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)????

[airsix]

I was wondering what the crankfire has over the distributor ignition besides 0 moving parts that can wear out.

Hi Mike! Wow, what a coincidence. Guess what I just did? I just came in from driving my 914 for the first time with crank-fired ignition! I can see it in the papers now "Monkey sucessfully fabricates hall-effect crank possition sensor for 914" (IMG:style_emoticons/default/laugh.gif)

Seriously. Remember a few years ago when I was trying to fab a crank possition sensor with magnets mounted in the rim of the fan pulley? Well the failure of that project has been bugging me for years so tonight I went out to the garage and dug out all the pieces and tried again. It wasn't the physical design that was the problem it was the wiring. This time I shielded the signal leads all the way to the ECU and bridged them to +12v with 1k ohm resistors so that when pulled to ground they would make a nice crisp square wave. It worked! Engine fired right up, I set the timing baseline with the laptop and went for a drive. It was sweet.

If you recall I was previously running a Crane optical sensor in the dizzy. With the optical trigger there was much less spark scatter than with points, but there was still a noticeable amount. I think it's probably because even with a tight dizzy there is gear lash between the dizzy shaft and the crank, not to mention dizzy shaft wobble. I bet at idle speed that dizzy shaft is rattling back and forth across that gear lash. Running off the crank-trigger there is much less spark scatter as viewed with the timing light. The engine definitely idles more smoothly. I don't expect that there is really any more power - maybe a little, or like has been said - the potential now to extract a hair more, but nothing earth-shattering. It definitely seems smoother though, and I like that. It's still firing through the distributor for now (for spark distribution only - not timing or crank possition). I've got the coils for waste-spark but need another compatible ignition amplifier. As soon as I round one up I'll try to go distributorless and see what happens.

-Ben M. (now with new improved crank-fire action)