View Poll Results: 4 rotor or 6 rotor
Voters: 38. You may not vote on this poll
1965 Dodge Polara 6 rotor project
12-22-10, 10:46 AM
#26
If you don't have at least 20-30k, this will not happen.
You will need two 20b's. Which are $4500 each. your already at 9k and have not done anything. You will then need to couple them together, and without in in depth knowledge in rotary engines with years of experience in building them, it's just not going to happen.
Just like the 100's of people on here every week that want to build a 4 rotor, and can't even get there stock 2 rotor to run...
2 rotors produce close to 1000 whp in race cars. 3 rotors will make that in a street car. 5000lbs or not, 1000whp is plenty.
You will need two 20b's. Which are $4500 each. your already at 9k and have not done anything. You will then need to couple them together, and without in in depth knowledge in rotary engines with years of experience in building them, it's just not going to happen.
Just like the 100's of people on here every week that want to build a 4 rotor, and can't even get there stock 2 rotor to run...
2 rotors produce close to 1000 whp in race cars. 3 rotors will make that in a street car. 5000lbs or not, 1000whp is plenty.
12-22-10, 03:30 PM
#27
Steam_Punk_Gen
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money is not that of an issue
now i have found a couple of 20b for $200 a pop plus rotary's are not that hard to understand when you have a mechanical designer background they are actually very simple creatures yes they may not be your conventional 4 cylinder or v6 or what not but the thought is there plus the secondary point of this thread is to prove it dos not take 70000 to do this, this is a thread for the poor man who wants to do this and succeed.
12-22-10, 03:40 PM
#28
now i have found a couple of 20b for $200 a pop plus rotary's are not that hard to understand when you have a mechanical designer background they are actually very simple creatures yes they may not be your conventional 4 cylinder or v6 or what not but the thought is there plus the secondary point of this thread is to prove it dos not take 70000 to do this, this is a thread for the poor man who wants to do this and succeed.
12-22-10, 03:46 PM
#29
now i have found a couple of 20b for $200 a pop plus rotary's are not that hard to understand when you have a mechanical designer background they are actually very simple creatures yes they may not be your conventional 4 cylinder or v6 or what not but the thought is there plus the secondary point of this thread is to prove it dos not take 70000 to do this, this is a thread for the poor man who wants to do this and succeed.
12-22-10, 10:25 PM
#37
Steam_Punk_Gen
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hahaha
well to all the haters i really dont care i will have the last laugh when i post some video anyways if you want to see east meats west then subscribe and i will keep this a constant post either way i will be posting and building i just hate flamers that dont have faith plus the local junk yard here has a very good supply of **** as i live next to 3 military bases as for bs meter whatever dude i will have the last laugh as for the 20b i was miss informed they are 13b that would be my fault on the bad post either way i see lots of good numbers coming from this i still need ideas for transmission would a 5 speed rx7 tranny take the stress of the weight of the car or can i retro fit my existing transmission.
12-22-10, 10:39 PM
#39
Rotary Enthusiast
Dude, you gonna fail so hard.... Get real man. Why don't you build a 20b with a giant S475 and put out like 800whp easy. That is if you can afford the $20,000 its going to take to build it. Either way im pretty damn sure you can't afford that. If you could, that car would be totally restored on a chassis you could eat off it.
12-22-10, 11:19 PM
#40
Rotary Enthusiast
just put a v8 and call it a day...people get the rotary bug and want to become engineers after that.So many ideas will float in your head but its been proven that rotaries with some good horespower will take lots of $$.There are many things to look out for when you build a rotary engine.........look around the forums to learn many setups then you get a good picture of what it takes to make a sophisticated rotary work.
12-25-10, 11:09 AM
#41
To answer your question; no, a stock RX7 trans will not survive very long with the amount of power you will need to make to move that sled in an exciting way. They are the weak link in a stock driveline already.
A turbo 20B would do the job just fine and not empty a bank account too much. Doing an engine swap I have always figured the cost down to the last penny before I started the project. Then double it. That is usually closer to the final cost.
If you've never had a rotary apart before, find a 13B core and rip it apart. You'll find they are very simple inside but putting one back together correctly is closer to building a watch. It takes longer to assemble one than it does to build a small block chevy, I've timed it.
A turbo 20B would do the job just fine and not empty a bank account too much. Doing an engine swap I have always figured the cost down to the last penny before I started the project. Then double it. That is usually closer to the final cost.
If you've never had a rotary apart before, find a 13B core and rip it apart. You'll find they are very simple inside but putting one back together correctly is closer to building a watch. It takes longer to assemble one than it does to build a small block chevy, I've timed it.
12-25-10, 05:49 PM
#44
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I would say go with the 4 rotor. As far as your 500hp goal, you could do that NA and no turbo with a properly built 4 rotor. BMI racing is currently running about 550hp NA with there 4 rotor drift car.
12-25-10, 07:09 PM
#45
6 rotor engines exist(ed) but as far as I know they have never been properly done with the basic geometry of the Mazda 13B. John Deere had a full rotary engine development program that they worked on all through the 80s. See http://protonet.org/doc/rota_text_1986_ltr.pdf
They had 3 rotary families. The first one was for small applications and was clearly based on the Mazda 13B family. They had 1, 2, 3, and 4 rotor engines just like Mazda did with .67 liters displacement per rotor. The second family was for aviation. This was 1.72 liters per rotor, with a 1200hp 6 rotor engine available. The third family was for military use, including generators etc. Displacement was 5.8 liters per rotor, including a turbo 6 rotor, 2250 horsepower engine with almost 35 liters of displacement.
Unfortunately, John Deere canned their rotary program before any of this hit production--sounds like company politics more than anything else. Only a few companies besides Mazda still work on the engine. The military does use air cooled rotaries in their unmanned drones though.
They had 3 rotary families. The first one was for small applications and was clearly based on the Mazda 13B family. They had 1, 2, 3, and 4 rotor engines just like Mazda did with .67 liters displacement per rotor. The second family was for aviation. This was 1.72 liters per rotor, with a 1200hp 6 rotor engine available. The third family was for military use, including generators etc. Displacement was 5.8 liters per rotor, including a turbo 6 rotor, 2250 horsepower engine with almost 35 liters of displacement.
Unfortunately, John Deere canned their rotary program before any of this hit production--sounds like company politics more than anything else. Only a few companies besides Mazda still work on the engine. The military does use air cooled rotaries in their unmanned drones though.
12-26-10, 01:05 AM
#46
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well to all the haters i really dont care i will have the last laugh when i post some video anyways if you want to see east meats west then subscribe and i will keep this a constant post either way i will be posting and building i just hate flamers that dont have faith plus the local junk yard here has a very good supply of **** as i live next to 3 military bases as for bs meter whatever dude i will have the last laugh as for the 20b i was miss informed they are 13b that would be my fault on the bad post either way i see lots of good numbers coming from this i still need ideas for transmission would a 5 speed rx7 tranny take the stress of the weight of the car or can i retro fit my existing transmission.
12-26-10, 01:20 PM
#48
I actually own Rotaries
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^^^ I agree!!!! sometimes people go a little overboard... I call BS on this thread
12-29-10, 09:44 AM
#50
Engine, Not Motor
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well to all the haters i really dont care i will have the last laugh when i post some video anyways if you want to see east meats west then subscribe and i will keep this a constant post either way i will be posting and building i just hate flamers that dont have faith plus the local junk yard here has a very good supply of **** as i live next to 3 military bases as for bs meter whatever dude i will have the last laugh as for the 20b i was miss informed they are 13b that would be my fault on the bad post either way i see lots of good numbers coming from this i still need ideas for transmission would a 5 speed rx7 tranny take the stress of the weight of the car or can i retro fit my existing transmission.
The best bet is to STOP, then RESEARCH. If you really want to take on a 4 rotor (I'm not even going to entertain 4+ rotors) as your first build, then you will need:
1. Several weeks research
2. A bucket of cash
3. A machine shop
I'd suggest you start looking through the engine options what Mazda has available first. Just start Googling up "mazda 3 rotor internals", "20B porting", "mazda race rotary", "787b" and any other terms you are pointed towards in your research so you can get an idea of how these engines are really put together. It is a long standing myth with the V8 guys that I run into that more rotors can just be "stacked" together to make larger rotary engines. You may not be aware, but this is not true at all. After 3 rotors (the 20B) you are outside Mazda production engines so that's when you need to call the machine shop or spend some money on 4 rotor kits. But you'll need the machine shop anyway to peripheral port the housings and make all the stuff that doesn't come in the kits (oil pan, dry sump system, intake manifold, etc. etc.).
An experienced rotary person can backyard a 4 rotor. It has been done. I've backyarded my own 4 rotor shaft as a demo for a machine shop to make me a real one. It is, however, not something you just sit down and do one day.
Spend a few weeks going over the whole 20B subforum here, reading back through the threads over the years to find out what it really takes. Hit up the Single Turbo subforum to learn how to do it reliably. Get the background info so that you can ask informed questions.