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Mazda RX-8 Problems and Solutions



  • moadhmoadh Posts: 15
    Thanks a lot pathstar, uve been a great help!
  • pathstar1pathstar1 Posts: 1,015
    Great, got it started? I suspect your friend doesn't understand you have to warm it up before shutting it off - that is, see the temp. gauge move up. The latest flashes (program for the engine computer) seem to just about eliminate the flooding, but if someone tries hard enough, you can still flood an RX-8.
  • pathstar, my husband wants to put a twin turbo on our 2004 RX-8 six speed manual. do you see any cons or future probmatic conserns that could happen with doing this? I have heard that it really uses up a lot of it very loud to do this? is it worth the effort/cost?
  • trispectrispec Posts: 305
    Here are a few additional bits of information about the popcorn/rattle noise that my 2005(group 2) RX-8 AT makes.

    1) On cold starts, the popcorn/rattle will start instantly if I put the transmission into reverse gear immediately. If I wait a minute or two before putting her in gear and for the high pitched fan noise (automatic choke mode?) to stop, the popcorn/rattle will not start until a mile down the road.

    2) If I drive will the RPMs religiously held around the 3000 level, the popcorn/rattle is minimized. when I get stuck in stop and go traffic, Huntington Ave in Boston at 5:00pm, the popcorn/rattle is much more noticeable.
  • trispectrispec Posts: 305
    Oops, forgot this one.

    3) If I'm driving in first gear at a constant speed at a high rev 5000, there is no popcorn/rattle, but the moment I shift to second, without letting off the gas, I'll here the popcorn/rattle for a few seconds. It's almost like there's too much gas flowing through the system and it takes a few seconds for the computer to balance things. Now if I attempt to smooth the shift shock (love that nissan add :)) by letting off the gas on the shift to second, there is little to no popcorn/rattle.
  • pathstar1pathstar1 Posts: 1,015
    The high pitched fan noise is probably the electric air pump. If you open the hood and start it you can locate that it's coming from the air pump.
  • pathstar1pathstar1 Posts: 1,015
    I can't say if putting a twin turbo on your RX-8 is worth the effort/cost. That's for you to decide. I wouldn't even try, but that's based on my personal situation. I don't see the point, unless you plan to race it and have sponsors, because what you will end up with is a "race car".

    Here's why:
    1. The renesis engine in the car is a "high compression" engine. It's very difficult to get a turbo charged rotary to last when the engine is low to medium compression - it's going to be trouble with a high compression engine. So to do it properly, you'd have to lower the compression ratio (machining of the rotors - i.e. rebuild the engine for turbo use).
    2. Adding turbos will presumably add a lot of HP and torque. That's why you do it. The stock transmission and differential will not hold the added torque - they can barely stand the stock power. So you will have to deal with that - different transmission and diff.
    3. You will have to add a different engine computer to control the air/fuel ratio, such as a "Motec". The stock PCM just isn't designed for boost. You will have to leave the stock PCM connected to the car if you want the stock instruments, antilock brakes, and DSC to work.
    4. The stock cooling system will not handle the extra heat - you will have to change the front of the car to add more airflow and will need a larger radiator.

    Based on experience with the 3rd gen RX-7 engine "upgrades", I suspect you will end up spending between $20,000 and $30,000 by the time you're done getting it reliable. It would take probably 2-3 years of "tinkering". Don't even think about using the car for "general use" during this time! It'll be down most of the time. Oh, and you'd better have a very good "tuner" lined up to help!

    Sell the RX-8 and buy a car with equivalent power to what you will end up with and it will cost less. A BMW 3 series, or Lexus IS350 come to mind. Both are heavier and don't handle as well, but that's what comes with that level of power with reliability. Or wait and see if Mazda bring back the RX-7 - if they do it would likely have the power and handling you appear to want.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,454
    good analysis.

    Why not just buy a second car, a 3rd gen RX-7 Twin Turbo. You can get a nice one for maybe $15,000, and it'll go as fast as you'll ever need for 1/2 the price of your modifications to an RX8. Worse yet, that RX8, once modified, will never be worth any more than a stock car, while the older RX-7 TT will hold its value.

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  • trispectrispec Posts: 305
    The June issue of Car and Driver had a write up on a turbo kit for the RX-8. I called these guys up and spoke with the lead engineer. They are based in Austin TX and as it turns out, I'm taking a trip down to Austin at the end of this month. I'm going to go check out their shop to really see what the heck they're doing. These guys say 340HP at 6000 RPM and 80% torque increase beginning at 3000RPM is possible. $10,000 for their full system, including the second PCM and intercool.

    Still to much for me, and I'd never take any of the risks Pathstar talks about. But having the bragging rights to even the possibility of creating a monster road burner out of my tame RX-8 is worth something to me.

    I'll post the visit to their shop here. Hopefully there will be pictures.
  • pathstar1pathstar1 Posts: 1,015
    Just to underline what Mr Shiftright opined, if you purchased a used 3rd gen RX-7, you'd get 325 HP (what mine is running - in conservative tune), and torque increase starting at 2000 RPM. In a 2800 lb car. They go for $15,000 for a nice one these days.

    And just to underline what I opined above, a few days ago I "tested" my cat. converter - to do this you open the throttle and watch the boost gauge to see the second turbo transition. A plugged cat. will prevent this from happening. Went from 70 km/hr to 160 km/hr (100 MPH) in 4 or 5 sec. - on a road with a limit of 80 km/hr. That's jail, isn't it, or at least a mandatory appearance before a judge?
    Just what we all need, a race car on the street!
    Oh, and the cat is working fine. ;)
  • trispectrispec Posts: 305
    Wow, not that I can really appreciate the full experience of 325 HP and real torque at 2000RPM. What kind of engine life would one expect out of a used TT RX-7 at $15K. Is that a re-built rotary 13B. Are 13B's expensive to re-build?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,454
    I think rotaries in general need a higher standard of maintenance than most Americans are capable of, but if you DO that maintenance, they can be very reliable and rewarding.

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  • pathstar1pathstar1 Posts: 1,015
    The 3rd gen engine is highly stressed - so much so that the heat it generates boils the coolant in the rotor housings, forming tiny bubbles in the coolant.
    On other forums the reliability is discussed a lot. General consensus is the 3rd gen engines last 100,000 mi if not abused by sloppy mods for extra power. Rebuilts don't last as long - perhaps 50,000 mi if done right. A Mazda rebuilt is $3000 or so from the "best sources". Expect another $1000-$2000 for installation (labour, new parts such as hoses, etc.). Don't forget the turbos! They will last perhaps about the same, though many say half as long. They cost $2500 or so for the set.

    If you do it yourself, it can cost as little as $1000 to rebuild a rotary, but it is more typical to approach $2000. It's not hard to do, as there are few parts. Lots of measurements to check though. If the rotor housing is worn or the chrome surface damaged, you just buy a new one or a good used one. Ditto for the rotor. The apex, side, and corner seals as well as the gasket set and sealant are the common parts all rebuilds need.

    Just so you don't panic, the last "normally aspirated" rotaries, the 2nd gen RX-7s, have engine life averaging 200,000+ mi. The second gen turbo engines averaged about the same as the 3rd gen.

    Moral is, "If you want to play, you have to Pay!"
  • trispectrispec Posts: 305
    I remember my dad having the 70HP engine in his 1965 VW bug rebuilt for $250 back in 1972. So a $1,000 here in 2006 to re-build a 200HP rotary seems very reasonable.

    Is the Renesis built with significantly more expensive parts? The rotors are lighter, but are they of some exotic material or machining?
  • pathstar1pathstar1 Posts: 1,015
    As far as I know, the engine design is very similar parts wise. Rotors are still cast steel. They've redone the internal "bracing", and that, I think, is how they lightened them. Maybe they are using new casting technology. Those rebuilding the older rotaries are starting to use the renesis parts, because they are more "evolved" (better) - apex seals for example. So I don't think there is any real change cost wise (other than the standard inflation). The funny part is rotor housings for the older engines were in short supply because Mazda's casting plant was overbooked making renesis rotor housings.

    Having an engine suddenly become popular again is not all good. ;)
  • moadhmoadh Posts: 15
    I have a 2004 MT RX-8.. im at around 44,000km now and the clutch is still quite healthy (although there seems to be a little vibrating action going on lately). I understand that a clutch's life depends on how driver handles it, but in approximate measure.. how much longer can the clutch survive? also, is there anything else besides the wheel, cover, and bearing that i need to replace the clutch?
  • Now they are recalling all the 2004s, 2005s and some of the 2006s for new engines if they don't pass a vacuum test. Hopefully the new engines will not be :lemon: s
  • Thanks pathstar for the reply as always. To report the progress and for another question: I was going to bring my car to the dealer 3 weeks ago, but the guy from the service told me to make sure I can replicate the phenomenon at will. Otherwise, my trip would be worthless. The fact was that some days I couldn't really feel the vibration. Then I remembered somebody telling me if I can scratch the tires, the clutch is healthy. I wasn't trying to scratch the tires but one day from a slight uphill, I did. So I was waiting to see more symptoms. I did notice when I feel the vibration there was a slight decline of power.

    A couple of days ago, at one point when the engine was warm, starting took a couple more seconds than usual. Remembering one of the threads on this board about starting warm engine, I thought it was nothing to worry about. But finally today, I encountered the real problem. I managed to start the warm engine, but immediately RPM got down to 5~600 and the car vibrated. Check engine light flashed, too. I reved the engine and somehow engine RPM settled to normal range and I was able to drive it away. However, check engine light stayed on. While driving it home, a couple of times I could feel the loss of power with light flashing. Each time I reved the engine and the car ran okay. I tried to keep the RPM high with lower gears. Now there is no question I will have to bring the car in, but can you tell what the problem is from this description?
  • pathstar1pathstar1 Posts: 1,015
    Many possibilities. Could be a bad coil. It's still on warrenty so I wouldn't be too concerned.
  • pathstar1pathstar1 Posts: 1,015
    Well, we just got our "recall letter". That site is full of it. The "recall", in Canada at least, involves a free extended warrenty.

    Even if it was as the site mentioned, why would anyone complain? You would get a free new engine when you've put, what, 30,000 to 50,000 miles on the one you have now. I don't see the problem!
  • lhesslhess Posts: 379
    lots of scoop on the "other" forum that our engines will be replaced with remanufactured ones. I was really worried about that. I have an early (july 03 build) 04 and just knew I was gonna be one of the "lucky" ones, even though I have had 0000000000 problems outta my car. My car has less than 9K miles.

    However, if they're gonna replace with NEW engines where necessary, I feel better!!

    Keeping my fingers crossed that Rex got good guts from the factory and I don't have to think about it any more!!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,454
    Nothing wrong with a factory remanufactured engine. Might even be better than a new one in that original defects are sure to have been corrected; whereas if they take something off the shelf, or make you an identical one to the one that gave up, well.......

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  • lhesslhess Posts: 379
    Maybe so, but there's a stigma that goes along with having a remanufactured engine and it certainly won't help resale numbers any.

    Also, if they haven't fixed the problem in the new ones, what's the point??
  • pathstar1pathstar1 Posts: 1,015
    Yes, we got the letter. Failure of "the test" will result in replacement of the engine. Little detail there, other than it's unlikely very many engines would be replaced. I mean, where would Mazda get them (the replacements)? They were short of engines just a year ago for production.

    Best part of this though, is Mazda is giving us all an extended warrenty. Free!

    I'm not sure I've "come clean" with all of you but our engine failed in 2004 - fall. We got the first RX-8 in Edmonton in late July of that year, as I recall. We think it failed from lack of lubrication (it sounded like a bearing failure, possibly caused by a metering oil pump failure), and we got a new replacement. Mazda never told us, of course, what failed. We surmize this because in hindsight, we realized we didn't have to add oil and didn't see the level drop for a while just before the failure.

    From the limited info. on the current issue, it's probably a different problem. Just the opposite. Oil leaking out of the engine and getting into the exhaust or something.
  • trispectrispec Posts: 305
    OK, checking the site under the owner profile, there is now a recall notice, where there has been none since I purchased my 2005 RX-8 AT last September.

    And now for my question: Is the popcorn/rattle I still hear related to the recall? I had just gotten over my worry over the friendly little noise from my engine/exhaust system.

    And the vacuum test, are dealers able to do it now? My RX-8 is in for the 15K service right now. Should I ask them to do it?
  • pathstar1pathstar1 Posts: 1,015
    I don't think your noise is related. It's oil out the exhaust damaging the cat. as I understand. That's probably why Mazda had to deal with it in this manner - pollution related.

    I'm not sure what Mazda's procedures are, but usually you have to wait for the letter for any recall related work. They call you, you don't call them. ;)
  • trispectrispec Posts: 305
    OK. I'll be happy about my popcorn/rattle. I use the sound to guage wheather I'm effiently burning fuel and let off the gas peddle.

    I add half a quart of oil every three or four fill ups. That seems normal from what others have said.

    You are correct I think about the dealers. My car is in for the 15K service now and when I asked them about the recall, they said it would be October at the earliest. They also said the focus is on cars in hot climates, Southern Cal, New Mex. Tx, Florida, etc.

    I've been in Texas for the last week. Texas has had 40 days straight of 100F plus in Dallas. Hot weather, can not be imagined, only experienced. Walk very slow and drive very fast is good advice down here.

    BTW, I went by the Austin based PTP shop to see their turbo kit. They didn't have an install to look at, but they say they are able to pump out 350HP on the AT. They just don't recommend driving over 6000 RPM for very long. Torque from 4000-6000 is 70% greater. $12,000 is what they recommend as the whole system, but there is a question about routing some pipe download below. They haven't done an AT yet. They don't lower in the Renesis the compression at all.
  • audia8qaudia8q Posts: 3,138
    it's unlikely very many engines would be replaced. I mean, where would Mazda get them (the replacements)? They were short of engines just a year ago for production.

    It looks like quite a few will be replaced...mazda has an engine reman. facility in the Carolina's where the Rotary engine gets re-manufactured.
  • mcusmcmcusmc Posts: 7
    Well we got our gorgeous 2006 RX-8 AT GT w/Nav in Winning Blue on August 9. We waited patiently since last August to order one, and as I noted before, we were just able to order the '06 on April 8. It is all we expected and more! We are really happy with it. I have a manual states to take care when washing interior rear window so as not to damage the antenna. If the antenna is in the rear window, what is across the upper portion of the windshield interior?
    I want to install a radar detector above the rear view mirror, but the suction cups would be on the material I previously mentioned. Thanks.
  • trispectrispec Posts: 305
    OK, I'm just a fifty year old kid, I know, but I've got to tell everyone about the repair really ugly dent in my RX-8. I was travelling 75MPH in the left passing lane and there was a loud bang from the front of the car. The bang turned out to be a deep quarter size dent and scatch right on the sexy crease of the fender, marring one of my favorite visual parts of the car. I couldn't get into the car without seeing the horrid dent.

    Mazda Gallery of Norword Mass told me $500 and said the reason for the cost was the entire panel needed sanding and clear coat edge to edge after the dent and area paint. I checked around and that was a reasonable price. It was totally worth. I feel like I just picked up a NEW car.
This discussion has been closed.