A four-stroke engine's cylinder fires only once every two revolutions.
A two-stroke's cylinder fires every revolution, so a 2-stroke has (all things being equal) double the output for the same cylinder size.
Problem is that 2-stroke petrol engines don't scale up in size well (though some industrial Diesels *are* 2-stroke).
The rotary fires (like the 2-stroke) once for each revolution, so it has potentially twice the output for the same volume as a 4-stroke, plus the rotary *does* scale up OK.
Piston engines absorb energy during the compression cycle, giving a negative torque, but rotaries provide positive torque for each entire revolution, since compression, power and exhaust occur simultaneously.
Rotaries can run to very high rpms compared to piston engines because their motion is continuous rather than reciprocating and because the few rotating parts are small-ish and can be made very robust, while piston engines are limited to lower and lower rpms as they scale up.
Rotaries are thirsty if you cane them, but I get 30 mpg touring at 70 mph in my 1985 Series 3, no mods.
Fuel consumption is an issue - it's to do with the combustion space being a long, thin rectangle, rather than the more ideal cylindrical space of a piston engine.
And having a turbo giving over 270 shaft HP from a 1.3 litre engine has got to be a temptation....
But no, NOTHING else in the car park looks as damn sexy!
1st gen - FB3s
2nd gen - FC3s
3rd gen - FD3s
The Rx7 was only one of the many cars that were powered by the rotary engine. Dr. Ing. Felix Heinrich Wankel invented this type of engine in the 1950's. This design was bought by Mazda and used in many of they're automobiles from the 1960's - today.
12A (1.2 liter twin rotor n/a) 13B (1.3 liter twin rotor n/a / turbo) and 20B (2.0 triple rotor n/a / turbo) are some of the rotary engine codes that are well known. The engine sits just behind the Rx7’s strut towers making it a true front mid engine car which gives the car great handling characteristics and the proud owner bragging rights. The turbocharged rotaries are terribly unreliable and in reality have to be overhauled every 70,000 miles. The apex seals are one of the weakest points in the motor, second warping the rotor housing from over heating occurs very often. These cars have terrible gas mileage and are not pleasant to drive behind with your windows down. A rotary engine burns oil from the factory to lubricate the rotor housing walls. Failure to pamper these cars will result in a blown engine very early in the cars life. These cars have a very hard time passing smog tests with high milage.
Rx7’s are great cars from beginning to end, I love them, but I already have a girlfriend that needs enough maintenance.. my 240Z does me just fine.
George: "Fuck that slow peice of shit, look at that RX7!!!! it will smoke that stupid rice rocket."
The replacement for displacement.
''Who you calling a wankle?''