. as of now the rotor housing and apex seal wear is still the largest contributor to dying rotaries than anything else and a simple swap of seals could virtually eliminate that.
in the aftermarket world we only see single piece ceramic seals, which give low initial compression until the engine is warmed up to operating temp.
I'm with you on this. Since Mazda wants to stay NA, why not use what's best for that engine? Some may say there may be cost issues? I don't think so because we're talking mass production. But don't forget, Glassman makes 2 piece ceramic seals. Also, isn't the Renesis mostly dying from loss of compression from the side seals? I heard the heat is taking them out prematurely.
Edit: I think what I read about those side seal failures where under racing conditions.
01-09-14, 07:50 PM
#941
in the renesis the major issues are a combination of both the side seals and the apex seals. the rotor housings do actually look quite trashed once they hit 100k miles even in cars that have never been severely abused. with the condition of the housings and the mileage at which most usually fail i would actually say it isn't the side seals causing lower compression numbers but actually the rotor housings.
the renesis has chrome that is about half as thick as the earlier 13B engines did, so it goes to steel liner much faster. many of those 100k+ engines i tore apart showed normal wear already down to steel. in older engines it took quite a bit to cause that much wear.
unless the side seals are stuck completely in the rotor the compression losses are usually minimal and i have yet to see that even on the MSP renesis engines. some did come apart with broken side seals, due to carbon breaking off the exhaust port and probably catching the seals as they passed over it. in other engines i saw chunks of the 5/6th port sleeve castings broken where the casting went through the engine and drug across the side of the rotor causing numbers to be extremely low and in the 30's.
the trailing exhaust port edge on the renesis has much to be desired. all it really serves as is a carbon trap, because it's always plugged up with a solid chunk of carbon that you can see the side seals have been scraping flat constantly.
i also still don't see why mazda felt it necessary to change the engine design. i have tuned even FDs to run as low as 2 hydrocarbons per million and nearly zero CO/NOx on the sniffer at idle all with a peripheral exhaust engine. keep in mind that was with a hard mapped ECU, not one that can even automatically adjust itself for ideal AFRs like mazda has been using since the 8 was introduced. maybe i'm missing something and the european standards require all cars to pass emissions on a dyno at all load variables before they get the green light for production, even then the technology was there to pull it off. i think mazda was just scared off by the thought that as the cars wore in they may fail standards and be recalled.
the renesis has chrome that is about half as thick as the earlier 13B engines did, so it goes to steel liner much faster. many of those 100k+ engines i tore apart showed normal wear already down to steel. in older engines it took quite a bit to cause that much wear.
unless the side seals are stuck completely in the rotor the compression losses are usually minimal and i have yet to see that even on the MSP renesis engines. some did come apart with broken side seals, due to carbon breaking off the exhaust port and probably catching the seals as they passed over it. in other engines i saw chunks of the 5/6th port sleeve castings broken where the casting went through the engine and drug across the side of the rotor causing numbers to be extremely low and in the 30's.
the trailing exhaust port edge on the renesis has much to be desired. all it really serves as is a carbon trap, because it's always plugged up with a solid chunk of carbon that you can see the side seals have been scraping flat constantly.
i also still don't see why mazda felt it necessary to change the engine design. i have tuned even FDs to run as low as 2 hydrocarbons per million and nearly zero CO/NOx on the sniffer at idle all with a peripheral exhaust engine. keep in mind that was with a hard mapped ECU, not one that can even automatically adjust itself for ideal AFRs like mazda has been using since the 8 was introduced. maybe i'm missing something and the european standards require all cars to pass emissions on a dyno at all load variables before they get the green light for production, even then the technology was there to pull it off. i think mazda was just scared off by the thought that as the cars wore in they may fail standards and be recalled.
Last edited by RotaryEvolution; 01-09-14 at 08:04 PM.
01-10-14, 10:24 AM
#943
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i also still don't see why mazda felt it necessary to change the engine design. i have tuned even FDs to run as low as 2 hydrocarbons per million and nearly zero CO/NOx on the sniffer at idle all with a peripheral exhaust engine. keep in mind that was with a hard mapped ECU, not one that can even automatically adjust itself for ideal AFRs like mazda has been using since the 8 was introduced. maybe i'm missing something and the european standards require all cars to pass emissions on a dyno at all load variables before they get the green light for production, even then the technology was there to pull it off. i think mazda was just scared off by the thought that as the cars wore in they may fail standards and be recalled.
i smogged an FD running with a JDM 99+ spec ECU, and in steady state, like you say, its just as clean as the Rx8, the big difference was in the transitions, the Rx8 STAYS clean, and the FD doesn't. some of that is because the FD uses a narrow band o2 vs the Rx8's wideband…
the US and euro standards are slightly, the euro standard is indexed with gas mileage, somehow, and the US one is just like a bag on the tailpipe, and a dyno test.
01-10-14, 12:13 PM
#944
Regardless of power and weight Mazda needs to bring back the rotary and further develope it. If some Spanish guys I know working our of a garage in there house can build reliable powerful rotarys on a budget I would assume Mazda could too.
The 2015 test mule pics are sexy
I would buy it but most Likly as a hard top and only with a rotary.
Mazda needs to make the rotary set the standard for reliability in a sports car. It's been done before just not buy Mazda. It's 3 moving parts figure it out.
As for the mx5. It's like a fat chick. No matter how much fun it is to ride you don't Really want to be seen in it
The 2015 test mule pics are sexy
I would buy it but most Likly as a hard top and only with a rotary. Mazda needs to make the rotary set the standard for reliability in a sports car. It's been done before just not buy Mazda. It's 3 moving parts figure it out.
As for the mx5. It's like a fat chick. No matter how much fun it is to ride you don't Really want to be seen in it
01-10-14, 12:26 PM
#945
Full Member
I did a little calculation based on that pic. The wheel rims are 95 pixels across, while the wheelbase (wheel center to wheel center) comes out at 501 pixels. If we assume 16" rims, that computes to 84.4" wheelbase, whereas if we assume 17" rims, then that equates to 89.6".
Interesting, I just measured again on my monitor.
Assuming it is 17" wheel like the current Miata and so has an 18" diameter at the edge of the wheel lip I came up with 95.7".
1.04" wheel = 18"
5.53" wheelbase= 95.7"
Interesting, I just measured again on my monitor.
Assuming it is 17" wheel like the current Miata and so has an 18" diameter at the edge of the wheel lip I came up with 95.7".
1.04" wheel = 18"
5.53" wheelbase= 95.7"
Redid the measures, with 16" rims it comes out at 90.6" wheelbase, while a 17" rim produces 96.3".
I thought I had read somewhere (perhaps the miata.net forum?) that, in order to shed weight, the wheels may get slightly smaller. A cue in this direction is the 4 bolt wheel hub, rather than a 5 bolt hub as in the NC.
Those rims look like a set of OZ Racing Ultraleggera. I checked their catalogue and unfortunately they make sizes from 15" all the way to 18", so no help there.
Andrea.
01-10-14, 12:33 PM
#946
01-10-14, 12:55 PM
#948
Senior Member
On the contrary, they are the ones that developed the rotary into one of the car industries most reliable engines 12A, 13B and how they became the most successful GTU cars in IMSA during the‘80’s, and only Japanese car company overall winner of Lemans, not from globs of power but from bulletproof reliability.
24 hours at LeMans on a race-only powerplant is one thing. decades of service and 200k+ life in the real world is another...
Fact is, the Mazda rotaries are some of the *least* reliable and shortest-life-expectancy production-car engines ever.
I love these engines, but they aren't anything like as reliable and long-lived as most decent piston-engine powerplants.
I still hope they produce another rotary sports car, but IMO there's no need for rose-colored glasses. Reliability and longevity have been MAJOR issues for every generation of Mazda production-car rotary engine.
01-10-14, 01:30 PM
#949
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Joking?
24 hours at LeMans on a race-only powerplant is one thing. decades of service and 200k+ life in the real world is another...
Fact is, the Mazda rotaries are some of the *least* reliable and shortest-life-expectancy production-car engines ever.
I love these engines, but they aren't anything like as reliable and long-lived as most decent piston-engine powerplants.
I still hope they produce another rotary sports car, but IMO there's no need for rose-colored glasses. Reliability and longevity have been MAJOR issues for every generation of Mazda production-car rotary engine.
24 hours at LeMans on a race-only powerplant is one thing. decades of service and 200k+ life in the real world is another...
Fact is, the Mazda rotaries are some of the *least* reliable and shortest-life-expectancy production-car engines ever.
I love these engines, but they aren't anything like as reliable and long-lived as most decent piston-engine powerplants.
I still hope they produce another rotary sports car, but IMO there's no need for rose-colored glasses. Reliability and longevity have been MAJOR issues for every generation of Mazda production-car rotary engine.
the part you dont know, is that we were replacing the Mazda 6 V6 engines left and right, and while the rotary has a strict diagnostic procedure before you're allowed to order one, with the piston engine, replacing the engine was the first step in the diagnosis.
or even better is the MZR engine in the CX7, those things are total junk, we were replacing major parts basically from day 1, they melt pistons, throw rods, eat turbos, and parts are $$$$$$$$
i will grant you that the overall failure rate of the rotary is higher, but if you think piston engine cars don't break you're wrong.
01-10-14, 02:06 PM
#950
the 12a was in fact a very reliable engine. the only thing that is killing it off now is the high mileage engines needing major parts, like rotor housings, which were discontinued about 20 years ago.
how many cars make it from 1979 to today without needing an engine overhaul? not too many. speaking of which i have just that, a 1979 Rx7 in for its first rebuild right now.
how many cars make it from 1979 to today without needing an engine overhaul? not too many. speaking of which i have just that, a 1979 Rx7 in for its first rebuild right now.