Because I don’t want to spam this nice forum.
Can you please email me ?
Unless it’s ok by Vladimir I post links here.
I will post videos and some words.
And a pic it worth a thousand words.

Mike

The reason Wankel engines are not wide spread is also the reason there are 2 plugs in most (ie, Toyo Kogyo, that is Mazda) designs. The combustion chamber formed by the rotors against the rotor housing is a terrible shape, long and thin, which means:

1. The flame front has to burn a long thin charge. More complete burning is possible if it's ignited in 2 places
2. The "chamber" has a large surface area, and moves as the rotor moves. Lots of heat is lost, very inefficient
3. A relatively large part of the charge doesn't burn. The unburned hydrocarbons in the exhaust pollute or have to be burned in what is essentially an afterburner... more air is pumped in, and the heat is wasted.

Lots of engineering has gone into trying to solve these problems using a stratified charge, where the mixture is in the correct air/fuel ratio in the middle of the "chamber" and becomes as close as possible to just air at the tips of the rotor and the sides of the "chamber". The supposedly coming soon Mazda 16X engine tries to address this by injecting fuel directly into the "chamber" area and by resizing all the dimensions of the housings and rotors to achieve the smallest practical surface area for the volume. They had not changed the dimensions since the '60's, except for the thickness of the rotors.

But at the end of the day, these problems seem intractable... you can't get the efficiency out of it. And then there is the problem that it needs to have huge area sliding surfaces lubricated, so you have to inject (and therefore burn) oil, which most people are not used to. And there is only one company working on it, and their design is essentially exactly the same as it was in 1968...

And... I've driven one for almost 20 years. They feel absolutely amazing, smooth (just rotating motion) and the faster it spins, the more power it makes. Takes less than a day to pull out of the car, disassemble, overhaul and reinstall, it's just a hand full of parts.