flyrotary@lancaironline.net Mailing List Archive

Good question. I've seen no indication that more is better as long as you have enough. I did test that MSD brand LS-1 coil and it worked great but saw no evidence that it gave more power or longer plug life. A friend of mine once compared it to starting a forest fire. Doesn't matter whether you do it with a match or a blow torch - result is the same. The spark from those Ducati ignition systems on Rotax 582's is a good example. Unless you stick the plug gap into a dark hole you can't see it. I'm sure things get more critical as you push the power limits of the engine. We aren't doing that though.

BTW, the stock 2nd gen coils give as big & hot a spark as I've seen. I'd still be using them if they weren't so darn heavy.

On plug life - I have over 300 hours on RX-8 Iridium plugs running almost all mogas. I made one long flight at around 200 hrs on 100LL and started getting SAG after about 2 flight hours. Here's the confusing part, after going back to mogas for an hour or so the plugs started working fine again. I have no idea what that means.

Tracy

On Wed, Jan 5, 2011 at 1:13 AM, Al Gietzen <ALVentures@cox.net> wrote:

So I’m still waiting for an answer to the question I posed a few days back. Do we have any real evidence that the higher current spark is needed in our application; or is going to result in any better performance?

Perhaps it’s obvious to someone, but I’m wondering whether it comparable to watts/channel on a stereo. 50 per channel into good speakers is enough to drive you out of your home; but the salesperson will try to convince you that 1000 watts must be 10 times better. The D580 certainly makes a very good spark, which ignites the mixture just fine. Once the arc is made and the fuel molecules are burning, does 120 ma spark give you anything that a 60 ma spark doesn’t if the voltage is the same? Presumably it is just a matter of spark duration.

Save me the need to do some researchJ

Al