The RX-7 confirmed to be in the pipeline for 2017---RX-Vision Unveil!!
01-25-14, 08:53 PM
#1326
Senior Member
Before the Ohlins coilovers it was slower around New Hampshire Motor Speedway (kind of a Miata track) than my 240Z...
My FD is a massive overdog that I'm going slow in. 240Z was an underdog car that gave grief to many a supercar!
I need tires and rear downforce...
My FD is a massive overdog that I'm going slow in. 240Z was an underdog car that gave grief to many a supercar!
I need tires and rear downforce...
01-25-14, 08:55 PM
#1327
Rotary Enthusiast
Life is all about choices. I was fantasizing about buying a 1996 Lotus Esprit S4S or Sport 300, but I think the Mazda RX-7 is a better car. Yes, the Lotus has a higher price tag and slightly more luxury, but in terms of looks, modern platform, and soulful engine, the Mazda still beats it every time.
01-25-14, 10:05 PM
#1328
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you know its funny, Audi has won lemans 12 times (second only to porsche), and i don't particularly think of them as a sporstcar makers, in fact i'd even go so far as to say they can barely keep their street cars running.
my brother and dad have had a few Audi's and they make the FD look like its simple reliable and easy to work on.
a TT won the 25 hours of thunderhill this year, which is shocking, not because it was fast, but because they got it to run that long (the R8 blew up, in practice)
my brother and dad have had a few Audi's and they make the FD look like its simple reliable and easy to work on.
a TT won the 25 hours of thunderhill this year, which is shocking, not because it was fast, but because they got it to run that long (the R8 blew up, in practice)
01-25-14, 10:16 PM
#1329
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according to rumor they were going to announce something in early 2014...
big power cars are rarely as fast in real life as they are on paper. you need a LOT more driver...
01-25-14, 10:40 PM
#1330
Rotary Enthusiast
The 2010 RE Amemiya RX-7 chasing a Ferrari:
And here's some touge action (post #33):
Is the RE Amemiya RX-7 a drift car? | Page 2 - GTPlanet
You can see here that the FD isn't just designed for the track. The balanced performance works in its favor on these winding, bumpy, narrow country roads. Larger, heavier, more powerful cars aren't particularly fun on the touge.
And here's some touge action (post #33):
Is the RE Amemiya RX-7 a drift car? | Page 2 - GTPlanet
You can see here that the FD isn't just designed for the track. The balanced performance works in its favor on these winding, bumpy, narrow country roads. Larger, heavier, more powerful cars aren't particularly fun on the touge.
Last edited by HiWire; 01-25-14 at 10:42 PM.
01-26-14, 08:18 AM
#1332
Full Member
If Mazda wanted a second rotary engine option with more power than a 2 rotor NA engine can provide, I doubt they would choose a turbo over a third rotor, at least if their goal is to keep costs down.
Even before all of the issues with users turning up the boost to ridiculous levels, there is the fact that an NA and a turbo engine are quite different in their power curves. Adding a turbo to a high revving, high compression NA angine would likely require a whole lot of detail differences, which could end up being more costly than a third NA rotor.
The only serious issue I can think about with an all side port 3 rotor is related to the siamese exhaust port: in a 2 rotor, the rotors are offset by 180° with respect of each other, so each rotor interferes with the exhaust phase of the other rotor in the same way. In an even firing 3 rotor, each rotor is offset by 120°. That would mean that the two rotors sharing the common exhaust port would interfere with each other in different ways, which would be bad.
Making an effective 3 rotor would then require finding a way to split the center exhaust port, possibly while maintaining its cross sectional area per each rotor. Thicker center plate maybe (even for the 2 rotor, to keep costs down)? Or perhaps extending the exhaust port vertically?
On the upside, separating the exhaust paths of the rotors would allow for a more effective exhaust system, better able to control the pressure waves produced by each rotor and to use them for better scavenging.
I'm not saying that a turbo 2 rotor is out of the question, only that, in my opinion, it's not the best option for Mazda.
Andrea.
Even before all of the issues with users turning up the boost to ridiculous levels, there is the fact that an NA and a turbo engine are quite different in their power curves. Adding a turbo to a high revving, high compression NA angine would likely require a whole lot of detail differences, which could end up being more costly than a third NA rotor.
The only serious issue I can think about with an all side port 3 rotor is related to the siamese exhaust port: in a 2 rotor, the rotors are offset by 180° with respect of each other, so each rotor interferes with the exhaust phase of the other rotor in the same way. In an even firing 3 rotor, each rotor is offset by 120°. That would mean that the two rotors sharing the common exhaust port would interfere with each other in different ways, which would be bad.
Making an effective 3 rotor would then require finding a way to split the center exhaust port, possibly while maintaining its cross sectional area per each rotor. Thicker center plate maybe (even for the 2 rotor, to keep costs down)? Or perhaps extending the exhaust port vertically?
On the upside, separating the exhaust paths of the rotors would allow for a more effective exhaust system, better able to control the pressure waves produced by each rotor and to use them for better scavenging.
I'm not saying that a turbo 2 rotor is out of the question, only that, in my opinion, it's not the best option for Mazda.
Andrea.
01-26-14, 08:34 AM
#1334
If Mazda wanted a second rotary engine option with more power than a 2 rotor NA engine can provide, I doubt they would choose a turbo over a third rotor, at least if their goal is to keep costs down.
Even before all of the issues with users turning up the boost to ridiculous levels, there is the fact that an NA and a turbo engine are quite different in their power curves. Adding a turbo to a high revving, high compression NA angine would likely require a whole lot of detail differences, which could end up being more costly than a third NA rotor.
The only serious issue I can think about with an all side port 3 rotor is related to the siamese exhaust port: in a 2 rotor, the rotors are offset by 180° with respect of each other, so each rotor interferes with the exhaust phase of the other rotor in the same way. In an even firing 3 rotor, each rotor is offset by 120°. That would mean that the two rotors sharing the common exhaust port would interfere with each other in different ways, which would be bad.
Making an effective 3 rotor would then require finding a way to split the center exhaust port, possibly while maintaining its cross sectional area per each rotor. Thicker center plate maybe (even for the 2 rotor, to keep costs down)? Or perhaps extending the exhaust port vertically?
On the upside, separating the exhaust paths of the rotors would allow for a more effective exhaust system, better able to control the pressure waves produced by each rotor and to use them for better scavenging.
I'm not saying that a turbo 2 rotor is out of the question, only that, in my opinion, it's not the best option for Mazda.
Andrea.
Even before all of the issues with users turning up the boost to ridiculous levels, there is the fact that an NA and a turbo engine are quite different in their power curves. Adding a turbo to a high revving, high compression NA angine would likely require a whole lot of detail differences, which could end up being more costly than a third NA rotor.
The only serious issue I can think about with an all side port 3 rotor is related to the siamese exhaust port: in a 2 rotor, the rotors are offset by 180° with respect of each other, so each rotor interferes with the exhaust phase of the other rotor in the same way. In an even firing 3 rotor, each rotor is offset by 120°. That would mean that the two rotors sharing the common exhaust port would interfere with each other in different ways, which would be bad.
Making an effective 3 rotor would then require finding a way to split the center exhaust port, possibly while maintaining its cross sectional area per each rotor. Thicker center plate maybe (even for the 2 rotor, to keep costs down)? Or perhaps extending the exhaust port vertically?
On the upside, separating the exhaust paths of the rotors would allow for a more effective exhaust system, better able to control the pressure waves produced by each rotor and to use them for better scavenging.
I'm not saying that a turbo 2 rotor is out of the question, only that, in my opinion, it's not the best option for Mazda.
Andrea.
01-26-14, 08:46 AM
#1335
Full Member
Andrea, I have broken down Renesis in my shop that I'm going to experiment with in a 2nd gen Mazdaspeed Miata. The center plate of the exhaust has a divider between the two chambers. So I don't think phasing will be a problem with a 3 rotor.
Attachment 522309
Attachment 522309
That's good, but still it seems like there is some connection between the exhaust paths of the rotors (i.e.: the divider doesn't seem to extend outward enough to contact the exhaust header).
One would need to fully separate them to avoid unwanted exhaust pressure wave related interferences between the rotors in a 3 rotor.
Andrea.
01-26-14, 08:52 AM
#1337
Well, I didn't know that.
That's good, but still it seems like there is some connection between the exhaust paths of the rotors (i.e.: the divider doesn't seem to extend outward enough to contact the exhaust header).
One would need to fully separate them to avoid unwanted exhaust pressure wave related interferences between the rotors in a 3 rotor.
Andrea.
https://www.rx7club.com/showthread.p...356&styleid=17
01-26-14, 09:36 AM
#1338
Full Member
Here's s thread for you were someone actually built a 3rotor using Renesis housings.
Wow. An actual 3-rotor RENESIS - RX7Club.com
Wow. An actual 3-rotor RENESIS - RX7Club.com
I read that thread quickly, unfortunately there are no pics if the engine internals. Was curious about the stationary gear mounted to one of the intermediate plates. Also not clear if an additional shaft bearing is fitted to one of the intermediate plates.
Obviously that's not how Mazda would make an all side port 3 rotor: the center rotor of that engine is running on primary ports only (even though they are likely ported) and on shared exhaust ports only.
A Mazda designed all side port 3 rotor would feature a proper thick center plate with an e-shaft bearing there, with the primary port for one rotor and secondary + auxiliary ports for the other, and with two completely separate exhaust ports.
Andrea.
01-26-14, 09:47 AM
#1339
The MAJOR problem with this idea is that the mass populace of rich-*** "enthusiasts" would MUCH rather have a bigger heavier bruiser of a "sports car" like a Corvette or a GTR or 911 than a tiny REAL sports car like an Elise, Exige, or Alfa 4C. And the fact will remain that on faster tracks, with the same power/weight, the more powerful big/bruiser ultramegasupercars will still have the advantage.
Everybody is already making the BRZ too. Make the car others aren't building.
Alfa engineers have said that a U.S. version of the 4C will weigh as much as 2500 lb. That's a TINY-*** car with a carbon fiber tub. Meanwhile, the much bigger steel FR-S/BRZ weighs only 250 lb. more than that.
As a structural engineer responsible for chassis development of a few road vehicles, in my experience the weight savings from aluminum or even carbon fiber isn't necessarily as great as you might think.
Meanwhile, it has been demonstrated that a 2750 lb. 200hp 4cyl. 2+2 rwd car is totally doable for reasonable $$$. Based on that, *surely* a conventional-construction 2600 lb. 2-seat 250hp 2-rotor NA is eminently feasible. With optional ~2750 lb. 350ish hp turbo or 3-rotor.
Those who want a 3- or 4-rotor turbo monster or a carbon fiber tubbed exoticar, is that *really* an RX-7, or something else?
NObody's building anything like the car I'm talking about, and it's totally doable for $35k or less, and it would perfectly fit a gaping void in the market for a high(ish) performance REAL sports car.
If you have money and you want an exotic carbon fiber car, the 4C is (I think?) on it's way. Or you could get an equally lightweight (lighter even) Exige and tweak hp out of that.
If you have money and you want big power, Corvettes, GTRs, 911s, etc. already exist, get one!
As a structural engineer responsible for chassis development of a few road vehicles, in my experience the weight savings from aluminum or even carbon fiber isn't necessarily as great as you might think.
Meanwhile, it has been demonstrated that a 2750 lb. 200hp 4cyl. 2+2 rwd car is totally doable for reasonable $$$. Based on that, *surely* a conventional-construction 2600 lb. 2-seat 250hp 2-rotor NA is eminently feasible. With optional ~2750 lb. 350ish hp turbo or 3-rotor.
Those who want a 3- or 4-rotor turbo monster or a carbon fiber tubbed exoticar, is that *really* an RX-7, or something else?
NObody's building anything like the car I'm talking about, and it's totally doable for $35k or less, and it would perfectly fit a gaping void in the market for a high(ish) performance REAL sports car.
If you have money and you want an exotic carbon fiber car, the 4C is (I think?) on it's way. Or you could get an equally lightweight (lighter even) Exige and tweak hp out of that.
If you have money and you want big power, Corvettes, GTRs, 911s, etc. already exist, get one!
250 lbs actually sounds like a lot to me.
I'd pay a pretty penny (and have) to take a couple hundred pounds out of my FD. Like I say, the Exige is cool, but it has a Lotus $premium, and it's just unlivably small inside. I'm not a big guy, but when I can't drive without my shoulder pressed against my passenger's, that better be because they're sitting in the homologation "passenger" seat of an ALMS prototype car.
But yes, I'm looking for a slightly more realistic, slightly heavier, slightly more powerful, rotary powered Exige. 2600 lbs, 350 hp minimum, I don't pay the lotus $premium, and I don't touch my passenger unless I want to. 2800 and 300 hp doesn't cut it, If I want that, i'll throw the air conditioning and emissions crap back on my car.
01-26-14, 10:01 AM
#1341
Uh, yeah, I said, it was TOO extreme. It was 2,000 lbs, and too small. It's also not being made anymore, so they aren't saturating the new car market with them anymore.
500-600 lbs would buy you a lot of real world livability and potential cost savings. 800-1,000 lbs buys you a yawn.
Face it, a BRZ is a major downgrade from an FD, even 20 years later. I think you've got to at least build something that the owner of the previous car would be interested in.
500-600 lbs would buy you a lot of real world livability and potential cost savings. 800-1,000 lbs buys you a yawn.
Face it, a BRZ is a major downgrade from an FD, even 20 years later. I think you've got to at least build something that the owner of the previous car would be interested in.
Last edited by ptrhahn; 01-26-14 at 10:07 AM.
01-26-14, 10:22 AM
#1342
Very cool!
I read that thread quickly, unfortunately there are no pics if the engine internals. Was curious about the stationary gear mounted to one of the intermediate plates. Also not clear if an additional shaft bearing is fitted to one of the intermediate plates.
Obviously that's not how Mazda would make an all side port 3 rotor: the center rotor of that engine is running on primary ports only (even though they are likely ported) and on shared exhaust ports only.
A Mazda designed all side port 3 rotor would feature a proper thick center plate with an e-shaft bearing there, with the primary port for one rotor and secondary + auxiliary ports for the other, and with two completely separate exhaust ports.
Andrea.
http://pulseperformance.co.nz/index.php?page=product
Yea Mazda wouldn't build it that way for the reasons you stated. But it was nice to see someone actually build it. I don't think the thick center plate would have to be that wide if Mazda actually built one.
01-26-14, 10:28 AM
#1344
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A big group of track rats down in FL who were driving the 997 GT3 switched to 993 race cars because they are lighter (so easier on the wallet) and more fun to drive.
There's a market for a 350 HP lightweight sports car and the lotus isn't that car. It's too expensive and dare I say too small to really even handle the factory power much less when modded but it's also too small from a practical standpoint as well. BUT with that said a car that is similar to the lotus would sell well if a big manufacturer decided to make it because they could sell the same thing for 50k not 75k and make it better in all categories with out adding that much weight and that car would be a winner/big seller. I would absolutely love a minimalist high performance well made sports car for 50k and I believe I'm not the only one.
By minimalist I mean exactly like the lotus, just a radio and AC. No carpet or gadgets or big heavy fancy seats, or fancy upholstery etc...
Why somebody like toyota hasn't done that is beyond me, OH wait maybe that's what the BRZ will become once they wake up and realize they are on to something. In the meantime Mazda will be twiddling there thumbs as usual.
There's a market for a 350 HP lightweight sports car and the lotus isn't that car. It's too expensive and dare I say too small to really even handle the factory power much less when modded but it's also too small from a practical standpoint as well. BUT with that said a car that is similar to the lotus would sell well if a big manufacturer decided to make it because they could sell the same thing for 50k not 75k and make it better in all categories with out adding that much weight and that car would be a winner/big seller. I would absolutely love a minimalist high performance well made sports car for 50k and I believe I'm not the only one.
By minimalist I mean exactly like the lotus, just a radio and AC. No carpet or gadgets or big heavy fancy seats, or fancy upholstery etc...
Why somebody like toyota hasn't done that is beyond me, OH wait maybe that's what the BRZ will become once they wake up and realize they are on to something. In the meantime Mazda will be twiddling there thumbs as usual.
01-26-14, 10:36 AM
#1346
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01-26-14, 10:39 AM
#1347
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The lotus isn't a loud car compared to a 997. The 997 Is super loud because the engine is behind your head with an exhaust that's 10 inches long and people love the sound
They can have options for carpet for you softies but anyone who needs nav, blue tooth, video screens and traction control can go elsewhere.
01-26-14, 10:54 AM
#1349
Thankfully there are things called mufflers
The lotus isn't a loud car compared to a 997. The 997 Is super loud because the engine is behind your head with an exhaust that's 10 inches long and people love the sound
They can have options for carpet for you softies but anyone who needs nav, blue tooth, video screens and traction control can go elsewhere.
Yea I'm a real softy.
The 1st time I test drove my 20b, I couldn't stand all the drone noise from my NA exhaust system. I practically had to rebuild my exhaust bypass setup just to refine it. I may now have one of the quietest NA 20Bs running around. Now when you step on the gas, she will really let you know she's there. I'm one of those that hate having road noise drown out my music.
01-26-14, 10:55 AM
#1350
Lotus DID do a fabulous job in making the interior without carpet, a lot of plastics, and exposed structural elements and making it really work. It's sort of "minimalist chic" or "racecar chic". It doesn't feel cheap, or like you just stripped a regular car.
I don't need carpet or wood, I need them to grab the chassis, and stretch it two inches side-to-side, and fore-and-aft, so I don't have to tell my passenger to move their knee so I can shift.
I don't need carpet or wood, I need them to grab the chassis, and stretch it two inches side-to-side, and fore-and-aft, so I don't have to tell my passenger to move their knee so I can shift.