New Mazda 'WIDE' (15B) Rotary 2007
#276
Registered
It seems from the reading I have done on the rotary, and again, I have studied the rotary only since the RX-8 came out, that one of the key limitations of the Renesis is the siamesed exhaust ports.
Otherwise, why look at header design at all?
Whenever I see siamesed exhaust ports, and they are all over automotive history, they exist because of compromises due to the engineering/ manufacturing budget. Not because they were they best way to build the engine. And yeah, I know engineering is about compromises.
Historically siamesed ports (and here I mean for two different cumbustion chambers) were often responsible for bad breathing and hot spots in the engine (I think my V8 reading backs this up but I cannot recall where).
Now that the Renesis has proven itself, And I believe it has, maybe the funds are available to correct any compromises that Mazda had to make to get the project out the door.
I guess what I am getting at that I would like to see Mazda build a halo car (maybe even call it an RX-7) to match what Toyota, Honda, and Nissan are doing. Something like that could happen it they build it on the MX-5/RX-8 platform.
Your halo car would need to make large reliable horsepower and these siamesed ports might be a problem with that. Even with FI.
Sorry for the ramble, but no worse than the rest of this thread.
Otherwise, why look at header design at all?
Whenever I see siamesed exhaust ports, and they are all over automotive history, they exist because of compromises due to the engineering/ manufacturing budget. Not because they were they best way to build the engine. And yeah, I know engineering is about compromises.
Historically siamesed ports (and here I mean for two different cumbustion chambers) were often responsible for bad breathing and hot spots in the engine (I think my V8 reading backs this up but I cannot recall where).
Now that the Renesis has proven itself, And I believe it has, maybe the funds are available to correct any compromises that Mazda had to make to get the project out the door.
I guess what I am getting at that I would like to see Mazda build a halo car (maybe even call it an RX-7) to match what Toyota, Honda, and Nissan are doing. Something like that could happen it they build it on the MX-5/RX-8 platform.
Your halo car would need to make large reliable horsepower and these siamesed ports might be a problem with that. Even with FI.
Sorry for the ramble, but no worse than the rest of this thread.
Last edited by jeffe19007; 01-06-2006 at 05:00 PM.
#277
widen the center plate, make the center exhaust ports independent and add two more "tertiary" ports with sleeve valves. The engine now has 8 intake ports instead of 6; airflow restriction solved.
Now, make the engine all aluminum, use two-stage direct gasoline injection (stratified charge ultra lean economy mode during idle and light load and cruising conditions and homogeneous charge at heavy loads) and the fuel economy will increase a lot.
Now, make the engine all aluminum, use two-stage direct gasoline injection (stratified charge ultra lean economy mode during idle and light load and cruising conditions and homogeneous charge at heavy loads) and the fuel economy will increase a lot.
#278
Originally Posted by jeffe19007
It seems from the reading I have done on the rotary, and again, I have studied the rotary only since the RX-8 came out, that one of the key limitations of the Renesis is the siamesed exhaust ports.
#280
Originally Posted by TeamRX8
don't be naive, a bunch of enthusiasts talking header theory smack is no indication of validity
#281
Registered User
Join Date: Sep 2002
Location: Illinois
Posts: 363
Likes: 0
Received 0 Likes
on
0 Posts
Where is the EGR? Honda still uses EGR [catalyzed] on the accord V6, new civic and others.
4 intake ports per rotor will allow for more intake flow, and wider rotors.
Direct injection in piston engines allows for substantially higher compression ratios, where all the extra torque comes from. ie. Audi 3.1 FSI V6 (not VR6) 12.5:1 compression, and 243 ft-lbs.
4 intake ports per rotor will allow for more intake flow, and wider rotors.
Direct injection in piston engines allows for substantially higher compression ratios, where all the extra torque comes from. ie. Audi 3.1 FSI V6 (not VR6) 12.5:1 compression, and 243 ft-lbs.
#284
Follower of CHRIST!!!!!!!
Join Date: Aug 2004
Location: Planet Earth
Posts: 3,241
Likes: 0
Received 0 Likes
on
0 Posts
So, and you can flame if you would like (lol), where is the rumor at on this "wide" 15B Renesis?
I read a bunch of this but lost track a while back, can someone summarize how much is good rumor and how much is bad rumor?
What's the guess on what DI can do for the Renesis, without going wide (power and fuel economy wise) and what it can do with also going wide?
Again...even if you answer you can flame me, but I just lost track of this thread and don't care to rummage between name calling, I'm smarter than you accusations, and off topic chat.
Note: I'm not calling anyone out, I've taken things off topic enough to be forgiving of such and more...lol.
I read a bunch of this but lost track a while back, can someone summarize how much is good rumor and how much is bad rumor?
What's the guess on what DI can do for the Renesis, without going wide (power and fuel economy wise) and what it can do with also going wide?
Again...even if you answer you can flame me, but I just lost track of this thread and don't care to rummage between name calling, I'm smarter than you accusations, and off topic chat.
Note: I'm not calling anyone out, I've taken things off topic enough to be forgiving of such and more...lol.
#285
I heard a rumor that Mazda is getting sick and tired of the torque, hp and mileage discussions and intends to replace the rotary engine in the RX-8 with the piston engine in the Mazdaspeed 6 (which is already developed). It will have a larger intercooler in the front, slightly increased boost, deliver 300 (actual) hp and the engine will be tilted to keep a low center of gravity.
#290
Out of NYC
iTrader: (1)
Originally Posted by rotary crazy
the engineers are not smarter they just have all the information and the tools to try things out plus they get paid for that!
Just my 0.02
and I think Mazda engineers knows what they're doing. The Torque is a-bit low for everyone's taste but its still good.
I think they still need some time to try to get full performance out of this Renesis.
So dont underestimate People at Mazda !
#291
Registered
Originally Posted by rx8wannahave
So, and you can flame if you would like (lol), where is the rumor at on this "wide" 15B Renesis?
I read a bunch of this but lost track a while back, can someone summarize how much is good rumor and how much is bad rumor?
I read a bunch of this but lost track a while back, can someone summarize how much is good rumor and how much is bad rumor?
#293
Registered
Join Date: Mar 2003
Location: Santiago, Dominican Republic
Posts: 2,525
Likes: 0
Received 0 Likes
on
0 Posts
I Dont think they will even hire you to "test things out" if u're not smart enough.
#294
Registered
Join Date: Mar 2003
Location: Santiago, Dominican Republic
Posts: 2,525
Likes: 0
Received 0 Likes
on
0 Posts
about the 15b or what ever they call it, it just logical, they have done this 2 times or maybe more ( 10a,12a 13b ), thats why the rumor got so many atention.
#295
Widening the engine is the easiest way for Mazda to increase displacement. Much cheaper than adding a third rotor, much cheaper than rescaling the rotors and housings. Its a very logical idea.
#296
Registered User
Join Date: Oct 2005
Location: Boise Idaho
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
if they do make a new disp motor it would initially be XXa not XXb. There was a 13A that never made it to production, and the 20B is derived from the 13B so it maintains that rev conotation. If they're using a 20B in GrandAm series why not go production.... mmm Mazdaspeed WB RX8 20B holy rice killah.
#298
Sorry Zoom44, that's not exactly true. The 15a was an engine that had identical trochoidal dimensions to the 10A/12A/13B. The only difference was the 15A housings were 90mm wide versus 80mm for the 13B. The 21A was completely different in dimensions. So the A and B do not refer to the trochoidal geometries AFAIK.
Also, I thought the 20b's in the Grand Am cars started life as Mazda engines, although they have been heavily reworked by their campaigners.
Also, I thought the 20b's in the Grand Am cars started life as Mazda engines, although they have been heavily reworked by their campaigners.
#299
Follower of CHRIST!!!!!!!
Join Date: Aug 2004
Location: Planet Earth
Posts: 3,241
Likes: 0
Received 0 Likes
on
0 Posts
There is no word from Mazda on a larger rotary. The rumor as it has now become, started here almost 3 years ago with an old member named Booger. He asked what the possibility of a wider engine would be and how it would work. It was nothing more than pure curiosity on his part and he started a discussion to talk about the pros and cons. That discussion slowly led to people actually believing that Mazda was working on one. That's where it came from. There is no "wide" 15B Renesis. It's turned into an urban legend.
Everything is rumor it seems and Mazda is HIGHLY mum on the subject, just check out their response to a bunch of questions on rotarynews.com
Thanks again RG!
#300
Registered
Originally Posted by tuj
Sorry Zoom44, that's not exactly true. The 15a was an engine that had identical trochoidal dimensions to the 10A/12A/13B. The only difference was the 15A housings were 90mm wide versus 80mm for the 13B. The 21A was completely different in dimensions. So the A and B do not refer to the trochoidal geometries AFAIK.
Also, I thought the 20b's in the Grand Am cars started life as Mazda engines, although they have been heavily reworked by their campaigners.
Also, I thought the 20b's in the Grand Am cars started life as Mazda engines, although they have been heavily reworked by their campaigners.
Race engine designations have been a little different such as the 13G 3 rotor race engine of the 80's which was the predecessor to the 20B race engine.