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Mazda RX-8



  • ukjimukjim Posts: 63
    I wish I had seen that, but I have to question the F1 rotary racer part, companies spend multiple hundreds of millions of dollars to build an F1 race car and as far as I know the specs do not allow a rotary engine, and if they did, and it had an advantage, it would be on the track racing. :confuse:

    Just as a follow up, present day F1 spec 2.4 ltr V8 reciprocating engines revving to 19K and developing 800+ HP is far more impressive. :)
  • trispectrispec Posts: 305
    Sorry, I certainly don't know if the car was a real F1. Looked like one though. Anyway, I think the advantage of the rotary in a racing car is simplicity, cost of maintaining it, and the engines compact size.

    Clearly the racing V8s offer much more performance, but there's a big price tag. Normal folk probably can't afford to play, but I think anyone could swing a rotary racer for week end tracking.
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  • tslbmwtslbmw Posts: 172
    Have any of you attempted to put a carseat (front facing) in the back of the RX8? It appears by the naked eye that it would not be a problem, but I wanted to hear that from an owner.
  • trispectrispec Posts: 305
    It's no problem. Even easier to install in the RX-8 than most other four door cars I think. The car seat strap that connects at the top hook will put a little dent in the back seats little head rest bump though. The dent went away after a few days once the seat was removed.

    I used one of those styrofoam filled cushions under neither the car seat to prevent dent's and marks on the back seat itself. The styrofoam cushion helped lock in position plus it covered the entire back seat so as to provided a nice barrier to food particles and toy parts from falling down into seats crevises.

    The car seat was installed for 9 months, until my son got to 8 years.
  • tslbmwtslbmw Posts: 172
    Thanks for the info, that's great to hear. The kids won't normally be in my car, but we also want the option. My wife's Element takes care of most of the familial duties.
  • tslbmwtslbmw Posts: 172
    My commute to work is about 10 minutes, is that long enough for the car to "warm up." I understand this can be an issue and occassionally cause the car to not restart. Is this still the case with the '07's?
  • trispectrispec Posts: 305
    Watch the water temp. Once the needle is past the second line of the dial at the left, you RX-8 can be shut off no problem. I take a much shorter trip 3 minutes, than you every day and simply watch until the temp passes that second line.

    Also, revving to 3000 before shut off is also nice finish to any RX-8 drive, no mater how short.
  • tslbmwtslbmw Posts: 172
    That sounds easy enough. Thanks for the tips. I believe I'm down to just choosing a color!
  • plektoplekto Posts: 3,738
    Enjoy! I am thinking of one as well. The thing is, it's not an appliance. It's more like a motorcycle. You need to check the oil every week or so, inspect it, let it warm up a bit before driving it hard, rev it a bit before shutting it off - just like your typical motorcycle with carbs.

    Once you get into the habit, it's easy(I have had a lot of old cars with carbs so it's no big deal) and you should have zero reliability issues.

    Of the colors, the dark grey/anthracite looks the best, IMO. The sunroof is useless, though - it's too far back to even see out of while driving and kills your headroom. Pass. Also pass on the packages - get the limited slip/traction control individually. The low-profile tires and bigger rims don't help nearly as much as just getting better tires for less money. The ride is a little bit softer, too, which is always a good thing in a sportscar.
  • sonnysayshisonnysayshi Posts: 11
    Folks --

    I will buy a new car soon, have been reading about the RX8 for some time.

    I know about the flooding issue and oil burning in the 8, but recently read a concern about proper oil weight, that the rotary's parts can suffer if you don't use the right oil. Anyone, what works?

    And did anyone test drive a Speed6, then choose the RX-8? If yes, how come?
  • plektoplekto Posts: 3,738
    The thing is - it's not *burning* oil. The engine design is such that it requires internal lubrication of the seals, which means it's closer to a 2-stroke engine in design. There will always be oil consumption in rotary engines.(the same is true with diesels, too.

    The proper oil to run in it, IMO, is a semi-synthetic blend. Unlike typical engines, the idea of breaking it in and seating the rings doesn't apply. You want as little wear and friction as possible from day one in a rotary, so changing oil is also critically important. A lot of people think that they are fine letting it go longer, because in a 4 stroke engine, if it's burning oil, putting in half a quart every few weeks kind of makes oil changes moot.(filter aside). Not so in a rotary.

    It's a lot like a motorcycle. Have to warm it up, not rev it to death for the first few minutes, check the oil and fluids every week or so, blip the throttle when shutting it off... But the results you get from the RX-8 are well worth it, IMO.
  • maltbmaltb Posts: 3,572
    RX-8 vs Speed6...
    The best answer to the question is to drive them both for yourself.

    They are two completely different vehicles with completely different drivetrains. I really don't think you can compare the two.
  • sonnysayshisonnysayshi Posts: 11
    Sorry, should have avoided the word 'burning' -- do you use a specific brand of oil, and what weight? Thanks for the insight.

    I do intend to drive both the 8 and Speed6, just wondering if others already had done so.
  • plektoplekto Posts: 3,738
    No problem :) My cars all burn oil at this point - so there's normal "burning" and abnormal "burning" ;)

    As for weight, I don't know. I would suggest a bit of oil stabilizer in it, though. It makes a great deal of difference in my truck.(new, 1/4 of a quart would be about enough for a full oil change - mine uses a quart - lol)

    Oh - I currently have an old 4-runner until I can get something better this fall.
  • pathstar1pathstar1 Posts: 1,015
    This brings up a repeatedly misunderstood issue with the rotary engine.

    Starting with a piston engine, they do burn oil. If they used no oil the rings and cylinder walls would wear out very quickly. Oil is needed between the rings and cylinder walls for lubrication. It needs to be a very thin layer, or the vehicle would use too much and not meet emissions as well as disappoint owners. Hence the "oil rings" scrap most of it off, but what is left is burnt. Note that on piston engines the rings and cylinder walls are exposed to the crankcase, and oil splashes from there to the cylinder walls (some designs also feed oil directly there). If you measured the volume of oil you drained out at oil change time you would find it was down about a quart (after 3000 mi of use). If it's not down it's because you have gasoline in the oil making up the difference.

    Now for the rotary engine. There is no way oil can get at the equivalent of the rings (apex, corner, and side seals) and cylinder walls (rotor housing inner surface), as the rotor housings are continuous and the oil is held below them. So oil had to be injected into the engine along with the air and fuel. Getting this mixture "just right" has been quite an engineering adventure. Too much and you carbon up the works (NOT GOOD!). Too little and you quickly wear out the apex seals (the rotor housing surface is chromium and doesn't wear much if at all). Mazda switched to electronics to meter this oil in the 2nd gen RX-7 (1989), and has continued to use this method since. The Renesis engine has improvements over the 3rd gen twin turbo version with better electronics, but mostly in the nozzles that distribute the oil into the intake stream (trying to get the droplets small so the oil arrives more consistently - it's a very small amount of oil and surface tension makes it difficult to distribute the small quantities required).

    Mazda could have used a separate injection oil tank, like two stroke street motorcycles used just before they went the way of the dinosaurs (my Yamaha RZ350 and DT200 both use this method, with a metering oil pump). I suspect it was considered too complex and required too much faith that owners would keep enough oil in a separate tank, so engine oil was used, from the oil sump.

    As for the thought that the rotary is some kind of two stroke engine, it is not. It is a "continuous combustion cycle" engine. The misconception is easy to get due to the oil injection, and the fact that there are no valves, that the engine is "piston ported" (rotor ported actually). You can visualize the equivalence of four "cycles" however. Facing the front of the car, the rotors turn clockwise, intake occurs in the 9 o'clock to 11 o'clock part, compression from 11 o'clock to 2 o'clock, ignition from 2 o'clock to 4 o'clock, burning or power from 4 o'clock to 6 o'clock, and exhaust from 6 o'clock to 9 o'clock. The rotor turns at 1/3 the speed of the the "crankshaft" (eccentric shaft). Note the power part or burning of fuel occurs at the bottom of the engine. This was done just in case there was a coolant loss. The hottest part is the last to loose coolant.

    So, I think you'll find the RX-8 uses just a little more oil than an equivalent piston engine (one with 230 HP). I find it's not necessary to add oil between changes. The amount of oil carried is enough that the injected (and burned) oil decreases the level just enough that at change time you are down to "add oil" levels, but still safe to run.

    Do keep an eye on the level, however. Certain use methods can use oil faster than others. And you don't want to EVER overheat or run low on oil with a rotary engine!
  • plektoplekto Posts: 3,738
    Oh, I *know* it's not a 2-stroke engine. I was using that analogy because most people understand how one works and how it needs to inject a little bit of oil as it runs. And, yes, it goes through more oil than a typical new 4-stroke engine. But that's normal.

    I find it interesting that owners complain as if the engine is faulty somehow for doing what it should normally do. Mazda needs to put a page in the brochure and manual explaining how it works and why you need to add a little oil regularly(as opposed to every 3-5K miles in a typical 4-stroke engine). The engine also appears to have a much smaller amount of oil in it compared to a typical 4-stroke, so being a quart down is more of a problem whan when you have 8 quarts total.

    Me? I would have had a separate little tank and used a special oil. Less chance to get the thing messed up if the oil is always "rotary oil"(some specific weight/etc that works best). But I can also see a LOT of people doing zero maintainence on their cars and it dying as a result.

    Either way, it's reliable and fun if you do the preventative maintainence/checks every weekend.
  • fedlawmanfedlawman Posts: 3,118
    "Mazda needs to put a page in the brochure and manual explaining how it works and why you need to add a little oil regularly."

    You're assuming the average owner reads the manual...
  • pathstar1pathstar1 Posts: 1,015
    "The engine also appears to have a much smaller amount of oil in it compared to a typical 4-stroke, so being a quart down is more of a problem whan when you have 8 quarts total."

    Better look again. The RX-8 holds at least 5 litres of oil. You can't drain it all out, because it's held in the cooler and you also can't fully empty the oil pan. We fully drained ours once, and had to put in the full amount. Shocking! ;) I started calling it "the truck".

    Also, Mazda has played fast and loose with the dipstick, raising and lowering its' calibrations (full and add marks) a couple of times since introduction. So it's kind of hard to know when you -really- should add oil. If I'm near change time I let it run a little low. Some have stated you can actually run it a quart low with no problems. Don't try to race it like that though! In hard cornering, the oil -could- slop away from the pump pickup. That would be a "bad thing" (tm). ;)
  • sonnysayshisonnysayshi Posts: 11
    Pathstar, thanks for the knowledge . . . as an utter illiterate in regard to cars, I appreciate the help. What brand/weight of oil do you use when you change?
  • plektoplekto Posts: 3,738
    Better look again. The RX-8 holds at least 5 litres of oil. You can't drain it all out, because it's held in the cooler and you also can't fully empty the oil pan. We fully drained ours once, and had to put in the full amount. Shocking! I started calling it "the truck".

    Also, Mazda has played fast and loose with the dipstick, raising and lowering its' calibrations (full and add marks) a couple of times since introduction. So it's kind of hard to know when you -really- should add oil. If I'm near change time I let it run a little low. Some have stated you can actually run it a quart low with no problems. Don't try to race it like that though! In hard cornering, the oil -could- slop away from the pump pickup. That would be a "bad thing" (tm).

    You just made my point. :) The design of the engine tolerates a low oil condition much less well than a typical engine. So you have to check the oil every couple of weeks. Of course, if you have a bike or an old classic car, this is perfectly normal. A little extra work and you're good to go. But the RX-8 isn't a put gas and forget it Honda Civic, either.(and it's not washing machine bland, either :)
  • maltbmaltb Posts: 3,572
    To add to what Plekto said, when you run too low on oil, there are a couple other bad things that happen:

    The oil temp rises as there is less mass getting cooled in the pan.

    The anti-wear additives are being worked X times as fast (depending on how low the oil is).
  • articistarticist Posts: 9
    Hi guys. It's good to be back on the board and read about RX-8 owners' words :) . I had been on this board a couple of times, and last time I posted, I was about to ship my car to Korea from US. Now I have settled in my home country. I was a little concerned about bringing my RX-8 into Korea since there is no official dealer/service center. I still couldn't part from the red hottie, so took the risk. Overall, I am happy driving this exotic looker in the city where 90% of luxury cars are BMW. Just hoping there won't be any major issue.

    I am about to make an oil change for the first time since I came to Korea and have a little bit of problem :confuse: . The manual says I am supposed to use 5W20 and I remember sometime ago on this board that synthetic oil is not good for rotary engines. Well, there is the problem. Apparently, it is not easy to purchase regular petroleum 5W20 here. Synthetic 5W20's are sold in a specialized stores for racing car tuning but not petroleum oil. Just wondering if I can use synthetic oil at all. Or, petroleum 5W30, which I can also purchase here. If neither, I should order oil from overseas (which is whole another problem).

  • pathstar1pathstar1 Posts: 1,015
    It's just the US owners manuals that try to keep 5W20 in the car. In other parts of the world (less pressure for fuel economy) 10W30 is fine. I suspect the 5W30 non-synthetic would work well. You'd have to verify, but using the "wrong" oil can void your engine warranty, but I suspect you don't have a warranty in Korea.

    Please note, synthetic is also petroleum oil. It's just got certain petroleum molecules in it that don't occur in nature. They have to be converted from "normal" oil. In fact, these days, most synthetic oils have moved back to being very close to normal oil. It's expensive to convert to the group 4 molecules and they are using group III more often now (eg Mobil 1 has changed from group IV back to group III last I heard). I think Royal Purple, Redline, and Amsoil still make group IV, and the German Castrol was group IV as well. Don't know if it's still available. Only reason I mention this is many think the group IV works best in the synthetic world.

    Mazda allege synthetics will harden certain seal materials in the engine. Lots of people use synthetic oils with good results. As always, YMMV.
  • articistarticist Posts: 9
    Thanks, pathstar as always. I was actually panicking thinking that if I can't get the right oil for my RX-8, what if any thing mechanical goes wrong. You are right, I don't expect to have my warranty cover in Korea. They don't even have Mazda sales here.

    Anyway, after some extensive search for 5W20 non-synthetic, I did find a website which says they import such. I know you are in Canada, and this particular brand is Petro Canada. Is it a good oil? I think they have SL and ILSAC GF-3 seal.

    Thanks again.
  • pathstar1pathstar1 Posts: 1,015
    Petro Canada used to be Gulf Canada. They were bought by a Liberal govt. (Federal) quite a while ago and renamed Petro Canada. Eventually, they were sold back to private industry. I don't think their oil is much different than any other. The bobistheoilguy site is the best one to compare oils. They have more information on oil than you really want to know. ;)

    For example, I learned synthetic group III oil doen't harden seals like group IV and group V does. So if that's true, Mobil 1 would be fine in the RX-8.

    At any rate, I don't think you have to be really worried. As long as you stick to the grades specified by Mazda it should work just fine. The weights are not that critical, except for mileage. Especially if you are sure to warm the engine up before reving it or putting high loads on it.

    Mazda are walking a fine line re fuel economy in the US, hence the insistance on 5W20.
  • Folks --

    After reading about the RX-8 for two years, bought a 2005 Nordic green last week. Can't make the smile go away -- I'm wondering, when using the paddle shifters, is there an 'ideal' RPM level to shift from one gear to another? Is it the same to go 1-2, 2-3, etc.? Thanks for any help.
  • plektoplekto Posts: 3,738
    It depends if you are looking to maximize economy or performance.

    Performance dictates that you shift at 2/3 to 3/4 of maximum(bottom of the red/orange area) if possible and try to always maintain about 2/3 max rpm. this, as expected, kills gas mileage.

    Maximum mileage you want the thing to barely be moving - so never let it get over about 3000 rpm if you can. Yes, it will be glacially slow by comparison. And you might as well be driving a Civic.(ie - you get this car to DRIVE it)
  • Thanks -- haven't revved over 5K yet, afraid I'll maim something. 3K feels like cruising level, 4-5K acceleration and passing. Any more, I feel like I'm asking for extra attention from the authorities.
  • plektoplekto Posts: 3,738
    The redline for your vehicle is 7500, and that's due to the transmission not being able to keep up - so it's an artificially low number(the *engine's* redline is 9000!).

    (Automatic is limited by software to not blow itself up as opposed to the manual with is limited by software to not blow the motor up)

    When I have driven them I pound it up to 6-7k with impunity. It'll take a while for your ears to get used to hearing it whine like a sportbike. Of course, make sure it's properly warmed up before flogging it. Give it a mile or so to get going, sort of like if you owned a motorcycle.

    Any yes, it is a crazy fast car for the price. Wind it up hard and you're essentially getting the same results as a ten year old 911.(non-turbo of course)

    1995 Porsche 911 Cabriolet 6.4 14.5
    1997 Porsche Boxster 6.0 14.5
    2004 Mazda RX-8 5.8 14.49 (6 speed) (MT Mar '04)

    Yes, a real shocker. In manu-matic mode, expect to add about 1/2-1 second, which is still very very fast.
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