Perry,

I don't have mail here at the office but the auto racers seem to use
very high volumetric efficiency numbers for the rotary--better than
1.0 (which I know sounds crazy). I'll look for the mail from
www.teamfc3s.org <http://www.teamfc3s.org> on sizing turbos.

Barry Gardner
Wheaton, IL

Perry Casson wrote:

Hi Barry,

Thanks for the reply, I'd sure like to see those number if your have
them.   I've seen some 1.2-1.4 numbers before and I'm starting to
believe them because without >1 VE's  the rotary does not seem to pump
enough air to make the rated HP.   If I'm doing my math right a 13B
pumps 162 CFM at 7000 RPM (if the VE is 1.0).  At sea level 162 CFM
works out to 730 lbs / hr of air which equals 9.72 lbs of fuel if
running a rich 12.5:1, that gives you 124 HP at .47 BFC.  Something is
not right here.

Perry Casson

Nothing is wrong Perry. 
Did you not see the graphs I sent? In case they did not come through
here they are again. 

Yes indeed the volumetric efficiency of the rotary is typically well 
over one over a wide RPM range due to dynamic supercharging as Chrysler 
used to call it. AKA tuned intakes. This has been true almost from the get go.
There are no silly poppet valves to get in the way. 

BTW the .47 BSFC may be a bit optimistic at sea level and 12.5:1.
That number is usually obtained leaned at altitude.

Paul Lamar

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