Slow responsiveness of [RECIP ENG DETONATING] simvar? Bug?

While testing out the functionality of the RECIP ENG DETONATING simvar, I’ve
noted that while it does seem to work, it seems quite slow. Is this a bug?
I’ve set up an engine with the new supercharger with enough top end boost to
significantly over-boost the engine at sea level. I’ve then set the
detonation_onset parameter in the engines.cfg file to ensure that detonation
happens if the engine is over-boosted enough. This engine does not have any
anti-detonation systems. The end result is successful, more or less - the
engine immediately starts to lose power. However, trying to monitor this event
seems difficult, since the simvar [RECIP ENG DETONATING] doesn’t seem to
trigger until a little while after it’s already hugely noticeable that
something is wrong with the engine. Ideally, it would immediately trigger the
simvar, even a few seconds before the engine failure. This would allow
detonation effects such as sounds to be triggered, giving the pilot a warning
that something REALLY bad is about to happen. On the same subject, I’ve noted
a similar behavior with the RECIP ENG NUM CYLINDERS FAILED simvar. After the
engine has completely stalled, the number slowly starts climbing until all
cylinders have failed. Again, ideally, this would be a metered response - if
the engine starts detonating, after X seconds cylinders start failing in a
staggered fashion, perhaps allowing the pilot to throttle back, and limp to
the nearest airport with only a couple of failed cylinders. If this simvar
also was immediately responsive, this would allow the sounds to be adjusted
appropriately. Edit: I should also note that the RECIP ENG DETONATING simvar
also only seems to work while ‘Engine Stress Damage’ is turned on in the
Assistance Options. While I can understand that this option should allow for
the user to turn on or off engine failures, the effects of detonation is
something can could still be monitored and acted upon (via sounds, effects)
even if outright engine failures aren’t desired by the user.

Hello @MV-JimStewart From what I can see in the code, cylinder detonation will
start only once the cylinder health has gone below 60%. And the RECIP ENG
DETONATING simvar will return true once at least 2 cylinders are
detonating. That could explain the delay you’re observing. A cylinder will be
set to failed state when its health has reached 0% and the health will
degrade at a rate that depends on the delta with the detonation_onset
parameter. I’m not sure why this would happen after the engine has stalled.
I’ll run some tests about this. Regards, Sylvain

Regarding the cylinders failing after the engine has stopped: the damage
evaluation still occurs when combustion has stopped but the manifold pressure
should drop back to the ambient pressure in that case. So the only reason I
could see for cylinders failing after the engine stalled is that your
detonation_onset parameter is set to a value that is below the ambient
pressure but that would be surprising, no?

I’ve have a question regarding this topic. I’ve also set up an engine with
similar properties, with enough top end boost to significantly over-boost the
engine at sea level. I’ve then set the “detonation_onset” parameter in the
engines.cfg file to ensure that detonation happens if the engine is over-
boosted enough. While monitoring engine parameters i’ve notice that as long as
I’m overboosting engine, the var “GENERAL ENG DAMAGE PERCENT” is increasing
but as soon as I lower power below " detonation_onset" value, damage
percent starts to decrease until it reach zero value. Is it possible to once
“Eng damage percent” starts increase it never comes back? It doesn’t seem
right that an engine repairs by itself.