> Oops again. Yeah, I used 6500 instead of 13000.
Anyway, my point was not to argue about the numbers, only that BMEP varies
with rpm and drops off significantly at higher rpms, due to restriction in
the intake and exhaust. Your 7 to 8.5 bar (roughly 100 to 120 psi) is
probably reasonable at the revs these engines see on the race track, since
folks are presumably pushing the upper limits of breathing.
None of which, unfortunately, gets Alexandre what he wants, which is
presumably BMEP across the rev range he is planning to run at, for the
purposes of guessing at optimum timing. With head porting and camshaft
design being the black arts they are, I suspect the only good way to answer
the question is to run the motor on a dyno and measure it. Of course,
getting best power implies finding the best timing first, so might as well
keep that rather than going through the BMEP calculation.
Anyway, that's my theory <G>
-- Randall
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|