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Mazda RX-8



  • trispectrispec Posts: 305
    I don't see why the cops would be detered from just downloading the entire contents of the "Black box" the moment they walk up to a car. Hell, the U. S. cops, with all their new powers of electronic searching, probably have been doing it already, and are just waiting to spring it on us.

    Pulling tin foil down over my ears, I am.
  • rorrrorr Posts: 3,630
    The way I see it, when the insurance company sells a policy for a specific make and model of car, they may do it with the understanding that they have access to the vehicle data which describes what was happening immediately prior to an accident.

    It might be fun explaining to an insurance company why a data recorder was intentionally disabled. And then it might be fun explaining to that insurance company why they should still honor your policy.
  • pathstar1pathstar1 Posts: 1,015
    No, a battery in good condition will hold for at least a month. It's not a small battery in the RX-8. Do keep the battery clean - I like to wash the top every time I wash the car. Do also once a year check the fluid level (if you can) and top up with distilled water. If you can't (cells sealed) cest la vie - that's life.

    Once again, unless Mazda has snuck one in lately, the RX-8 doesn't have a recorder. Further, if you disconnect the battery for a few minutes, you will erase any trouble codes stored in the PCM (engine computer).

    If you want to worry about surveillance, turn off your cellphone.
  • I just received a Recall on my 2005 RX-8 for the Emissions and I wonder if I take it in and they reprogram my computer and stuff are they going to make my car run any different that I can notice. It is saying I could have carbon build up and my plugs and converter could get build up. Any word on all this. Thank You
  • plektoplekto Posts: 3,738
    The car eats cats by its nature and it should be considered an expendable piece of equipment(and designed so it's as generic and simple to replace as possible, IMO, but that's another story).


    The engine by design burns oil. Think of it as a 3-stroke engine(which is actually what it is - heh). 4-strokes optimally burn no oil, and 2-strokes burn oil mixed with their gas. This burns some oil via blow-by(somewhere between a 2 and a 4 stroke engine), but it's *NORMAL* for the car to run this way.

    Mazda needs to hammer this home with massive campaigns or notices or something. But it also needs to use a $200 cat that's attached to nothing at all(O2 sensor and such well away) and cover them under their warranty)

    Unfortunately, oil damage cats over time, and there's nothing that can be done about it. Diesels do this, too, which is why they didn't have cats on them for decades.
  • pathstar1pathstar1 Posts: 1,015
    The rotary engine doesn't burn oil from blow-by. It injects it into the intake runners under computer control. It's true the oil is necessary, to lubricate the apex seals. Unlike a piston engine the rotary seal running area (the rotor housing) isn't exposed to the crankcase, so oil can't be "splashed" onto it from there. Also, because of this there can't be "blow-by" in a rotary. When the rings in a piston engine wear, the combustion gases can leak into the crankcase, overpressuring it, and forcing some oil back into the combustion chambers (on the intake cycle). In a rotary, worn apex seals just leak the gas into the next chamber.
    The rotor is "filled" with oil - the engine uses it to cool the rotors. Any leaks along the side oil seals will add too much oil to the combustion chambers. This may be the area that Mazda is worried about and is testing for.

    All manufacturerers must, by law, install a cat. that will last a certain number of miles. This is what Mazda is struggling to meet, by eliminating oil that can leak into the exhaust system, and carefully controlling the oil that is injected into the intake. Hence the computer control of the oil injector system. In the case of the renesis, there is further need to limit this oil - too much and the side exhaust ports will plug with carbon.

    Cats that can stand oil are just now coming on stream. They burn the carbon/heavy hydrocarbons in pulses something like an impulse jet engine. They are what will make diesel engines more acceptable in the US. They may also be what will save the renesis from extinction. I'll bet they aren't going to be cheap though. ;)
  • plektoplekto Posts: 3,738
    My bad about the way it burns oil, but the fact that they do burn oil normally is sometihng that the public needs to know about. That, and that the thing eats normal cats.

    So they should make the cat as simple and inexpensive as possible, then cover it under a 100K year warranty.

    It fails smog? Run it over to the dealership and they'll install a $200 cat(their cost) and you're good to go.

    I'd still own a RX-8, even with it burning oil.
  • pathstar1pathstar1 Posts: 1,015
    I don't think you understand. If the cat can't go the required distance, Mazda can't sell the RX-8 in your country. If they can't sell it, they will not make it. I agree your idea is good, it's just not possible under the current regulations in the US.

    The rabbit hole is much deeper than you imagine, grasshopper. ;)
  • plektoplekto Posts: 3,738
    I'm positive that they can get a waiver if they cover it under the warranty, since it's a different type of engine entirely.
  • trispectrispec Posts: 305
    Ouch. I found the document below via a google search (catalytic converter warranty). Is this still correct? If so, I can sure understand why Mazda is worried; 8 years or 80K miles on a cat seems very tough for the RX-8.

    Is the EPA document below what you sort of what you were referring to?


    United States Air and Radiation EPA420-F-96-020
    Environmental Protection March 1996

    Office of Mobile Sources
    EPA Environmental Fact Sheet




    The Performance Warranty covers repairs which are required during the first 2 years or 24,000 miles of vehicle use because the vehicle failed an emission test. Specified major emission control components are covered for the first 8 years or 80,000 miles. If you are a resident of an area with an Inspection and Maintenance (I/M) program that meets federal guidelines, you are eligible for this warranty
    protection provided that:

    * Your car or light-duty truck fails an approved emissions test;and


    Design and Defect Warranty Coverage for 1995 and newer light-duty vehicles:

    * Emission control and emission related parts are covered for the first 2 years or 24,000 miles of vehicle use; and

    * Specified major emission control components are covered for the first 8 years or 80,000 miles of vehicle use.

    According to federal law, an emission control or emission related part, or a specified major emission control component, that fails because of a defect in materials or workmanship, must be repaired or replaced by the vehicle manufacturer free of charge as long as the vehicle has not exceeded the warranty time or mileage limitations for
    the failed part.


    What Are Specified Major Emission Control Components?

    There are three specified major emission control components, covered for the first 8 years or 80,000 miles of vehicle use on 1995 and newer vehicles:

    * Catalytic converters.

    * The electronic emissions control unit or computer (ECU).

    * The onboard emissions diagnostic device or computer (OBD).
  • pathstar1pathstar1 Posts: 1,015
    That's just the warranty. The EPA requires all vehicles sold to have cats. that -WILL- last the 80,000 mi. Some failures are to be expected, covered by the warranty, though I'm not sure if any allowed numbers are quoted in the law or ruling if it isn't a written law. If the manufacturer can't meet this, they can't sell the vehicle in the US. BTW, Canada has said "us too" to this ruling.

    No-one is allowed to change the cat with anything other than the stock approved part either. We have, using a Random Tech. 5" metallic one (and now revealed as guilty as charged ;) ). This uses a strip of stainless, impregnated with platinum and rohodium, crimped to a zig zag, rolled up and inserted into a stainless canister. They work, they last with higher temps., and being "high tech", I think they work better (three way cat, takes out hydrocarbons, CO and NOx). I even put one on my 3rd gen RX-7, replacing a mid-pipe, with no loss of power. They are called "ultra high flow cats". We had to use them on the RX-8 when we messed with the fuel mixture to get more power, as that overheated the stock cat.
  • plektoplekto Posts: 3,738
    are covered for the first 8 years or 80,000 miles of vehicle use

    They don't have to last any period of time. They just have to be covered free of charge by the company(which of course is a bit of a problem, since it's a chunk out of their profits)
  • trispectrispec Posts: 305
    BTW, I got my Extended Warranty Letter last week. I jumped on the site to check if there had been any updates to the "Recall warning" that was listed in the "Owner" section of the Mazda site three weeks ago. It now seems that MazdaUSA has pulled the "Recall warning" down and replaced it with the standard "No recalls for your vehicle."

    Was that a mistake on the web site, or is that normally how they tell folks about recalls on their vehicle?

    PathStar, did you say your RX-8 rotor side seal went bad. Is there an actual seal substance, like the Apex seal, on the sides of the rotors? Or is the oil in the rotor providing the seal? How does the rotor oil circulate?

    Sorry, I guess I need to buy a model of the Renesis.
  • pathstar1pathstar1 Posts: 1,015
    No, we think our metering oil pump failed. The failure sounded like an eccentric shaft bearing failure, though (which wouldn't be related to the metering oil pump). Of course Mazda never told us what they found when they got the engine back.

    The oil is pumped into the eccentric shaft - there is a hole in it that feeds the oil to the centre of the rotors. On each side of each rotor there is a circular seal just outside the sun gear. It's pressed into the side of the rotor. This keeps the oil from getting into the "side seals" and "corner seals". These two plus the apex seals keep the combustion gas in the chamber. The oil seals keep the oil in the rotor, and it lubricates the eccentric, which the rotor pushes on to turn the eccentric shaft. It also cools the steel rotor. Power is transmitted by the rotor pushing the eccentric - so you could say the "stroke" of the engine is the major diameter of the housing minus the minor dia. There are "stationary gears" that the rotor rides on (rotor has a sun gear on the edge of the centre hole - this keeps it in phase and aligned as it moves around but the rotor doesn't push against it to transmit power although there is reaction force against it - the stationary gear acts like a planet gear).
    The oil is pumped from the sump through the filter into the rear of the eccentric shaft, it flows through a hole into the rear rotor, then out another hole in the eccentric shaft to the front rotor, then out another hole to the front end of the eccentric shaft, and is dumped through a pressure regulator back into the sump. In this way all moving parts are lubed. except the apex seals, corner seals, and side seals. They get their lubrication from the oil that is injected into the intake stream. A very simple design in concept.

    Lots of people like to say the rotary is a "two stroke" engine. Mazda says it's a "four stroke" - I think it should be called a "continuous combustion" engine. It sounds like a two stroke because it is "piston ported" (rotor ported but whatever).
  • plektoplekto Posts: 3,738
    How about three-stroke? ;) It definately needs a classification that puts it in a category by itself. Peolpe think "Rotary" and these days it might as well be "VVT" or some other term to them. They think it's a different application of the same technology 95% of the time, since 4-stroke gas engines are all they've every known.
  • trispectrispec Posts: 305
    Agreed. The confusion is rampant. What should one tell the government agencies or even the automotive techs? In Boston, the inspection folks needed to know how many cylinder. The computer program needed an answer before it could continue processing my inspection sticker. So now, the government of my state officially thinks I drive a two cylinder car. I hope this does come back to bite me when I go for an EPA test where they stick that probe up the tail pipe.

    I can hear it now, "Well sir, that two cylinder engine you've got there is way out of spec, I can't allow you back on the road until you replace that engine completely."
  • jeffyscottjeffyscott Posts: 3,855
    The confusion is rampant.

    I read a review, don't recall where, that complained about the small displacement of the engine. Pay no attention to how the car drives or accelerates, just look at that 1.3L displacement number and say "that's small".
  • plektoplekto Posts: 3,738
    Well, antique technology from nearly 200 years ago is huge. ;)

    All that metal and wasted displacement. Of course you need 5L or more to get good results out of a 4-stroke engine. It's a hopeless kludge that's been made to work.

    Compare its efficiency to a rotary or better yet, a turbine engine. :)
  • rorrrorr Posts: 3,630
    Actually, to my (twisted) way of thinking, a two-rotor would be equivalent to a V6.

    Think about it. Three lobes (roughly akin to cylinders) x 2 rotors.

    Of course, that's not really fair to a V6. For every SINGLE revolution of a rotor, you get 3 power pulses (one for each lobe as it spins within the housing). So, for a two rotor design, you get 6 power pulses per revolution. But for a 4 stroke motor,you need TWO complete revolutions of the crankshaft for each cylinder to generate a power pulse. So, for a V6 engine you only get 3 power pulses per revolution of the crank. For this reason (rotaries use ALL their displacement in every revolution while piston engines use HALF of their displacment in every revolution) I've heard it said that a 1.3l rotary would be roughly analogous to a 2.6l V6.

    Another question regarding displacement:

    Is the displacement of a rotary engine the total displacement within the housing minus the displacment of the rotor itself? Or is the displacement measured as the maximum volume achieved within each lobe at the rotor spins x 3 lobes x 2 rotors?
  • pathstar1pathstar1 Posts: 1,015
    The rotor spins at 1/3 the eccentric shaft speed. So for every rotation of the eccentric shaft you have two chambers fired for a two rotor engine. It's the same as a four cylinder four stroke piston engine. A three rotor is the same as a six cylinder engine. BTW trispec, that's what you should tell the pollution guys. It's equivalent to a four cylinder four stoke. If they are able to pick off a spark plug signal, they would see the RPM match.

    As far as displacement, each rotor face displaces 654 cc. Times two gives just over 1300 cc. This is really unfair though. The Euopean racing authorities call it a 2600 cc engine, probably based on full displacement of piston engines occuring over two crankshaft rotations - equivalency needed for racing fairness. Again, I differ from the norm., I think it's really half way between the two, or about 1950 cc. The problem is caused by the rotary being a 1/3 ratio whereas a four stroke piston engine is 1/2 ratio. If you count all rotor faces (three eccentric shaft rotations) it is 3900 cc. But that's just getting silly. ;)

    The rotary is not "more efficient" than a piston engine. It's hard to compare the two, but the telling way is fuel efficiency. I challenge you to beat a piston engine. Best vs best, the piston engine will win. Even matching HP and/or weight. The rotary IS smoother. It used to be able to rev. higher, but no longer. Now we have streetable Hondas reving just as high as the renesis. I don't think a racing rotary will be capable of 19,000 RPM like F1 engines for quite a while.
  • trispectrispec Posts: 305
    I guess what has captured me is the unique place in history that the Rotory Engine holds. Against colossal odds, a unique design, of amazingly beautiful simplicity, keeps popping back onto the scene in an industry which is so brutally competitive, it's a wonder that human beings can survive the design and production process of any cylinder combustion engine.

    Come on folks, a single person use to be able to build an engine. A NASCAR pit crew guy I use to know, once described to me the process, of tearing down an engine and re-building it for a race. By comparison, a rotory engine is no more complex than a model airplane engine. Well not quite, but the picture is there.

    I high rev it through the streets of Boston on a fairly complex daily commute. I don't worry about over torquing through a turn. I don't worry about over revving the engine. And I do love the jet engine wirrr sound up shifting 1st to 2nd off a 6K RPM rev where a I paddle shift with no shift shock!!!!!! :) No piston eninge at any price, behaves like this. And I could reasonalbly rebuild it myself (well if pathstar helped).
  • plektoplekto Posts: 3,738
    So in reality, 654cc times three, times two(dual rotor) = 3924CC. This would be according to 4-stroke standards, where they take the maximum area times every cylinder, despite the fact that each cylinder isn't producing power all at once, either. The ratio isn't considered - just maximum displacement.

    Mazda's numbers are off, IMO - and make no sense, plus they hurt sales. A 3.9L rotary engine that put out 210+HP and got ~20mpg, that's not so unreasonable in people's minds. Even if they figure 2/3 of 3.9L, to be fair(since the rotary has less compression/chance in displacement per face when it cycles), it would be 2616cc. A 2.6L 210Hp engine with 20mpg - again, not too far off.

    That said, rotary engines are more efficient than 4-stroke, but not as efficient as 2-stroke. Hence, why I like to call the three-stroke engines. :) Mazda, though, isn't really pushing the limits on this engine. With a turbo added, it would scream(or better yet a belt-driven supercharger) 300hp and suddenly its smoking a 350Z. :)
  • jeffyscottjeffyscott Posts: 3,855
    A 3.9L rotary engine that put out 210+HP and got ~20mpg, that's not so unreasonable in people's minds.

    I don't know about that...350Z has 3.5 liters, 300 hp, and 19/25 mpg.

    Rotary and 2-stroke are not more efficient in terms of fuel usage, they do produce a lot of power from a small engine.
  • rorrrorr Posts: 3,630
    Okay pathstar1, you've officially made my head hurt.

    When I see 9k rpm on the tach in a rotary, is that the eccentric shaft speed or the rotor rpm? (I'm thinking now that is the eccentric shaft speed so 9k rpm would actually be 'only' 3k rpm for the rotor itself).

    Okay, now I can see the relationship between a 2-rotor and a 4-cylinder; yeah, that's the best analogy.

    I think that what's wiggin' me out is the difference in the rotational speed between the rotor and the eccentric shaft; I still can't wrap my mind around it. After your description, now for some reason I'm picturing a 3.9l 4-cylinder making it's peak 238 hp at 3000 rpm. You're right, that's just getting silly. Because THAT analogy would indicate a mountain of torque. And we KNOW we're not getting that out of a Renesis.

    Personally, I think the rotary's biggest advantage is packaging efficiency. It's physical size (dispite just HOW one goes about measuring displacement vs. a piston engine) really frees up the engineer to place the powertrain low and back in the chassis. Personally, I don't give a rip about 'hp/displacement' arguments or whether it drinks fuel like a 2.6l (or 3.9l).

    I've always liked the idea of using the drivetrain out of a wrecked RX-8 for a really quick Lotus 7 knockoff.....
  • pathstar1pathstar1 Posts: 1,015
    Correct, indicated RPM is eccentric shaft speed. Rotors are turning at 1/3 that. Just visualize the "sun/planet" gears - the sun gear on the inside of the rotor, and the planet gear on the - housing, actually. It's called a "stationary gear", and it is - it's bolted to the housing. That's where the 1/3 ratio is from.

    The rotary Lotus has been done. I suspect you could even buy one (or a kit anyway). Not sure you could register it though. There is even a very active rotary aircraft group.

    The rotary is best suited for racing. Reason is it's so easy to rebuild and so tolerant of overreving. It's difficult to get one to work "on the street" and meet pollution requirements. Based on Mazda's travails with the RX-8. Just look at all the extra "stuff" jammed into your engine compartment to get the engine to meet the requirements. Part of the reason the 3rd gen RX-7 was pulled from the market (other than Japan) was the pollution requirements.
  • trispectrispec Posts: 305
    Most streets and highways in New England are in awful condition. Even when a road is resurfaced or re-built, often paving quality is rough, bumpy, and badly joined to existing surfaces and curb siding. Add to these conditions, lots of cold wet spray from rain and slushy snow, and you got a nightmare commute situation through out the various metro areas across seven states.

    The RX-8's more forgiving suspension and low torque Renesis, is a huge advantage. Adding snow tires or all seasons, round out the package. So, unless there's 4 or more inch's of fresh snow, the RX-8 is going to go just fine.

    Any other sports car or even near sports car, Z's cars, 'Vetts, 'Stang, etc just turn into scary torque bouncers and spinners. Even near exotic cars get in trouble. An M6 paired up with me on a particular bad road construction that involve train tracks running down a street. The torque from his 390HP V8 was loosing it every time he hit a rail.

    I've driven lots of cars in my lifetime. Nothing even comes close to the pure joy of my RX-8 with it's very practical little features and stunning all around balance and performance for a relatively low price.
  • trispectrispec Posts: 305
    Wouldn't a Renesis bring the price of this street ready F1 racer down to an even more reasonable level? Especially if the $13K transmission is replaced with the standard Mazda 6 sp auto with paddle shifters. Probably wouldn't go 205MPH, but the package might still provide enough well over 100MPH thrill for any track.

    How about the mind blowing image of the Caparo T1's aerodynamic down force enabling travel upside down in tube tunnels at 150MPH. Ala MIB :shades:
  • I read in the Mazda 3 forum that Mazda is releasing a product that will let you connect your ipod to the factory stereo (and keep the use of the steering wheel audio controls).

    Will this product be compatible with 07 RX8's??
  • I'm looking for a car that'll last me at least 5+ years. is the rx8 a car i should be looking at, or should i go towards the mazdaspeed6?
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