My CDI is running 18:1 compression and still has plenty of torque, although percentage wise when you compare the rotary which is 10:1 (i think) that's an 80% increase in compression, it's still pretty significant.

I will say this, I have the last inline 6 diesel that mercedes made and when it's idling or even accelerating it's very difficult to tell it's a diesel, the technology is definitely advancing a lot more then many other engine technologies and I think it's a good call that Mazda put R&D into combustion engines rather then wasting it on electric hybrids like the other japanese manufacturers.

The skyactiv gas motor is another good example, running 14:1 (high for a gasser) and it makes 15% more torque then it's low compression counterpart.

 

Audi is running diesels in their le mans car and mazda is going to run the skyactiv diesel in their Grand Am car.

 

YES yes and yes phinsup, So since my question has not been answered yet i will try again.
Is compression the only reason why diesel wouldnt work on a rotary??? Dont feed me the cylinder preasures garb Btw we are not comparing 14L cummins to car rotary which are 1.3L. I wish some one would do that math 14L rotary vs 14L diesel
I know some rotarys run giggle gas if we are still stuck on cylinder preasures.
What of cast liners for the rotary? I drive a 1.6L vw diesel so if we are trying to do a apples to apples it would be 1.9L TDI vs a 13b rotary?

 

Compression and heat. With compression ignition comes increased cylinder head temps (in a piston engine). Heat is a killer on gasser rotaries. You would need to develop housings, rotors and apex seals that could stand the added heat and compression. I don't believe there is an apex seal or even a housing that would last long with a 40% increase in compression.

So yes it could be done with current technology, however you better carry a spare in the trunk.

A turbo or supercharger does not increase compression.

 

Hold up a sec turbo and blowers do increse compression not just air flow intake. if that was the case you wouldnt have to back off the timming when boosting. So to the heat issue thicker walls not doable? higher volume water pumps?

http://www.gtsparkplugs.com/Effectiv...ssionCalc.html

 

A turbo increases the density and volume of fuel/air available for combustion, it does not increase compression.

 

Oh god getting off topic, please dont hijack.
http://www.gtsparkplugs.com/Effectiv...ssionCalc.html

 

Actually, there are and have been several diesel wankel engines. Typically they are spark assisted diesels using stratified charge combustion. None have gone into production, but Curtiss Wright/ John Deere had prototypes running for 30 years, and several companies currently do as well. In certain applications, SCSI rotary engines offer significant advantages over any existing engine technologies.

There is a fair amount of technical information publicly available on the CW/JD engines if you do a little research.

Also the compound wankel engine with the wankel supercharger mentioned was made by Rolls Royce.