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Discussion Starter #1
"RX-7: The rwd 2+2 sports car should arrive for the 2003 model year. Power comes from a 1.3-liter twin-rotor rotary engine that is expected to generate 280hp without turbocharging. Insiders predict a sticker price in the $25,000 to $30,000 range, putting it up against the new Nissan Z."

http://www.autonews.com/html/main/stories/asiafutureproduct821.htm


How could 1.3L produce so much HP? That's 215hp per liter. The current NA highest outpout is the S2000 which is 120hp per liter.
 

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That's rotary technology for you. I think the key is that a rotary engine has two power-producing combustions per revolution instead of just one in a conventional engine. Someone had posted a formula to compare rotary displacement with conventional, but it's probably around 2x. (meaning a 1.3 rotary is equivalent to a 2.6)


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It is a rotary engine, you can't really compare to the otto cycle engine. BTW, what does rotary fell under? What kind of engine is it? Brayton?
You are also going to look at a pretty bad fuel consupmtion, so there are prices you have to pay.
 

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A rotary engine is a Wankel Cycle engine.

Here's some rotary info from Pettit Racing:

"Rotary engine displacements seem small when compared to piston engines of similar power. In fact, both displacements are measured the same way. Displacement is the sum total of positive combustion chamber volume increases for one complete revolution of the main shaft (crank or eccentric). In a piston engine, this means the total amount of space swept by its pistons. In a rotary, it is easiest to think about the difference between the maximum and minimum volumes for a single chamber multiplied by the number of rotors (where each rotor has 3 chambers). Remember that the rotor actually revolves at one third the speed of the eccentric shaft, which is the reason only one chamber's displacement is used in the calculation. The difference in power is due to the fact that the rotary uses its full displacement to produce power for each revolution of the eccentric shaft while only half the displacement of the piston engine is producing power for each revolution of the crankshaft. Other differences also play a role; rotaries do not have the losses of reciprocating motion and there is no valve train to power."

I was almost right, a rotary does not have two combustions per rev, it has one, while a conventional engine has one half per rev.

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Tony
'01 Spectra Blue
'94 Turbo Miata


[This message has been edited by webmaster (edited October 17, 2000).]
 

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Discussion Starter #6
Is the Wankel the same as the Miller Cycle? I think the Millennia uses a Miller Cycle. Mazda seems to like using kooky engine technology.
 

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Originally posted by kota:
Is the Wankel the same as the Miller Cycle? I think the Millennia uses a Miller Cycle. Mazda seems to like using kooky engine technology.
No. A Miller cycle engine is something else. It uses a supercharger to make up for something...

"A Miller-cycle engine is very similar to an Otto-cycle engine. The Miller-cycle uses pistons, valves, a spark plug, etc. just like an Otto-cycle engine does. There are two big differences. First, a Miller-cycle engine depends on a supercharger. Second, a Miller-cycle engine leaves the intake valve open during part of the compression stroke, so that the engine is compressing against the pressure of the supercharger rather than the pressure of the cylinder walls. The effect is increased efficiency, at a level of about 15%."

Hmm. That should really say ONE big difference. It depends on the supercharger BECAUSE it leaves the intake valves open and need the supercharger pressure...

Info from Mazda

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Tony
'01 Spectra Blue
'94 Turbo Miata


[This message has been edited by webmaster (edited October 17, 2000).]
 

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"" XVL: This as-yet-unnamed production version of the XVL concept will compete
against the Lexus IS 300 in the 2002 model year. The rwd sedan with a V-6
will occupy the same $30,000-plus price range as its fwd I30 cousin but offer
more performance and handling than the I30. It also may offer a continuously
variable transmission. ""

Yeah - it (whatever they end up calling it in production..) should be a nice car and definately will be an IS300 competitor. The toroidal CVT transmission is neat technology.
 

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Rumors about the new Mazda's:

1> There may be two versions... A 2 seat Rx7, and a 4 seat model (perhaps with a different name).
2> Once it reaches production for the USA, the new (side port) normally aspirated 13B may end up making less than the 280hp they got in the prototype. I am thinking more like 250hp.
3> Fuel economy won't be much different than the IS300. (Mazda has been making improvements in rotary thrist)
4> It will probably weight less than the IS300 and offer superior performance.
5> They (too) may offer a toroidal CVT transmission.
6> The Lexus IS300 will be a more reliable car... Mazda is "OK", but they aren't Toyota/Lexus.
7> The styling will be toned down a bit from the Rx-Evolv prototype, but it will still be controversial. Some people will love it, some will hate it.
8> It (they) will be compact cars similar in size to the IS300. They will be smaller than the Nissan XVL based sedan. Smaller than a Nissan Maxima. There will probably be some shared components with the MX-5/Miata.
 

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Discussion Starter #14
They are coming out with a sedan based on the RX-Evolv.

Isn't CVT bad for performance? It's used on the Civic HX and the main advantage is better mpg.

[This message has been edited by kota (edited October 17, 2000).]
 

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Does anyone have a position on where
to find pix for teh Mazda RX-EVOLV
and Nissan/Infiniti XVL?


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Actually, CVT suppose to give you the best performance because you can always stay at the power band. I think the only problem is to get it to handle high output power and to keep the system simple and light weight.
 

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Discussion Starter #17
They have pictures of RX-Evolv on Mazda's homepage. For the XVL info, try searching the archive.
 

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Traditional CVTs have a belt that limits maximum torque capacity and thus you found them in low power economy cars (Subaru Justy, Civic HX)

But the new Nissan and Mazda toroidal CVTs are able to handle high horsepower and theoretically provide both superior performance (to an auto and maybe even manual) as well as better fuel economy.

They have an ECU decide which ratio is appropriate for best economy OR performance depending on conditions. With infinite ratios to pick, they can get the RPM's "just right" unlike a discrete ratio trans.
 
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