Thank you. I'd wondered how this would compare to a rotary engine. It's interesting how enthusiastic the rotary-engine crowd is, since my takeaway was always "well if it's so much better why isn't it more common".
It's super tempting as an engine designer to take something that works well as a fluid pump and try and turn it into an internal combustion engine. But sealing and lubricating a combustion engine is a much more difficult problem than sealing and lubricating, say, an oil pump. Plus, in order to meet emissions standards, you need to worry about things like flame propagation and avoid little nooks and crannies where unburnt fuel mixture is likely to hide.
Usually the limited success of these sorts of engine designs isn't a case of a mad genius being too far ahead of his/her time, but rather that the advantages, however compelling, don't make up for one or more fatal flaws.
- The vast majority of rotaries will need a full rebuild before 100k - worse
- They rev to 10,000 RPM with an unbelievably smooth power delivery - better
- I'm lucky to see 22 mpg - worse
- The engine is so small and light that the RX8 has perfect 50/50 weight distribution - better
- If you turn the engine off before it's warm it can flood - worse
- 231 bhp from a 1.3 litre engine? - better
Oh, and the noise - BETTER!
I do believe with more time and money invested the Wankel Rotary could be better than a standard Otto Cycle IC engine in every way. But electric is the future now, so that won't realistically happen.
-Almost no torque at low rpm - worse
-Easy to flood, then once flooded major work - worse
-Feed it a quart of oil every 1,000 miles - worse
The flooding issue I mentioned. It may have been different with the RX7, but the RX8 has a de-flood procedure that works 9 times out of 10. And failing that a bump start usually does it. Although I've never flooded mine, I'm always careful not to shut her down cold.
Oil usage in the real world is not much worse than many other performance cars, in fact it's better than most Honda S2000s. But for people who are not used to having to regularly top up oil I could see it being a ball ache.
Neither had I...just never let a valet, mechanic, or relative try to start your old RX-7 ;)
wank-wank-wank-wank-BANG!-wank-wank-wank-wank
That's a complicated question with a complicated answer, but it basically boils down to there having been hundreds of billions of dollars (trillions?) spent on R&D for traditional (pison, conrod, crank, block) engines, while only a tiny amount has been spent on R&D for rotaries and other "different" designs.