I need your old fucntioning stock coils

[C. Ludwig]

Originally Posted by TitaniumTT

Thanks man, it will for sure be interesting to see the results.

For a long time the RX8 coils were actually recommended for some N/A rotaries and to me for my project becuase of thier short dwell time. Rotaries only allow for a short dwell time. 5ms is too long for the D580's, you're at something like 90% duty on them in the higher revs on a 13B, factor in the renni's higher redline and it gets even worse. I'll have to do the math when I have the time, someone else can if they'd like, it's like this - 9000rpm = how many spark events and how much time between spark events, don't forget that the coil is discharging for a set amount of time as well, and how much time before the next spark event. Divide that by your dwell and you have your ignition duty cycle. I can tell you that at the higher RPM's 5ms is WAY overworking D580. Yeah it's giving out great spark at that dwell time, but it's being overworked. Now maybe the D585's can handle it, but for how long?

5ms is a 75% duty at 9000. That's assuming no time spent in discharge. In practice the duty versus available charge time would be higher. On the other hand, very few rotaries are living at or seeing 9k.

On the other hand yet again, this is where the Mercury coils shine. Designed for a 2-stroke engine they'll achieve 90+% saturation in around 3ms. If you want a hot inductive coil well suited for a rotary application this is where you should be looking.