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As long as we're talking relative runner lengths of primary and secondary
runners, I started wondering about having two runners per rotor.
I've never been clear about why there are two, and wondered if perhaps
it had something to do with running up and down through the gears (which
airplanes do not do).
Could someone provide me with a quick and dirty explanation of why we
have primary and secondary runners, and why we need them both for steady
state operation? Seems as if DIE would also be greatly simplified
if there were only one runner per rotor.
I missed that class waaaaay back when .... Jim S.
Finn Lassen wrote:
Well, after attending Ed's presentation I see there
is a significant difference (inches) between the required runner length
for the primary vs the secondary ports. That is for the 1988 NA stock (non-street-ported).
So combining primaries with secondaries close to the ports may sacifice
some of the DIE effect. How much I don't know. It will be good to get some
real world data in this configuration. Obviously it will fly as-is. I'm
just talking about egging the last few HPs out of an NA installation at
the optimized RPM and inlet temp.
Finn
sqpilot@earthlink wrote:
Hi,
fellow rotary enthusiasts....just a quick update on the progress of my
new intake system. I purchased the Austrailian 90 degree intake manifold
from Mazdatrix. I cut the top off, and brought it to my machinist
friend, who took a boring bar on a Bridgeport, and plunge-cut two nice
receptacles for my 90 degree aluminum bends. I purchased two 4"x12"
90 degree bends from Burns stainless, as well as two 45 degree bends.
I had them expand the end of the 4"x12" 90 degree tubing, so that the 45
would slide right into it. It fit nicely. The machinist is now making an
aluminum mounting plate with two holes in it that the two 45 degree tubes
will slide into, and it will be welded on the outside. This mounting plate
has four 5/16-18 threaded studs screwed into it, to which my throttlebody
will mount. He put it on his computer, so he can duplicate this piece easily
if needed. It is a very simple system, with only one 90 degree bend to
take the tubes over the top of the engine, and then one 45 degree bend
to position the throttlebody on the cold side of the engine, similar to
Paul Lamar's setup, with the exception that the intake manifold goes from
4 into two right in the casting, so only two intake runners are needed.
Since the longer tube has been expanded, I can slide the shorter 45 degree
tubing in or out to fit just where I need it, or for tuning the intake
system. I should have everything back from the machininst in a couple of
days, at which point I will post some pictures. I hope I described this
sufficiently enough to confuse everyone. The pictures will clarify everything
much better than my description, I'm sure.
Sure am sorry I was unable to attend Shady Bend. Unfortunately, I had to
work to pay for my third manifold. Paul, the manifold collector,
Conner.
--
Jim Sower
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T
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