RotaryEvolution

iTrader: (30)

except this has been the first time they have completely halted rotary car production in over 40 years. although there were gaps between the FD and the RX8, the FD was still being produced and sold in europe and asia.

just like crack, once you finally let it go you may just realize how much of a mistake it was to pick up in the first place.

in my hopes they either build the engine right this time or finally let it go. we, the enthusiasts, will be fine without the factory support now. there will always be engines floating around or reworking processes to keep them alive for some time to come.

the fatigue in the renesis engine wasn't due to a lack of care but it certainly did not help the matter any. the engines just have a tendency to eat themselves alive with the side port exhaust. even people who took extreme care of their car wound up losing compression in a constant battle to see who would give up first. there may be a magical formula to keeping them alive for extended periods akin to older rotary engines, but there shouldn't be, and only a few seem to have stumbled luckily along the formula(making it to and beyond 150k on a single engine, but those cases are extremely rare.).

i still do not know what that formula is for the renesis and i know these engines like the back of my hand. i do know the traditional 13B peripheral exhaust formula, drive the car and keep oil and coolant in it as well as properly maintained and it will be fine.

mazda doesn't have an entrance requirement to buy an RX8, even people who owned older rotaries who bought them new still had the same issues as those who treated it as if it were any other car.

NCross

iTrader: (18)

My number one problem with the RX8 is that you cant just directly swap in an older 13b. Too many electronics dependent on the stock ECU.

I have seen $2-3000 RX8s on craigslist with blown engines that I would love to just do an s5 NA or t2 swap in and just drive it. I love the styling and the rear door seems useful, but I would be afraid of longevity of the Renesis.

Could you build a 13b s5 NA Renesis mix? Eliminate the side exhaust ports via s5 housings and plates and use the s5 oil injection ports and keep the RX8 intake? So it would basically be an s5 engine with RX8 intake and electronics? Seems more reliable. I know very little bout the Renesis intake and compatibility though.

NCross

iTrader: (18)

I'm just basing it off of who I see driving RX8s. I was too young to notice back in the 80s. Although I see how the FC would appeal to woman. Especially the vert.

RotaryEvolution

iTrader: (30)

you could build a hybrid renesis with older parts, yes. the problem being the peripheral exhaust retaining too much heat to critical parts on the rotor for sealing(side seals).

but with that said i would also suspect you may lose some performance benefit that does come with the side port exhaust and it may not perform its best with a hybrid non turbo setup.

that all said i am building now a 13B-MSP which will use either GSL-SE rotor housings or later model 13B housings which will be modified to accept coolant seals for the MSP engine sealing. but this engine will be turbocharged and the intent is to supplement that heat isolation by allowing the exhaust to bypass the side ports and exit the engine directly through a 5 port exhaust manifold to the turbo. water injection will further add to the reliability and dissipate some additional heat and keep carbon buildup at minimum. exhaust will still travel through the side ports to help eliminate turbulence but about 80% of the exhaust will go directly out the PP, the PP exhaust will also be timed so it opens first inducing exhaust travel out the port mainly.

NCross

iTrader: (18)

I really mean build a series 5 13b with Renesis intake more or less. Youd have the reliability of the s5 engine (better oil injection, more longevity, slightly simpler etc) with the Renesis intake so your electronics would (or should) still work.

Would the ECU throw a WTF code for the MSP missing?

RotaryEvolution

iTrader: (30)

nope, can't do it that way.

take a look at some 6 port pictures and you will see that the auxiliary ports on the renesis along with the irons are much wider than the older generations. ie the auxiliary ports are actually about twice the size of the FB/FC ports and have different actuators(the sleeves are built into the intake).

there should be no codes set for a peripheral exhaust, airflow will just be increased(which will probably result in some torque loss).

the oil injection on the older engines wasn't superior but it did the job. the renesis also doesn't have inferior oil injection but it simply cannot handle the demand of heat placed on the sides of the rotors. in fact you would most definitely need to also premix if you used older housings on a renesis to make sure the side seals were adequately lubed since the older 13B didn't focus on that area, it didn't need to. even a single failing nozzle of the 4 on a renesis would most definitely eat an engine, so it heavily relied upon it to do its job..

j9fd3s

iTrader: (3)

objection! that is speculation. the Rx8 outsold the FD by more than 10X. although i will grant you there are only 260,000 Rx8's vs 550,000 1st gens.

well Porsche can't let it go, because they are more of a religious cult, and less of a car company. Mazda is known more for fun cars than some dinosaur that an honorary doctorate stole from the Czechs, because Hitler asked for a $1000 car. you can ask yourself why Hitler asked Dr Porsche to build the peoples car, and you can ask why there are not more air cooled cars, and you can ask why nobody else puts the engine in the rear...

having studied German cars, Bugs Bunny had a better grasp of physics than Dr Porsche did

but yet when you get a Porsche you get the keychain and people at parties are impressed

Cookboy

iTrader: (10)

^ true dat, as they say. FB will lap with 911's all day, just to **** 'em off.

earthtone7se

I really admire what Porsche has done with the 911 and with themselves as a company. I hear people say that the Z car is Japan's 911 because it has existed continuously for so long but I disagree. Some of you may want to choke me for this (j9fd3s lol) but I believe the 911 and RX-7 are kindreds. Let me explain:

1. Porsche and Mazda both had to overcome several engineering hurdles over the years to keep them in production.
2. The dynamic purity of both cars was always the focus, and was maintained despite many obstacles.
3. The powerplants and their positioning in the chassis was unique (Front-mid mounted rotary, rear mounted flat-six)
4. Both vehicles are arguably the heart and soul of their lineups.

There will be another rotary powered car from Mazda, and it will be glorious! Keep in mind that the 996 911 in NA form suffers from some serious reliability issues, but the 911 presses on, and so can the rotary sports car. Japanese automakers don't feel a need to continuously produce a car. Mazda doesn't feel that the legacy of the RX has been tarnished because there has been a halt in production. I don't either. They just need to come correct this time around.

earthtone7se

Hell, Mazda should build a 3-rotor hybrid supercar if they get the rotary figured out!

j9fd3s

iTrader: (3)

hmm i actually agree with most of that.

RotaryEvolution

iTrader: (30)

except porsche sold overpriced cars which were cheap to build, which led to them building more expensive and finely tuned cars down the road.

the result, people paid up front for porsche to actually build decent R+D into their cars while that cult still led them into the fields with the "one style fits all" mentality. people 10+ years ago were paying premium for the same crap, sounds like some companies i know of.

difference between porsche and wankel, wankel was exiled. maybe hitler knew something that it took us and the japanese years to realize.


"god damn car is flooded again, i'll get my tow rope and you get the truck..."

earthtone7se

Ha haa, owning a GSL-SE is like being in a relationship with a woman. As soon as you figure out some little quirk that will make it run or stop running, here comes something new lol!! LOVE IT!!!

NCross

iTrader: (18)

Well Wankel did develop engines for the **** bombers right? Not to mention Porsche was scooped up by VW some time ago. Plus the 911 shared platforms with the number one selling vehicle of all time. Kind of funny that there are so many rotary Beetle swaps out there. It's as if people are trying to build it the way it was supposed to be built. NSU powered "peoples car".

earthtone7se

I'm curious to hear what some of the other members are expecting/hoping to see with the next RX?

earthtone7se

Ok, basically the 3 biggest issues with the RX-8 were:

1. Crap gas mileage. 2. Early engine failure due to side ports. 3. Owners who didn't understand the engine.

I think those issues can be addressed in the following ways:

1. With direct injection, more displacement (16x), clever induction design, today's modern engine management, and the full range of Skyactive technologies, 250hp NA should be attainable with a "real" 30+mpg highway figure. With a curb weight around 2500lbs and clever aero, this is so so doable.

2. Returning to the original style exhaust port layout should do away with the early engine failures due to cooked side seals. The side ports were a way of making more power, but I believe the 250hp goal can be reached with the old port layout, the tech listed above, and the increase in displacement. Ports can be enlarged and made variable with intake manifold design. The exhaust back pressure is a bit more tricky due to high temps, but valving farther down the path where exhaust gasses have cooled is easy these days. It doesn't have to be done "at" the manifold.

3. I would be very surprised if Mazda would be able to bring oil consumption levels to anything near those of the modern piston engine. The nature of the rotary is to consume some oil. To me, a no brainer fix to this issue is a dry sump system. non-enthusiast owners can just have the reservoir topped off every 5K miles with the oil change. A dry sump system is even better for performance applications. This is a sports car after all.

An affordable, simple, somewhat economical, lightweight, powerful, rotary powered sports car is within the capabilities of Mazda. They would be nutless cowards not to build it.

j9fd3s

iTrader: (3)

Porsche actually bought VW. Porsche is one of the most profitable car makers, VW isn't.

the 911 heritage is actually pretty funny. when Hitler, wanted a peoples car, he called Dr Porsche, because they were friends. the german word for people is volk, and the word for car is wagon, so VW is literally "peoples car".

Porsche, who at the time was unemployable, "borrowed" the design of the beetle from Tatra, Tatra (company) - Wikipedia, the free encyclopedia

After the war the US helped VW restart production and the rest we know.

much different than say a Jaguar XK120, where they designed the car during bombing raids..

j9fd3s

iTrader: (3)

1. basically there are all these "new" technologies that have helped the piston engine, and haven't been applied to the rotary, so there is scope for improvements.

2. the old exhaust port layout might be impossible, the reason for the side ports in the first place is that there is a pocket of unburned fuel at the trailing end of the rotor, and the peripheral port just dumps this right into the exhaust, while the side port cycles it around again.

that being said, in an IM240 style emissions test a 99+ FD is just as clean as an Rx8, in a steady state. the FD is dirtier in transitions, but it doesn't have a wideband o2, or any of the other modern control system stuff the Rx8 has.

3. the Rx8 basically uses less than a quart between oil changes, i don't see why that isn't fine?

3a. the rotaries are always held to this weird double standard. every time i go to the dealership they are elbow deep in the CX7/mazdapeed 3/6 engines, but apparently this is ok?

PK_12A

iTrader: (3)

I have read through this thread many times and I think earthtone7se and j9fd3s are on to something, especially with the application of modern computer controlled efi systems millage should be able to be improved as well as emissions I use what has been done to retro fit old muscle cars as an example of this done right, from 8 to 18 in some cases. As for oil use I have explained this to non-enthusiasts like this, in a rotary some of the seals inside the engine require supplemental oiling, this is taken care of by a secondary low volume oil pump, this is why rotary engines use oil, most get it pretty quick, as for using only 1qt between changes, that isn't bad at all, that's roughly what my trucks 350 uses so not bad at all.
Personally I'd like light, quick, and affordable, maybe a turbo option, think gen 1 or MX-5 type deal.

Rx72jz0260

iTrader: (1)

I can't wait to see what the future holds for this family. Very excited

j9fd3s

iTrader: (3)

i wonder if its too simple just to have a miata coupe, and offer the rotary in that.

earthtone7se

Less than a quart if you actually change the oil when you're supposed to. There are lots of knuckle headed people out there that hardly ever go to change their oil. In a modern piston engine that hardly burns any oil at all, this may be doable, but in a car that burns even just under a quart every 5K miles, this is catastrophic. Like I said, put a dry sump tank on there and it isn't a problem anymore. I guess the weakness of the side seals is the hurdle. Maybe Mazda just needs to find the right compound like they eventually did with the apex seals. Another problem may be that Mazda tries too hard to pass the RX cars off as regular cars. They pumped up the fact that the RX-8 had a rotary engine but didn't explain to people that it requires special care. There should be big *** notifications all over the place that explain that the engine eats oil and that the levels must be maintained or the engine will fail. Remember the stickers in the cabins of early turbocharged cars? Not that hard to do.

earthtone7se

Basically that's all they would have to do. The Cayman is just a Boxster with a roof. They could do one of a few different things:

1. Make a Miata coupe with a rotary and badge it RX-7.

2. Make a Miata coupe with the same engine as the Miata and call it a Miata coupe, and make it available with the rotary and re-badge that RX-7.

3. Make a new coupe with a slightly stretched Miata chassis, put the rotary in it, style it differently, and call that the RX-7.

Even if they go with option one I'd be happy. In fact, that may be the best option as a business case for Mazda. I'd almost encourage option one because it will mean that the RX-7 has a better chance of continued production.

PK_12A

iTrader: (3)

If anything, it's a pretty good starting point, the new Camaro IS based off the ZETA chassis aka the Pontiac GTO and it ain't to bad actually it's pretty good or so I am told. It almost seems right, look at all the rotary conversions, not to mention the MX-5 would make a good home for the rotary just because it is a good sports car to begin with, change the bodywork, add a fixed hard top option, give it decent base package and you'd have a likely winner.

jim_chung

iTrader: (2)

As fun as it is to read the preceeding threads, I doubt Mazda will ever build another rotary engined car.

The world's car manufacturers, like all other global business', are merging into larger and larger conglomerates whereas Mazda has lost Ford both as a major shareholder and development partner and is now a very small player. In order to survive alone, they have to build cost effective cars that sell. It's a romantic notion that ideals and dreams somehow run car companies but they don't. I suppose Mazda embraced the rotary in the 1960s as something to make them different from the other Japanese manufacturers but now that they are a brand known for making interesting fun to drive cars, they don't need the rotary anymore.


There'd have to be a solid business reason to produce a rotary, perhaps a change to a hydrogen powered economy or proliferation of hybrid cars that see a significant benefit to using a rotary engine as the backup power source.