Hi Charley,
Note that I said "about" 2%. The "actual oxygen ratio" of air does not
change significantly with temperature so why mention it. With the
relatively short "trunking" having about 2.6 times as much cross
sectional area as the carbs, pressure drop is not significant either.
Especially if you consider a slight ram effect. Temperature effect on
air at critical flow, is admittedly, by you, irrevelent also.
In any event, the gains can be & are, very significant. Especially since
I stated a very conservative case. The under hood & outside air
temperature differences are likely to be greater than I stated.
Sorry if I do not meet your "standards" for accuracy.
Rick,
Whether you think it is 10% or 20% gain, the "reality" is that it is
still significant. Are you guys just in a bad mood or what? How much
experience have you had with actual measured evaluation? I have measured
actual inlet port temperatures, at the head, compared to acceleration
numbers & found my conclusions to be reasonable.
Dave Russell
BN2
Charley Braum wrote:
> Best I can come up with using gas flow rates is about a 15% increase
> in mass flow with a drop in temperature from 200 deg.F to 100 deg.F
> taken at a standard atmosphere (0 psig or 30 inches HgA).
>
> Of course this doesn't take into account the actual ratio of
> additional Oxygen entering the carbs or the effects of the additional
> pressure drop through the trunking.
>
> Using the temperature change effect on air at critical flow (which a
> carb does not achieve) the increase in mass flow is much less, an
> increase of about 4% from 100 deg.F down to 60 deg.F.
>
> I suspect the air flow mass increase for the cold air box is
> somewhere in between.
>
>
> CB
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