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I believe you 100% on the RX-8 housing wear.
The hi power 13B-MSP is a 9,000rpm engine and the revs wear housing chrome and apex seals exponentially as they increase.
Not to mention the compromises for emissions/gas mileage.
Mazda didn't even rev their factory race engines with ceramic seals and cermet housing coatings any higher.
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Anyways, the new 16X or whatever should be a nice low rev turbo motor and Mazda has already stated they have new seal materials and design as well as the revised oiling.
I'm not sure about the part in bold. The Rx-vision has a tachometer where the first red area starts at 8000rpm, while the solid red starts at 9000.
The Rx-8 had a similar arrangement with a first red area starting at 8.5k and fuel cut at 9000 rpm, where the "solid" red started. The series 2 Rx-8 had the same arrangement, with the addition of the variable rev limiter during warmup, a feature that I 100% expect to find in the new car.
A direct comparison of the tachometers would indicate that the engine in the Rx-vision should rev to the same 9k fuel cut as the rx-8, even though the redline is 500rpm lower.
And in 2012 Mazmart seemed to confirm that the new engine will still be 9000rpm-capable (link 1 and link 2), even though things could have changed by then.
its a dummy model, the tach could say 20,000 RPMs but still not offer any actual truth.
there's no stereo either, which would make it a pretty damn boring car if it was as accurately depicted once sold.
Good point. But then, the fact that Mazda didn't use an absurdly high redline in the tach of the Rx-vision, but actually decreased it when compared to the one on the Renesis brings in some more credibility. Just a little bit
Low rev turbo meaning makes it power in the lower rpms so it will spend its life at lower rpm.
Its like on my EFR powered TII- you feel the same acceleration shifting at 6,500rpm and getting back down into peak torque as winding it out to 8,000rpm- so it is natural to shift early.
Occasional trips to 8,000rpm will do the motor no harm (even on 3mm stock apex seals I have found).
Living at 6,000- 9,000rpm because that is the only place you have power will wear the apex seals much faster.
Wear is exponential as rpms increase.
Case in point- my 4 port auto RX-8 makes a little more power than the high power 6 port from idle to 6,500rpm.
6 port RX-8 makes 30hp more by reving from 6,500rpm to 9,000rpm and so it is geared to make the most of that.
4 ports "die" of carbon fouling leading to low compression.
6 ports die of seal wear leading to low compression.
Low rev turbo meaning makes it power in the lower rpms so it will spend its life at lower rpm.
Its like on my EFR powered TII- you feel the same acceleration shifting at 6,500rpm and getting back down into peak torque as winding it out to 8,000rpm- so it is natural to shift early.
Occasional trips to 8,000rpm will do the motor no harm (even on 3mm stock apex seals I have found).
Living at 6,000- 9,000rpm because that is the only place you have power will wear the apex seals much faster.
Wear is exponential as rpms increase.
Case in point- my 4 port auto RX-8 makes a little more power than the high power 6 port from idle to 6,500rpm.
6 port RX-8 makes 30hp more by reving from 6,500rpm to 9,000rpm and so it is geared to make the most of that.
4 ports "die" of carbon fouling leading to low compression.
6 ports die of seal wear leading to low compression.
Oh, you mean in that sense. Then yes, I completely agree.
What do you guys think will happen to do the value of clean OEM FDs if a new car comes out?
For better or worse any new RX will be very different from any rx7. It might remind people that rx7s existed and bring a little more demand to the market but with the 25year import rule, supply will increase as well.
From what I've read the past week it sounds like it will be NA and considering 1st gens are still running its a smart move for reliability. The secret sauce may be a small electric engine (similar to CRX setup) to increase low end torque and HP while keeping emissions lower (that's from years ago reading). For it to compete with the 370Z they would want 350hp to go against the Nismo unless they do a Mazdaspeed version to match it.
And burning clean 2 stroke oil rather than dirty 4 stroke oil should also help with emissions, so...
the 12A engines had a spec that was 2.5cc in 6 minutes @2000rpm. it would be safe to say the oil injection has zero effect on emissions, its such a small percentage of the gasses that go through the engine.
also Mazda did a study on just where the oil is going, and thus the new engine should do a better job of lubricating the parts that need it.
three, if your crankcase oil is that dirty, you could change it... you know that the bearings and such that live in the oil usually come out looking pretty good, so even dirty oil can't be that bad, you'd have other problems, like failing thrust bearings and such
the 12A engines had a spec that was 2.5cc in 6 minutes @2000rpm. it would be safe to say the oil injection has zero effect on emissions, its such a small percentage of the gasses that go through the engine.
also Mazda did a study on just where the oil is going, and thus the new engine should do a better job of lubricating the parts that need it.
three, if your crankcase oil is that dirty, you could change it... you know that the bearings and such that live in the oil usually come out looking pretty good, so even dirty oil can't be that bad, you'd have other problems, like failing thrust bearings and such
Yeah, I know about that study. It was found that most of the oil is lost through leakage past the oil control bands due to deformation of the side plates.
And then Mazda released a patent showing a way to solve that problem: drill a few holes on the sides of the rotor just to the inside of the outer oil control band to allow accumulated oil to flow back in the rotor, thus reducing the accumulation of oil behind the bands and, hopefully, reducing the leakage.
Probabily I should have used the word "used" rather than "dirty". With "dirty" I mean that the oil has already been used over and over again, and thus it may contain some combustion residues and other elements (hence "dirty") that degrade its performance. In this sense, even an oil that was changed just 10 miles ago is "dirty" when compared to new oil.
The purpose of the oil filter is to prevent unwanted contaminants to enter the oil circuit, but no filter is perfect. It's not like the oil that comes out of the oil filter is identical to new oil that has just been poured in the oil pan. If the oil in the pan is starting to lose some of its performance, then what comes out of the filter will not have regained those lost characteristics.
So, even if using crankcase oil to inject it in the combustion chambers is good enough, it's undeniable that using fresh oil can only be better. Especially if this oil is an oil that is specifically designed for being injected in the engine (2-stroke oil).
It may allow a reduction of the injection volume, as the designers could count on the performance of fresh oil at all times.
As for emissions, the injected amount may not be large, but with the ever-tighter emissions every little bit helps. Plus, one should also consider how (in)efficiently that small amount gets burned.
With the figures you report (2.5cc per 6 minutes at 2000rpm), assuming an average speed of 40km/h (what I regularly see reported by my car, including all the time that the engine is running, even if the car is not moving), I compute 6.25l (around 1 1/2 gallons) of oil required to go 10000km (about 6000 miles). With a reduced injection amount thanks to newer materials, it shouldn't take a giant oil tank to go from one oil change to the next.
Probabily I should have used the word "used" rather than "dirty". With "dirty" I mean that the oil has already been used over and over again, and thus it may contain some combustion residues and other elements (hence "dirty") that degrade its performance. In this sense, even an oil that was changed just 10 miles ago is "dirty" when compared to new oil.
The purpose of the oil filter is to prevent unwanted contaminants to enter the oil circuit, but no filter is perfect. It's not like the oil that comes out of the oil filter is identical to new oil that has just been poured in the oil pan. If the oil in the pan is starting to lose some of its performance, then what comes out of the filter will not have regained those lost characteristics.
So, even if using crankcase oil to inject it in the combustion chambers is good enough, it's undeniable that using fresh oil can only be better. Especially if this oil is an oil that is specifically designed for being injected in the engine (2-stroke oil).
so the used oil is used because it has combustion residue in it, which makes it fine with bearings, but bad in the combustion chamber?
i do agree that they might find an oil that is better for seal lubrication, and or burns cleaner.
in terms of the problems with the rotary, this is a rather small one.
so the used oil is used because it has combustion residue in it, which makes it fine with bearings, but bad in the combustion chamber?
i do agree that they might find an oil that is better for seal lubrication, and or burns cleaner.
in terms of the problems with the rotary, this is a rather small one.
Maybe I'm reading this wrong, but oil is not good for the bearings BECAUSE it has combustion residue. It is good DESPITE containing combustion residue.
Same for the oil that is injected in the combustion chamber.
I'm not a mechanical engineer, but it is fairly safe to assume that if an engineer could rely on a continuous supply of fresh, never used before oil, he'd prefer to use that to lubricate something rather than reusing the same oil over and over again.
Obviously an unlimited supply of new oil is not easy to come by, so the usual solution is to recirculate the oil. Again, not because it's better for the part needing fubrication, but because it's good enough and vastly more practical (and cheap) for the end user.
The main problems for the rotary, as perceived by the general public are:
(not necessarily in this order)
A good lubrication system can make sure that all parts are adequately lubricated, thus reducing wear (problem #1) and friction (problem #2), and at the same time reducing and/or eliminating problem #3 (if there's no need to top up the oil between oil changes, then this problem can be considered solved for all practical purposes IMHO).
It may not be the the key to solve all of the problems of the rotary, but sure it can help with a few of them. Perhaps not in a decisive way by itself but every bit helps.
Maybe I'm reading this wrong, but oil is not good for the bearings BECAUSE it has combustion residue. It is good DESPITE containing combustion residue.
Same for the oil that is injected in the combustion chamber.
I'm not a mechanical engineer, but it is fairly safe to assume that if an engineer could rely on a continuous supply of fresh, never used before oil, he'd prefer to use that to lubricate something rather than reusing the same oil over and over again.
Obviously an unlimited supply of new oil is not easy to come by, so the usual solution is to recirculate the oil. Again, not because it's better for the part needing fubrication, but because it's good enough and vastly more practical (and cheap) for the end user.
exactly, an engineer needs to do something that is practical, and cost effective while meeting the targeted service life, and in a minimal amount of time.
really old cars had a 'total loss' lubrication system, but not only is it a mess, it doesn't work!
The main problems for the rotary, as perceived by the general public are:
#2 is definitely true. in the 80's and 90's the rotary was ok, but the piston engine has gotten a lot better since the mid 90's.
#3 i haven't found to be particularly different than a piston engine, sure the rotary is a bit low when its time for an oil change, but its time for an oil change.
#1 is a whole mixed bag, and mostly there is a double standard. when a Mazda breaks its the end of the world, but when you have to re-engineer your whole BMW just so the suspension stays in it, its cool. i work in the industry, so i see it, but i don't understand it.
#3 i haven't found to be particularly different than a piston engine, sure the rotary is a bit low when its time for an oil change, but its time for an oil change.
exactly, an engineer needs to do something that is practical, and cost effective while meeting the targeted service life, and in a minimal amount of time.
really old cars had a 'total loss' lubrication system, but not only is it a mess, it doesn't work!
Hmm, let's see: a 5 cylinder, 4 stroke engine with 5 independent exhaust stacks running a total loss, premix-only lubrication system with 18% oil in the fuel. Yeah, I think I know how messy a total loss lubrication system can be
But never as bad as with the little 5cc single rotor that I have in my avatar. That thing runs on 25% oil, mostly castor oil. The exhaust almost contains more liquid than gases
(sorry for the giant pic)
Back on topic:
I was just trying to say that if an engineer could completely ignore all other factors (cost practicality etc.) and only had to concentrate on designing the system providing the best possible lubrication to a part, he'd most likely use an once-through system, where the part always gets fresh oil.
Back to the real world, obviously an oil recirculation system is FAR more practical when it's possible to implement it. But if one has to run a total loss system (as with the rotary for the combustion chambers), then why run it on used, possibly contaminated oil, especially when designing it to run fresh oil should not be that difficult? You get the worst of both worlds, that is the need to top up the oil periodically, the (possibly) degraded performance from using already used oil and you are forced to run the same oil type both for the circulation and the total loss systems. Also, the sump has to be larger with the current cranckase oil injection system, so you also get longer oil warmup time due to having more oil to warm up.
Originally Posted by j9fd3s
#2 is definitely true. in the 80's and 90's the rotary was ok, but the piston engine has gotten a lot better since the mid 90's.
#3 i haven't found to be particularly different than a piston engine, sure the rotary is a bit low when its time for an oil change, but its time for an oil change.
#1 is a whole mixed bag, and mostly there is a double standard. when a Mazda breaks its the end of the world, but when you have to re-engineer your whole BMW just so the suspension stays in it, its cool. i work in the industry, so i see it, but i don't understand it.
Notice that I specified "as perceived by the general public". Just do a search for "rotary oil" and among the first results you get is "Did they fix the reliability and oil consumption for Rotary?"
I think Mazda is going to release the next rotary as dual fuel Hydrogen and gasoline hybrid.
Tokyo is trying to build a "Hydrogen society" and is starting by showcasing hydrogen power at the 2020 Olympics as they did the Shinkansen high speed rail in 1964.
Running off gas and Hydrogen as transition vehicle is something the rotary can do as Mazda has proven with the RX-8s they leased since 2006.
Mazda also showcased this duel fuel concept with the addition of a turbo in the past.
Luckily for us California is also building up its Hydrogen infrastructure.
Maybe the Hydrogen fuel tank is what is under that long RX-Vision hood in front of the engine (liquid Hydrogen is slightly less than 1/10th the mass of gasoline- so bulky, but not heavy)?
Back to the real world, obviously an oil recirculation system is FAR more practical when it's possible to implement it. But if one has to run a total loss system (as with the rotary for the combustion chambers), then why run it on used, possibly contaminated oil, especially when designing it to run fresh oil should not be that difficult?
good point! i've always wanted one of those r/c engines, so cool. real Rx7's have been cheaper so far though
Notice that I specified "as perceived by the general public". Just do a search for "rotary oil" and among the first results you get is "Did they fix the reliability and oil consumption for Rotary?".
another good point, they fixed the oil consumption in the 80's, reliability has been a mixed bag though. one of our old customers (he flew for the Luftwaffe!), had a 1971 Rx2, that he bought new. and he had gone to the factory and taken the tour and met Mr Yamamoto.
compared to his Rx2 the FD had 3 times the power, and 2x the gas mileage, but reliability was about the same, engine life is/was about 8 years/80k miles.
actually i kind of think that part of the problem is that with the rotary, when the engine has a problem, you just change it, and keep driving. and this is very different from other cars, particularly the German ones, where an engine job is this giant nightmare
I think Mazda is going to release the next rotary as dual fuel Hydrogen and gasoline hybrid.
Tokyo is trying to build a "Hydrogen society" and is starting by showcasing hydrogen power at the 2020 Olympics as they did the Shinkansen high speed rail in 1964.
Running off gas and Hydrogen as transition vehicle is something the rotary can do as Mazda has proven with the RX-8s they leased since 2006.
Mazda also showcased this duel fuel concept with the addition of a turbo in the past.
Luckily for us California is also building up its Hydrogen infrastructure.
Maybe the Hydrogen fuel tank is what is under that long RX-Vision hood in front of the engine (liquid Hydrogen is slightly less than 1/10th the mass of gasoline- so bulky, but not heavy)?
Honestly, even if the engine may be advertised as being "hydrogen-ready", I doubt that Mazda would release a car with a hydrogen fuel system. Even if it's a dual fuel vehicle, for 99% of the buyers the hydrogen part will be unused, and thus just dead weight.
The dual fuel capability may be good on a concept and, maybe, for a limited production version of the car, but not for the main production run IMHO.
And putting a high pressure hydrogen tank under the hood doesn't sound like a good idea to me. What happens in a crash? Pinto take 2?
Originally Posted by j9fd3s
good point! i've always wanted one of those r/c engines, so cool. real Rx7's have been cheaper so far though
Do you mean the piston or rotary model engine?
Originally Posted by j9fd3s
another good point, they fixed the oil consumption in the 80's, reliability has been a mixed bag though. one of our old customers (he flew for the Luftwaffe!), had a 1971 Rx2, that he bought new. and he had gone to the factory and taken the tour and met Mr Yamamoto.
compared to his Rx2 the FD had 3 times the power, and 2x the gas mileage, but reliability was about the same, engine life is/was about 8 years/80k miles.
actually i kind of think that part of the problem is that with the rotary, when the engine has a problem, you just change it, and keep driving. and this is very different from other cars, particularly the German ones, where an engine job is this giant nightmare
Yes, exactly. I really hope that Mazda does a good job with the reliability of the new engine. Their statement about their intention to do 3 times as much testing as other cars is a very good sign.
#2 is definitely true. in the 80's and 90's the rotary was ok, but the piston engine has gotten a lot better since the mid 90's.
#3 i haven't found to be particularly different than a piston engine, sure the rotary is a bit low when its time for an oil change, but its time for an oil change.
#1 is a whole mixed bag, and mostly there is a double standard. when a Mazda breaks its the end of the world, but when you have to re-engineer your whole BMW just so the suspension stays in it, its cool. i work in the industry, so i see it, but i don't understand it.
my honda insight uses about 1/2 quart of oil in the 12,500 factory service oil change interval. the oil pan holds about 3 quarts.
it gets upwards of 70mpg without doing crazy things to get it
they need almost no maintenance for 100k, then you change the plugs, adjust the valves and service the EGR system and drive for another 100k
the battery is the worst part of the car though, since NiMH batteries don't last forever. battery maintenance is almost required unless you want to spend $3k for a new battery like we spend $3k on a new engine every so often.
Last edited by RotaryEvolution; 02-18-17 at 08:06 AM.
What do you guys think will happen to do the value of clean OEM FDs if a new car comes out?
Most likely bump the price of the FDs a bit, on the extreme side the FDs might get a huge spike in price as people start collecting them like all the other 90s era JDM hero cars. Either way I'm sure it will bump the price of the FDs.
02-04-17, 05:48 AM
