Rotary question

[gledhill]

What do you call it when you stack two rotary engines together and how does it work?

Never mind I tried searching 3 rotor and came across this page www.3rotor.com

[soloracer]

It doesn't.....next question?

[inline6turbo]

Is this a joke or a legit question? Don't want to waste time explaining and linking if it's a joke :p

[soloracer]

Originally posted by gledhill
What do you call it when you stack two rotary engines together and how does it work?

Never mind I tried searching 3 rotor and came across this page www.3rotor.com

I happen to own two 3 rotor engines (called 20b's) What you fail to understand is it is not "two engines stacked". The 20b is only one engine. Think of it this way - is a V8 engine just two 4 cylinder engines tied together? Of course not. A V8 and a 4 cylinder are two different engines, both of which have pistons. You can't just join two 4 cylinders together to make V8 and you can't just add another rotor to a 13b to make it a 20b.

For the record there is also a 4 rotor engine and no it's not just two 13b's joined together or a 20b with another rotor.

[gledhill]

Thanks for clearing that up? I really don't know that much about the rotary engine. I have been tossing around the idea of getting an RX8 or an S2000 just for some summer fun. I'm worried about the maintenance of the RX8. Plus the RX8 seems to have a pretty weak engine.

[ekguy]

Originally posted by gledhill
Thanks for clearing that up? I really don't know that much about the rotary engine. I have been tossing around the idea of getting an RX8 or an S2000 just for some summer fun. I'm worried about the maintenance of the RX8. Plus the RX8 seems to have a pretty weak engine.

If you don't know rotary engines don't get one. It's a labor of love. I miss mine to death but it was about as bad on gas as my v8 Explorer. Just keep that in mind haha.

And no you can't stack em together to make a 4 rotor. They exist but are extremely rare from what I know. Haven't really kept up with my rotary knowledge since I sold mine a good 6 years ago.

[soloracer]

Depends what you want I guess. Are you going to have more than one other person in the car with you at any time? If so the RX8 is your car since it has back seats while the S2000 is a 2 seater. Do you want a convertible or not?

The RX8 was never meant to be a powerful car. It is however a car with great balance and terrific handling.

If both were the same price I would probably go with the s2000 myself since I think they are more rare and I wouldn't mind adding a convertible to my collection.

[Bizzareo]

Originally posted by soloracer


Think of it this way - is a V8 engine just two 4 cylinder engines tied together? Of course not. A V8 and a 4 cylinder are two different engines, both of which have pistons. You can't just join two 4 cylinders together to make V8


actually its been done, the hayabusa engines have been modified to make v8's in kit cars... :poosie:



But your explanation makes sense.

Think of each rotor as a piston, not a separate engine, I believe the largest you can get in a car is 4 rotors, theirs a bunch of crazy Aussies who use those for racing.



Originally posted by ekguy


If you don't know rotary engines don't get one. It's a labor of love. I miss mine to death but it was about as bad on gas as my v8 Explorer. Just keep that in mind haha.


This is pure truth, I believe the 4 rotor is very similar in design to the 20b but built on a custom block . Since mazda used it in Le Mans way back in the 90's.

I wish Mazda would make some diesel versions of their wankel's would be somewhat more cost effective.

Also while were on the subject of rotaries there may be a new RX7 coming out! :clap:

[jxiplatform]

Sounds like a knock knock joke or something.

[Tomaz]

Originally posted by gledhill
What do you call it when you stack two rotary engines together and how does it work?

You get a twin-prop kit plane :bigpimp:

Those are AWESOME!

[syritis]

Originally posted by Bizzareo
This is pure truth, I believe the 4 rotor is very similar in design to the 20b but built on a custom block . Since mazda used it in Le Mans way back in the 90's.
the 4 rotor used in the mazda 727 was called the 26B however the 20B and the 26B are vastly different. the biggest difference is the 20B uses a very unique "intermediate iron" that has both a primary intake runner and a secondary intake runner
http://www.rotaryresurrection.com/galleries/other_eng/pictures/MVC-018S.jpg
the unique plate is the larger red one, second from the right.

where as the 26B doesn't have any intake runners in the "irons". they built into the aluminum rotary housings, this style of intake porting is called peripheral port or peri-port
http://photos-a.ak.fbcdn.net/hphotos-ak-snc3/hs132.snc3/17977_413410230496_634525496_10771049_1820407_n.jpg

so simple question is no you can't just stack two 13B motors together due to MANY other factor such as firing order, tension bolts, eccentric shaft, intermediate bearings, oil pan, engine mounts, intake manifolds, oil and coolant passages and counter weights.


Originally posted by Bizzareo
I wish Mazda would make some diesel versions of their wankel's would be somewhat more cost effective.
there are some home made ones in Australia, however if i remember correctly there was a huge issue with rotating mass and compression.

[mobius]

I wish Mazda would make some diesel versions of their wankel's would be somewhat more cost effective.

Much, much easier said than done. Toughest design factors being temperature and compression.

Although, there has been mention that a company out of BC has created a small 40-50 HP diesel engine designed for UAV's. I don't know what's come of it though.

[syritis]

i keep seeing this diesel rotary topic everywhere. it's kind of a stupid idea.
rotaries don't make much torque, it's all horsepower due to the engines ability to rev high. however horsepower isn't used very much in the city so if you want more torque go buy an actual diesel motor, you'll just get more torque anyways.
now i hear what your saying "rotaries can rev higher so they would make horsepower and torque." well no diesel motors are limited to roughly 5500rpm due to the nature of diesel to burn very slowly. think about it, gasoline V8's and V10's have been built to hit 20000rpm and with the diesel and gasoline rotating assembly much the same it's not the motor that is limiting the RPM. so changing the motor won't make any difference.

[Maxt]

The succesful diesel rotaries, were HUGE and were only used by the military for power generation.
Syritis's 4 rotor picture is not an r26b, its the scoot 12a based 4 rotor using the Jeff Bruce shaft(run by 2 piggybacked power FC's :nut: ) .
The real Mazda 4 rotor r26b is actually very similar to the 20b, except the rear journal also popped off as well like the 20b front lobe. The R26b had 2 thick irons like the 20b containing a stationary gear. Mazda originally had allowed for side ports in the 4 rotor design ,but ended up with P-port to get the necessary power out of it.
People have stacked 2 13b's together with couplers to make 4 rotors, but it was just that, 2 13b's with 180 degree firing. Once could stagger the coupling 90 deg and end up with 1324 order or something like that but balance would be an issue. The great sound of a real 4 rotor comes from the 90 deg firing order.

[Supa Dexta]

2 busa tops ends with an engineered bottom end:

http://www.h1v8.com/i/engine%20gallery/carlisle_engine.jpg

[g-m]

yeap its really difficult to make a diesel rotary because its very hard to make high compression on a rotary. Dumb question.

www.howstuffworks.com

[Bizzareo]

^ there is ways to make compression, its the design/nature of the rotary that makes it appealing to diesel. I'm afraid I have just brought up the turbo/supercharger debate about rotary's, and that also means the difference in apex seals.

[syritis]

Originally posted by Maxt
Syritis's 4 rotor picture is not an r26b, its the scoot 12a based 4 rotor using the Jeff Bruce shaft(run by 2 piggybacked power FC's :nut: ) .
The real Mazda 4 rotor r26b is actually very similar to the 20b, except the rear journal also popped off as well like the 20b front lobe. The R26b had 2 thick irons like the 20b containing a stationary gear. Mazda originally had allowed for side ports in the 4 rotor design ,but ended up with P-port to get the necessary power out of it.
People have stacked 2 13b's together with couplers to make 4 rotors, but it was just that, 2 13b's with 180 degree firing. Once could stagger the coupling 90 deg and end up with 1324 order or something like that but balance would be an issue. The great sound of a real 4 rotor comes from the 90 deg firing order.

all very true. i though the scoot motor would better show the intake ports but i think cuz i know where they are. here is more pictures for the actual 26B
http://www.mulsannescorner.com/Mazda-MF1.jpg
http://www.rotaryeng.net/4rotor.jpg

There are many differences other then the obvious extra rotor between the 20B and the 26B. just like the 13B-rew is not the same as the 13B-turbo or the Rx8-Renesis, mostly refinements to small details and some more noticeable changes.

this website has a pretty good list of the different rotary motors.
http://www.turborx7.com/repics.htm
I think one of the pictures may have a typo in it though, maybe max could recognize it.
http://www.turborx7.com/images/repics/diffeng.jpg
shouldn't the housing listed as 12A with the 3 exhaust ports be a 10A?