Theo,
Thanks for your input - Very interesting !!!
At 11:05 AM 1/29/06, Theo Smit wrote:
>MSD does two things. First, below 3000 RPM you get multiple spark events,
>which is helpful in preventing misfires and the resulting plug fouling. At
>high RPM, the high coil primary voltage (up to 300 or 400 volts) saturates
>the coil even though the time between ignition events is drastically
>reduced. Conventional coil drive systems lose most of their fizzle at
>higher RPM, and this can lead to high speed misfires. I'm not saying that
>they are a cure-all, and you are correct that without a good timing
>reference the battle is lost from the outset, but the MSD systems and
>their ilk do provide useful benefits besides the big decal. A system like
>the MSD6AL also includes a rev limiter, and if you're at all interested in
>running your car in track or autocross events, then a rev limiter is an
>absolute must.
>You can use the optical sensor from the Allison system to trigger the MSD
>input as well, and get the benefit of more reliable ignition triggering
>plus the improved coil firing that the MSD offers. No sense in going halfway...
>
>To answer Barrie's comment - the problem with ignition is that the typical
>engine cylinder is not a big room filled with an explosive mixture - it
>has rich spots and lean spots all swirling around. If the coil fires when
>there's a big glob of fuel hanging on the electrodes, it won't fire the
>plug... and it also won't fire if the mixture at the plug, at the firing
>instant, is 25:1. The multiple spark business gives you better odds, and
>it does actually work. You just have to decide whether or not it's worth
>the $130 or more to get it, and I do agree that if you're on a budget,
>then fix your distributor first, and install an Allison, Pertronix, GM, or
>other points replacement trigger and amplifier.
>
>Best regards,
>Theo Smit
>
Regards
Barrie Robinson
barrie@look.ca
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