Mazda RX-8 Buyer's Guide

Robert
By Robert Bowen
Mar 21, 2022 | Mazda, rx-8, Buyer's Guide | Posted in Buyer's Guides | From the April 2011 issue | Never miss an article

Photograph Courtesy Mazda

[Editor's note: This article originally appeared in the April 2011 issue of Grassroots Motorsports, back when the RX-8 was still in production]

Mazda’s association with the rotary engine dates back half a century. In fact, while many other marques made earlier attempts to popularize this revolutionary engine, only Mazda achieved real commercial success with it. And while the rotary has powered some exotic machines, from rare sports cars to IMSA champions, it can also be found in something available to just about any enthusiast: the company’s RX-8 coupe.

In July 1961, Mazda President Tsuneji Matsuda signed a contract to develop the company’s own version of the rotary. Instead of pistons that go up and down, the rotary uses spinning, triangle-shaped rotors to produce the four strokes of combustion. 

While Mazda’s first rotary-powered production car was the 1967 Cosmo Sport, from 1979 through 1995 the engine was synonymous in the U.S. with the brand’s RX-7 sports car. That model alone carried the torch for the industry’s most unusual engine. Mazda continued to develop the RX-7 through three generations, from the sporty but not-so-fast original car to the hardcore final model. 

In fact, the last iteration of the iconic sports car, known to fans as the FD, was so focused on driving performance that it discarded almost every other feature in pursuit of that goal. Twin turbos, big—for the time—wheels and massive bolstered seats made for impressive acceleration and no-holds-barred lateral grip. Driving enthusiasts loved the car.

But the lack of headroom, ultra-stiff suspension, fragile engine and lofty price tag killed the car in the American market. Ordinary buyers were simply not willing to ignore comfort, no matter how much performance the car offered in return. 

It was a sad day for enthusiasts everywhere when Mazda USA dropped the car after the 1995 model year. Nearly three decades after Mazda put the rotary engine into production, the tri-lobe wonder was just about dead. Production for overseas markets continued until 2002.

Resurrected Rotary

The rotary engine’s obituary was a bit premature, although American fans had to wait nearly 10 years to see it brought back from the dead. Rather than give up on the dirty, fragile and thirsty engine—the original rotary design was powerful but not entirely perfect for every need—Mazda spent the intervening decade working to improve it.

At the 2001 North American International Auto Show, Mazda revealed the results of those efforts, housed in a neat sports car/sedan hybrid. Engineers basically went back to the drawing board with the engine, rethinking port layout and packaging. It was still a two-rotor, 1.3-liter rotary based on the old 13B-designation engine, but it had changed enough that Mazda dubbed it the Renesis. 

Instead of featuring ports around the circumference of the combustion chamber like all other rotaries, the Renesis’s ports were cut into the side of each chamber. This prevented overlap between intake and exhaust open periods, improving emissions and fuel economy. It also kept the ports away from the troublesome apex seals. 

Before the Renesis engine, rotary designs placed the exhaust port right in the path of the apex seal, and unburned fuel had a tendency to get flung away. Moving the ports to the side of the rotors improved efficiency and performance.

Mazda promised output close to the old RX-7’s Turbo without the need for forced induction. On paper it seemed like an elegant and simple solution to a few of the rotary’s weak spots. 

The display model bearing the new engine was a thinly veiled production version of the RX-8. It was a sports car, but envisioned and packaged in a new way. Compared to the final RX-7, the new car’s roof was higher, and there were two rear-hinged access doors allowing use of the back seat. In place of the RX-7’s cramped two-person quarters was room for four full-sized human beings.

Just as impressive as the new engine and more practical bodywork was the chassis layout. The side-port Renesis was more compact than the old 13B and allowed engineers to move it far back in the chassis, nearly under the dashboard. The stubby carbon driveshaft ran to a limited-slip differential, and the fuel tank was moved up in front of the rear wheels. The payoff was a claimed 50/50-percent weight distribution. 

The RX-8 Debuts

The production RX-8 arrived at American Mazda dealers in the middle of 2003 as a 2004 model. It was nearly identical to the Tokyo Motor Show display car from two years earlier. 

The RX-8 delivered everything the concept promised, as the six-port version of the Renesis engine was rated for 238 horsepower—just a bit shy of the somewhat fragile turbo engine used in the final RX-7. The new mill zinged to a 9000 rpm redline, with peak power coming just 500 rpm before that. This version of the Renesis engine was available only with a six-speed manual transmission.

The Renesis engine is tiny, so it fits low and toward the center mass of the car. Photography Credit: Courtesy Mazda

There was another choice, though. Cars shipped with the available four-speed automatic received a four-port version of the Renesis. The automatic RX-8 produced a still-respectable 197 horsepower at a more pedestrian 7200 rpm.

The suspension of the new car was basically an evolution of the last RX-7, although new tuning and modern tires greatly reduced harshness without giving up any handling prowess. The new suppleness over bumps and the predictable body lean were welcomed by reviewers who were scared off by previous car’s handling and ride quirks. Even the electric power steering was well received for its linear assist and excellent feedback.

Automatic cars were fitted with 16-inch wheels and tires, while six-speed cars had 18-inch tires and wheels. That second combination was good for nearly 0.9g according to contemporary reports. Zero to 60 took a little less than 7 seconds. The RX-8 wasn’t as blindingly fast as the final RX-7, but it didn’t bruise its occupants’ kidneys or require $10,000 in backup funds in case it blew up. Reviewers loved the cars but weren’t sure what to make of the four-door package.

The RX-8’s design is polarizing, but the unusual shape accommodates some genuinely useful rear suicide doors. Photograpy Credit: Courtesy Mazda

Both the automatic and the manual were rated by the EPA at 18 mpg city under their old system, with 25 or 25 mpg highway, respectively. The revised fuel economy figures put the RX-8 at 16/22 mph. Those aren’t particularly impressive numbers for a 1.3-liter engine, hinting that the rotary’s old fuel-efficiency demon had not been exorcised.

The low torque ratings—just 159 lb.-ft. for the six-speed car—also looked weak on paper, but reviewers reported that the engine felt just fine, thank you, as long as the driver was willing to spin it up near its power peak. The RX-8 was a fun ride, but maybe not something for the masses. Enthusiasts took to the RX-8, though, and it quickly became a staple in autocross, endurance racing and track events.

While the manual-transmission RX-8 was not a steal at $25,680, it was still a great performance value. Check every box on the order sheet, and you’d be looking at a total of a little more than $30,000 for the manual or about $32,000 for the automatic. 

Music to Your Ears

Big news for the RX-8 came for the 2009 model year, as the car received a facelift and small but significant design changes. The suspension geometry was revised in the rear, and the chassis was strengthened at the suspension pickup points. Weight decreased slightly as well, improving overall performance.

Photography Credit: Per Schroeder

While the Renesis boasts improvements over preceding rotaries, it has a reputation for not being as reliable as traditional piston engines. Early RX-8s had a number of engine-related problems that were addressed later in production. Mazda USA went so far as to extend warranty coverage to eight years or 100,000 miles for 2004-’08 RX-8s that were already in service. This included repairs that were performed before the new warranty took effect in mid-2008.

Overall, the RX-8 has continued to be the automotive equivalent of indie-label music. It’s different, appeals to many people, and sometimes seems to follow its own direction. The car has enough power to be entertaining and handles better than anything with the same amount of versatility. Today it’s also not terribly expensive to buy.

If you’re willing to overlook a few quirks, the car makes an excellent choice for daily driving, track days and autocrossing. It doesn’t hurt to like the Black Keys, either.

Things to Know

The Mazda RX-8 is still in production. If new is what you want, then head down to your local Mazda dealer and lay down the cash for one. If you want a used one, shop around: We’ve seen prices all over the place. Early cars with blown engines can be found for as little as $5000—or maybe even less—but your average, decent-condition RX-8 will be somewhere in the $12,000-to-$25,000 range; it depends on the year, trim and condition.

We recommend buying the newest one you can find. Mazda-certified preowned cars are nice, but they aren’t a must since the factory engine warranty already extends to 100,000 miles or eight years. And if you have the scratch, the 2009-and-up cars have some suspension and driveline improvements that make them more desirable.

Photography Credit: Courtesy Mazda

Engine and Drivetrain

According to Jim Mederer of Racing Beat, one of the country’s oldest rotary tuners, the RX-8’s Achilles heel is the cooling system: “Mazda has stepped up and extended warranties for this problem, but the engine is still at risk in hot climates.” Jim also reports seeing excessive ignition coil failures—possibly related to high underhood temperatures. 

Thanks to the cooling challenges faced by the Renesis engine, Racing Beat advises against anything that squeezes big power out of the engine, especially turbocharging. 

On a related note, Racing Beat’s PCM reflash lowers the underhood temperature needed to turn on the cooling fans. Jim adds that the reflash also improves the high-rpm mixture and raises the rev limiter to 9300.

“The transmission on the 2004-’08 models is a bit weak for track use, and it may develop shifting issues,” explains Jason Saini, RX-8 racer and owner of Mazda prep shop Team MER. “You will need the transmission and shifter but little else to make this swap,” he explains. The 2009 and later cars also have a slightly more desirable 4.77:1 final drive ratio, he notes.

“Stock class rules allow competitors to modify the exhaust behind the catalytic convertor, and most will use this opportunity to jettison the bulky stock muffler for a much lighter-weight option,” explains Chris Harvey, national-level RX-8 autocrosser and Tire Rack’s brake and suspension brand manager. “Racing Beat offers a very nice bolt-on race muffler for the application, while other competitors choose to design their own custom piece,” he continues. “Coupled with a free-flowing, drop-in air filter, the rotary powerplant emits a proper snarl while negotiating the cones.”

Body and Interior

Jim strongly recommends installing a supplemental water temperature gauge: “The stock gauge stops moving at about 160 Fahrenheit and doesn’t move again until about 205 Fahrenheit, thus making you think the coolant temp is controlled and stable when it isn’t.”

A tip from Chris: If you can stand the aroma, an RX-8 can transport four tires without the need for a trailer.

Chassis

“The bare essentials for track use would be steel-braided brake lines, performance brake pads and high-temp fluid,” Jason explains. “Some sort of suspension upgrade to lower the car would be next on my list, along with track-dedicated wheels and tires.”

Jason recommends steering clear of the budget coil-overs found on today’s online market. “If you can’t afford a good set of quality coil-overs or race dampers, just get some Koni Sport shocks and lowering springs and you’ll be amazed at how well the car handles,” he explains.

The RX-8 features a very adjustable suspension, meaning aftermarket parts aren’t always necessary for an ideal alignment. “On my 2006 model, we were able to obtain 1.8 degrees of negative front camber to increase grip and extend competition tire life using the stock alignment allowances,” Chris explains. He then tweaked the rear toe and camber settings to adjust the steady-state balance, he adds.

“The lightweight four-seater is blessed with 18x8-inch factory wheel sizes that must be retained for SCCA Stock class competition,” Chris explains. “Generous wheel well openings allow competitors to fit wide tires on the wheels without modifications.” He adds that 245mm through 295mm section widths have all been successfully used at national-level autocrosses, “with most competitors settling on the 285/30R18 Hoosier A6 as the tire of choice.”

The front anti-roll bar size has been an area of much debate among the national Solo crowd, with most top-level competitors migrating to a stock or slightly stiffer-than-stock front bar to find the best balance on high-grip surfaces, Chris says. “This choice is contrary to many other Stock-class cars, which require the front anti-roll bar size to resemble a small tree trunk in the battle to control body roll.”

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Comments
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aircooled
aircooled MegaDork
1/28/22 6:49 p.m.

80,000 miles.

Great car, but...  80,000 miles...

tremm
tremm Reader
1/28/22 9:05 p.m.

And at 13 or 15mpg or whatever they were :/

aircooled
aircooled MegaDork
1/29/22 2:12 p.m.

I am still just a bit amazed.  Mazda HAD to know the engines would not last.

They went from one of the most reliable engines made (if you feed it oil and not boost), to one of the least.

I am guessing it was a bit of a sunk cost thing.  They has already gone that far.  Just go with it and hope for the best(!) Bigger 13B style motor = really bad mpg.  Turbo = not super long life either (but maybe longer than the Renesis?).  Of course, they spent all the money on the Renesis, not a turbo.

M007chan
M007chan
2/13/22 9:46 p.m.

In reply to aircooled :

Mazda made certain choices that made further choices forced upon them by Ford into a dire mix.

Mazda reduced oil pressure in order to reduce parasitic losses and placed the bottom of the oil coolers low enough that some oil wouldn't drain back during oil changes without either removing the thermostats or jacking up the front of the car.

Ford mandated 5W-20, for all climates and use cases, and also mandated longer recommended oil change intervals, both in North America, as opposed to the rest of the world.

The Series 2 walked back the oil pressure reduction, which helps; but the only full solution to longevity is to ignore Ford's oil viscosity & interval changes imposed on North American consumers. A 3000 mile oil change interval and a climate appropriate viscosity addresses a great deal of troubles.

For reference, I was at 97K miles before a coolant bottle rupture killed the seals on the  original engine, necessitating a rebuild. That was at least 7 years after a 245F overheat due to a malfunctioning radiator fan motor; but that event was approximately 6 months after I'd switched to Evans Waterless coolant (the same as OEM for Koenigsegg) so insead of immediately needing a rebuild, I got 13 years out of the original engine.

aircooled
aircooled MegaDork
2/13/22 11:14 p.m.

Thanks for the reply.  I figured someone had to have some info on this.  A bit too late for friend that bought a Series 1 new though (1 original and 1 warrantee motor before retired, 120k and 80k miles I think).  He is in a warm climate (SoCal), so the oil viscosity compromise probably had a big affect.

Any guesses on how many miles could be expected if you did all of the above?

fidelity101
fidelity101 UberDork
3/21/22 9:59 a.m.
aircooled said:

80,000 miles.

Great car, but...  80,000 miles...

In a world of 1 to 10, the vast majority are between 3 and 7, yet we tend to talk to each other like we are either 1 or 10

I was the 7th owner on mine and got 74k, looked like the motor had been opened up before too. 

 

lovely car just wish it had a wankel instead of a renesis in it

 

220mile tank for commuting wasn't great either

 

now its just yard art...

 

and ford berkeleying things up because of management and budget stuff? not surprised. 

RX Reven'
RX Reven' GRM+ Memberand UltraDork
3/21/22 4:15 p.m.
aircooled said:

Thanks for the reply.  I figured someone had to have some info on this.  A bit too late for friend that bought a Series 1 new though (1 original and 1 warrantee motor before retired, 120k and 80k miles I think).  He is in a warm climate (SoCal), so the oil viscosity compromise probably had a big affect.

Any guesses on how many miles could be expected if you did all of the above?

In a world of 1 to 10, the vast majority are between 3 and 7, yet we tend to talk to each other like we are either 1 or 10

The original blew at 87 and the re-built made it to 157 for a total of 244.  The mechanics at Mazda let me know that I had the highest mileage re-built engine they could remember seeing so consider that an outlier.

I averaged about 21.5 mpg with an 85% freeway commute which is outstanding given 236 hp and 3,050 Lbs...my FB gets 17.5 mpg with 100 hp and 2,350 Lbs because it's carbed and has a three speed auto.

Loved, loved, loved that car...no problem driving at 9/10 all day without scaring yourself.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
3/21/22 5:45 p.m.
fidelity101 said:

lovely car just wish it had a wankel instead of a renesis in it

Uhhhh... it is a Wankel.

Rufledt
Rufledt UberDork
3/22/22 1:45 a.m.

My 2009 is still going strong on almost every original part!  it's still only at 17k miles though.   I figure the amount i drive it (basically only autox events) i'll wear it out in 2055 or so.  Tons of parts are probably going to age out long before they wear out.

f1carguy
f1carguy New Reader
3/23/22 4:15 p.m.
f1carguy
f1carguy New Reader
3/23/22 4:21 p.m.

In reply to Rufledt :

That's the way I see it. My buddy begged me to sell him my 2004 mica red with 113K ($ 4300) and he drove it to work with the low compression for another 30K and then sold it for $3800! 

The owner's manual for Australia states the for temps like FL to use 50 weight oil! RX-8 forever! 

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