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Rob 930 Rob 930 is offline
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Join Date: Dec 2002
Location: Seattle
Posts: 661
JFairman said:

The advantages and theory of twin plugs and flame front travel vs igniton timing has all been said, but there's another VERY big advantage to it for a race car or aircraft.

Ignition systems all eventually fail and if you have twin ignition sytems and sparkplugs and one fails in service the plane won't crash and burn, and the race car will still finish the race.

Thats the biggest advantage for some folks.
I agree with this for aircraft, but the problem with our cars is that we rarely have the ready ability (or foresight) to check that both banks of plugs are actually firing. I've heard of two instances with twin-plug 911s where an entire bank of plugs was not firing (for some reason), unbeknownst to the driver. The engine can seemingly run okay on one set of plugs, but the timing would be set wrong and it may have serious consequences. Before track days, I always unplug one bank of coils, then the other, to make sure my engine is actually firing both sets of plugs.
Old 03-07-2008, 08:27 AM
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