Last post on Mar 13, 2012 at 4:42 PM
You are in the Mazda RX-8
What is this discussion about?
Mazda RX-8, Coupe
#1923 of 3618 who starts these things?
Apr 08, 2004 (3:18 pm)
So, I am talking to a kid in my apt complex who also has an RX8...I can say kid cause he is 22 and, well, I am not!....anyhoo, he tells me that his dealer told him about the "Upcoming 2005 Mazda Miata Rotary Engine Sport Coupe" that he should tell his sister about.....where do rumors like this start?....he tells me the dealer told him it was going to have "2 or 3 rotors" in it.....ah....ummm.....why do people say things like this?.....
well....I did my best to inform him that the trade mags have said nothing of the sort and that he doesn't need to worry about it - he has Mazda's best car - an RX8!.....
#1924 of 3618 who starts these things?
Apr 08, 2004 (9:01 pm)
Speculation only, but there was once talk of a rotary powered Miata. The "new Miata" is supposed to be built on the RX-8 chassis ("slightly" modified). Last I heard it was to be powered by the same basic engine the current model uses.
There may be a new RX-7. Current rumour is turbo charging the renesis is not practical, so Mazda may increase the displacement (for the first time in 25 years!) or go to three rotors. Not sure if they will call it an RX-7. Pro RX-7 is the history of that model, con is maybe they want to emphasize the renesis differences and may call it an RX-9.
Current sales of the RX-8 bode well for the sevens' return!
Apr 09, 2004 (6:08 am)
I think a lot of people voice what their "wish list" would be.
I can see the appeal of a rotary Miata, but I think Mazda is looking to hold the RENESIS to their top model, which today is the RX8.
RX7 would be great. I'd be more interested in seeing future RX8s (RX9s?). I'd prefer more rotors as opposed to force feeding via supercharging or turbos.
Apr 09, 2004 (6:42 am)
Mazda has certainly built motors with more rotors so they know how. I believe their LeMans winning engine was a 4-rotor.
#1927 of 3618 adding a rotor
Apr 09, 2004 (7:05 am)
But how efficient do you think it would be with an extra rotor? Folks already complain about the mileage in the RX8. I'm sure a 15 mpg RX7 would have a tough time in the market with the current gas prices. Granted, the car should be lighter, so that will help, but by how much?
Apr 09, 2004 (7:26 am)
The Japaneze Cosmo (extreme luxury car) used a three rotor engine, automatic only. It was also turbocharged, and those engines (massaged) are sometimes swapped into 3rd gen and 2nd gen RX-7s. They put out 450+ HP in massaged form, though I think stock they were 325 or so.
The Lemans winning 787 is a four rotor. They had to build a honeycomb stiffener bolted onto the oil pan flange to stiffen the engine. It would otherwise twist the housings out of line even with the extra strong dowel pins they used! For those who have never seen the engine apart, it is a sandwitch construction composed of front end plate, rotor housing, centre plate(s), rotor housing, rear end plate. Add more rotor housings and centre plates for more than two rotors. There are bolts (rods really) that hold the entire sandwitch structure together (in drawings you can see the bolt heads in the bellhousing - there are 18 bolts in the former rotary - not sure if the same number is used in the renesis). There are short hollow tubes that the bolts pass through on each of the sandwitch parts. These tubes align the parts by extending into adjacent housings. The end and centre housings are cast iron, and the rotor housings are aluminum.
The result is there is no one really heavy part. You can easily pick up any part of a rotary engine, unlike the block of a piston engine (hernea maker). The heaviest part is the eccentric shaft, which weighs about 70 lbs.
I could go on, but I'm probably boring people.
Oh, as for efficiency, I doubt "RX-7" (or its' functional replacement) owners would care. The object is power and speed, not efficiency. The RX-8 is the "practical car". A three rotor renesis would put out 350-375 HP. It would sound awesome at 9000 RPM!!!
Unfortunatly, the eccentric shaft on the Cosmo engine tended to "wobble" as it wasn't properly supported in the centre. A renesis version would have to address that issue to safely attain 9000 RPM speeds. Some Cosmo engines went BOOM big time when the wobble got out of control .
#1929 of 3618 Rumors...and pathstar
Apr 09, 2004 (6:49 pm)
Pathstar - No! No!...not boring!....I know so little...this is like going to class, except I have jazz music on and I am eating ice creme!!...wait...I did that in college too....anyhoo, so my rumor was sortof two separate things molded into one....ah...I could see where that could happen. all I know is that I parked next to a Miata the other day and got a chance to see the RX8 next to a Miata....ya gotta go with the RX8 shape, don't ya?.....maybe it's just me......and wouldn't ya think a new RX7 (RX9) would be in the curvy RX8 style too?.....
well, needless to say, I love the Mazda car and hope I have many happy years with her!!....and hope all of you do as well!!.....
Apr 10, 2004 (6:44 am)
In the hardback RX8 book that came with a "pre-order" last summer, there was some interesting development info for a 3 rotor engine. They also address turbo and supercharging issues.
I'm certain production development on any of that sort of technology is "top secret" to Mazda, however. I'm betting on a new ECU along with some catalytic converter upgrades, first. Then I would predict some sort of turbo or supercharging given the high cost of making a 3 rotor RENESIS.
Personally, I think the next rotary, whether a reborn RX7 or an update to the RX8 is going to be very interesting given the success of the RENESIS. Also, the overwhelmingly positive press the RX8 has received will help to ensure an upgraded RENESIS sometime in the near future.
I still don't see a rotary going into a Miata, though.
#1931 of 3618 infant/toddler carseat in back?
Apr 12, 2004 (4:27 pm)
I've been reading the messages for awhile and am excitedly looking forward to getting my own RX8 soon, hopefully in about a month or two. A baby is in the future though so I'm wondering if anyone has fit two adults in front and a child safety seat in the back (both back-facing and front-facing kinds). My partner and I are both 6' so we'll need the legroom in front. Anyone have any thoughts? Recommend any particular brands/models for baby seats? We are determined to prove our minivan and station-wagon driving friends wrong and show them that a baby and a sports car are compatible!
Apr 12, 2004 (6:47 pm)
is excellant. At first you get a little claustrophobic because the front seatback is almost in your lap. You acually have a lot of room in the back (I'm 6' 230 lbs). Front seats have even more room. I would think a car seat should be no problem. Access is good too with the extra doors. Go to the dealer and try it out! They should have a list of recommended car seats (car dealers are into that stuff - good for sales).