Crankfire vs. Distributor????, anyone have hard numbers???? Options

[Mueller]

Does anyone have dyno numbers or know where to point me to for a comparison between the two different types of ignition??

Knowing that I can turn my regular distributor into a fully electronic programmable electronic ignition (okay, it'll still have the rotor which must distribute the spark) I was wondering what the crankfire has over the distributor ignition besides 0 moving parts that can wear out.

for the distributor the path for the spark still needs to go from the coil>rotor>cap>sparkplug wire>sparkplug....

the crankfire is coil>sparkplug wire>sparkplug

what effect does the rotor and cap have on ignition if everything is the same (advance curve and coil rating)????

[lapuwali]

Speaking strictly theoretically, if you have the distributor provide both the timing signal and distribute the spark (the box figuring the advance), then you're still subject to spark scatter from slop in the distributor drive. Much less of a problem on a Type IV, since the dizzy is driven off the crank rather than the cam. I've seen some positive statements quoted for one of those multi-coil setups driven off the dizzy (which is only used for the timing signal, not even distributing the spark). Generally, they'll say things like "still runs smooth with a huge plug gap", or something like that. So far, I haven't seen any quantitative tests that show the advantages of running that huge plug gap. (NOTE: this was on other engines, not a Type IV, not even an aircooled engine).

Besides the obvious wear problem, I think the main advantage of a distributorless system is that, by reducing spark scatter, you can run the timing a lot closer to the detonation limit w/o going over it. Many distributors (esp. cam driven ones) can show 6-8 degrees of spark scatter even when new. It's even worse if you're running points. However, in practice, that spark scatter doesn't seem to prevent Jake, et al, from reliably getting 70-80hp/liter out of a Type IV. I suspect that if unless you're running right on the limit, you'll never see the difference between a fresh distributor and a distributorless system. Of course, you don't see much difference between a fresh set of points and a breakerless system, either, unless you're revving the piss out of the engine.

I like the idea on a theoretical level, but I strongly doubt there are any practical benefits other than eliminating wear as a factor. On a 120hp/liter S2000 or a 180hp/liter bike engine, maybe. On a 60hp/liter Type IV, no.