3 Rotor Motor
10-08-2002, 12:19 AM
#26
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Rich,
are you suggesting a 3 rotor RX-8 or RX-7 would add 600 lbs to the total weight of the car?
I feel the running gear would be adequate for the extra ponies. From experience I know Mazda parts are pretty strong.
are you suggesting a 3 rotor RX-8 or RX-7 would add 600 lbs to the total weight of the car?
I feel the running gear would be adequate for the extra ponies. From experience I know Mazda parts are pretty strong.
10-08-2002, 08:26 AM
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3300-2970=330. With another rotor and substantially more power, I think there would need to be upgrades to the rest of the car. 300 lbs seems reasonable to me, and 2970 is the only weight I've seen from a reputable source. The actual weight gain isn't important, it would certainly add substantial cost and at least some weight. I don't want any more weight or cost, and I know that some of the people clammoring for an extra rotor are those that have been saying that they want it to cost less than current estimates have it. My point is that they can't have it both ways. The RX-8 hits a mark, and a 3-rotor would hit a different mark. I like the car that they're making, although if I get one it will be a stretch financially. Any more cost and I wouldn't be here. I suspect many others are the same.
10-08-2002, 12:37 PM
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precisely, the 3-rotor would be hitting the upper range of Mazda's market, in the new RX-7, supposing one'll come out in 3 or 4 years...
a -2800 lb, +350 hp RX-7 would warrant a near $40K sticker, don't you think?? how much is a Z06?? it'd smoke it. :D
oh, btw, i only know the FD's (ballpark) price in Canadian... just for comparison (inflation excluded, as you in the States had a very stable inflation rate throught the 90's), what was the FD's R1 price?? +$35K?? if the same price for much more car now (becuase inflation would infact dictate a real price similar to that of the FD's, again, supposing) would be one helluva steal, no??
a -2800 lb, +350 hp RX-7 would warrant a near $40K sticker, don't you think?? how much is a Z06?? it'd smoke it. :D
oh, btw, i only know the FD's (ballpark) price in Canadian... just for comparison (inflation excluded, as you in the States had a very stable inflation rate throught the 90's), what was the FD's R1 price?? +$35K?? if the same price for much more car now (becuase inflation would infact dictate a real price similar to that of the FD's, again, supposing) would be one helluva steal, no??
10-08-2002, 08:05 PM
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Why stop at the Z06 when you can kill a $80k Viper. This months Motor Trend compares those two directly and the whole time I'm thinkin' with a few mods how bad the rx-8 would make them look and be under $40k and still be able to carry the kids to soccer practice.
10-09-2002, 03:03 AM
#32
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if you mean "around a corner" appended to the term "kill", than yes i agree...
but a +550 bhp or whatever gazillion litre V10 the Viper is packing is still a +550 bhp or whatever gazillion litre V10... i don't think that an RX-7, no matter how muscley and expensive it is from the factory would out gun the ultimate contemporary symbol of American machismo in a straight line... i mean, it's not THAT much heavier, but yes, it IS that much more expensive, so the smart money would see where the bargain is...
but a +550 bhp or whatever gazillion litre V10 the Viper is packing is still a +550 bhp or whatever gazillion litre V10... i don't think that an RX-7, no matter how muscley and expensive it is from the factory would out gun the ultimate contemporary symbol of American machismo in a straight line... i mean, it's not THAT much heavier, but yes, it IS that much more expensive, so the smart money would see where the bargain is...
10-09-2002, 11:26 PM
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Dude, you're the one that started the comparison to the Z06, the Viper is not much faster. And since when has anybody here really tried to say that the Rx-8 or fictional new 7 be FAST in a straight line?
The Viper is 500bhp and ran a 12.37 @ 117.21mph. If you wanted to, I think you could make a RX-7 or 8 compete for less than 80 grand.
In case you want to know the Vette did a 12.85 @ 114.36
The Viper is 500bhp and ran a 12.37 @ 117.21mph. If you wanted to, I think you could make a RX-7 or 8 compete for less than 80 grand.
In case you want to know the Vette did a 12.85 @ 114.36
10-09-2002, 11:30 PM
#34
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I've heard, saw dynos that seem to suggest the Z06 is underrrated by GM.. I've seen 400 Whp dynos! 
And some people breaking 11's stock with slicks! The Z06 is a bargain in the performance/price ratio.. Now if only it wasn't a Chevy.. Can't stand Chevy interiors..
And some people breaking 11's stock with slicks! The Z06 is a bargain in the performance/price ratio.. Now if only it wasn't a Chevy.. Can't stand Chevy interiors..
10-10-2002, 03:30 AM
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oh, Viper isn't much faster??? 
huh, well, again, i don't know anything about American "sports" cars, and far less about drag racing (other than what can be gleaned through knowledge of racing and other technical stuff in general)...
hmmm... oh, i'm not saying the hypothetical new RX-7 has to be that fast, i'm just supposing that with a mean 3 rotor it COULD be, from the factory... but i definitely think a sticker of $50K US would kill it, because people WOULD buy Corvettes instead, and it would be naive to think they would buy a 7 even if it was faster... maybe those Viper people could be swayed, maybe, but i doubt you could convince most of the Corvette crowd (if they were going to choose one or the other)... so really, my comparison was just for fun, and i REALLY don't think they should price/make the hypothetical RX-7 that expensive when (knock on wood) it comes out...
and ya, the Big 3 have a history of underrating their truly fast cars, don't they?? i mean, not so much anymore, but back in the day... the Corvette is probably the only car that GM could afford to under rate, marketing wise anyway...
huh, well, again, i don't know anything about American "sports" cars, and far less about drag racing (other than what can be gleaned through knowledge of racing and other technical stuff in general)...hmmm... oh, i'm not saying the hypothetical new RX-7 has to be that fast, i'm just supposing that with a mean 3 rotor it COULD be, from the factory... but i definitely think a sticker of $50K US would kill it, because people WOULD buy Corvettes instead, and it would be naive to think they would buy a 7 even if it was faster... maybe those Viper people could be swayed, maybe, but i doubt you could convince most of the Corvette crowd (if they were going to choose one or the other)... so really, my comparison was just for fun, and i REALLY don't think they should price/make the hypothetical RX-7 that expensive when (knock on wood
) it comes out...and ya, the Big 3 have a history of underrating their truly fast cars, don't they?? i mean, not so much anymore, but back in the day... the Corvette is probably the only car that GM could afford to under rate, marketing wise anyway...
Last edited by wakeech; 10-10-2002 at 03:35 AM.
10-17-2002, 08:37 PM
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As always, I'll back the Z06 and say its the best.
I'm not sure I want to see a 3 rotor engine in the 8. I'm afraid, like Rich points out, that it would add too much weight. A 3 rotor would be great for drag racing, but not for the street.
I am optimistic about a new generation 7 having a three rotor, though. In that case Mazda could work out the weight ratios and again give its loyal followers another 50/50 sports car.
I'm not sure I want to see a 3 rotor engine in the 8. I'm afraid, like Rich points out, that it would add too much weight. A 3 rotor would be great for drag racing, but not for the street.
I am optimistic about a new generation 7 having a three rotor, though. In that case Mazda could work out the weight ratios and again give its loyal followers another 50/50 sports car.
10-17-2002, 09:29 PM
#37
I don't see why it woudl be THAT much more...
The rotors weigh what, something 15 lbs a piece? Then they extend the housing for it and that's another, maybe... 50 lbs? So let's say 100 lbs extra.. I'm sure they can balance that in the car if they wanted to.
Or am I missing something?
The rotors weigh what, something 15 lbs a piece? Then they extend the housing for it and that's another, maybe... 50 lbs? So let's say 100 lbs extra.. I'm sure they can balance that in the car if they wanted to.
Or am I missing something?
10-17-2002, 10:27 PM
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I heard the 20B weighed about 130lbs more than a 13B. It is not an excessive amount of weight, so I don't think it would be a big deal in the RX-8. But I have also heard that 3 rotor FD's handling went down the drain after the conversion. If that is what will happen with the 8's than I would rather see a single turbo configuration. I'm not interested in sacrificing handling characteristics for power.
Maybe the 8 won't be able to accomodate a 3 rotor without massive modifications anyway.
Maybe the 8 won't be able to accomodate a 3 rotor without massive modifications anyway.
10-17-2002, 10:27 PM
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I heard the 20B weighed about 130lbs more than a 13B. It is not an excessive amount of weight, so I don't think it would be a big deal in the RX-8. But I have also heard that 3 rotor FD's handling went down the drain after the conversion. If that is what will happen with the 8's than I would rather see a single turbo configuration. I'm not interested in sacrificing handling characteristics for power.
Maybe the 8 won't be able to accomodate a 3 rotor without massive modifications anyway.
Maybe the 8 won't be able to accomodate a 3 rotor without massive modifications anyway.
10-17-2002, 11:37 PM
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"massive modifications" to the RX-7 to get that 20B to fit was probably a big reason the handling fell in the toilet, too... i've heard things like shortening the driveshaft, moving the transmission back, etc...
but when you say the 20B-REW was 130lb heavier than the 13B, which 13B are you talking about?? the 13B-REW?? or the 13BT?? or just the plain ol' 13B??
but when you say the 20B-REW was 130lb heavier than the 13B, which 13B are you talking about?? the 13B-REW?? or the 13BT?? or just the plain ol' 13B??
10-17-2002, 11:51 PM
#41
These were aftermarket conversions though, right?
If Mazda developed a 3 rotor Renesis *drool*, then I'm sure they'd work out handling characteristics to match the engine and car.
Here's hoping for it
If Mazda developed a 3 rotor Renesis *drool*, then I'm sure they'd work out handling characteristics to match the engine and car.
Here's hoping for it
10-17-2002, 11:51 PM
#42
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I know, a mid-engine 3 rotor RX-7! :D Even in 3 rotor it's not going to be a big engine, and the extra weight would be easy to distribute. Also would give it a use for the extra space in the back when they re-adapt the 4-seat RX-8 platform to the 2-seat RX-7.
That would totaly rip a porcshe to peices.
The engine itself is not very complex, so adding another rotor and fabricating it shouldn't be too hard, but re-engineering an RX-8 platform to MR might be impossible, if not expensive.
(conspiracy theory) Maybe that transmision tunnel is high in the RX-8 passenger area for a reason. It might just be the best no-compromise sports car solution.
That would totaly rip a porcshe to peices.
The engine itself is not very complex, so adding another rotor and fabricating it shouldn't be too hard, but re-engineering an RX-8 platform to MR might be impossible, if not expensive.
(conspiracy theory) Maybe that transmision tunnel is high in the RX-8 passenger area for a reason.
It might just be the best no-compromise sports car solution.
10-18-2002, 05:59 PM
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After reading some of the other posts, I am more in tune with a 3-rotor motor, as same does not appear to increase weight, affect weight distribution too much, at least not so much as to require too much to keep the balance at 50/50. Remember, the motor is set behind the front wheels to begin with.
The 3 rotor would increase torque and horsepower with minimal weight gain.
This RX-8 should compete favorably with the BMW M3.
Give me one now.
The 3 rotor would increase torque and horsepower with minimal weight gain.
This RX-8 should compete favorably with the BMW M3.
Give me one now.
10-20-2002, 01:06 AM
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I went ahead and weighed some rotary engine parts in hopes to see how much more a 20B weighs than a 13B with similar manifolding etc. Here's what I found:
All weights are to the closest 1/2 pound
FC 13B rotor housing: 13
12A eccentric shaft: 14
13B rotor: 9.5
four port (old) 13B intake manifold: 5.5
'73 rear iron housing (without stationary gear): 28.5
total: 70.5
It's not very complete, but probably pretty close. I mean c'mon, the 20B only has one more rotor, rotor housing, side housing, and a length of eccentric shaft. The extra manifold length on an NA Renesis won't add any significant weight to the engine. I just don't want to see another complicated mess of manifolds and wires like what the 13BRE, 13BREW, and 20BREW had. No turbos mean simplicity, like the rotary itself.
I'd like to see a three rotor Renesis too. I'm just not sure if I'd like to see it in the RX-8. Hmm, on second thought, how much extra could it weigh, and cost?
All weights are to the closest 1/2 pound
FC 13B rotor housing: 13
12A eccentric shaft: 14
13B rotor: 9.5
four port (old) 13B intake manifold: 5.5
'73 rear iron housing (without stationary gear): 28.5
total: 70.5
It's not very complete, but probably pretty close. I mean c'mon, the 20B only has one more rotor, rotor housing, side housing, and a length of eccentric shaft. The extra manifold length on an NA Renesis won't add any significant weight to the engine. I just don't want to see another complicated mess of manifolds and wires like what the 13BRE, 13BREW, and 20BREW had. No turbos mean simplicity, like the rotary itself.
I'd like to see a three rotor Renesis too. I'm just not sure if I'd like to see it in the RX-8. Hmm, on second thought, how much extra could it weigh, and cost?
10-20-2002, 01:40 AM
#45
Originally posted by Jeff20B
I went ahead and weighed some rotary engine parts in hopes to see how much more a 20B weighs than a 13B with similar manifolding etc. Here's what I found:
All weights are to the closest 1/2 pound
FC 13B rotor housing: 13
12A eccentric shaft: 14
13B rotor: 9.5
four port (old) 13B intake manifold: 5.5
'73 rear iron housing (without stationary gear): 28.5
total: 70.5
It's not very complete, but probably pretty close. I mean c'mon, the 20B only has one more rotor, rotor housing, side housing, and a length of eccentric shaft. The extra manifold length on an NA Renesis won't add any significant weight to the engine. I just don't want to see another complicated mess of manifolds and wires like what the 13BRE, 13BREW, and 20BREW had. No turbos mean simplicity, like the rotary itself.
I'd like to see a three rotor Renesis too. I'm just not sure if I'd like to see it in the RX-8. Hmm, on second thought, how much extra could it weigh, and cost?
I went ahead and weighed some rotary engine parts in hopes to see how much more a 20B weighs than a 13B with similar manifolding etc. Here's what I found:
All weights are to the closest 1/2 pound
FC 13B rotor housing: 13
12A eccentric shaft: 14
13B rotor: 9.5
four port (old) 13B intake manifold: 5.5
'73 rear iron housing (without stationary gear): 28.5
total: 70.5
It's not very complete, but probably pretty close. I mean c'mon, the 20B only has one more rotor, rotor housing, side housing, and a length of eccentric shaft. The extra manifold length on an NA Renesis won't add any significant weight to the engine. I just don't want to see another complicated mess of manifolds and wires like what the 13BRE, 13BREW, and 20BREW had. No turbos mean simplicity, like the rotary itself.
I'd like to see a three rotor Renesis too. I'm just not sure if I'd like to see it in the RX-8. Hmm, on second thought, how much extra could it weigh, and cost?
10-20-2002, 04:16 PM
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Mazdaspeed RX-8
I think there is some untapped horsepower left in the NA Renesis engine and that 300HP for the Mazdaspeed version is not out of the question. :o
10-20-2002, 08:22 PM
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The RX-Evolve
That had a 280Hp renesis the 8s 250 is conservitive I bet with some porting and polishing you could gain 40HP out of that thing remember it was made for emissions and milage this time around the basic N/A mods could go along way for the renesis or not. But all I can say is that you can get 300hp out of it without a turbo.
with this zero overlap of the ports is the perfect place to start a bridge port. the exhaust would be mostly closed so you would have minimal overlap compaired to a normal BP and a large increase in power.
The fact is that we don't know yet. But this is the first time we have gotten a completly new engine that has so many unknowns in years. Its gonna take a few years or more of experimenting to figure out exactly what they like and don't like. Its exciting and disturbing to think about what these tuners will go through to find the formula.
with this zero overlap of the ports is the perfect place to start a bridge port. the exhaust would be mostly closed so you would have minimal overlap compaired to a normal BP and a large increase in power.
The fact is that we don't know yet. But this is the first time we have gotten a completly new engine that has so many unknowns in years. Its gonna take a few years or more of experimenting to figure out exactly what they like and don't like. Its exciting and disturbing to think about what these tuners will go through to find the formula.