is the rx7 engine a 1.3 or not

[Jono FD3]

To get all scientific...
 
The reason why they are registered as 2.6\'s nowadays is not because of the power output, but because of the way the engine turns more efficientl than a satandard one.
 
In a standard cumbustion engine, each piston has to move up and down twice (1. Suck, Squeeze, 2. Bang, Blow). Whereas in a rotary this is not required, the same cylinder does the same process with 1 full turn of the rotor.
 
To put it another way...my wifes 1.4 litre polo is infact a 700cc but because the cylinder moves up and down twice, it is calcuated at 1400cc.

An over complicated way of explaining it!!
Basicaly a piston engine is a 4 stroke using valves to controle the intake & exhaust, as everyone knows this means the piston moves 4 times to 1. draw fuel mix in 2. compress mix 3. ignite & burn fuel & 4.get rid of gasses. where as the rotary works on good old 2 stroke technologey using ports that the apex seals expose & close as they pass.. basicaly making the rotary a 2 stroke engine.

J

[Grant Monkhouse]

I read an exact same thread about this on ausrotary, goes on for a few pages, but from what I can remember  from a post by rice racing is that the rotary actually works out at an equivalent to a 3.9 litre v6. If I get time I will post the link to it. Saves a lot if discussion and confusion from me trying to explain it.

[Grant Monkhouse]

Here read this,
http://www.ausrotary.com/viewtopic.php?f=16&t=33795

Even the first page is intense reading. Explains a lot.

[pigeon]

I thought it was done on swept volume. So basically with one revolution of the engine the front rotor will fire on two of its chambers and the back rotor will fire on two of its chambers. So 650x2 for the front + 650x2 for the rear = 2600.

[Brett]

Wonder where you stand if you are doing an engine swap?

[PGiljevic]

http://www.ausrotary.com/viewtopic.php?f=3&t=158905&hilit=1080+wankel

This is a much better thread ^

In summary if you hate reading

If you look at a 13B with its 654cc per Individual chamber capacity (thus 1308cc) you can see it aspirates this ONCE every single revolution thus you can compare the 13B to a 2 stroke if you must do so on an equivalence basis (but remember you are not counting the other 2/3rd\'s of the combustion faces!

Now if you compare it to the much more common 4 stroke engine you can see that 2 faces ONLY are being counted in the engine and thus it has aspirated a total of 2616cc over 720 degree\'s of crank shaft rotation....... nice little bit of info there but it still misses a whole 1/3rd of the engine!

Finally the ONLY TRUE way to look at a Wankel Rotary is to view it in its own cycle! (and not comparing it to something that it is NOT!) this is only over 1080 degree\'s of crank shaft rotation, where ALL of the working faces can be accounted for (just as when you do a compression test to see if the poor little donk is healthy or not) For it is only when the entire engine has complete one full cycle of work can it thus be rated, be that as functional or in its true capacity sense. You will then see that the humble 13B is indeed 654cc x 3 working faces x number of rotors ! = 3924cc.

Equivalence capacity to time scale (revolutions) for 13B engine, has one power pulse per 360 degree\'s per rotor
1308cc 360degree\'s (2 stroke)
2616cc 720 degree\'s (4 stroke)
3924cc 1080 degree\'s (Wankel Rotary)

[Grant Monkhouse]

http://www.ausrotary.com/viewtopic.php?f=3&t=158905&hilit=1080+wankel
 
This is a much better thread ^
 
In summary if you hate reading
 
If you look at a 13B with its 654cc per Individual chamber capacity (thus 1308cc) you can see it aspirates this ONCE every single revolution thus you can compare the 13B to a 2 stroke if you must do so on an equivalence basis (but remember you are not counting the other 2/3rd\'s of the combustion faces!
 
Now if you compare it to the much more common 4 stroke engine you can see that 2 faces ONLY are being counted in the engine and thus it has aspirated a total of 2616cc over 720 degree\'s of crank shaft rotation....... nice little bit of info there but it still misses a whole 1/3rd of the engine!
 
Finally the ONLY TRUE way to look at a Wankel Rotary is to view it in its own cycle! (and not comparing it to something that it is NOT!) this is only over 1080 degree\'s of crank shaft rotation, where ALL of the working faces can be accounted for (just as when you do a compression test to see if the poor little donk is healthy or not) For it is only when the entire engine has complete one full cycle of work can it thus be rated, be that as functional or in its true capacity sense. You will then see that the humble 13B is indeed 654cc x 3 working faces x number of rotors ! = 3924cc.
 
Equivalence capacity to time scale (revolutions) for 13B engine, has one power pulse per 360 degree\'s per rotor
1308cc 360degree\'s (2 stroke)
2616cc 720 degree\'s (4 stroke)
3924cc 1080 degree\'s (Wankel Rotary)

Thanks Rice i will have a read through the link, very intersting stuff, enjoy understanding these engines, the more information the better. Some of the stuff is confusing to me but when i sit and concentrate on technical aspects like this i understand it eventually.
 
I like to tell people that my FD is a 1.3 to see the shock when they ask the HP the engine can produce.
 
But if we are honest it just isnt:Giggle