Ignition Insights
In the newest gasoline powered automotive offerings, the ignition systems are quite remarkable. If you have an older vehicle, odds are there is room for improvement. Understand that the ignition system is responsible for igniting the air and fuel charge in the cylinder. It can do a mediocre job and deliver mediocre results, or it can do a stellar job and simply amaze you with performance & economy. The importance of the ignition system cannot be overstated.
Sixty years ago, the ignition system was comprised of the distributor, points, a condenser, the rotor, distributor cap, ignition wires, ballast resistor, ignition coil, and spark plugs. Ignition coils would output about 17 kV of spark energy tops. The 1970’s ushered in electronic ignition that used transistor technology to eliminate the points and condenser. This allowed for higher output coils that delivered a hotter spark in the 22-25 kV range (as there were no points to fry). In 1986 GM introduced their DIS (Distributorless Ignition System) that eliminated the distributor altogether. Coil output was in the 100 kV range! Later, ignition coils were connected directly to the spark plugs; known as Coil On Plug, or COP. This eliminated the ignition wires.
The latest ignition technology coming from the OEMs is Ionic Feedback. This uses the spark plug as an input sensor when it isn’t actually firing. Isuzu started using an elementary version back in 1998 that could detect a cylinder misfire. It would then trigger a second spark to at least ignite the Air-Fuel mixture to reduce emissions. Sophisticated sensing algorithms can use ionic feedback to determine AFR (to validate readings from the O2 sensor), as well as peak cylinder pressures in Crank Angle Degrees (CAD). It becomes an ignition system feedback mechanism by measuring the ability of the spark plug electrodes to conduct electricity. The ECU treats the spark plug as a variable pull-down resistor.
If you look at a spark plug firing on an oscilloscope, you would see the KV Spike followed by the Firing Line; then the Coil Oscillations (which dissipate residual electrical energy from the coil). The KV spike represents the amount of voltage required to burn a path between the electrodes. Once the spark jumps, it ionizes the path. In plain terms, the air and fuel molecules between the electrodes are now on fire. The ignition coil is like a transformer. It takes battery voltage (let’s call it 14 volts) and transforms it to thousands of volts to initiate the spark. It was once believed that combustion could be improved if the firing line were extended. Typical KV spikes are in the 7000 volt (7 KV) range. Firing lines (spark duration) usually last for 0.9 to 1.2 milliseconds (0.000 900 to 0.001 200 seconds). Eventually someone discovered that extending the firing line was like tossing matches on a forest fire. The fuel was already burning!
Going back to the drawing board, it was discovered that the intensity of the KV spike is what lit the fire. Increasing the intensity of the KV spike would improve the burn, but extending the firing duration really didn’t help much. The concept of Plasma Discharge Ignition (PDI) was born. The problem with electricity is that it is lazy. It will follow the path of least resistance every time. How do you get a higher intensity spark (higher KVs) given the resistance values of the spark plug?!
Someone found that wadding up a piece of toilet paper and jamming it into the coil terminal of the distributor cap would increase the total gap in the ignition path, and bolster the KV spike. Of course, you had to have an ignition coil capable of delivering that amount of energy, or you just got a misfire. Increasing spark plug gap worked equally as well. Later some electronics geeks realized that adding capacitance in the right place did an even better job. Fast forward a few years, we now have Pulstar Spark Plugs that incorporate this majestic capacitor right in the spark plug itself. Following the PDI guidelines, they concentrate the total coil spark energy into a mere 9 nanosecond (ns) blast instead of a 1 millisecond (ms) spark. Their “Demonstrator” (table-top box used by Pulstar salesmen) shows their Pulstar Plug and a standard resistor plug firing side by side. The visible difference is night and day. The Pulstar spark is so intense it generates visible ozone fog in the display case!
If you do a YouTube search for PDI ignition and Running Engines on Water you will find a couple people running single cylinder engines (like a Briggs & Stratton) on water! They modify the ignition system for PDI, then put water in the gas tank. No other modifications. BAM! The engine is running on water! Granted, it doesn’t carry much load, and frankly, it runs like crap... BUT IT IS RUNNING ON WATER!!!
AquaPulser System
Arvind Srivanisand of AquaPulser took that concept to a marketable level. One of the technologies used in our X-Prize Sonata was the AquaPulser system. The performance increase is beyond belief! You can actually feel the boost in combustion efficiency. (That’s is putting it mildly. The performance gain is simply beyond words!) It requires non-resistor spark plugs. NGK makes popular plug sizes in non-resistor versions. NGK is a top-notch company, and their products are great quality. If you have a distributor or coil packs that use ignition wires, they should be non-resistive as well. Granatelli makes solid-core wires that sport their patented RFI Suppressor Ring technology which allows them to be used on computer controlled engines.
I did a test where I removed a coil and disconnected the injector for that cylinder. I then installed a standard resistor spark plug in the coil. I started the engine (it had an obvious misfire caused by the dead cylinder) and observed the spark. Honestly, I could hear a faint clicking noise, but couldn’t actually see the spark in natural light. Next, I installed the Pulstar Plug and started the engine again. The faint clicking became a pronounced tinking. Furthermore, the spark was clearly visible even in broad daylight. Next I installed an NGK non-resistor spark plug. It clicked a little louder than the stock plug, and I could barely see the electric arc. However, it was not nearly as bright as the Pulstar Plug.
Phase II of the test was to activate the AquaPulser system. Starting with the resistor plug, the spark intensity was a bit brighter (and louder) than the NGK plug without the AP system; the AquaPulser intensified even the normal resistor spark plug. Next I plugged in a Pulstar Plug. The thing just buzzed.
MPG Plus (Granatelli) Ignition Wires
The capacitor perpetuated the spark like an arc welder. (That explained why the engine barely ran with both AquaPulser and Pulstar Plugs). Finally, I installed the non-resistor NGK. HOLY MOTHER OF ALL THINGS DEEMED RIGHTEOUS!! It was like a camera flash going off. Not only could I see the spark, it was somewhat blinding — even in broad daylight! Furthermore, instead of a tink or zap, it made a ka-pow ka-pow explosive noise!
OK, back to Earth, I did many thousands of miles of testing with the AquaPulser system. What I found is that it dramatically increased performance and fuel economy. However, it only lasted for about 3k-7k miles before toasting the spark plugs. I tried NGK and even some aircraft certified plugs (that cost $18 each!) with the same results. If you think about it, when the spark plug fires, it creates an electrical arc. That is the principle behind welding. That extremely high energy burned up the spark plugs fairly quickly. I confess, I abandoned PDI because I simply could not keep spark plugs working. (AquaPulser markets primarily to drag racers that can swap plugs between each race. It does extremely well in that environment.) I still use Pulstar Plugs, though.
With the experimental lessons covered, let’s look at practical things that can be used reliably on modern engines. A good start is the Pulstar Plugs. They work on a 1958 Imperial with the 392 Hemi as well as a 2018 Toyota Prius using the Atkins Cycle. The Pulstars concentrate available spark energy into the KV spike to blast a mild PDI spark outwardly into the combustion chamber. Next, if the engine uses ignition wires, MPG Plus/Granatelli solid core wires will deliver more of the coil energy to the Pulstar Plugs. Granatelli makes the exact same ignition wire under the Granatelli name with a blue silicon jacket and the MPG Plus brand with a green jacket. The choice boils down to color preference. If the engine has a distributor, use a brass terminal distributor cap. NAPA Beldin brand distributor caps have the brass terminals, as do Blue Streak parts. Use the rotor matched to the cap.
Spark Plug Marked for Indexing
Some engines can benefit from indexing the outer ground strap on the spark plug. It is an obstruction that blocks flame propagation, so the intent is to ensure the open area faces the air/fuel charge. Facing the ground strap up (toward the head) and slightly towards the exhaust valve seems to work best on most engines. Start by drawing a line on the ceramic so you can see where the ground electrode faces when you install the plug. After marking all your plugs, install one and see where it lands. If you don’t like the result, swap it out for another plug and try again. Often I can get 5 out of 8 plugs to index by swapping them around. For the ones that simply will not index properly in any cylinder, indexing washers are used (Moroso pictured). They replace the stock plug’s compression gasket/ washer. Try different thickness indexing washers to get as close to desired position as possible. Here you may get more accurate results by swapping plugs around, even with the washers.
Indexing Washers
Properly Indexed Spark Plug
Another trick is to make your own “Magic Spark Plugs”. Start with a standard spark plug; no fancy iridium - platinum - ruthenium - unobtanium. First bend the outer ground strap away from the center electrode. Chalk the plug in a lathe and cup the center electrode with a drill bit. Then reposition the outer ground strap back in place, being careful to center it side-to-side. Then, with the plug still in the lathe, drill a 1/16” hole in the outer electrode. Use an ignition file to deburr sharp edges. Finally, set the gap. The cupped center electrode creates a “satellite dish” effect. The hole in the outer electrode acts as a blow-torch nozzle. The spark energy is broadcast out into the cylinder’s air/fuel charge like a blow torch.
Magic Spark Plug
Regarding aftermarket performance ignition coils, the factory coils are amply capable of powering Pulstar Plugs. I tried a low-priced aftermarket coil with lower primary resistance & higher output. Fortunately for me, the weak-link-in-the-chain wasn’t the ECU’s IGBT driver, it was the coil. I had a no-start condition that turned out to be a dead coil (the “performance” coil). Being the electronics guy, I had already bench-tested this coil and determined that the optimal dwell was ~2.1 ms. The factory coil required 2.8 ms. Needless to say, the ECU fried the “performance” coil with too much dwell. If you try Pulstar Plugs and feel (for some unknown reason) like you need more spark, choose ignition coils matched to the engine (MSD, Jacobs, or other trusted names). Magic Spark Plugs may certainly benefit from stronger coil output.
FE2 - FE3 Depending
MPGenie Basics 051 - Ignition Introduction
MPGenie Basics 051 - Ignition, Sparky Part 1
MPGenie Basics 051 - Ignition, Sparky Part 2
MPGenie Basics 051 - Ignition, Sparky Part 3
MPGenie Basics 051 - Ignition, Building an Ignition Wire
