Quote:
Originally Posted by arcosine
Not quick to blame, I had one a long time ago. You can reduce the friction all you want, but if the heat escapes through all that combustion chamber surface area, you loose.
|
Yea well, either way doesn't hurt to have double digit percentage increases in mechanical efficiency AND combustion efficiency
(Mazda is undergoing a similar fuel efficiency leap lol)
But don't hate on short stroke engines, the BMW S65B40 for example is a beauty. Piston and head design matters more than dimensions anyways. Mazda Skyactiv engines may have good bore/stroke ratio, but the extremely high compression ratio usually gives the combustion chamber a bad shape, so they gave it that rather deep piston bowl. In fact the low compression ratio on the EJ engines probably helped the heat rejection (at a greater efficiency penalty of course).