Is my perception of RX-8s a reality?
11-22-2008, 03:31 AM
#76
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Actually the rx8 has an identical cooling system to the FD. The oil coolers are identical as far as I can tell, and I would not be surprised if the radiator were not identical as well. At least it is very, very similar within a couple of inches. The twin e-fans are similar if not identical. They run the same thermostat temperature. The only difference would be the fan switch-on temperature which is said to be lower with the rx-8. The only other difference is that the rx8 has fewer vacuum hoses and solenoids to fail, and there are no twin turbos or intercooler to take up space and create additional heat. Therefore this engine should in theory run cooler with fewer long-term issues.
In reality, the average FD engine expectancy for a stock setup was 50-75k miles, and honestly many rx8s are not even making it that long.
For a different reason, though.
7500? F- that. Try 2500-3000. Recommendations be damned, trust me on this one. If you follow mazda's recommendation of 5-20 for 7500 miles at a time, you will have a rough looking engine when it has to come apart. That sounds like rotary suicide to me, and I am a rotary engine builder.
Maybe when driven on a circle track or on a dyno? On average renesis seem to be failing in the 50-80k mile range at this point. Not all of them, probably not even half, but probably somewhere in the 25% range is my best guestimate. The engine itself is CAPABLE of doing 300k or more, but IN ITS CURRENT IMPLEMENTATION of mazda's PCM programming, lean OMP mixture, shitty cat life and coils that fail every 25k miles, it is unlikely that most will make it past 125k-150k at best. I didnt say ALL, I said MOST, as in more than 50%.
In reality, the average FD engine expectancy for a stock setup was 50-75k miles, and honestly many rx8s are not even making it that long.
For a different reason, though.
7500? F- that. Try 2500-3000. Recommendations be damned, trust me on this one. If you follow mazda's recommendation of 5-20 for 7500 miles at a time, you will have a rough looking engine when it has to come apart. That sounds like rotary suicide to me, and I am a rotary engine builder.
Maybe when driven on a circle track or on a dyno? On average renesis seem to be failing in the 50-80k mile range at this point. Not all of them, probably not even half, but probably somewhere in the 25% range is my best guestimate. The engine itself is CAPABLE of doing 300k or more, but IN ITS CURRENT IMPLEMENTATION of mazda's PCM programming, lean OMP mixture, shitty cat life and coils that fail every 25k miles, it is unlikely that most will make it past 125k-150k at best. I didnt say ALL, I said MOST, as in more than 50%.
11-22-2008, 02:02 PM
#80
kevin@rotaryresurrection
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While there are definitely engines failing earlier than they should, the 100k mile warranty does help provide a bit of a safety net for most RX8 owners. In addition running a higher viscosity oil with additional injection and/or pre-mixing seems to help longevity significantly as well. With the stock NA setup for the RX8, the cooling system does not seem to be the weak link from what I understand. Insufficient oil injection especially in the center of the apex seals which was supposedly addressed by the new injectors on the '09 models is blamed for a lot of the troubles.
Not every (or even most) engines that fail are due to improper maintenance, but the bulk at least anecdotally seem to be '04 models and AT versions moreso than the MT versions.
11-22-2008, 02:14 PM
#81
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and while the cooling systems are similar, I did say the FD had an insufficient cooling system, it was insufficient for a twin turbo setup which generates a lot more heat!
as far as oil is concerned, I agree with you on the 5w-20, I run 10w-30 (would like to go thicker in the summer but not sure if the injectors could handle it at higher rpm's), I do however wait the recommended 7500 miles, I top off my oil every other tank of gas and even at 7500 miles it still looks nice and clean because it's constantly burning it off... if I were racing I'd do it a lot more often but I don't see it as an issue in the normal commute.
Remember that rotaries tax the oil supply FAR greater than "normal" cars. Oil not only lubricates in our engine, but it does up to 40% of the cooling as well. And not only that, we have cars that are geared pretty insanely, like an older MR2 or something, so we regularly spin 4 or 5 grand consistently. This heats up the oil a LOT. Consistent heat breaks down the lubricating properties of oil.
Also note that rotaries CAN fuel-dilute the oil. On rx8s this does not seem to be too much of an issue. Probably because of the much more precise fuel injection control, and the cutoff ring helping oil sealing. However it is still possible given the design of the rotary, to get fuel diluting the oil supply, and making it less able to do it's job. Go ahead, pull out your dipstick and walk away from the car a couple of feet, and tell me you don't smell a bit of gas on there.
So why take the risk of running oil that has seen a lot of heat and potentially begins to break down, or oil that is even 5% gas diluted over all those miles, and potentially begins to break down. About 15 bucks is all it costs to prevent even the possibility of this.
with the programming, I believe you're mistaken... Mazda runs the car on the rich side to prolong cat life...
11-22-2008, 02:21 PM
#82
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I basically agree with all of this, but I do not personally believe the revised OMP/injector on the 09+ will resolve the issues entirely. It will certainly help...how much, remains to be seen. I think it is like putting a band aid on a bullet wound. Maybe I will be proven wrong.
I actually know a lot more MT owners with replaced engines. My early build 04 AT made it 117k on original engine before I tore it down, and could have gone significantly longer in reality based on what I saw in teardown.
I actually know a lot more MT owners with replaced engines. My early build 04 AT made it 117k on original engine before I tore it down, and could have gone significantly longer in reality based on what I saw in teardown.
A couple of the '09 owners here have reported that the new engines seem to be using noticeably more oil than their previous RX-8s, which might be a good sign in terms of longevity...?
Last edited by PotatoSoup; 11-22-2008 at 02:24 PM.
11-22-2008, 08:05 PM
#83
Hey guys, I'm currently car shopping and the RX-8 seems to fit my criteria. Although I did some research and it sounds like a lot of people are having issues with the engine "flooding", I believe that it's a misconception and it really has to do with the ignition? Is it really a big problem with these cars? Is everyone encountering this issue? If this car is gonna stall out on me and I'm gonna have to call a tow truck every other day, then I will have to take the RX-8 off the list of potential cars I'd like to consider. Honestly, is this a car I can just hop in and go, or do I need to take extra precaution every time I drive this thing? There are so many good deals out there, and it almost seems like the RX-8 could be a good bang for the buck.
Basically, I want to know if these cars are as troublesome as some of the people on here make it out to be. Thanks guys
-Jimmy
Basically, I want to know if these cars are as troublesome as some of the people on here make it out to be. Thanks guys
-Jimmy
I've had better luck with Mazda products than with products from Nissan, Ford, Chevy, Isuzu (though it was cool for a while owning a car designed by Guigario), Plymouth, or Dodge.
In the interest of full disclosure, I should clarify that I have, historically, used 3000-3500 miles oil change intervals on all of my cars.
Last edited by longpath; 11-22-2008 at 08:19 PM. Reason: forgot to mention my default oil change interval
11-22-2008, 08:27 PM
#84
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Turn us overnight into one of the socialist scandinavian states? no. But, the intention of the far loonie left is to do it step by step- some giant, some not so.
As for a turn even more to the left necessary, do we need more morons like these:
http://www.youtube.com/watch?v=hxMIfannqg
How about Bill Clinton basically acknowledging the "scam" that effectively began under his administration:
http://www.youtube.com/watch?v=nTxT4jrIak
Bush's fault? Learn the facts, kid
As for a turn even more to the left necessary, do we need more morons like these:
http://www.youtube.com/watch?v=hxMIfannqg
How about Bill Clinton basically acknowledging the "scam" that effectively began under his administration:
http://www.youtube.com/watch?v=nTxT4jrIak
Bush's fault? Learn the facts, kid
11-22-2008, 08:43 PM
#85
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Turn us overnight into one of the socialist scandinavian states? no. But, the intention of the far loonie left is to do it step by step- some giant, some not so.
As for a turn even more to the left necessary, do we need more morons like these:
http://www.youtube.com/watch?v=hxMIfannqg
How about Bill Clinton basically acknowledging the "scam" that effectively began under his administration:
http://www.youtube.com/watch?v=nTxT4jrIak
Bush's fault? Learn the facts, kid
As for a turn even more to the left necessary, do we need more morons like these:
http://www.youtube.com/watch?v=hxMIfannqg
How about Bill Clinton basically acknowledging the "scam" that effectively began under his administration:
http://www.youtube.com/watch?v=nTxT4jrIak
Bush's fault? Learn the facts, kid
11-22-2008, 09:04 PM
#86
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and neXib, i apologize if you felt at all offended, insulted, or belittled by what i saw in some posts from the previous page, which is not representative of what all americans are like...
Last edited by REsuperD; 11-22-2008 at 09:06 PM.
11-22-2008, 09:57 PM
#87
And no, I don't take it personal either way.When it comes to these cars and oil changes and all. For me it's the point that do you want to save 50 bucks on delaying oil changes and having an engine failure being more possible, or do you want to take care of your car. I want the latter. I spend a shitload of money on my car.
11-23-2008, 10:42 AM
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No, because there were never any NA 3rd gens. I guess you mean 2nd gens, and yes I have seen some with over 200k as well. They are still the exception rather than the norm, as I have parted out a couple hundred 2nd gens in years past, and also built a couple hundred more 2nd gen engines. Average for the 88 and previous non turbo rotaries was 150-175k, and 89-91 was 125-150k. Some died earlier, some died later, the majority fall into those areas.
I would agree with that, but I was pointing out that the same exact cooling system found its way into this car as well. I would call it sufficient, but not by a large margin, for this application. I am not a track guy, but I would bet weaknesses show up in a hurry for track use.
I dunno man, I would still call that suicidal. I would never dream of stretching a rotary engine oil change past 3500 miles under ANY circumstances. Hell, I run full synthetic castrol GT in my denali, and even then I never let it go beyond 5000 miles. With the relatively low cost of oil (compared to dealership troubleshooting visits or parts costs) I just don't see the reasoning behing taking the chance. Oil is the life blood of the engine. 2500-3000 mile oil changes may be overkill, but with rotary engines you need all the help you can get for reliability's sake.
Remember that rotaries tax the oil supply FAR greater than "normal" cars. Oil not only lubricates in our engine, but it does up to 40% of the cooling as well. And not only that, we have cars that are geared pretty insanely, like an older MR2 or something, so we regularly spin 4 or 5 grand consistently. This heats up the oil a LOT. Consistent heat breaks down the lubricating properties of oil.
Also note that rotaries CAN fuel-dilute the oil. On rx8s this does not seem to be too much of an issue. Probably because of the much more precise fuel injection control, and the cutoff ring helping oil sealing. However it is still possible given the design of the rotary, to get fuel diluting the oil supply, and making it less able to do it's job. Go ahead, pull out your dipstick and walk away from the car a couple of feet, and tell me you don't smell a bit of gas on there.
So why take the risk of running oil that has seen a lot of heat and potentially begins to break down, or oil that is even 5% gas diluted over all those miles, and potentially begins to break down. About 15 bucks is all it costs to prevent even the possibility of this.
If you re-read what I wrote, I said "lean OMP ratio", not "lean FUEL ratio". Yes, mazda fattened up the fuel mix, but the oil/OMP injection ratio is probably too lean. Check out my "117k renesis teardown" thread for more information and visual proof.
I would agree with that, but I was pointing out that the same exact cooling system found its way into this car as well. I would call it sufficient, but not by a large margin, for this application. I am not a track guy, but I would bet weaknesses show up in a hurry for track use.
I dunno man, I would still call that suicidal. I would never dream of stretching a rotary engine oil change past 3500 miles under ANY circumstances. Hell, I run full synthetic castrol GT in my denali, and even then I never let it go beyond 5000 miles. With the relatively low cost of oil (compared to dealership troubleshooting visits or parts costs) I just don't see the reasoning behing taking the chance. Oil is the life blood of the engine. 2500-3000 mile oil changes may be overkill, but with rotary engines you need all the help you can get for reliability's sake.
Remember that rotaries tax the oil supply FAR greater than "normal" cars. Oil not only lubricates in our engine, but it does up to 40% of the cooling as well. And not only that, we have cars that are geared pretty insanely, like an older MR2 or something, so we regularly spin 4 or 5 grand consistently. This heats up the oil a LOT. Consistent heat breaks down the lubricating properties of oil.
Also note that rotaries CAN fuel-dilute the oil. On rx8s this does not seem to be too much of an issue. Probably because of the much more precise fuel injection control, and the cutoff ring helping oil sealing. However it is still possible given the design of the rotary, to get fuel diluting the oil supply, and making it less able to do it's job. Go ahead, pull out your dipstick and walk away from the car a couple of feet, and tell me you don't smell a bit of gas on there.
So why take the risk of running oil that has seen a lot of heat and potentially begins to break down, or oil that is even 5% gas diluted over all those miles, and potentially begins to break down. About 15 bucks is all it costs to prevent even the possibility of this.
If you re-read what I wrote, I said "lean OMP ratio", not "lean FUEL ratio". Yes, mazda fattened up the fuel mix, but the oil/OMP injection ratio is probably too lean. Check out my "117k renesis teardown" thread for more information and visual proof.
11-24-2008, 08:12 AM
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I also have yet to have the engine flood on me. The car for the price is absolutely a pleasure to drive and makes me smile every morning on my way to work.
11-24-2008, 08:18 AM
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I was also terrified of flooding every time I got into the car and to be honest, I haven't tested it 100% yet, I'm still too paranoid, why take the chance...I always just make sure the temp guage shows the car is warm before I shut it off so if I've only driven a block or so in cold weather, I'll wait a few minutes or rev it up to 3K to get all the excess out and then kill it.
An example of how rare I consider flooding to be: My friend and I both have '04s and we had another 8 owner over with an '06 Shinka. Well the Shinka would not start, we didn't know why. I looked at my friend and said "Do you think it's flooded? Do you know what that even sounds like?" He said he didn't, he'd never actually flooded his. I said me neither. Neither had the Shinka. (Turns out he was just out of gas and his guage was off.)
Something we all talk about and know about but probably few of us have actually experienced. The only person I know who has flooded theirs said it was because they turned it on in cold weather, drove it three feet down the driveway and shut it off. Makes sense. Just don't do that.
An example of how rare I consider flooding to be: My friend and I both have '04s and we had another 8 owner over with an '06 Shinka. Well the Shinka would not start, we didn't know why. I looked at my friend and said "Do you think it's flooded? Do you know what that even sounds like?" He said he didn't, he'd never actually flooded his. I said me neither. Neither had the Shinka. (Turns out he was just out of gas and his guage was off.)
Something we all talk about and know about but probably few of us have actually experienced. The only person I know who has flooded theirs said it was because they turned it on in cold weather, drove it three feet down the driveway and shut it off. Makes sense. Just don't do that.
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