1: This is not an appliance car It needs to be looked after. The engine's in an extremely high state of tune. It's basically a 1973 engine design tuned to maybe double and a bit again it's original horsepower. Imagine doing that to an early 70's civic and get some idea of how high-strung the engine is. That doesn't mean treating it with kid gloves - but it does need a careful eye on it, on oil, coolant and ignition systems, to keep it running healthy. And don't rip the guts out of it when it's cold for fuck's sake.
2: Keep on top of problems Most cars when they have a problem, they just run like crap for a bit. With the RX, problems tend to snowball. Both because the engine's in such a high state of tune, and because there's so little mechanically to fail, it doesn't take much to start a long chain of degredation. To give an example, a fouled sparkplug killed an ignition coil in my car, which both killed the catalytic converter, and could've potentially caused the oil injectors to clog with carbon. Either one could've killed the engine in short order if it hadn't been caught. It's a car that demands your keep on top of problems because if it goes out of tune, it really impacts the lifespan of the engine. There're a lot of initially minor problems that, in any other car, would be annoying, but in an RX will eventually lead to the destruction of the engine if not solved quickly. (In one case, a weak fuel pump destroyed an engine by causing it to lean out and detonate at high RPM - then destroyed the replacement engine on its shakedown drive)
3: Give it good, clean petrol In my car, the difference between a car that feels tired, doesn't like hot-starting and is chirpy when cold, and one that is strong, fit and healthy, is a tank of petrol. Bought from the same station. On different days. It doesn't tolerate **** fuel at all well. Which is annoying, because fuel quality in this country varies wildely. It's also the difference between seeing the fuel light at 300km, and seeing it at 400km.
4: Be mindful of the common problems. It's not the apex seals that kills them, more often than not, it's the rear stationary gear bearing. The symptoms are similar because the rotor will misfire and it'll struggle to run. The result's the same, especially if the rotor bangs off the housings or damages other components along the way. It'll still drive home on 1 rotor, mind. Mazda spec'd too thin a grade of oil from the start, and at low RPM's the oil pressure in the bearings can get low enough for the e-shaft to hit the bearings under load and grind them down. Earlier (Pre -06) cars injected too little oil into the combustion chamber, which wore the apex seals down. The ignition coils on all RX8's are shite and prone to cooking themselves, then the cat, then the engine. Good owners upgrade them.
5: You can't really upgrade the power output. Remember what I said about the engine being in a high state of tune? All the low hanging fruit has been plucked by Mazda. the exhaust, intake and engine are already fairly highly optimised, to the point where replacing them means there's very little to be gained. The side-port engine means there's very little to be had from an exhaust upgrade since there isn't a strong exhaust pulse, while it limits what can be done with a turbo or supercharging. Turbocharging an RX8 is especially tricky - the side exhaust ports on the engine mean it's vulnerable to backpressure in the exhaust overheating the side-seals, causing the springs to warp and pop the seals out. Usually this results in a seal hitting the exhaust port, shattering, and taking the entire engine with it. (This is also how a bad cat kills them, btw) The ECU being a bit of a smart bastard doesn't help - it doesn't take kindly to chiptnes.
6: The fuel 'economy' 500km to a tank is the absolute max. With a failed ignition coil and an ECU that massively leaned the engine out to the point of near detonation, I once managed 600... but it'll never happen again. 300-450 is more normal. That's what it does. Don't like that, buy a Volkswagen.
7: It will get you into trouble. It just wants to rev and rev and go faster and faster - fast enough to get your arse to prison if you're not careful. I've seen number with a 1, 2 and 5 in them on a public road.... (Not in the State, Garda)
Now, the good stuff. What it offers
1: 9000rpm+ It's a tractable engine - it'll pootle along at 2000rpm happily on long journeys, just don't expect it to accelerate. All the fun happens after 4500rpm. Especially in the six-speed manual. It's more like an old 2-stroke in that it really rewards the use of the gearbox to keep the needle high in the rev-range. And unlike a conventional bouncer engine, the rotary really doesn't give a fuckwhat RPM it's doing. If anything, it's happier having the bollox rev'd off it - it never really feels stressed by RPM the same way a piston engine does. There's a reason why rotary owners say 'A redline a day keeps the mechanic away'. Keep the rev's up and let it spin, that's the best way to help it live. Half the morons complaining about it being gutless have either never heard of a manual gearbox, or don't understand the concept of a kickdown. Smack it down two gears and boot past anything in a whirl of noise and a haze of carbon.
2: The chassis It's a stiffened MX-5 chassis, that's all you need to know. All the weight's low down in the frame. It just sort of snouts and snuffles its way along the road finding the best lines. With the engine almost beside your legs, on the right road it can be sublime. On ****e roads, the suspension's just soft enough to take the worst of the bumps out of it.
3: It's a GT car, not a sportster No really. It'll try do everything and anything you could ask of it. I've driven mine to building sites with the boot loaded with construction materials. I've made cross-country trips with friends in the back seat and still been friends when I got there. I've tiptoed over iced-up mountain passes in winter through silent-hill fog. Then ripped down a motorway outside the state at stupid-kph. I've taken it onto race-tracks at speed in the worst storm of the year. It'll bomb up the N11 all windows open blaring Iron Maiden from an epic sound system, or cruise down in quiet comfort. It might not be the best at any of these things, but it'll still make a bloody good attempt at them.
4: It's comfortable I'm a big fat bastard, and even I'm comfy in the leather seats. The heater's epic - producing good warmt in minutes of starting. And you can put people in the back quite happily. (The trick being to put the short ones in the front). It has just enough toys in the cockpit with just the right ambience to feel 'modern', but without rapidly dating the car like so many early android or i-drive systems. It's a weird sort of timelessness, more like the car the 1980's thought we'd be driving, than what we actually got.
6: It's unique There really is very little like it out there anymore. Maybe the Honda S2000, but that's a different sort of car in a lot of ways. There's nothing out there that offers high RPM naturally aspirated fun anymore - nothing within the realm of mere mortals anyway. It's the last truly different car there is - likely the last rotary-engined car there ever will be, and the last glimpse into an alternate world where maybe automotive history evolved just that little bit differently. It's the last car that relies on you.
7: Reliability's better than its reputation No really. Provided you keep an eye on it, it's a fairly reliable car. Mine's been no-worse than any other ten year old car, and been a lot better than most. It's had it's problems and it's worn-out parts but they've all been easily fixable. And there's a lot you can do to it to solidify it further. Ignition upgrades, oiling upgrades, different oil grades. It's a car that responds well to an enthusiast's touch and is normally fairly easy to work on for just about anyone, even rebuilding an engine from the ground up is relatively straight forward - normally taking only a day or two. All it asks is that you keep an eye on it and don't let problems fester - otherwise, you can treat it like any other car. Mine's never flooded and failed to start.
But the biggest piece of advice I can offer prospective owners is this: Test drive it first. Take it out around traffic. Take it on the motorway. Take it down your favourite road if you can. Run the engine through its full range - it should charge to the redline (Good Cat/Ignition), make sure it starts hot without struggling (Good compression) and just check it out and make sure you grok what it's offering. The RX8 offers more than just numbers on a page - but that means it's also the sort of car that you need to sit in and take for spin to make sure you really want what it offers and you're willing to give it what it demands.
Also gut the cat. For epic flames. The NCT doesn't give a bollocks. Only downside is the tangy smell of 2-stroke seems to do weird things to bikers.....
Generally, the shit you should watch for is well documented. If it starts hot - after being driven hard up to temperature, shut down, then let soak for 10-15 minutes, the engine's probably fairly solid - enough for now anyway. (Or they have a fast starter)
Generally they're reliable cars once you keep an eye on them and don't let problems fester.
When you test drive it, put your foot down in second and make sure it charges up to the redline. If it feels ike it's running out of breath at 5-6000rpm and struggling either you have a stuck intake valve (Annoying), or a clogged catalytic converter (Potential engine death very soon, and expensive). Either problem can have a rattling noise, or other symptoms.
A dead cat is a total killer for one of these. Any backpressure on the exhaust will cook the side-seals. Eventually the seal-springs warp, popping the seal out. If the seal clips and exhaust or inlet port its game over for the engine.
The cats die on them. Usually by being blowtorched after an ignition coil goes pop. If it's a trailing coil - which it usually is - the first warning you'll have is the CEL for a dead catalyst - since the trailing coil really is only there to ignite the rich mixture lurking at the apex seal.
Other shit to watch for. If the owner has fitted an upgraded set of ignition coils and remapped the engine to match, you're dealing with a solid car. Even just the upgrade is worth having. A D585 coil swap and dwell remap was the single best thing I ever did to my car. It's much happier. Rotary engines loved good spark.
Stationary gear bearings die (Especially on UK/Ireland cars for some reason.) If it sounds like a diesel on startup, this is what's happening. Some people think the oil grade Mazda spec is too thin. Others than the recommended time between changes is too long. 10W40 mineral oil is the recommendation from most rebuilders. Ask the owner what they've fed it, and how often they had to do it. Cars that use no oil are ticking time-bombs - it needs to inject oil to save the seals from grinding themselves down. No oil consumption suggests blocked oil injectors which indicates either a lifetime crawling around town, or neglected oil changes. Cars that use a litre every 300km are either being driven hard, or have an oil control ring problem - but it's not critical if you monitor it. Maybe you'll get carbon. Ignorant owners will feed it synthetic oil. Good owners will add 2-stroke premix to their fuel to help since Mazda were a bit stingy after a lot of people complained about the RX7. Great owners will have what's called a Sohn adapter fitted, which causes the engine to suck clean 2-stroke oil from a dedicated reservoir rather than using crank oil.
Fuel pumps can go. Usually it manifests itself as a surprise stall in high temperatures because the pump can overheat on a low fuel tank, and is barely able to meet engine demand at full throttle. Sometimes it manifests as a surprise lean condition when fuel pressure drops, or a lack of power. Lean detonation will kill the engine in a blink of an eye. In one case, it killed an engine, then the rebuilt engine on the shakedown drive.
Almost every RX8 will have a coolant warning light. The level sensor jams. Ignore it and check the level on the bottle. Keep an eye on your coolant because the engine runs hot, and overheating will warp the housings. Otherwise, it's an annoyance. Some people modify their fans to kick in at lower temperatures.
Don't buy the automatics. They're shit. The 4-speed is a slug. And even the 6-speed auto looses power compared with the manual. The good manual ones have a 9000rpm redline. The basic manuals have a 7500rpm redline and are down on power by 30-40bph.
Which leads to, don't buy the cars that've been babied. If it's never been above 4000rpm it's had to easy a life. The engine carbons up at low revs and needs some good high rpm running to keep from fouling the plugs, or jamming the seals with carbon deposits. Don't worry about 'abusing' it. Let it rev freely - it's supposed to. Just don't stomp on it when its cold and it'll be happy.
Worthwhile modifications really work towards smoothing the rough edges. An ignition coil upgrade and a dwell remap reap wonders. A Sohn adaptor can help the engine, as can grounding kits or similar. Otherwise, be wary of any power claims from any intake kits or cat-backs - the standard system is good. You might get some power from a header kit - but Mazda's already taken all the low-hanging fruit. The engine comes from the factory in a very high state of tune so there's not much to do that's cheap.
Shit that's gone wrong on mine in the last year... well.
A fouled sparkplug killed an ignition coil, which killed the catalytic converter. I'm now running upgraded coils and a decat (Woo! Flames!)
A pothole broke a droplink
Needed new brakes through wear and tear.
Carboned up the MAF to the point where it struggled to beat 20L/100km running painfully rich.
Backed into a Volkswagen hidden in a cloud of smog.
Had a sticker from a concerned anonymous complaining about the environmental impact of my car stuck to the back window...
Blew a shock around Mondello
That's basically it.