> Just as an FYI, the NGK extended tip plug would cause my 11.7 to 1
> compression
> U20 to knock more easily than the standard plug. I could run more initial
> and
> total advance with the standard plug which was better for this motor.
The projected tip plug puts the spark closer to the center of the combustion
chamber, which actually is better to burn as much fuel as possible (for both
power and milage). This also has the effect of a SLIGHTLY increased timing
advance. Combine this with a more efficient and powerful ignition system,
with a larger spark gap, which lights the fuel off faster, and the "slight"
increase can become significant.
In theory the best thing to do in this case would be to back off the timing.
Tuners calibrate spark to what is called "minimum best torque". This is the
MINIMUM spark advance that will produce the MAXIMUM torque at a given
operating condition. Theory again being that the less time the expanding
mixture is pushing down on the piston while it is moving up, the more power
will make it to the wheels.
This is NOT to say that anyone who puts a high power ignition system in
their car could benefit from decreasing the timing. Greg is pushing the
limits in a unique, high power engine configuration which could probably
benefit from a custom curved distributor advance.
Most of our cars (stock), because of the "scatter" inherent in the
dizzy/points system have a relatively conservative spark curve and settings.
The slight advanced timing effect of projected nose plugs, an EI dizzy, and
a powerful aftermarket ignition, would not normally result in knock/ping,
but instead a slight power/milage increase. If you get some knock, back off
the timing a bit and see how the overall performance responds.
I have run the NGK BPR6ES plugs for as long as I can remember. I have
switched to the BPR6ES-11 with the electronic (EDIS) ignition and regapped
to .054" with great results so far.
Daryl
'66 1800cc R/G engine, EFI, EDIS.
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