Quote:
Originally Posted by BongoBennie
So on the engine note..... I looked around, is there any good threads about building an engine for eco? like thin titanium rods, knife edged crank, lightweight short skirt pistons? 13:1 like compression, turbocharging with economy in mind, I did see the lean burn tuning..... on that note, is there anything about the D15Z that makes it suitable for lean burn use, or is it all in the tune?
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If you look at the 1ZZ-FE development paper for example, you'll see that connecting rod mass does affect fuel economy on the order of ~0.5% for a ~10% increase. For the ultimate eco engine, you could have a low rev limit like a Prius (4000rpm), extremely thin titanium (you can go titanium MMC if that cash is really burning a hole in your pocket) or maraging steel rods or something that weigh 1/2 of stock (might not be able to go this light because of stiffness problems), extremely delicate and light pistons, knife edged crank, extremely weak valve springs, titanium valves, reduced deck clearance, 14:1 compression ratio with 280 degree intake cams that have very low lift. That would be like the dream efficiency engine, given a well sorted combustion chamber and direct injection and other goodies. Oh, multipoint laser ignition as Mazda is developing would help a little too, but you can't buy that.