Not Ranked
bore etc, ya gotta pull the heads and measure.
for increased or improved performance , timing/ air fuel ratio etc a chassis dyno is the way to go. however, forget the numbers that get printed out re hp and torque at rear wheels as they are only a barometer to what engine crank dyno's might be. the numbers will vary from dyno to dyno.
however, to ensure proper timing and jetting, the chassis dyno will tell you if you are at optimum settings as well as rear wheel hp and torque. jets, timing etc can be adjusted and changed and the subsequent dyno pulls and air/fuel ratios will tell you if the changes were better or worse. then set it up to the optimum settings. you can readily tell if the changes were +/- from where you started.
you can estimate crank hp /torque from the rw numbers usually allowing for a 17-21% parasitic loss from drivetrain/ exhaust etc and divide the rw numbers by the reciprocal. ie, a 300 rw hp number assuming a 21% loss would equate to a 380 crank hp ( 300 divided by .79). while not necessarily accurate, it would be a close approximation.
as i said at the outset, the true key is the directional change of rear wheel measurements from optimal air/fuel ratios and the changes made in timing/jetting or different carbs and/or intake manifolds.
that is the real key, TUNING...NOT what the hp/torque numbers are !
many engines under ideal conditions and open exhaust on an engine dyno provide disappointing chassis dyno numbers because of the parasitic loss and / or the different dynos that are used. forget the numbers, go for the optimum settings from the chassis dyno. then you know you have the max set up for your engine regardless of xyz hp / trq claims by the builder or prior owner or your own expectations. at least you know that you have the best settings for max output of YOUR engine in your car...not a test stand dyno under ideal conditions.
bill
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