Higher Voltage Cops Advantages Or Disadvantages??
Senior Member
Joined: Jul 2002
Posts: 205
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From: Albuquerque, NM
The advantage is that you can run bigger gaps if you have higher voltage COPs. Bigger gaps are better for efficiency because you get a bigger spark kernal, and better chance to ignite the air/fuel mix. If all you do is race, then stock COPs and small gaps will be fine. But for the street, you'll have a smoother running engine with bigger gaps. I run TR6's, and when they were gapped at .038" she ran smooth, when I stepped up the combo and gapped at .034" I have a little low rpm miss. I'm gonna put on the Accel's and new TR6's @ .038" next time.
Senior Member
Joined: Dec 2002
Posts: 1,005
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From: Fairfax, VA
Originally Posted by JeffsLightning
Anyone here have problems with misfire on the Granatelli's?
Has anybody tried the MSD COP's?
SL
Member
Joined: Jan 2005
Posts: 25
Likes: 0
From: GARDEN GROVE, CA
A (claimed) higher voltage rating does not automatically equate to more energy to the plug.
The sparkplug is the voltage regulator in the system. If it only takes 10,000 volts to jump the gap, that's all you get.
The big numbers you see advertised are "open circuit" readings, with the sparkplug disconnected. The measured voltage will rise to whatever the turns ratio works out, minus effects from stray capacitance, etc.
I'm guessing that the 20kv spec on the Visteon site (OEM) is a realistic number, measured on a plug firing in a pressurized chamber.
Energy stored in the coil's magnetic field is 1/2 (L)( I)**
L is the inductance of the primary winding, I is the coil current at spark time.
Increasind dwell is an easy way to increase coil current. Coil current could also be increased by powering the coils from a higher voltage, such as from a Boost A Spark, etc.
Note that the energy goes up with the square of the current. Doubling the current would result in four times the coil energy, and probably a melted coil.
My calculations show that increasing the dwell by just half a millisecond would result in a nearly 70% increase in coil energy.
A thread on another forum asks about the ability of the tuners to increase the dwell, and apparently, it is possible.
The sparkplug is the voltage regulator in the system. If it only takes 10,000 volts to jump the gap, that's all you get.
The big numbers you see advertised are "open circuit" readings, with the sparkplug disconnected. The measured voltage will rise to whatever the turns ratio works out, minus effects from stray capacitance, etc.
I'm guessing that the 20kv spec on the Visteon site (OEM) is a realistic number, measured on a plug firing in a pressurized chamber.
Energy stored in the coil's magnetic field is 1/2 (L)( I)**
L is the inductance of the primary winding, I is the coil current at spark time.
Increasind dwell is an easy way to increase coil current. Coil current could also be increased by powering the coils from a higher voltage, such as from a Boost A Spark, etc.
Note that the energy goes up with the square of the current. Doubling the current would result in four times the coil energy, and probably a melted coil.
My calculations show that increasing the dwell by just half a millisecond would result in a nearly 70% increase in coil energy.
A thread on another forum asks about the ability of the tuners to increase the dwell, and apparently, it is possible.
Senior Member
Joined: Mar 2001
Posts: 1,352
Likes: 0
From: CORAL SPRINGS, FL. USA
Excellent info John Anthony! I would like to add that what many people don't realize is that too much spark can cause the fuel to "bounce' off the spark kernal. This is called spark deflection and was a problem back in the 60's muscle car era, when coil companies were coming out of the woodwork when Mallory first introduced their hi-voltage coil. Like you said, 20,000 volts is the magic number.
