Heres a R&T article you may find interesting.....

Technology Update: Renesis Rotary
Mazda reinvents the Wankel—again

By Douglas Kott

“The piston engine goes boing, boing, boing, boing, boing—but the Mazda goes hmmmmm.” Remember Mazda’s admittedly cornball 1970s’ TV ad? Complete with a kid on a pogo stick embodying the evils of pure reciprocating movement, the spot touted the smoothness of this novel powerplant that melds the Otto cycle’s four events of intake, compression, power and exhaust with a rotating motion. Like the Porsche 911’s air-cooled flat-6 or Saab’s quirky 2-strokes, the Wankel will be forever linked with Mazda, as it has twirled beneath the hoods of RX-2s, RX-3s, three generations of RX-7s—and even, for the Japanese market, a 26-passenger bus called the Parkway Rotary—for more than three decades.

Yet the concept was dreamed up—quite literally—in the summer of 1919 by a 17-year-old German boy, Felix Wankel. In his dream, Wankel drove a car of his own construction to a concert, where he even remembered boasting to his friends, “My car has a new type of engine: a half-turbine, half-reciprocating engine. I invented it!” Wankel succeeded in turning his vision into hard prototypes, at first with the German government and later with NSU, which first built a Wankel-type supercharger that enabled its 50-cc motorcycle to set a world speed record of 122.7 mph in the mid-1950s. NSU ultimately focused on four wheels, building a single-rotor 2-seat roadster called the Wankel Spider in 1963, followed by the homely Ro 80 2-rotor sedan of 1967.

Both GM and Mercedes-Benz took long, hard looks at the rotary’s viability. But it was Mazda, largely through the engineering brilliance of Kenichi Yamamoto, that refined the design and made the rotary engine a reliable, mass-produced reality. Since the Japanese introduction of the Mazda Cosmo Sport roadster in 1967, Mazda worldwide has sold more than 1.8 million rotary-powered cars, trucks…and the occasional bus.

Sadly, the last U.S.-market RX-7 blinked its taillights goodbye in 1996. Why did that sports car, practically deified by the automotive press including Road & Track, go away? Partly because of the overall softness of the sports-car market, and partly, according to Philip R. Martens, Mazda’s managing director, because it just didn’t make business sense to meet stringent U.S. pollution laws. “We could have made it comply with emissions, but the costs of the catalytic converter and some of the other things were just too high,” says Martens, whose daily driver around Hiroshima is the latest twin-turbo 280-bhp RX-7 variant, still sold in Japan.

Enter the new Renesis rotary, a 2-rotor Wankel capable of similar output without turbos and having, more importantly, a clean bill of U.S. emissions health “into the foreseeable future, which to me is 10 years plus,” says Martens. Showcased in the new RX-8 (see “Sports Car Tsunami,” March 2001), the Renesis is the anchor point for a whole family of engines. “The essence of the program was not to develop an engine tailored for one car; I believe there’s enough bandwidth in the sports segment for more signature products along that range,” Martens said.

Key to the design is moving the exhaust port from the periphery of the rotor’s trochoid-shaped housing (picture a cocoon, or a fat peanut shell) to the side plates, where the intake ports also reside. Not only does this design eliminate port overlap, the two side exhaust ports per chamber offer nearly twice the area of the single peripheral port for greater power.

And where unburned hydrocarbons used to have an easy escape path out the exhaust, the Renesis’ side-port design corrals them against the trailing apex seal, below the port; they’re then carried through to the next combustion cycle, lowering emissions. A double-walled exhaust manifold plus the absence of turbochargers also means less heat loss before the 2-stage converter, critical to emissions at start-up when an engine is at its dirtiest. “Our research center has spent a tremendous amount of time working on the catalytic treatment,” says Martens, “to make sure we don’t choke the exhaust, which is key to the free-revving performance we want.”

Free-revving indeed; the rotors are a full 14 percent lighter than their earlier counterparts, enabling a 10,000-rpm redline that takes bragging rights away from the Honda S2000’s 9000-rpm zenith. (It should be noted that each revolution of the rotor translates to three revolutions of the eccentric shaft, the rotary’s equivalent of a crankshaft.) There are numerous other smaller changes—an elaborately baffled oil sump whose ultra-slender 1.6-in. depth allows the engine to be set lower in the car; injectors that more finely atomize the fuel; a triple-path induction system that takes full advantage of the resonance “supercharging” effect; and an advanced engine-management system that’s said not to use oxygen sensors at all.

If a chink exists in the Renesis’ armor, it’s in torque production—in current tune, it generates 153 lb.-ft. at 7500 rpm. Curiously, those numbers are identical to the S2000’s, and that car has been criticized for lack of low-end grunt. But Martens stresses that it’s how the torque is distributed—and how it’s matched to the car’s yet-to-be finalized gearing—that will ultimately impact the RX-8’s fun-to-drive quotient.

“We want to have the feeling of, ‘Oh my god, I didn’t know this would do that in this range,’ ” he said. “Flat torque curves are great, but what we really want is a lively car. It has to have a unique identity when you get in and drive it.” We anxiously await the production version.

Hey i read that at Wal-Mart :D
The torque numbers are down....again 153lbs of torque? It was 190lbs a couple of months ago. I hope mazda knows what they are doing.

bump

oh.. what time brings

yep...

Heres a R&T article you may find interesting.....

Technology Update: Renesis Rotary
Mazda reinvents the Wankel—again

By Douglas Kott

“The piston engine goes boing, boing, boing, boing, boing—but the Mazda goes hmmmmm.” Remember Mazda’s admittedly cornball 1970s’ TV ad? Complete with a kid on a pogo stick embodying the evils of pure reciprocating movement, the spot touted the smoothness of this novel powerplant that melds the Otto cycle’s four events of intake, compression, power and exhaust with a rotating motion. Like the Porsche 911’s air-cooled flat-6 or Saab’s quirky 2-strokes, the Wankel will be forever linked with Mazda, as it has twirled beneath the hoods of RX-2s, RX-3s, three generations of RX-7s—and even, for the Japanese market, a 26-passenger bus called the Parkway Rotary—for more than three decades.

Yet the concept was dreamed up—quite literally—in the summer of 1919 by a 17-year-old German boy, Felix Wankel. In his dream, Wankel drove a car of his own construction to a concert, where he even remembered boasting to his friends, “My car has a new type of engine: a half-turbine, half-reciprocating engine. I invented it!” Wankel succeeded in turning his vision into hard prototypes, at first with the German government and later with NSU, which first built a Wankel-type supercharger that enabled its 50-cc motorcycle to set a world speed record of 122.7 mph in the mid-1950s. NSU ultimately focused on four wheels, building a single-rotor 2-seat roadster called the Wankel Spider in 1963, followed by the homely Ro 80 2-rotor sedan of 1967.

Both GM and Mercedes-Benz took long, hard looks at the rotary’s viability. But it was Mazda, largely through the engineering brilliance of Kenichi Yamamoto, that refined the design and made the rotary engine a reliable, mass-produced reality. Since the Japanese introduction of the Mazda Cosmo Sport roadster in 1967, Mazda worldwide has sold more than 1.8 million rotary-powered cars, trucks…and the occasional bus.

Sadly, the last U.S.-market RX-7 blinked its taillights goodbye in 1996. Why did that sports car, practically deified by the automotive press including Road & Track, go away? Partly because of the overall softness of the sports-car market, and partly, according to Philip R. Martens, Mazda’s managing director, because it just didn’t make business sense to meet stringent U.S. pollution laws. “We could have made it comply with emissions, but the costs of the catalytic converter and some of the other things were just too high,” says Martens, whose daily driver around Hiroshima is the latest twin-turbo 280-bhp RX-7 variant, still sold in Japan.

Enter the new Renesis rotary, a 2-rotor Wankel capable of similar output without turbos and having, more importantly, a clean bill of U.S. emissions health “into the foreseeable future, which to me is 10 years plus,” says Martens. Showcased in the new RX-8 (see “Sports Car Tsunami,” March 2001), the Renesis is the anchor point for a whole family of engines. “The essence of the program was not to develop an engine tailored for one car; I believe there’s enough bandwidth in the sports segment for more signature products along that range,” Martens said.

Key to the design is moving the exhaust port from the periphery of the rotor’s trochoid-shaped housing (picture a cocoon, or a fat peanut shell) to the side plates, where the intake ports also reside. Not only does this design eliminate port overlap, the two side exhaust ports per chamber offer nearly twice the area of the single peripheral port for greater power.

And where unburned hydrocarbons used to have an easy escape path out the exhaust, the Renesis’ side-port design corrals them against the trailing apex seal, below the port; they’re then carried through to the next combustion cycle, lowering emissions. A double-walled exhaust manifold plus the absence of turbochargers also means less heat loss before the 2-stage converter, critical to emissions at start-up when an engine is at its dirtiest. “Our research center has spent a tremendous amount of time working on the catalytic treatment,” says Martens, “to make sure we don’t choke the exhaust, which is key to the free-revving performance we want.”

Free-revving indeed; the rotors are a full 14 percent lighter than their earlier counterparts, enabling a 10,000-rpm redline that takes bragging rights away from the Honda S2000’s 9000-rpm zenith. (It should be noted that each revolution of the rotor translates to three revolutions of the eccentric shaft, the rotary’s equivalent of a crankshaft.) There are numerous other smaller changes—an elaborately baffled oil sump whose ultra-slender 1.6-in. depth allows the engine to be set lower in the car; injectors that more finely atomize the fuel; a triple-path induction system that takes full advantage of the resonance “supercharging” effect; and an advanced engine-management system that’s said not to use oxygen sensors at all.

If a chink exists in the Renesis’ armor, it’s in torque production—in current tune, it generates 153 lb.-ft. at 7500 rpm. Curiously, those numbers are identical to the S2000’s, and that car has been criticized for lack of low-end grunt. But Martens stresses that it’s how the torque is distributed—and how it’s matched to the car’s yet-to-be finalized gearing—that will ultimately impact the RX-8’s fun-to-drive quotient.

“We want to have the feeling of, ‘Oh my god, I didn’t know this would do that in this range,’ ” he said. “Flat torque curves are great, but what we really want is a lively car. It has to have a unique identity when you get in and drive it.” We anxiously await the production version.

wow, that is interesting!!!

So they purposely wanted carbon to be carried throughout the engine to reduce emissions?

Isn't this the reason for the excessive 'carbon lock' issue with our engines?

maybe

Sure sounds that way, doesn't it?

yes it does

Emissions > Reliabilty

That was evidently their thought process, or they didnt forsee the issues we are having.

Keep in mind that they had to meet emissions requirements to bring the car to the American market at all. I'm not defending their decision, but they didn't really have the choice to make the car more reliable but with more emissions.

At least they gave us the 8yr/100k warranty. So, they are eating a lot of the downside of this.

wth?

Emissions > Reliabilty

That was evidently their thought process, or they didnt forsee the issues we are having.They foresaw the carbon issues with the side port since they had experienced this already in the early 70s and they made some changes to mitigate it somewhat. As rg explains it:

"The shape of the side seals is interesting as well. It is a wedge shape. This is to help remove any carbon from building up in the groove which would cause it to stick. Carbon is also the reason for the interesting shape of the Renesis exhaust ports as well as the overly large seal clearances in the Renesis over the 13B. And some of you thought carbon was related to synthetic oils! Shame on you! That was actually the reason why we haven't seen a side ported rotary until the Renesis. Back in the '70's Mazda did try the side exhaust port and back then they also found it to be superior. The problem was the carbon would cause seals to stick and break. You can't market that. They met the standards of the time with the peripheral exhaust port so that's what they stuck with."

So, it would be reasonable to add a cat inspection (say, every 6 months), and free replacements if need be, to Mazda's 'honey do' list?

Keep in mind that they had to meet emissions requirements to bring the car to the American market at all. I'm not defending their decision, but they didn't really have the choice to make the car more reliable but with more emissions.

At least they gave us the 8yr/100k warranty. So, they are eating a lot of the downside of this.

Yeah, too much eating I have heard from a close Mazda source, Mazda are not happy with the cost of failed engines particularly in the US where the previous reman guys stuffed up so many times with owners have engines changed 3 and 4 times.
This guy told me if the new series II RENESIS with the extra lube nozzle for each rotor chamber and the other mods they have done does not halt the number of failed engines they doubt we will see a future at all until alternative energy sources are mainstream.
BTW, the number of engines replaced has topped 50,000 according to him. (about 25%)

The "COST" I am referring to is not only the financial one but the image cost too.

Yeah, too much eating I have heard from a close Mazda source, Mazda are not happy with the cost of failed engines particularly in the US where the previous reman guys stuffed up so many times with owners have engines changed 3 and 4 times.
This guy told me if the new series II RENESIS with the extra lube nozzle for each rotor chamber and the other mods they have done does not halt the number of failed engines they doubt we will see a future at all until alternative energy sources are mainstream.
BTW, the number of engines replaced has topped 50,000 according to him. (about 25%)
That is stunning! How reliable is your source's info?

BTW, I'd feel a lot better if those Series 2 Renesis engines had Sohn adapters with a clean Idemitsu supply and/or a good premix regime, maybe some FP+. Wonder what your source thinks of these ideas that are so popular among enthusiasts?

Yeah, too much eating I have heard from a close Mazda source, Mazda are not happy with the cost of failed engines particularly in the US where the previous reman guys stuffed up so many times with owners have engines changed 3 and 4 times.
This guy told me if the new series II RENESIS with the extra lube nozzle for each rotor chamber and the other mods they have done does not halt the number of failed engines they doubt we will see a future at all until alternative energy sources are mainstream.
BTW, the number of engines replaced has topped 50,000 according to him. (about 25%)
that's an awfully bold statement. i'm not challenging it but would love to know how accurate that is.

25%, yeesh.......

And I bet 60-70% OF THAT 25% were 04's.

That makes me faithful in my engine with 71K on it :uhh:

You guys know how old this thread is?

^ it was bumped for a reason, it's interesting info in hindsight.

You guys know how old this thread is?
Of course, that's why Al commented on the new perspective that time brings, which is also why I added rg's perspective on the original side exhaust port rotaries from the early 70s. Old farts like (Chris and) me understand the importance of historical perspective.

I actually find some of these old threads VERY interesting. It's neat to see what people's thoughts were BEFORE the release and view and comment on them NOW that the 1st Gens run is over and the new RX8 is out.

Good find Chris

thread revival i live 4 it!!!

That is stunning! How reliable is your source's info?

BTW, I'd feel a lot better if those Series 2 Renesis engines had Sohn adapters with a clean Idemitsu supply and/or a good premix regime, maybe some FP+. Wonder what your source thinks of these ideas that are so popular among enthusiasts?

In Australian Management and been there for 15 years now, I thought I was Mazda nut, this guy is WOT...but a sincere and great bloke.

Of course, that's why Al commented on the new perspective that time brings, which is also why I added rg's perspective on the original side exhaust port rotaries from the early 70s. Old farts like (Chris and) me understand the importance of historical perspective.

And this old Fart!

Yeah, too much eating I have heard from a close Mazda source, Mazda are not happy with the cost of failed engines particularly in the US where the previous reman guys stuffed up so many times with owners have engines changed 3 and 4 times.
This guy told me if the new series II RENESIS with the extra lube nozzle for each rotor chamber and the other mods they have done does not halt the number of failed engines they doubt we will see a future at all until alternative energy sources are mainstream.
BTW, the number of engines replaced has topped 50,000 according to him. (about 25%)
Here's a kind of partial confirmation from a guy who works in the new Mazda remanufacturing facility:
And finally on a 16x side note, I haven't asked the Japanese engineers about it but I asked a few supervisors and there reply was its kept in secret but with the way the economy is now its probably on hold. Part of the reason why the opened our facility was to bring in a engineer from japan to investigate on how to improve the next engine and see why some fail. Depending on how the research goes and how well our reman engines are will have a huge determination on whether there will be anymore rotary engines built in the future, no joke. Like I said when we started our trianer from mazda japan(Yoshii) told us to please do a good job, his job depends on whether we do a good job in both building and investigating since we may determine the future. So nothing really new on the 16x, Mazda is not doing great right now but its doing better then most, its very small compared to other car companies and has survived tough financial times in the past.

That's pretty scary for us rotorheads. I don't think that Mazda will ever give up on the rotary, but it's seeming more and more likely that they will take an extended break from selling production rotaries and only have them in development for a while, like the time between the end of the FD run and the introduction of the 8.

I hate to say it, but the series II 8 may be the last rotary we see for a while. Historically rotary cars are not big money makers and Mazda has lost bucketloads of cash on the FD and the 8. It's hard to see how bringing the 16x to market in this economy would make sense for them, though I hope they do it anyway.

But who knows what the future holds with this economy. The only thing that's certain is that it will recover eventually, and when the smoke clears Mazda may actually be in a very strong position. They've shaken off Ford control and, while they're hurting, they're doing better than most car companies. In a few years they may be in a position to take a gamble on a new rotary. We'll see I guess.

That's pretty scary for us rotorheads. I don't think that Mazda will ever give up on the rotary, but it's seeming more and more likely that they will take an extended break from selling production rotaries and only have them in development for a while, like the time between the end of the FD run and the introduction of the 8.I agree, but minor point: the FD was still produced in Japan until the end of August 2002.

Yeah you're right, and the 8 was introduced in Japan in '03, so I guess there wasn't much of a break in selling rotaries in Japan. But whether they stop selling rotaries completely or just restrict them to the domestic market, it's all the same for those of us who don't live in Japan.

Update from Ashley:
I have just come back from talking to my Mazda Parts Manager mate ...

You can't get away from this guy...A quick 10 minute visit, turns into a few Hours!!!...

Anyway, got talking on the RENESIS and Fords Involvement initially.
The Mazda Australia's state service rep told him that Mazda originally wanted a total of SIX oil injection nozzles (as used in the 09's) as engineers where concerned about sealing and longevity based on their 40 years of knowledge.

It has been well documented the "Hurdles" Mazda went through to bring the Evolv into production as the RX-8.

ALL the engineers said the oiling system would give problems in a very short period of time, the Bean Counters (Ford) basically said if you don't sign off on this car now..it won't happen.

So, we all know the outcome.
It appears the Mazda's Rotary Engineers warnings came true.

Michael also said Mazda are losing millions with the world wide rebuilds/replacements.
Remembering that apart from the US/Canada all other distributors are replacing RX-8's with all brand new Japan made RENESIS's out of a crate.

Here once the warranty claims are paid most dealers are Binning/Trashing/Destroying the old engines!..

Trying to save a penny has cost at lot more in the end.

Update from Ashley:

Makes you wonder if this is true???

I have no reason to doubt Michaels sincerity and the MA service rep who has been working for MA for 17 years...

Michael (Parts Manager) for 24 years at one Mazda dealership.

Makes you wonder if this is true???

Of course Mazda/Ford would never admit to this, but every bit of anecdotal and circumstantial evidence points to this being true.

The only other plausible theory for the 6-nozzle improvement is that Mazda want to use it as something of a real-world test-bed for the 16X down the line.

It's for one of those two reasons that Mazda made the change in the '09+ RENESIS, so take your pick. They didn't do it just because they were bored!

In Australian Management and been there for 15 years now, I thought I was Mazda nut, this guy is WOT...but a sincere and great bloke.

And I wish they still made 2 stroke street motorcycles.

Faster than Superman.

Well, plenty of spare, cheap engines from the recalls for me though, got to be able to build a few good ones out of all the shot ones, pre-mix in the tank, et voila, problem solved.

8 year engine warranty FTW.

Premix FTW.