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Posts filed under ‘Rotary’

400 Horses for a 2017 Mazda RX-7?

July 30, 2014 by Matt

Mazda 16X New Rotary Wankel Engine Motor

With a rumor mill almost as productive as the one prophesying the return of the Toyota Supra, the latest scoop from the “new RX-7” cloud of unsubstantiated gossip foresees 400+ horsepower from a next-generation rotary powerplant.

People tend to forget that car specifications—power, weight, grip and the like—are driven more by what market niche the car is intended to fill rather than what’s technically possible. So let’s assume for a moment, contrary to all actual and official evidence, that Mazda really does plan to unveil a true RX-7 successor in the next few years. A better way to speculate about the new car’s eventual output would be to “think like a marketer” and determine which corner of the sports car spectrum the car would be designed to occupy. I can think of three possible targets for Mazda’s new performance flagship:

  1. Toyota/Subaru GT86/BRZ competitor: Unlikely. The Toyotaru Twins offer slightly better performance than Mazda’s own Miata but adhere to a similar “driver-first” ethos. Making what amounts to a marginally faster hardtop Miata with a rotary engine would be a lot of fun, and would take advantage of the current mini-backlash against the current crop of overpowered, inert speed appliances, but fundamentally, such an approach would still edge too closely to the Miata’s territory.
  2. Pony car / Corvette killer: The article alludes to this possibility when it conjectures that a new RX-7 would “seriously challenge the Porsche 911.” The problem with this theory is that the high-end performance car market segment is currently engaged in a DEFCON 1, no-holds-barred arms race, outputs soaring above 600 hp with roadholding to match. In theory, Mazda could make a strong showing in this category by replicating yet amplifying the third-generation RX-7 formula: A high-strung turbocharged rotary offering competitive power in a lightweight chassis with hair-trigger reflexes. They certainly have the technical chops. But the matter of resources rears its ugly head: The automaker simply doesn’t have the capital to develop and support such a car on a mass-production scale. The fact that residents of this market segment like the Mustang, Corvette, Viper and Camaro are upping the power ante practically ever other week doesn’t help either. Besides, this niche is the obvious choice, and while Mazda’s approach to it would be unique, I’d like to think their target selection would be a little more…nuanced.
  3. Porsche Cayman / Nissan 370Z alternative: This makes more sense. Does it basically take over from where the RX-8 left off? Yes—but with the power and styling the RX-8’s chassis always deserved. If an RX-7 successor can take what actually worked about the ‘8—and given Mazda’s track record, there’s no reason to think they wouldn’t—and shore up the areas in which it was deficient, sharpening the car’s focus by axing the back seats and giving us a bonafide sports car, they might have a winner on their hands. Here’s the recipe for success in this niche: A direct-injected, 300+ hp rotary; 2 seats; perfect (and I do mean perfect) looks, transcendent driving dynamics and a curb weight under 3,000 lbs. The time is ripe; the 370Z’s basic platform has been around since 2003 and has always been somewhat awful when pushed to 10/10s. And while the Cayman is as dead-nuts perfect as a sports car can be, it’s been rampaging alone in its market segment for far too long. It’s time, Mazda.

Image credits:

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Forbidden Gem: Mazda HB Cosmo

February 18, 2013 by Matt

Mazda HB Cosmo Silver

I often wonder why Japanese automakers decline to bring their some of their most desirable creations stateside.

The car that immediately comes to mind when pondering this reluctance is the Nissan Skyline, but there have been a raft of other very nice automobiles withheld from our market, among them the 1981-1989 Mazda HB Cosmo. The predecessor of the even more delectable JC Cosmo, it was Mazda’s rotary flagship, a slightly larger grand tourer complement to the RX-7 and a direct competitor to cars like the Skyline and Toyota Soarer.

Mazda HB Cosmo Silver Engine Motor 12A Turbo

Available with no less than 7 engine options during its 8-year model run, among them gasoline- and diesel-powered piston engines as well as the aforementioned rotary, the most exciting mill on the option sheet was the first production turbocharged Wankel, the 12A Turbo. A non-intercooled, lower-compression variant of the standard 100-hp 1.1L 12A, the 12 Turbo featured a so-called “impact turbo” designed to better harness the rotary’s unique exhaust pulse signature. With additional injectors and a sophisticated (for its time) knock sensor system, the 12A Turbo developed a highly respectable 163 hp, more than enough to move the 2,500-lb Cosmo forward at a brisk pace.

Mazda HB Cosmo Silver Interior Inside Cockpit Console Dash Dashboard

Naturally, the car’s rear wheels received the power, and Mazda blessed the chassis with their characteristically brilliant tuning expertise. A manual transmission was standard equipment, and the interior was clean and functional, if very “period.” Of note are the upright cassette player, the near-ubiquitous ’80s maroon cloth interior scheme and the faux-digital instrument cluster.

Mazda HB Cosmo Silver

Of all the cars that could’ve but didn’t make the trip over the Pacific, the HB Cosmo is a real head-scratcher. The engine is smack dab in the middle of the chassis, and a quick glance at the interior layout leads me to think the cluster could very easily have been moved whole-hog over to the left side of the dash, eliminating a couple of reasons related to the potential difficulty of adapting the car to a left-hand-drive market. A more likely theory is that Mazda felt the HB Cosmo wasn’t a good fit from a marketing standpoint. After all, they had been burned by the failure of the previous Cosmo to catch on in the US, and there weren’t really any small-ish, quick GTs for sale here at the time, probably because there simply wasn’t any demand for them. Mazda also could’ve felt like sales of the Cosmo would have cannibalized those of their RX-7, which shared an engine, a mechanical layout and really wasn’t that much smaller. Still… As a rotary, GT and ’80s styling enthusiast, I say it’s a shame the HB Cosmo never made it here.

Image credits: Tennen-Gas

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Driving the Only Left-Hand Drive
Mazda RX-7 Spirit R in the World

December 16, 2012 by Matt

As soon as I think I’m over my obsession with the 3rd generation Mazda RX-7, or FD, a clip like this pops up and reminds me of all the reasons I fell in love with the elemental sports car as a 15-year-old.

It does get talky in parts, and the host makes much the same point articulated more astutely by Chris Harris—pining for a lower-power, full-engagement sports car instead of the mega-horsepower digital “robots” de rigeur nowadays—but the shots of the Spirit R blasting along the California coast are worth the occasional superfluous foray into familiar automotive history.

To state the obvious, it’s an achingly beautiful car. I honestly can’t think of a lovelier vehicle to emerge from Japan, and the knowledge of its (considerable) capability only strengthens the pull of its lines. As much as I wish the FD had been offered in the US for longer than three model years, I wonder sometimes if the shortness of its production run coupled with the powder-keg nature of its twin-turbocharged rotary don’t actually enhance its appeal. It’s so ephemeral, so uncompromising, both in its looks and in its accoutrements vis-a-vis the driver, so utterly irrational… We need cars like this; cars that don’t make a lick of sense “in the real world.” As much as I appreciate what Mazda attempted to do with the RX-8, with its suicide doors and livable back seat, those very concessions to practicality turn me off to it. I would “use” the RX-8’s compromises exactly once: As talking points to convince my wife that the car wasn’t a completely frivolous expenditure, and then bemoan their presence for the rest of my ownership experience. No, even if I had to sleep on the couch for a couple of weeks, give me the FD RX-7. Its purity is worth the pain.

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Mazda RX-7 Spirit R in the World

Interesting Engines: Mazda’s R26B

October 6, 2012 by Matt

Mazda R26B 4 Four Rotor Engine Motor Le Mans Win 787B

Mazda’s 4-rotor, 2.6l, 700-hp R26B is the only engine by a Japanese manufacturer to win the 24 Hours of Le Mans race outright. In doing so, Mazda scored an achievement that has always eluded such pillars of the Japanese racing scene as Nissan, Toyota and Honda.

The year was 1991, and Mazda had something to prove. Perennially stung by criticism of their signature Wankel engine as an unreliable gas guzzler, the automaker had long sanctioned factory entries into endurance racing series across the globe. And though Mazda had achieved a remarkable amount of success through the years in that form of racing, Le Mans stood as the unconquered peak, the title that would perhaps finally demonstrate, to the racing world at least, that the rotary engine deserved to taken seriously from a competition standpoint.

The ultimate incarnation of a long series of endurance-focused rotaries, the R26B built on the foundation laid by its 4-rotor predecessor the 13J-M, itself a variation of the 3-rotor 20B, and added a number of refinements. At its core, the R26B was a basic non-turbocharged rotary engine, but with racing-derived features like intake ports on the periphery of the rotor housings instead of on the side plates (as in all production Mazda rotaries), an arrangement that produced a great deal of overlap between the intake and exhaust “stroke” of the rotor but which allowed for much greater airflow potential at high rpm, where racing engines live.

Mazda R26B 4 Four Rotor Engine Motor Le Mans Win 787B Diagram Schematic Drawing Cross Section Cutaway

Also, the R26B was fitted with steplessly variable intake runners, able to optimize intake length and thus airflow seamlessly for any engine state, as well as 3 spark plugs per rotor instead of the usual 2, promoting more uniform burn of the fuel-air mixture. The engine was capable of cranking out 900 hp at upwards of 10,000 rpm, but was detuned to “only” 700 at 9,000 rpm to in the interests of durability.

Mazda R26B 4 Four Rotor Engine Motor Le Mans Win 787B Cutaway Drawing

And it worked. Fitted to a durable, proven 787B prototype chassis and driven by the trio of Johnny Herbert, Volker Weidler and Bertrand Gachot, the R26B vindicated Mazda’s efforts once and for all at Le Mans in 1991. Perhaps sweetest of all were the primary reasons for the win: Not power, where it was outclassed by the Jaguars and Mercedes running that year, but fuel economy and durability, two attributes which allowed the R26B-powered 787B to keeping lapping the circuit longer and shrug off failures that sidelined other teams. It’s an amazing engine, and Mazda is rightly proud of their success.

To see 1991 Le Mans winner Johnny Herbert driving his race-winning 787B just last year, click here. It’s a spine-tingling clip.

Editor’s note: This post is part of an ongoing series examining unique and significant powerplants. Read the other installments here:

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The RX-7 Story, Part II: Red

September 28, 2012 by Matt

Mazda RX-7 RX7 FB Red

I pine for this car. Yes, I do.

This is the car on which I cut my teeth mechanically. Before the red RX-7 came along I congratulated myself on being able to change a starter unassisted; afterward I would tackle almost anything with little hesitation (and in many cases, preparation).

It was another eBay purchase, February 2000. This was still before eBay Motors came along and the listing for this car was beyond terrible. Two lines of text and no picture, but the kicker was that it was located just down the road in Greensboro. Having a little extra saved up, Aaron and I made the two-hour round trip to check it out.

Mazda RX-7 RX7 FB Red

When we arrived we couldn’t believe our eyes. Except for a blown engine, the car was pristine, perfect, cherry—literally. The seller worked in an automotive paint shop and had painted the car himself with loving attention to detail. However, aside from his artistic talents with a paint gun, he was a stereotypical American auto enthusiast who, “didn’t know nothing ’bout no rotary engine.” Thus, when the engine blew, he was baffled. Aaron and I, being rotorheads, saw opportunity. We thanked him for his time and returned to Raleigh, intent on scooping it up.

And I did. No one else must have driven out to see the car since my bid was less than $300. The owner delivered the car the following week on a flatbed trailer, visibly bothered that his eBay sale hadn’t gone as well as he had hoped, but a man of his word.

Mazda RX-7 RX7 FB Engine Motor 12A Wankel Rotary

So the plan was hatched. Between the black RX-7 with its strong engine but rusted-out northern chassis and the red RX-7 with its blown engine but sound body, I would make one complete and perfect little sports car. My dad was less than optimistic about my chances of success, having never attempted something as involved as an engine swap, but his skepticism just spurred me on. To shorten the story, I learned a lot, made a couple of time-consuming but non-terminal blunders along the way (keep grease away from the clutch disc!), and by early August, after about a month and a half of work, I fired up the good engine in the red car for the first time. That was an experience unto itself since the car had no exhaust but the manifold at the time and rotary engines create noise all out of proportion to their small displacement. Not only that, but I had squirted some automatic transmission fluid into the combustion chambers to lube the seals pre-startup, and the ensuing cloud from the burning ATF completely blanketed the cul-de-sac. But it ran, and ran well. I was ecstatic.

So where is it now? Why didn’t I keep it? The reasons sounded much more plausible at the time, but today I wish, oh how I wish I had reconsidered. After having the car for a few months and enjoying it thoroughly, for easily-preventable reasons the good engine ate an apex seal. Being in college at the time and in a bit of a temporary financial pinch, I somehow decided the car had to go. So in a fit of misdirection I put it up on eBay and sold it, with a blown engine, for $1500. I probably made money on the whole ordeal, but I still regret it.

The buyer arrived to haul it away the same way it had arrived in my parents’ driveway: On a flatbed trailer. From what I gathered, he was a Wankel enthusiast from somewhere around Goldsboro and planned to do a blow-through Weber turbo install. I never heard from him again after the car disappeared around the corner. Funny thing that’s never happened before or since: My mom witnessed the transaction and actually teared up as the red RX-7 was being trailered away. I didn’t quite know what to make of it then, and still don’t, really. I never knew she’d been so attached to it. If I had only known then how much I would long for it now, perhaps I would have been more sympathetic.

Editor’s note: This post is adapted from a “car history” post I wrote on an older blog of mine some years ago. Read the first installment of the two-part series here.

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The RX-7 Story, Part I: Black

September 19, 2012 by Matt

Black RX-7

Acquired mid-October 1999, this was my first real project car. It also doubled as my first eBay purchase. On a whim while at the State Fair in Raleigh that fall, I decided to really go for this car. Aaron owned an ’86 model, the first year of the 2nd generation and a very different machine, albeit with the same “heart”—a rotary engine. I bought it in the days before eBay had a separate section of their site devoted solely to cars, so killer deals (read: bad listings) could be found by trolling the search fields regularly. Aaron happened upon the listing for the black RX-7 and tipped me off to it. There were no pictures and a very terse description of the car.

I won the auction with a bid of around $500. The car was in Shrewsbury, Pennsylvania. I talked my friend Jonathan into driving up there with me to retrieve the car. It wasn’t that difficult, seeing as how a friend of his (and unbeknownst to him at the time, his future wife) attended Messiah college nearby and he was eager to visit her. We drove the family minivan north through the night, stopping only for dinner at a roadside Blimpie’s. I left him at the college and drove back down the highway to a motel near Shrewsbury, intent on picking up the car the next day.

The following morning, after a few wrong turns I found the house and the car. The actual owner of the car (a student) wasn’t present, so I did the title transfer with his parents, who were a little perturbed at having to sacrifice part of their Saturday morning to get rid of a front yard eyesore.

Paperwork squared away, I turned my attention to the car. It hadn’t moved in a year or so and was a bit rough, with a mismatched silver front right fender. Amazingly, it started well enough and ran, at least until I got the car about 50 feet out of the driveway, at which point it went completely dead. No cranking, no dash lights; nothing. I panicked for about 10 seconds and set about trying to solve the problem. I wasn’t keen on having to tow the car from PA to central NC, so there certainly was a sense of urgency. I knew it was an electrical problem, so I rooted through the minivan to see what I could find to aid diagnosis. After some searching I came up with a spare taillight bulb and a pair of twist-ties. I rigged these together to function as a test light and poked around the engine bay of the RX-7 looking for the break in the system. Turns out a fusible link, one of the main fuses protecting the electrical system, had broken from the strain of not having had current flowing through it in some time, so I twisted the two halves of the link together, tried the car again and it fired right up. I drove the minivan back up the highway, picked up Jonathan from Messiah, and we booked it back down I95 and I85, going 80+ mph the whole way. We made excellent time, and returned home that night.

At the time, I was 20 and had very little experience working on cars, though I had a considerable amount of “theoretical” knowledge. With Aaron’s assistance and encouragement, though, I started to tear into the RX-7. A project day at his house cured a couple of electrical bugs, and he showed me how to prep and paint the fender to match the rest of the car (though I later “got happy” with a can of spray paint and ruined the day’s work). I bought a high-flow downpipe and catalytic converter to install as well, and while we were able to get it on, the rest of the exhaust system crumbled as we unbolted it, having been exposed to many northern winters. I drove it home with no catback, and marveled that such a little engine could make so much noise…

Continue reading with “Part II: Red.”

Editor’s note: This post is adapted from a “car history” post I wrote on an older blog of mine some years ago. The photo above does not depict the actual car; the only image I have of it resides in one of my parents’ photo albums and will be added once scanned.

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Mercs I Would Consider: The C111

September 12, 2012 by Matt

Mercedes C111 Orange

Okay, so being an experimental car, I can’t really consider this one from the standpoint of a possible purchase. But it’s still one of my favorite Mercedes.

Appearing in at least three distinct incarnations starting in 1969, the first two C111 evolutionary steps represented testbeds for Mercedes’ Wankel, or rotary, engine program, and the last housed the automaker’s latest high-performance diesel engine efforts. More than an engine platform, though, the C111 was an outlet of sorts for Mercedes’ engineers. The automaker’s racing program had been shuttered in the aftermath of the 1955 Le Mans disaster, and its development team was hungry to apply themselves to something more exciting than standard-issue production sedans. As it was produced, then, the C111 was trimmed and finished to a degree unheard of for an average technology demonstrator. No spartan development mule, all three generations sported a tractable engine, decked out interior, a refined chassis and even air conditioning. Indeed, as the late Paul Frère reports in this Road & Track feature article:

The C111-II is so elegant and businesslike that, with modern technology under its skin and wider tires, it would be the hit of any motor show today. No wonder that at the time, the factory received many blank checks from potential customers [eager] to acquire a replica.

Mercedes C111 Orange Wankel Rotary Engine

Despite the luxurious trimmings, all three incarnations of the C111 were very quick. The initial 3-rotor Wankel-powered C111-I’s engine pumped out a characteristically smooth 280 hp, and the II’s 4-rotor engine raised that power figure to an even 350. That was a lot of power for the late ’60s and early ’70s, and it allowed the car to reach 60 mph from a standstill in under 5 seconds, as good as any contemporary muscle car from our neck of the woods. Even the later, diesel-powered C111-III, while not quite as fast as its predecessors, set several speed + economy + endurance records.

The bodywork was steadily refined throughout the car’s evolution, and has a distinctly Teutonic, functional feel to it, kind of what a German GT40 Mark 3 might have looked like. That said, I think it looks fantastic, and as Frère alluded to in the above quote, the C111 has a kind of timeless appeal. Completely free from any Mercedes styling cues—gullwing doors excepted—the car sort of stands alone in the automaker’s history as one of the few times they really gave their engineers and stylists free rein to consolidate their expertise and innovative leanings into one car.

Mercedes C111 Wankel Rotary Engine Motor 4-Rotor

Why wasn’t it produced? As much freedom as Mercedes gave their development team with the C111 project, they were clear to point out that the car was a technology demonstrator, and had no chance of progressing beyond that stage. Also, as refined as it was, the engine technology was the C111’s real raison d’être, and when Mercedes started hitting hurdles with their Wankel engine program, instead of persevering like Mazda did, eventually overcoming most of the technical and production challenges, the German automaker decided to pull the plug and direct its resources elsewhere.

Mercedes C111 Interior Inside Cockpit Console Dash Dashboard Gauges Instruments

It’s a shame. I see the C111 as a sort of a proto-BMW M1, which was itself a kind of pre-Acura NSX: An archetype of a truly user-friendly supercar. It had some rough edges, to be sure (Frère spotlights an outdated steering system and tricky handling at the limit, among other things), but overall the C111 made a considerable effort to “meet the driver halfway,” as it were, instead of being the hot, cramped, sweaty, evil-handling supercar its Italian contemporaries were. Between its refinement, looks and technological bravery, I have a great deal of admiration for it.

Editor’s note: This post is part of an ongoing series highlighting Mercedes models worthy of enthusiast consideration. Read the other installments here:

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Rumors Abound Concerning
Potential New Mazda RX-9

July 31, 2012 by Matt

Mazda RX-9 Concept Red

Time for a bit of rotary news.

Autocar reports some insider knowledge of Mazda’s plans for an upcoming successor to the recently-axed RX-8 and legendary RX-7.

If the rumors are true, the new RX-9, as it’s likely to be called, will be built around the Japanese automaker’s latest refinement of the rotary, known internally as the 16X. Unlike nearly all previous generations of Mazda’s iconic engine, the 16X features a longer equivalent of a rotary’s stroke, greatly increasing its efficiency and alleviating much of its bemoaned lack of low-end torque.

Design-wise, now that Mazda has thankfully abandoned its cartoonish Nagare design theme in favor of the much handsomer Kodo styling philosophy, there’s no reason to expect the RX-9 to sport a grotesque, grinning maw. No, I’m hopeful the upcoming sports car will feature a more aggressive variant of the recently-released CX-5‘s attractive nose.

All the pieces are in place: Brand-new Wankel engine, appealing design direction… All that’s left is to build it. Substantiate the rumors, Mazda!

Editor’s note: The car pictured at top is a Mazda concept and doesn’t officially represent a definite design direction for a new production sports car.

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Potential New Mazda RX-9

The Engine Swap Hall of Fame:
4-Rotor Mazda RX-7 FC Build

April 23, 2012 by Matt

4 Rotor Mazda RX-7 FC Build Project 2nd Gen FC3S 26B John Huijben RX7Club

This build isn’t even done yet, but the engineering and fabrication is so stunning that I feel compelled to feature it.

The skinny? It’s custom-engineered, 2.6l, peripheral port, 4-rotor Wankel engine transplant into a 2nd generation (FC) Mazda RX-7. Every piece is so jewel-like that it’s difficult to know where to begin.

John Huijben, an engineer and machinist based in the Netherlands, decided on a bit of a whim to put this engine together in his spare time. In his words, it’s more of an engineering exercise than anything else, and not meant to be a part of a fully integrated car. Put another way, it isn’t remotely the most practical or sensible way to build a powerful RX-7, but Lord help me if it isn’t absolutely fascinating. My kind of project, in other words.

4 Rotor Mazda RX-7 FC Build Project 2nd Gen FC3S 26B John Huijben RX7Club

Here’s the shell: a basic Series 4 (’86-’88) RX-7, a touch rusty, stripped down the degree it’ll have to be to accept the engine.

4 Rotor Mazda RX-7 FC Build Project 2nd Gen FC3S 26B John Huijben RX7Club

One of the build thread’s highlights is the CAD work. Stunning exploded views precede almost every major update and illustrate the benefits of careful design over a less thought-out, more improvised approach to engine building.

4 Rotor Mazda RX-7 FC Build Project 2nd Gen FC3S 26B John Huijben RX7Club

The slide throttle in particular is a complete work of engineering art. Less restrictive than a conventional butterfly throttle, especially at WOT, its design and implementation are peerless.

4 Rotor Mazda RX-7 FC Build Project 2nd Gen FC3S 26B John Huijben RX7Club

The part of the 4-rotor build that takes the cake, though, has to be the custom eccentric shaft (a rotary’s equivalent of a crankshaft). Instead of mating two e-shafts from smaller, 2-rotor engines, Huijben decided to design and machine his own custom piece from a solid steel billet (shown at top in photo above). Given its precise balancing, oiling and harmonics requirements, it’s a tour de force of engineering.

I’ll definitely be keeping up with the build’s progress. Can’t wait to see it come to life for the first time!

H/t to Aaron for the link to the build. Thanks!

Editor’s note: This post is part of an ongoing series showcasing awesome engine swaps and builds. Read the other installments here:

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4-Rotor Mazda RX-7 FC Build