Yet another direct fire question...complicated
11-10-03, 06:26 PM
#1
...94% correct.
Thread Starter
Yet another direct fire question...complicated
Okay, I see a lot of direct fire setups and each one sends a direct signal to the leading coils. The trailing coils are left to fire off the distributer. Why?
If my understanding of direct fire is accurate then the leading coils are sparking continuously, and with signifficantly more energy in each spark. This leads to a more efficient combustion, which means more power/economy/etc...etc...etc...
Why are the trailing coils left to fire with the distributer instead of wiring each plug to it's own independant spark source? Kinna like FC/D ignition.
If my understanding of direct fire is accurate then the leading coils are sparking continuously, and with signifficantly more energy in each spark. This leads to a more efficient combustion, which means more power/economy/etc...etc...etc...
Why are the trailing coils left to fire with the distributer instead of wiring each plug to it's own independant spark source? Kinna like FC/D ignition.
11-10-03, 08:16 PM
#4
My wife bought me 2 RX-7s
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The trailing igniton isn't really critical for power, more so for economy and emissions, so upgrading the trailing isn't really necessary, aside from being a PITA for the reasons posted above.
11-10-03, 08:34 PM
#5
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i suppose you could use two coils for the trailing, but you would have to run both through the cap, one plug through the leading cap place, and the other through the trailing, but there is absolutly no gain in this.
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11-10-03, 10:52 PM
#9
Beware Of Squirrely Wrath
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If the leading fire at the same time, then shouldn't the trailing also fire at the same time? Not the same as the leading, but the same as each other. I can understand not needing individual coils, cause it'd be overkill, but I'd think that firing at the same time would make the engine run a little smoother, wouldn't it?
Just wondering,
Brian
Just wondering,
Brian
11-10-03, 11:36 PM
#10
...94% correct.
Thread Starter
I think that I MAY understand. The rotor encounters the plugs at wierd intervals. The trailing plug is exposed to the fuel/air mix first, and before it is compressed to the propper setting. If the trailing coil is firing constantly then preignition would occur.
11-11-03, 12:04 AM
#11
Hunting Skylines
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Originally posted by Makenzie71
I think that I MAY understand. The rotor encounters the plugs at wierd intervals. The trailing plug is exposed to the fuel/air mix first, and before it is compressed to the propper setting. If the trailing coil is firing constantly then preignition would occur.
I think that I MAY understand. The rotor encounters the plugs at wierd intervals. The trailing plug is exposed to the fuel/air mix first, and before it is compressed to the propper setting. If the trailing coil is firing constantly then preignition would occur.
You can fire the leading together because when one rotor is at TDC the other is in the exhaust cycle. This extra spark actually helps reduce emissions slightly.
You can't do this with the trailing because the apex seal has already passed the spark plug and it would be firing into the incoming air/fuel mixture.
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