I have some dyno data for a rotary car, 12A, ported, NA, 2x50mm TB, EFI,
87 octane fuel. We were in search of real world ground truth on timing
(split, T&L identical, etc. ). I saw 165 RWHP with stock timing split,
167 RWHP firing them simultaneously and 163 w/ the trailing disabled
though EGT was up ~50F. Leading disabled was a disaster - ~120 RWHP,
EGTs up 200F, glowing headers. All power figures quoted are at 7500 RPM.
The motivation for doing this little experiment was the fact that
Mazda's LeMans winning efforts used 3 plugs per rotor and fired them
simultaneously while using 80 octane fuel. Conclusion from our little
test, sample quantity 1, is that you might get a touch more HP firing
simultaneously. There is some literature that suggests the split timing
is more for low and mid emissions purposes. It also showed that dropping
the trailing affected HP very little, well within statistical jitter in
our case. Dropping leading looked dangerous and seemed to suggest that
more of the fuel was burning on the way out rather than providing
combustion chamber/rotor pressure/power. I'm sure this would be a bad
thing for you turbo folks! I know this is apples and oranges, but ...
there ya go.

     -Mike
    

Great data Mike.  It parallels exactly with my results but I didn't have
dyno numbers to go with them.  I also saw a 35 - 40 degree drop (nice thing
on a rotary) when using same timing on lead & trail.

Tracy
  

Hey now that's a good tip. I noticed oil and coolant temperatures climbed sharply and fast when the engine was running on trailings only (because the leadings were fouled by lead). Never thought about normal temperatures dropping if both leading and trailing had the same timing. I'll have to give that a try. Could explain why my oil temps have been a little higher than everyone elses while generating less power. But I just realized, if you are talking about EGT dropping only 35-40 degrees, then the effect on oil and coolant may not be that great.

Perry