Smart Coil Comparison

IGN-1A Ignition Coils: When It Absolutely, Positively Must Be Ignited

Are you absolutely sure your spark plugs are getting enough energy to ignite the mixture?

That 102mm turbo and those 2000cc/min injectors won’t do you any good if the flame kernel never forms. Under boost, ignition quality becomes the difference between clean power and misfires, hesitation, or detonation.

We’ve always been confident that the IGN-1A Ignition Coil is the gold standard for high-performance applications — but we wanted hard data to back that up. So instead of relying on marketing claims, we set up a controlled laboratory test, fired up the oscilloscope, and compared some of the most commonly swapped logic-level coils head-to-head.

The results were not even close.

What Is Ignition Energy (and Why It Matters)?

An ignition spark is simply the release of energy stored in the ignition coil. Electrically speaking:

Energy = Voltage × Current × Time
(E = V × I × T)

To ensure fair and repeatable results, voltage was held constant across all tests. Only spark current and spark duration were measured, allowing us to calculate true ignition energy in milli-joules (mJ).

This is the same methodology used by Australian ignition specialists Dtec, whose test procedure we followed closely:

Ignition Coil Energy Testing – Dtec (dtec.net.au)

How the Testing Was Performed

All coils were tested using the following setup:

  • Constant 13.5V power supply

  • Primary coil charging across a range of dwell times

  • Secondary voltage clamped to 825V using a string of Zener diodes

  • Spark discharge measured across a resistor using an oscilloscope

This produces a current-vs-time trace, where the area under the curve represents the actual energy delivered to the spark plug.

That small blue triangle on the oscilloscope trace?
That’s the difference between lighting the mixture — or not.

Test Repeatability & Limitations

Each coil was tested multiple times to confirm repeatability. Absolute values may vary slightly with different test fixtures or voltage conditions, but relative performance and saturation behavior between coils remained consistent across runs.

Note: These tests compare ignition energy delivery under controlled electrical conditions. Actual required energy at the plug will vary based on spark gap, cylinder pressure, mixture, and combustion chamber design.

Coil Saturation: The Hidden Limiting Factor

Increasing dwell time allows a coil to store more energy — but only up to a point.

Once a coil reaches saturation, it can’t store any more energy. Any additional dwell simply turns into heat, not spark. Some coils reach this limit extremely quickly, making them unsuitable for performance or boosted applications.

Real-World Coil Test Results

Toyota 1UZ Coil

  • Time to Saturation: 2.5 ms

  • Max Spark Duration: 1.5 ms

  • Max Spark Energy: 52 mJ

Recommended Use: Factory / stock engines only

These coils are perfectly adequate for a stock Lexus LS400 — but that’s where their usefulness ends. They saturate extremely quickly and simply don’t deliver enough energy for modified engines. Use them only if you already have them and plan to stay naturally aspirated and near stock power levels.

See how the light blue trace plateaus, that is the coil hitting saturation.

Audi R8 Coil

  • Time to Saturation: 3.0 ms

  • Max Spark Duration: 2.0 ms

  • Max Spark Energy: 75 mJ

Recommended Use: High-revving naturally aspirated engines

The R8 coils stood out for how quickly they build energy. They were the only coils tested to exceed 50 mJ at just 2.0 ms of dwell, making them a solid choice for high-RPM NA engines running wasted spark or COP setups.

Miata “Pencil” COP Coil

  • Time to Saturation: 2.0 ms

  • Max Spark Duration: 0.9 ms

  • Max Spark Energy: 38 mJ

Recommended Use: Motorcycles (at best)

Despite being commonly suggested as an upgrade, this coil was underwhelming. Even fully saturated, energy output barely reached 38 mJ. While the tested unit was used, several other used coils in this test performed far better. These are likely motorcycle-derived coils and are not well-suited for performance automotive use.

GM LS Coils

(D580, D581, D510C, D585, D514A)

  • Time to Saturation: ~5 ms

  • Max Spark Duration: 2–3 ms

  • Max Spark Energy: ~100 mJ

Recommended Use: General purpose (with caveats)

LS coils are popular for good reason — they’re solid performers — but each variant has trade-offs:

  • D580 (LS1): Breaks 100 mJ, but needs ~7 ms dwell

  • D581 / D510C: Faster charge, less total energy

  • D514A (LS2): Better balance, shorter duration

  • D585 (Truck): Strong numbers — but dangerous

⚠️ Important Warning on D585 Coils
D585 coils have built-in over-dwell protection. If commanded beyond ~5 ms, they self-discharge early. At high RPM, this can result in up to 6 degrees of unintended ignition advance.

Unplanned timing advance under boost = detonation.

 

Mazda MZR Coil

  • Time to Saturation: 4.0 ms

  • Max Spark Duration: 2.5 ms

  • Max Spark Energy: 97 mJ

Recommended Use: General purpose / lightly boosted

These were a pleasant surprise. Nearly 100 mJ in just 4 ms of dwell puts them in the same class as LS coils, without the same drawbacks. A very respectable choice for NA or mild boost builds.

IGN-1A “Big Daddy” Coil

  • Time to Saturation: 9.0 ms

  • Max Spark Duration: 3.3 ms

  • Max Spark Energy: 225 mJ

Recommended Use: Forced induction, extreme performance, no compromises

This is where everything else gets left behind.

The IGN-1A is physically larger — and for good reason. While it requires slightly more dwell time, it keeps storing energy long after other coils are fully saturated.

Performance milestones:

  • 4 ms: 78 mJ (beats R8 coils)

  • 5 ms: 110 mJ (tops all LS coils)

  • 6 ms: 150 mJ with 3.0+ ms duration

  • 8 ms: Over 200 mJ — double any other coil tested

  • 9 ms: Still climbing

No self-discharge. No hidden timing issues. Just massive, consistent ignition energy.

While these coils do continue to produce more energy, for longevity we don't suggest dwelling them past 8ms.

Note on Authenticity
Because ignition energy varies dramatically with internal construction, counterfeit or imitation IGN-1A coils may not perform anywhere near the values shown here.

We’ve documented the physical and electrical differences between genuine and counterfeit IGN-1A coils in detail here:
Article: Real vs Fake IGN-1A Coils – What to Look For

The Bottom Line

If you’re running:

  • High boost

  • Large injectors

  • High cylinder pressure

  • Ethanol

  • Or just want maximum ignition stability

IGN-1A coils deliver unmatched spark energy, duration, and safety margin.

When it absolutely, positively must ignite — there’s no substitute.