Engine efficiency is a huge deal in racing. An engine builder is in constant pursuit of the most effective and efficient burn of the fuel charge in the combustion chamber for maximum horsepower. Engine efficiency is the relationship between the total energy contained (possible) in the fuel, and the amount of energy used to perform useful work. If the air/fuel mixture is underutilized, unburned fuel exits through the exhaust valve, and untapped torque and horsepower escape the engine.
Can a spark plug make a difference in the efficiency of an engine? E3 Spark Plugs believes so. Under independent dyno tests referenced by the company, E3 Spark Plugs “Diamond Fire” design have seemingly demonstrated gains in stock engines, and also have shown output improvements in some higher performance, high-compression engines.
E3 Lead Engineer Don Ward clarified, “The more efficient the cylinder the less our spark plug does. But in stock engines and engines with lower compression, our engines make power and easily make torque as well.” In large part, the E3’s emit a more robust flame kernel, and consequently, a cleaner more complete burn than a conventional plug is the result. For stock-type classes (street stock/factory stock), where common off-the-shelf parts are more frequently used, and compression ratios are regulated, E3’s spark plugs may be a wise choice.
Many factors are involved in the most effective combustion function of an engine. An engine must have atomized fuel within the air entering the combustion chamber, and a strong spark that quickly builds a strong flame kernel to reach all the fuel in the combustion chamber. E3 sparks plugs have demonstrated the ability to provide an intense rapid spark that can result in an increase in horsepower and torque. There are limiting factors to consider however. Spark plug wires and their condition can be a choking point for energy provided by the ignition system. Keep in mind that the plugs are the component at the end of the ignition delivery system. The spark plug will only provide the energy that is transmitted through the spark plug wires.
The Full Picture
Professional engine builders bring together an integrated engine package that is not merely compatible, but rather the components are complementary and exploit one another’s design features and capabilities. Thus, the carburetor needs to have enough capacity to optimally fill the cylinder. The intake (single or dual plane) must have the correct design for the application. It requires adequate runner length to deliver enough velocity for a strong air-fuel charge to the combustion chamber. The cam must provide enough lift and duration to allow the heads to ingest the complete fuel charge. The heads need to have proper port profile so the combustion chamber can accept the air-fuel charge. The piston design must properly compress the fuel charge into the head. Lastly, the distributor, ignition wires, and ultimately the spark plugs have to deliver the strongest spark possible at the right time to maximize performance.
Fuel atomization is key to an effective combustion and realizing the engine’s output potential. Very fine droplets need to remain in suspension and form a heavy and dense fuel charge for combustion efficiency. The piston crown and combustion chamber should be designed to promote high swirl, tumble, and velocity of the fuel-charged air. As the piston travels to TDC, the fuel mixing and swirl need to be sustained, so that the flame kernel from the spark plug effectively burns the charge across the entire combustion chamber for an effective burn. Chevrolet engineers discovered how well air velocity helps combustion when the Vortec cylinder heads were being designed. The cast iron Vortec head was one of the first to purposely integrate tumble instead of large swirl numbers in the design for this very reason.
The E3 ground strap causes the air to tumble and mixes better. It’s more atomized, so you get better burn and a more complete burn. – Don Ward
The engineers at E3 Spark Plugs point to independent dyno tests performed at Williams Precision Engines in St. Paul, Indiana. On a 383ci Chevy, the Diamond Fire E3 spark plugs delivered impressive results. To start the testing, a conventional-style plug with the center electrode and a J-wire grounding strap was installed and used for a baseline. Afterwards the E3 Diamond Fire spark plugs were installed and reportedly produced an 8 lb-ft gain at 3700 rpm. That’s a noted improvement for simply a spark plug change on a mild street engine, and one you can feel in the driver’s seat.
The E3 engineers maintain that the Diamond Fire plugs open-ground electrode design exposes the flame kernel to the piston crown while the conventional J-wire spark plugs impede the flame travel into the combustion chamber. They claim that the fuel charge is concentrated in the center of the combustion chamber and the flame kernel from DiamondFire is more able to reach it. The E3’s ground wire is sort of three legs of a stool with a top wire connecting the three legs, and it’s attached to the cases threads in three different spots.
With this design, a larger and rapidly expanding flame kernel develops which is able to burn more of the fuel quicker, so cylinder pressure increases and produces better fuel economy. Another attribute is that the ground strap projects the flame farther into the combustion chamber. According to E3, the edge-to-edge discharge from one side of the ground strap to the other more efficiently uses the voltage of ignition system. E3’s triple plated for improved rust resistance, and has a hot-lock groove for securing the insulator in the outer case.
Ward also explained, “When the fuel and air come in the combustion chamber, the better it is atomized, the easier it is to burn, because you have more oxygen in the fuel. The E3 ground strap causes the air to tumble and mixes better. It’s more atomized, so you get better burn and a more complete burn.”
Forced-induction engines also are experiencing significant performance increases. Ward stated, “With an engine that’s boosted, the air is more atomized because you have more cylinder pressure and as you squeeze it, it should atomize. I’ve found in the last several months that these NHRA factory stock class with the blown factory motors…all of them have seen an increase by putting our spark plugs in. In the Ford cars, I’ve seen 20 to 30 horsepower increases. With the GM cars, I’ve seen 8 horsepower increase and that’s an average.“
It wasn’t that long ago that a spark plug lasting 100,000 miles was unthinkable. Even into the 1980s, car owners were settling for 20,000-30,000 miles before changing the spark plugs. The E3 DiamondFire plugs now come with a 100,000-mile warranty. That alone is worth the purchase. According to Ward, the plugs provide strong consistent performance over their service life. He compared the DiamondFire plugs to Iridium plugs from other manufacturers. “Generally as the gap or tip wears, the benefits of an iridium spark plug will go away because it takes more required voltage, so it is not as hot at 100,000 miles as it was at 10,000 miles. With an E3 plug, your benefit of the ground wire lasts throughout the 100,000 miles of the plug,” he stated.
E3s DiamondFire spark plugs have been extensively used by race teams in NHRA Top Fuel, dirt track, off-road racing, drag boat racing and many other forms of racing. Racing is a true test for any product, and these plugs have won races in Top Fuel, Funny Cars and other classes.