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Here is an advert for a CDI system that claims it will fire a V8 to 15,000

RPM.

Tracy, how do you know the engine won't run any leaner with a more
powerful spark?

Paul Lamar

Well,  it is an advertisement  :-)

Actually, there is a big advantage to CD systems with distributor equipped
V8 engines.  With inductive systems, it takes a relatively long time to
saturate the coil which limits how many sparks per second you can generate.
A V8 turning 15,000 needs to have a system which gives 1 spark every 1 ms.
A typical inductive coil needs 3.5 - 5  ms to saturate so this would not
work at all.  BUT, with a coil per plug system (like the 13B), each coil has
much more time to saturate.  The leading coil for 86 - 91 13B has a 4 ms
sat. time and has to spark 2 times per rev.  Do the math and this works out
to a 7500 rpm limit.

So, if you are going to run over 7500 rpm on your 13B, you could definitely
benefit from a good CDI system.  That's why Racing Beat swears by CD.  Below
7500rpm (where we run them), I don't think there is any advantage.

As far as lean burn limit goes, I don't get any misfire until the mixture
has been leaned way past the best BSFC point.  Power drops off about 50% (!)
before lean misfire occurs.  Why the rotary is so tolerant of lean mixtures
is still something I'd like to know more about.  This is a total guess (so
don't flame me if wrong) but I think it may be due to the centrifugal force
which throws the richer fuel-air mixture (or maybe a bit of un-vaporized
fuel particles?) out toward the plugs where it is ignited.  If the spark
were on the other of the combustion chamber it might not work well at all.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

Here is what Klause is claiming for his system.

Paul Lamar
 
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