Ed Anderson wrote:

Paul, I took my spreadsheet routine and with a gasoline BTU of 20891
BTU/LbMass and 11:1 rich fuel mixture caluculated that with 100% Ve that a
two rotor 13B size engine can produce 240HP at 6000 rpm with a NA intake.
So looks like the Mazda engineers just may have been telling the truth on
the Lemans engine {:>).

Air Fuel Mixture Ratio(Air Part)      11.00
Initial Engine RPM                          6000
RPM Step                                      100
% Throttle Opening (Enter Percentage)      100%
MSL Altitude in feet                          0
Enter Air Temperature (Select 15F - 160F, in 5 Degree  Increments)      59
Enter Boost (psi Gauge)  Calculations Compensate for Altitude      0

  Prop RPM Horse Power Fuel Rate Gallon/Hour
 RPM    HP        Fuel Rate    Radiator   Oil Cooler (Heat
rejection -BTU/Min)
6000      239         19.35         6768     3384
6100      243         19.68         6881     3440

So our 160-170 HP rotaries at 6000 rpm are producing approx 33% - 25% less
power.  Does that imply our intakes are at a Ve of approx 75%?  The only
thing I don't have is whether their compression ratio was similar - but that
would not account for more than a few percent of the difference in any case.
So, your/their  view that large diameter intakeswith no turns into a PP
combustion chamber gets more air/fuel into the mixture certainly looks
possible . Even though I had larger dia pipes on my initial 86NA engine and
they gave me 300 rpm less at static than my current smaller pipes, it may be
that the smaller ports into the NA engine simply could not benefit from the
larger dia intake I then had.  Perhaps if I put the original intake back on
the engine I would see a futher increase.  But, that will have to wait.

Anyhow, just thought you might find it interesting if not surprising.

Ed Anderson

Ed Anderson
Matthews, NC
RV-6A N494BW
eanderson@carolina.rr.com

I don't expect they would lie :-) There are ten thousand automotive
engineers around the world looking over their shoulder.

The volumetric efficiency of P-ports is well over 100% over a wide
range. That is the beauty of a wankel. Straight shot into the housing
with no silly poppet valves to wiggle around. (I expect I will hear
from Vance shortly :-))

BTW the SAE pdf paper about the Leman engine is on Todds web site.
Thecarricos.com
 
Paul Lamar
 
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