Twin Fire vs Single Fire Coils?

LamboV12

Active Member
OK - so who can give me a laymans explaination between the two?

BDM use to be twin fire, now are single fire. Some have said single is better,
so what's the difference?
 

Raywood

The Pirate
Staff member
Calendar Participant
Troop Supporter
Some say there is no difference but knowing that a coil has to saturate prior to firing I would think that the single fire is better especially when it's doing it a thousand times a second.

But as you say BD and HD and a lot of others had dual fire for years with no problem so who's to say.

I will be doing the dual coil set up that some have done ensuring that I have the sharpest spark available.

My 2 cents,
Ray
 

Lone Dog

Motorcycle Junkie
Lee has it:

Dual fire ignition systems fire both spark plugs from a single coil at the same time. The majority of the spark energy goes to the cylinder under compression while a small portion goes to the cylinder on the exhaust stroke causing a small wasted spark. Single fire ignitions separate the firing pulses, only firing the cylinder under compression. The main advantage of dual fire systems is simplicity and low cost. The advantage of single fire systems are smoother engine operation and the elimination of the popping that sometimes occurs when long duration camshafts are used. There is no horsepower advantage with single fire ignition systems.
 

LamboV12

Active Member
Thanks for the info.... I'm going to stay with single fire... Whats interesting is the single fire cost slightly less...:eek:
 
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