Wankel engine vs Piston engine

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posted on Oct, 10 2007 @ 07:43 AM
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With a hardened eccentric shaft, they can surpass the 10,000 mark 12-15k I have heard of before, now you ar talking F1 type revs on a car
but, you have to do a lot of other things such as larger primary and secondary fuel injectors.

I also wanted to comment on that animation ... the reason it has two plugs is for better and more thorough fuel combustion. the one on the bottom fires first, the one on top fires just a instant afterwards ... leading and trailing plugs and they have different gaps ... NGK plugs and they look different than any other plug I have seen. You buy the plugs on a hot or cold scale ... colder plugs if you run in higher rpms ... since the engine is hotter, it keeps the plugs clean ... hotter plugs since the retain more heat and help keep them clean on a car that is rarely driven over 3000 rpms (what a shame for a rotary).



Since that other video is no longer available ... here is a video of a 6 second rotary powered RX-7 6 second RX-7

not too impressive since it doesn't show the whole dragstrip ... so ...

here is another video ... a 2nd generatinon RX-7 with a LS1 vs a 3rd generation RX-7 with a rotary ... guess who wins
it even looks like the LS1 got a jump ... who said 8 is better than 2?



Ok, that is enough for now I suppose. I will try to keep up on this thread. I may need to refresh a few things here and there ... but I KNOW the difference between propaganda and reality on at least this subject




posted on Oct, 10 2007 @ 08:02 AM
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one more thing ... I think I may have confused the racing seals with the reliability mod ... I think ceramic might be for racing and cabon might be for increased longevity, usually on ported engines.

If it is turbo, as with any turbo engine ... if you have been using the turbo, let the car idle for at least a minute before turning it off, or longer. Buy a turbo timer, this way, you can turn the key, walk inside, and the car will shut off for you.


Of course, the RX-8 has no turbo, so no worries about that. Just use a quality oil, and do the maintenance as required.


I know most people use 87 octane in n/a cars, but, in rotaries, I chose to use the highest non-race octane (92/93) ... since, that rating represents the fuels resistance to (pre) detonation due to heat and pressure. I would rather play safe than sorry, and now, 15-20 cents a gallon doesn't make as much difference as it did when I paid 70 cents a gallon for regular. Though, if you take care of your care, and don't drive it really hard for long periods of time (running at 7000 rpms for 10+ minutes), not much to worry about.



I will leave with a couple personal experiences. My last RX-7 had headers ... when I would start it up, within a minute, the headers started to glow red (it was running a bit rich) ... and it would burn the grass underneath it. Emphasizing just how hot the exhaust is. In fact, it is so hot, glass packs only last minutes to hours. Special catalytic converters and mufflers made with steel guts is required. Another RX-7 in my youth, I stripped down, removed interior pieces, the top (was a cabriolet convertable), took off the a/c, changed to an electric fan, etc. ... well, we were stupid and removed the exhaust back to the catalytic converter. When friends would follow me, they said when I shifted at high rpms, they could see a flame shoot out, and occasionally, molten metal coming from the converter bouncing on the road. Needless to say, I drove like a bat out of shell back then ... redline at every shift, etc. I was used to playing with donuts and the gas hungry power of the monster big block vehicles with all the torque, so I was fully enjoying playing with all the high end horsepower at nearly 2-3x the revs as I was normally accustomed to in those big engines. In fact, my Pontiac 400 cid rarely had to go over 2000 rps when I accelerated that huge vehicle at a moderate pace.

I have sites you can visit for info, parts, mods.


I need to stop ... I haven't let my passion for cars out for quite some time



posted on Oct, 10 2007 @ 08:41 PM
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That doesn't change anything I said my friend.

They still use a lot of oil, you've explained why that's normal but it doesn't change the fact that they go through tons of it. And the NEW RX-8 still has this problem.

And they DO have problems with their apex seals. Even the NEW ones. Granted not nearly as much as the old. Its one of the things these engines are infamous for.

So how does that make me ignorant? :p



posted on Oct, 10 2007 @ 09:06 PM
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I think all and all you guys are claiming rotory superiority, but fairly noting its drawbacks. Its been a good read.

Im still convinced that the straite cylinder engines have much better responce. Im not wrench jocky, but after watching coutless video's and reading numerous articles, the Supra is the best built drag car capable of the largest modifications, and the Skyline R34 is the ultimate race car. Both use strait piston engines.

The rotory is cool, and capable of good power, but not without jumping double the amount of hurdles needed to get the same out of a straite engine.


its too bad that we couldnt see the time on that drag someone posted earlier.

this one does show the final time

www.youtube.com...

This Supra was for sale by owner, too bad we missed it. 1520 hp at the wheels with a single turbo pushing 60psi.

www.youtube.com...



posted on Oct, 10 2007 @ 11:33 PM
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what makes the supra engine so great is ... its ability to handle HUGE/SICK amounts of boost and not blow up too quickly. Chalk one up for toyota on that block.



I found it ignorant to paint the rotary like it is junk, when, the problems lie in the owners, not the engine. I would say, for an engine that has had a fraction of the R&D, money, and time spent on it ... it does quite well. But of course you don't think of that. btw, did you know rotaries are used in some generators, planes, boats, and even rc toys? They have never stopped production of the rotary ... the year they ended the RX-7 in Japan, was the year they introduced the RX-8. There used to be a 3-rotor family car offered overseas, people buy them now and put them in their 7s. One company, makes a Bonzai edition here in Florida using the 3-rotor.


Some engines are made poorly ... I was in new cadillacs that had poor idles and made noises engines shouldn't. They told the customers it takes 10-20,000 miles for it to stop ... yeah, because it wears out, not breaks in. Give me a honda or toyota piston over a domestic piston anyday for daily driving and most other uses ... for the strip though, some good, even if short lived and high-maintenance, american muscle please. Nothing like a 400+ cid engine to rip tires off of a rim


You also fail to mention how many problems people have with piston engines who also don't take care of them. Let's see, all three of my RX-7s had the original engine, ran like a charm and each were above 100,000 miles. One was over 200,000 miles. So ... please, if I don't believe your rotary slander, it is because of personal experience. Yes, I know people who have blown motors, but, they ABUSED them ... these people also abused their piston cars and blew them up too.

Now, let me tell you, I don't know how my ex's 7 was still running. She had it for a year, never even checked the oil. I pulled the dipstick out and it was thick, black, and only on the very tip of the stick ... though it was still running years later when she sold it (after I taught her to check her fluids and such). They are more resilient than you put off ... or even I am claiming ... but, I thought I would lay out the fault, which is, the driver not being A) a responsible driver and B) responsible with maintenance ... which is required for ANY vehicle to truly run the best the longest. Even a supra would break if you abused it enough. I know my 454 bent a rod just driving it slowly to work one morning. Things happen, even if you DO take care of it.

I also have known piston engines to go through oil. It isn't unheard of you know. I never claimed rotaries were perfect, but you darn sure wish to claim piston superiority and infallibility ... that isn't so.

I claim they are both good, something you seem to have a lack of ability for. Respect each thing for it individual strengths and cater to its weaknesses ... pistons are heavier and thousands more moving parts (rotaries have only 3 main moving parts on the engine. the gear, the shaft, the rotor.


So, you whole argument is a quart of oil every 3000 miles (OR LESS), and, user error. With mine, I always needed an oil change before I needed to add oil, unless I was stupid and raced it around for a thousand miles or so. Almost always had a 1/4-3/4 left in the 'good' area of the dipstick.

Way to win an argument that really isn't there, since, I avidly support both engines. I miss my big block ... I miss my rotary ... do you understand yet? Oh, I also support hybrids ... moreso Honda's, but hey, saving gas is a great thing. Going 2-3x as far on the same amount adds up over the year, and adds up faster as gas price increases.

btw, you can actually stop the rotary from injecting oil and use a small amount of 2-stroke in your gas tank ... now that removes your argument of burning oil your motor oil.


Actually rotaries have a better engine response ... if they are above a certain rpm. Stock configuration and torque on the older ones makes take offs from a stop a little doggish, but, at 2800 rpm it seems like the power just starts to get crazy, and, it revs like nothing else. blip the throttle and it soars to 7000 rpms. If you remove the power steering, a/c, stock fan, and put a lightened flywheel it is almost scary how easily that engine spins (remember, it is rotating, not reciprocating ... continuous motion vs reversing motion) ...

most of my piston engines I wouldn't dare take them to 5000 rpms very much, and most didn't rev too fast, but, they did rely more on low end torque, and that is a good thing. Torque is great for city driving with red lights and stop signs.


go back to that diagram ... each face of the rotor is in part of the combustion cycle at all times, that means for every 1 revolution each face provides power once ... or 3 power strokes per rotation. A piston goes up and down 4 times for one power stroke. The rotors are also staggered evenly, so that adds to the smoothness (from evening out the power pulses and countering the slight up and down in the chamber needed to facilitate the combustion cycle) ... just as piston engines do their complicated dance of which one is in its power stroke to keep it balanced. So, every time one rotor goes around, you also have two power strokes from the other rotor.




Here are some vids with times

2nd gen in the 11s

3rd gen in the 9s

2nd gen in the 9s (same as below)



8.22 run ... RX-7 FD3S (same as below)





I could go on.



But, I would rather not. I just wish you would open your mind and release your hate. You obviously don't understand it well enough, so, it is easier to dismiss it than to learn and comprehend. I don't care if you like them ... makes no difference. Again, I like both. I think the rotary could be much much better than it is ... so should the piston.

I will continue to debate you if you continue to smear the engine from naive dismissal. I have owned, played with, talked to, read online and have books at home I have read up on ... this wonderful, under-rated, mis-hated work of art of an engine.


Take care



posted on Oct, 11 2007 @ 12:25 AM
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im not sure if you were talking to me or not.

I was not aware that i said anything nagative about the rotor engine. I recognised your efforts to point out the cons for me so that i did not have to look. It was a compliment.


I was curious if you were comparing a rotor engine to ANY piston engine, or if you would make an exception to the straite piston engines which is BY FAR the more superior engine over rotor.

Yes other machines also use rotor engines, like say... lawnmowers...and stuff, nobody said they didnt work.

If you want fast responcive tourque you want a straite piston plant. rotors have high rpm, but that means squat if it takes too long to get there.

who uses a rotor engine? RX-8

who uses a straite piston engine? all generations of supras, BMW M3, skyline (9000 rpm), jaguar (pre-ford), cummings, and basicly any industrial power plant.

i realy dont care which one is better, but if you look at the industry and what worked, i think you will find your answer.



posted on Oct, 11 2007 @ 06:09 AM
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Originally posted by GradyPhilpott

Bear in mind that the Wankel engine hasn't exactly taken the world by storm and even Mazda only has one car in its stable that uses one.


Worked fine for WW1 aircraft and couple of tanks me thinks, I forget the benefits of our beloved 4 stroke at the mo.. Do know it has many many more parts so on paper rotary should trump. Think it may be due to the limited engine configuration.

IMO tho 2 strokes rule!! Beat any 4 stroke for power (if you match the cubic capacity) and I miss the smell of 2stroke oil in the morning. Prob is reliability (and irresponsible riders)



posted on Oct, 11 2007 @ 09:37 AM
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well, since you want to claim your opinion as fact, then so will I

the rotary IS a superior engine. Just because it isn't widely used doesn't make it inferior.

So,



Does that make you happy?



How about this, list all the cons of a piston engine ... I am waiting for a several post reply, because that is what you would need if you were honest with yourself.



See, I realized along time ago, piston lovers are like political extremists and nationalists ... they are so far in love with what they think is right, they cannot stand to allow any other thougth to cross their mind.

You want an example of this? Fine, look at how a mustang person despises a camaro person, even a camaro person despises a firebird person (and they are the same car with a few cosmetic differences). I dealt with that when I used to talk about Trans Am Firehawks, of course, you have the Camaro SS folks saying it is better ... but, SLP did BOTH the cars! Same car manufacturer, same tweaking company. LS6 vs Hemi. Supercharger vs turbocharger vs NA. American motorheads despise import motorheads. Basically you either own what they do, or they look down on you. I won't even start on the standard vs. automatic war!!! (stick for me)

It is actually ridiculous how people can't appreciate and respect others passions. In fact, it is silly how they can't appreciate it personally all the variety. They fill their life with pointless bickering. I was ashamed of my fellow car enthusiasts even as a teenager when this internet thing was first taking off ... the car chat rooms were filled with cross-hate ... only a few respected each other.

It is apparent you don't care to know the facts. Fine, your choice. It is a car. But, until you drive them, and see their potential, your saber rattling is ineffective.

How many stock piston engines produce 120 hp per piston? How many 1.3L piston engines produce 240 hp stock?

Ok, how about tuning? How many piston engines produce upwards of 2-300 hp per piston? Not many, but, most autocross, race, and drag rotaries do just that. In fact, you can seach autotrader right now and find a few RX-7s producing 400+ hp and completely street worthy and reliable.

Of couse, being blind, you couldn't see that.

Check this write up of why this pilot uses 13B Mazda rotaries for his planes: 13B replacement for plane

Of couse, honestly, I don't expect you to read the link, because, that is what someone with you argument rarely will do.

I never asked you before to love the rotary, or to own one, but, if you were my neighbor, I would love to own one just to show you they are reliable, how they perform, and the advantages.


See, yes, an older naturally aspirated rotary was a little sluggish off the line, but, the newer ones have better torque curves. The turbos have better torque curves. The 20B has an awesome torque curve, and that doesn't have a turbo.

But you know what, most 1.3 piston engines, don't have too great of a torque curve ... most 1.3L piston engines can't get off the line, not go very fast anyway.

The point is, you have been comparing large engine cars to a small engine car. How about comparing similar things? Well, the piston loses. Give me a 4-rotor, and I will SMOKE a 8-cyl ... and still be doing it with only 2.6L.

The 787B won the 1991 Le Mans, the first and only victory for a Japanese manufacturer. They outlawed the rotary from following seasons. In most racing there are horrible sanctions placed upon the car ... or you would see it running at the top consistently. That is fact. One of the things they do is forbid it to run against same sized engines, they are forced to run in a higher class. Like putting a stock MR2 against a stock Supra. Who do you think would win?



Whatever though, again, you opinion is just that. But, facts are better than opinions, but to have blind hate is ridiculous ... but a trend in today's society.


For me, I can take pleasure in rotaries, big blocks, small blocks, 6 cyl, 4 cyl, 3 cyl, 2-stroke ...

I plan to own one of each in the future, and have already owned most of them ... and one day maybe that Suzuki Hayabusa 1300 cc bike


No prejudice here. No hate. No discrimination. I will not be an Archie Bunker type towards anything.



I really just wish everyone could get along, respect things for what they are, appreciate their strengths and positive aspects ... and be happy for each other.

I don't hate on someone who doesn't know how to drive a standard. I think it would be a great experience for them to learn, but it is their choice. That is all I am saying. NO product is superior to the other really, they each are great in their own respects.

If you wish to play more, I will ... it is fine. I will argue till we are both blue in the face. If you say blanket statements, I will have fun doing the same. If you wish to discuss intelligently, that would be much better.

The weaknesses of each engine can be overcome ... but they both have them. Don't kid yourself.



Take care and have fun



posted on Oct, 12 2007 @ 06:30 PM
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All the rotary tech stuff is good to know. Although I think you forget about HP per dollar and I dont think this guy said he was building a drag car. Sure an RX-7 with a crazy rotary motor can run 6s but it wont get the daily grind done at all and I think you know this. Comparing the rotary RX-7 vs the LS1 RX7 is kinda apples and oranges, are they both modified per same dollar amount is the LS1 even modified? Also anyone who knows jack about the LSX series knows the old Camaro vs Trans Am rivalry died many years ago. Popular sites such as LS1tech are proof of this. These days a Camaro or TA guy will even give you props for shoving an LS1 in a Pinto.

My statements on the LS1 RX7 swap were purely based on a dollar per dollar though process. My TA ran 11.66 NA with a Cam swap and suspension components. I highly doubt you'll get a 13B to do that with the 900-1000$ I spent. There are also LSX motors running 10s all day long with 18-20mpg on the highway some even more. LSX power reliability and price < every other motor. I noticed you mentioned the Supra's block for stoutness. Forget to mention the 03-04 Conbra block doing the same thing and the 5.4L ford that runs 1140rwhp on the stock long block including factory MAF. Personally Im in the same boat as you I love all cars although my budget keeps me domesticly minded.

As far as stick vs auto, my personal choice, I have a 6spd in my SN95 mustang pulling street duty, and TH400 in my TA pulling drag duty. Drag auto pwns everytime no question.



posted on Oct, 13 2007 @ 01:54 AM
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reply to post by Kenpachi
 


6-speeds are great
and I agree, in drag, an auto cannot be matched for speed and never missing a gear
auto-x/racing ... stick every time.

FD3S RX-7s run in the 12s and 13s stock (12s takes a near perfect launch and shifts) ... so yes, $1000 will get them in the 11s, and, still run good as a daily driver. They get 17-20 mpg city, and 25-30 mpg highway. Of course, a led foot in any car will not get those figures, even the LS1.

A LS6 crate engine costs around 4500 ... I could buy a nicely built rotary for the same price. I couldn't do a 3-rotor conversion, because of the logistics and modifications ... but, if you are converting it to a piston engine, I am sure you run the same mod costs.

How I really feel, all the b.s. aside, they are completely EQUAL. I would own a rotary or a big/small block any day. I have no problems keeping them running, well, besides that 454 that was bored and built for drag racing, it was my fault for driving it like a normal car back and forth to work ... holley double pumper, dual-plain intake, the thing was a REAL monster.

One of the reasons that the RX-7 will run 11s with only $1000 worth of mods is weight. An F-body weighs considerably more. So does the LSx blocks. Cubic inch for cubic inch, a stripped rotary block vs a stripped LSx block is not only much lighter, but much more powerful (per c.i.) ... this is no fault. It just means each engine has a certain purpose. I know pretty much since the late 80s, rotaries have been producing 100-200 hp & tq per liter stock, which would put my beloved GrandVille at 760-1520 hp & tq stock (the last year of the RX-7 produced out of the 1.3L engine 276 hp 243 ft-lb and weighed 2800 lbs - Type RZ stock)

My favorite cars, in this order are:

1975 Pontiac Grand Ville Brougham Convertible (455)

1993 Mazda RX-7 R1 (US)/2002 RX-7 RZ (Japan)

1988 Mazda RX-7 TII 10th Anniversary

1999+ Pontiac Trans Am Firehawk (with the extra SLP options
)

19xx Honda CRX (HF and Si)

200x Acura NSX-R


Now I know, not a lot of american cars on there. well, though I like some of them, none will compare to the two I put up there, so, I would rather have them above all others. The new ones, after being in every new Cadillac and most of the others with my job last year, just really disappointed me on interior quality and drivetrain smoothness and quality. The CTS-V was a monster, so was the GTO ... the power was a fun experience.

The one thing I really give the Cobra credit for is replacing the live rear axle with independent suspension. That was a HUGE disappointment with the F-bodied cars. I was never a Ford enthusiast, there were always hit and miss with their designs in my eyes (thought that is true for all manufacturers). I thought the GT90 was a beautiful concept car, so much so I bought a couple models


It has been a while since I been on the chat/message boards ... so I guess after the death of the F-body they learned to get along? That is wonderful to hear. I don't wish to tease myself with a car I will never buy. I drool over a Navy Blue Metallic T/A Firehawk 6-spd, but, I shall never own one. With all honesty, I will most likely NEVER own any of the cars I mentioned above. I have to beat in my head gas mileage is the most logical choice.

Here is the figures I worked out in my head. If I drove 10,000 miles a year (conservative), and I can average about 50 mpg in the Civic Hybrid ... that is 200 gallons. If I had the Grand Ville, I will give it a bit of credit and say 10 mpg ... that is 1000 gallons, and lets say the average car today gets about 20 mpg (rotaries, non-econoboxes) 500 gallons. Now, I have had many years where 20,000 was the norm (I have even done 20,000 in 3 months before).

So, at $3/gallon, the grandville costs $3000-6000 a year in gas., the average car costs $1500-3000 a year, and the hybrid costs $600-1200 a year, comparatively. With etimates that gas will be doubling in the next few years, so does the savings.

Even if I really LOVE those other cars, unless I am rich and can throw away a thousand or more dollars a year away, it is completely illogical to buy one of those 'dream' cars. Granted, the CRX is feasable, but, I do know how much extra pollution goes out the pipes as well, compared to what I would get instead, which is an Insight, which, I truly like the way they look and they get more than 50 mpg (which I know the CRX can do as well). No family, I don't need a big vehicle. I am waiting to see what comes out in the next couple years ... I hear rumors of 100 mpg+ vehicles under $20,000. If so, then, that may be my next move instead ... since in the above estimates, that car would only use $300-600 a year in gas at $3/gallon ... It could pretty much pay for itself in gas savings on all those except for the CRX.


I used to have such an extreme passion for cars. I buried my head in the internet and absorbed as much as I could. I have drifted away a bit though. Being comfortable in the quiet gas-saving Civic Hybrid ... I have stopped caring about hp and tq, and starting becoming more calm and cautious. I still have the soul of a racer deep inside, but, I have done well to suppress it. Filling up once every 600-800 miles on 12-13 gallons compared to every 250 miles on 18 gallons will do that to you.


I don't care what people drive, really. It is their choice. I would prefer they get at least 20 mpg in the city ... really 30 mpg, but that is pushing it. If that were so, it would help national security, keep prices regulated (if you think supply and demand still have anything to do with it and that itself isn't manipulated) ...

I will always wish I had a chance to take a Firehawk for a spin. I will always wish I still had my GrandVille and one of my 7s. But I finally woke up to a bigger picture and stopped being so selfish and narrow-focused. It sounds silly to say this, but, getting good gas mileage changed my driving life completely. I never thought I would be the way I am now. Though I suppose going from 70 cents a gallon to $3+ a gallon helped burn this way into me. Nearly two years at around 50 mpg. I really find it hard to go back to the old ways, but it sure is fun to talk about ... and I know trying to convince someone who is looking for power isn't going to take the gas mileage thing too seriously.



posted on Oct, 13 2007 @ 09:11 PM
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reply to post by FreeThinkerIdealist
 


Well if you're ever in the neighborhood.



That's my SLP Optioned weekend warrior. I dunno all the rises in gas prices in the world wouldnt change my mind on the freedom that comes with this O-Zone destroying monster of selfishness, you only live once might as well make it fast I say.



posted on Oct, 14 2007 @ 07:55 AM
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Very nice. I like the staggered tires.

One thing I liked about the Firehawk hood over the WS6 hood was it being more subtle and smooth, without the loss in power.

I would definitely enjoy the ride


If I ever get well off enough to afford the gas ... I know which four cars I would own. I am used to having more than one car around anyway


Thanks for the offer





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