George Lendich wrote:
Paul,
The biggest primary port size(so far) is the 20B.
This is a little less in area size of 1.5"
How well 1.5" will feed the PP and up to what RPM - I don't know!
But it should work at least up to 4,000 RPM, as indicated when the
secondary cuts in.
The Velocity will increase of course, which would help with inlet flow
past 4,000 RPM.
An interesting thing Francois mentioned was that for best BSFC he uses
the primary only for fuel delivery.
There are no assumptions on total PP area required, only some more info.
George ( down under)
Are you adding the primary and secondary ports together? You should be.
P-ports have one tube. Side ports have two or more tubes.
One large tube has less internal skin friction drag than two or more
smaller tubes
of the same area.
Small diameter tubes fill the intake chamber better at low RPM than large
tubes. That is why Mazda uses multiple small diameter tubes for cars. We
are
not using the Mazda engine to power cars in case you haven't noticed. We
don't
need low RPM engine torque! This is a recording.
The most powerful wankel engine will have both peripheral and two side
ports of the
largest possible total area given the restrictions on port timing.
You better think!!!! Think what your doing to me :) Sheesssss!!!!!
Paul Lamar
Paul,
I'm not trying to confuse the issue, or go against your figures on port
sizing; just coming at it from another angle - mainly for my own benefit!
The way I see it is the MINIMUM area needed for a primary Port is the area
of the 13B primary port i.e. 1" ( NOT allowing anything for drag or
turbulence) see 530 sq mm.
The secondary cuts in at 3,800 RPM (so someone said) so that area is good to
that RPM or 50.6% of power requirements.
If 50.6 % percent is 530 sq mm than 100% is X (1047mm) or 1.44" diameter
(Internal diameter), 1.45" for 3,700RPM
I did it another way and got 1.49", so 1.5" is close to the minimum are of a
PP - I would assume!
I would suggest that the ram effect of the higher Velocity will off-set any
drag or turbulence requirements, so no need to add the extra 20%. This 20%
is the difference between Jerry's figures and your 2" OD figure.
I don't know if I'm right here but this is just another way to establish the
minimum port area - for my own benefit. Also I'm trying to establish the
minimum port are in an attempt to maintain a smooth idle. I'm aware of the
other factors affecting idle, but I feel a higher velocity will help.
George (down under)
Have you been talking to Rolf or Jerry?
Why are you concerned with minimum area? The damned engine will run with a
half inch hole in the rotor housing. The intake velocity will approach super sonic.
Is that minimum enough for you?
We have two examples of P-port engines generating close to 300 HP tested
on dyno's with two inch runners. One of which with fixed length runners
dominated road racing road racing in the US for a decade where low speed torque
and engine response was and still is absolutely essential. Then P-ports were more or
less outlawed in US road racing as too powerful. Not fair to piston engines.
Why don't you believe it?
Shessdsssssssssssssssssssssssssssssss!
Paul Lamar
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