QUOTE(athlonxp @ Nov 11 2008, 12:18 AM)
increase cc will increase the torque
turbo will spool faster
can reach 9k rpm with 60mm stroke..850 cant do that
Get your facts straight, increase cc wouldn't always increase torque, yes, most of the time it would, but it will depend on the design of the engine itself, in the case of the Mira EF series engine, the bore is bigger than the length of the stroke, so the bigger you increase the bore, the higher the powerband will become, which is the same case as F1 engines which have bores bigger than the length of the stroke thus their powerband is on the top most of the rev range.
That is why I mentioned the 850cc ED series would be a better choice to be rebored and fitted with bigger pistons as it's stroke is very long at a length of 81.0mm(compared to the original bore of 66.6mm, bigger bores from Daihatus EF 68.0mm, Mitsubishi 4G13 71.0mm, Daihatsu EJ, which is from kenari/kelisa 72.0mm and if not mistaken, Toyota 2E 73.0mm)
, all of these, it will never reach the stroke length of 81mm, even if u take a 81mm piston, I doubt there's enough space on the deck for such massive overbore.
This is where most people don't get it for hybrid engines, You don't even need to rev that hard to make more power anymore, same issues and arguments going on all along wif the B20B, the K24A, the 7A-"G"E, and various other hybrid stroker kits. Most just don't get it that they no longer need to rev as much to get to the peak of the power band(which is actually a good thing, as torque builds up from much lower revs and thus, better drivability)
Believe it or not, but any properly done up(as in installed properly, with the right parts, not like "properly done up" as in going all crazy with one-off bits and pieces)
850cc with only 68mm Daihatsu EF turbo pistons(basically built up like any Daihatsu EF except using the 850cc ED block wif the matching 68mm pistons)
would beat the heck out of any 660cc block running even the biggest piston you can fit, on the street, or on the track. You never find those guys running 660 overbored blocks to have problems with the clutch burning out due to the massive torque but there's always people with 850cc simple hybrids having that problem.
Well... I guess I better STFU then, guess that's what happens to most of the know-hows in the forum, they always get tired of even trying to explain and juz STFU instead. Maybe you know better, as you probably built a lot of overbored Kancil turbos by yourself before.
Good luck to the TS in his search for power then.