Do your 30,000 volts ignition coils always deliver all those volts to the spark plugs all of the time?
No!!
Your spark plugs will not always use or use the full 30,000 volts for every single spark.
However, the capability of your coils to produce that 30,000 volts is definitely something your ignition system (and by extension, your spark plugs) can and does "leverage" in important ways.
The Hand Held Dyno® Ignition uniquely leverages the extra volts by extending the duration of the spark by keeping the plugs lit longer. (Up to 6 times longer than CDI). We call this Long Duration Spark.
The benefit of LDS is a more complete combustion that produces easier starting, more confident idle and more performance.
Here's how to understand it:
- Voltage is a "Demand-Driven" Supply:
- The actual voltage required to make a spark jump the spark plug gap (this is called the breakdown voltage) is determined by the conditions inside the engine's combustion chamber at that precise moment. These conditions include:
- Cylinder pressure: Higher pressure (like during high engine load or with forced induction) makes it much harder for the spark to jump, demanding higher voltage.
- Air-fuel mixture: Lean or very rich mixtures can sometimes require more voltage than an optimal mixture.
- Temperature: This plays a role, though pressure is often more dominant for voltage demand.
- Spark plug gap: A wider gap (due to design or wear) requires more voltage.
- Condition of the electrodes: Worn or fouled plugs can alter voltage requirements.
- Your ignition coil's voltage will rise only to the point needed to overcome these conditions and bridge the gap. If the conditions only require 10,000 volts for a particular spark, the voltage will rise to 10,000 volts, the spark will occur, and the process repeats for the next spark. The coil doesn't "push out" 30,000 volts if only 10,000 volts is needed.
- How the 30,000V Capability is "Leveraged":
The "leverage" of having coils rated at 30,000 volts comes from the voltage reserve or headroom they provide.
This is crucial for:
- Handling Demanding Conditions: When your engine is under high load, high boost (if turbocharged/supercharged), or if you're running very lean mixtures for economy, the voltage required to initiate the spark can increase significantly.
A coil with a 30,000V capability has the muscle to meet these higher demands without faltering, ensuring a spark still occurs reliably.
- Compensating for Spark Plug Wear: As spark plugs age, their electrodes wear down, and the gap between them widens.
A wider gap requires a higher voltage to jump. Coils with a high voltage rating can continue to fire these worn plugs effectively for longer before misfires occur, giving you more consistent performance over the life of the plugs.
- Ensuring Consistent Spark Initiation: Having ample voltage capability means the coil can quickly and consistently achieve the necessary breakdown voltage, even if that voltage is relatively high. This leads to more reliable spark initiation.
- Overcoming Variability: Not every combustion event is identical. Slight variations in mixture, pressure, or temperature can occur. A high voltage reserve ensures the system can handle these variations.
- Supporting Performance Modifications: If you modify your engine for higher performance (e.g., increased compression, forced induction), the demands on the ignition system often increase. High-voltage capable coils are better suited to support these modifications.
Think of it like this:
Imagine you need to lift a 50kg weight.
- If you can only lift a maximum of 55kg, you can do it, but you're near your limit. If the weight suddenly became 60kg, you'd fail.
- If you can lift a maximum of 100kg, lifting the 50kg weight is easy, and you have plenty of reserve if the weight unexpectedly increases or if you have to do it many times.
Your 30,000V coils are like the person who can lift 100kg. They may only be "asked" to produce 10,000V or 15,000V for many sparks (lifting a lighter weight), but they have the capability to deliver much more when the engine conditions "ask" for it (lifting a heavier weight).
In conclusion:
While your spark plugs won't see 30,000 volts on every firing, (on your stock engine you will likely only ever use 10 to 15,000 volts) the capability of your coils to reach that level is "leveraged" by ensuring your ignition system can reliably deliver the necessary voltage across a much wider range of demanding engine operating conditions and spark plug states.
This translates to more consistent combustion, better performance under stress, and tolerance for plug wear.
In the video you can see the extra long spark. The length of the gap in open air is indicative of the amount volts being drawn from the coils.
Here's the "rule of thumb" scale presented more generally:
- 1 mm gap ≈ 3,000 volts (3 kV)
- 5 mm gap ≈ 15,000 volts (15 kV)
- 10 mm gap (1 cm) ≈ 30,000 volts (30 kV)
- 15 mm gap ≈ 45,000 volts.