high volt ignition coils

[RICE RACING]

Harness and completed coil packs, can be taken off in 20 seconds, modular front and rear rotor assembly.

[t_g_farrell]

Thats a nice setup and some sturdy brackets.

How much do those things weigh in at?

I once heard that CDI wasn't good with a rotary and was confused about
why that would be. Looks like it works fine but as you say at idle its not
the best but once your up in the revs its better than most regular ignitions.

Another myth debunked.

[RICE RACING]

Its all quite light, all up weight is less than the stock parts swapped out.

The problem with CDI on a rotary is the burn time is quite small, ~ around 420usec, it can multi strike all it likes but the even is long gone after then to establish good combustion, it does help but it never makes it as good as a long burning inductive ign set up. Any revs above 2000rpm to 3000rpm my own testing and feeling is the CDI is superior as shown by what mixture it will reliably fire, it will burn a much leaner mixture without misfire and also a much richer mixture as well.

I did a test where I can swap out both my ign systems (stock and HKS DLI) with the full CDI coil on plug and on return to idle and idle quality the stock will always work better. Many years ago when I was pioneering *seemed that way* the Crane Hi6 and LX92 on each leading coil I found the same thing, but I never had the equipment to actually measure what was happening, I did note that the idle was worse and without multi strike it was bad, but once revs and speed (time for combustion were shortened) the CDI immense current and voltage come into its own and there are big gains to be had.

This is why the HKS use a "twin power system" transistor for low speed and capacitor for high speed.

[TitaniumTT]

Originally Posted by t_g_farrell

Another myth debunked.

I wouldn't go that far. Seems to me that each system has it's place. To me a good powerful inductive system on a street driven rotary would be superior as long as combustion pressures aren't that high. I'll be doing my own dyno testing in a few weeks using two different CDI setups.

[RICE RACING]

Yeah agreed its a subject that gets people agitated lol.

I love CDI, if I had no ECU bullshit to contend with I'd run a magneto we are very limited with this modern rubbish.
Very high energy and long duration ignitions can run richer than 8:1 AFR and 150% water to fuel ratio's.

Most I have ever been able to experiment with is ~9.5:1 AFR and 60% water to fuel ratio's on my own design COP CDI system. It's a real limitation having to tune for the inadequacy of spark power rather than to maximize reliability & power.

Its no fucking different in glow plug 2 strokes IMHO, I do that as a hobby (bit obsessive I know!) and the same applies, you run a glow plug that is hot and it can take far far more fuel (richness) and you can make a shit load more power than you can on a lean mixture (yes I do data log it lol!) all the while being far more reliable and cooler on the engine. Being able to initiate the ignition event is the most critical aspect, if this cant be done your just chasing your tail and setting up the engine to suit your ign limitations and this is the wrong way to set up any engine.