Lynn,  I suspected the same but without the experience to back it  up.  I  had asked Rolf  just a few minutes ago what velocity the mix would reach in the p port runner and he calculated around 13,000 fpm for 6000 rpm.  At this speed the suction stroke is repeating every .0075 of a second.  Air/fuel mix  moving through the intake at such a velocity might even  have a scrubbing effect on the runner walls as opposed to a wetting effect.   Even if this is wishful thinking on my part, I don't see fuel building up on the inside of the bends to any appreciable amount.   By the way,  I am sure you have seen various  p port intake manifolds.  The one I had a chance to look at was a 90 degree sweep with a carb mounted on top.  I think it was about 12 inches long.  Does that sound right to you? It may have been shorter.  It was definitely a sweep so no problem with fuel deposition in that case.  I saw this car run through about $500 worth of rubber  burning out just because we were watching.   Jerry

I cannot picture cracking motor fuel into a number of compounds in the
milisecond or two it spends in the runner. While there may be a number of differing
velocities measurable in the runners, they will not be far enough apart to
affect the product be burned. When the mixture is exposed to the 375-400 degree
rotor face, and then compressed about 9 times its volume, I suggest that it is
more likely to recombine any faulty mixture.

 I can picture wetting the outside of a turn in that runner at low
velocities, and perhaps if a very large number of other situations exist inside that
engine, you could get it to detonate. But detonation would have to be the goal of
the experiment, and getting it to work would be difficult. The NA rotary does
not detonate under anything like ordinary use.

So if the engine was highly loaded at low revs, and the gross mixture was
reduced from near ideal to just leaner, with a very low octane fuel, it might be
possible to get it to detonate. Detonation is charge temperature dependant.
Nothing else.

A long list of factors are involved in producing the high charge temperature.

Ignition timing, octane, RPM, plug heat range, carbon deposits and oil
fouling are just a few.

Fuel dropping out of suspension suggests a change in velocity in a fixed
system.
However moving from a homgenious mixture to something less just takes the
removal of some energy from the flow, such as reducing the throttle setting just
slightly, or inlet air temp dropping slightly. The precip of fuel droplets
makes the mixture look leaner to the engine (any engine). Remember pulling the
choke out on cold days? The mixture that runs fine on a warm day (rich enough)
will not even allow a start on a cold day, because that mixture precips into
large droplets and (due to reduced surface area) becomes too lean to even light.

A NA rotary can be loaded on the dyno and taken from too rich to run, through
too lean to run, with no damage at all.

Lynn E. Hanover

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