On page 69 (earlier yellow edition) of DV he says when comparing HIF to HS:'
...These carbs tend to have a higher flow capability than the earlier carbs
of the same size........... '
With the HIF6 flowing approx 14% more than a HS6 (using the figures in his
book) it is reasonable (but not a certainty) that a HIF4 might flow approx
162 compared to the HS4 at 142.
He goes on to get an improvement of about 25% on a modified HIF6. If you
apply the same margin to a HIF4 you might get 202 which is not a million
miles from a HS6 flow and given that a single HS6 is a pretty decent single
carb setup you might want to speak to APT at www.aptfast.com to see how
realistic it is to get a pair of HIF4 carbs up to the 200cfm mark and whether
it might not be cheaper to get a single or pair of HIF6s.
If anyone HAS put the HIF4 (HIF38) on a flowbench it will be APT.
In a message dated 05/12/00 12:52:04 Pacific Standard Time,
<< Daniel - thanks for reply.
I am familiar with Vizard's book and airflow numbers with SUs and Webers.
However, Vizard's comparisons are for HIF6 (1.75") against other SUs,
including HS4 (1.5") BUT nothing for HIF4 (1.5"). That's why I am wondering
about use of dual HIFs.
Oh, plus the fact that I already have a pair of rebuilt HIF4s.
Has anyone other than David Vizard done similar airflow tests with SUs?
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