Engines need spark inside the cylinders to kick off the combustion process, and it’s the ignition system’s job to make that happen. If you plan on adding a power-adder to your engine you better be ready to upgrade the ignition to provide the required spark.
With the help of Performance Distributors, we’re going to take a look at modern EFI ignition coils and spark plug wires, how they work, and why you need to upgrade when you’re trying to make big horsepower.
Project Red Dragon’s new 370 cubic-inch LS engine is going to need a lot of spark to reach our 1,000 horsepower goal. The stock coils could have done the job, but we’re not going to take any chances and that meant a new set of coils were needed. Our friends at Performance Distributors educated us on what to look for and helped us out by providing us with a set of their LiveWire spark plug wires, and their Sultans Of Spark (SOS) coils for Project Red Dragon’s turbo LS engine.
Coil And Wire Basics
When you turn the key or hit the starter button in your vehicle, that’s how the ignition process starts and a signal is sent to the coils to do their job. An EFI vehicle uses a coil for each cylinder as a part of the coil-on-plug system. This system eliminates the need for a single coil to fire all the cylinders via a distributor. The vehicle’s ECU is the brains of the operation and tells each coil when to fire — that’s how a modern coil-on-plug EFI system works.
An ignition coil doesn’t have any moving parts, so it might be hard to grasp how it works. Brian Caruth from Performance Distributors explains how a modern EFI coil functions.
“EFI coils are built with the same basic principles as older traditional coils, yet the technology has been updated to meet the needs of present-day distributorless ignition systems. The key design of the coil consists of an iron core surrounded by primary and secondary windings which are installed in a plastic case that’s filled with epoxy. It’s designed to increase input voltage from a 12-volt system and convert it to kilovolts in order to fire the plug.”
The coil is what makes the power, but it still needs to be delivered to the spark plug and that’s the job of the spark plug wire. OEM spark plug wires are made to handle OEM levels of spark, so if you’re looking to increase the volume of much juice flowing to the spark plug you’ll need to upgrade the plug wires.
Caruth breaks down how plug wires transfer all the voltage from the coils to your spark plugs.
“High-performance wires, particularly our LiveWires, are an 8mm spiral-core plug wire. They are built using a Kevlar core surrounded by a ferrite core, which is wrapped with a copper/nickel conductor. The conductor is covered with EPDM for electrical insulation, which is then covered by a silicone jacket for heat and chemical protection. We go a step further by adding a fiberglass sleeve to the plug wire for increased insulation qualities and higher heat resistance.”
We’ve established that a set of aftermarket spark plug wires are going to have a higher quality level than their OEM counterparts high-performance engines need these spark plug wires to not only generate more horsepower, but also to run as they’re designed to.
“The conditions of the spark have much to do with the plug wires. Many modern engines are built with higher compression than engines in the past, and with the addition of power adders such as turbocharging, an efficient spark is critical with increased cylinder pressure. That’s where low resistance wires become a necessity to ensure spark energy is not lost,” Caruth states.
EFI coils eliminate the spaghetti bowl of spark plug wires routed all around the engine by either using a silicone boot that connects the plug directly to the coil, or a short plug wire connected directly to the coil above the cylinder head. – Brian Caruth, Performance Distributors
The spark plug wires need to transfer power to the spark plugs as efficiently as possible so the amount of horsepower generated can be maximized. A spark plug wire with lower resistance can transfer power to a spark plug more efficiently than one with a higher resistance level. For a boosted application, this is important because you need a consistent and intense spark to make sure the fuel is being ignited inside the combustion chamber.
“The lower the resistance the higher the inductance, which translates to more spark energy at the plug. Plug wires with high resistance are less efficient, especially with high-performance coils, and decrease the spark energy when it reaches the plug. Lower resistance also increases RFI suppression, which is vital to electronic components such as the ECM, two-way radios, and hand-held programmers,” Caruth says.
Engines that use a turbocharger for a power adder have increased timing needs, so spark plug wires play a crucial role in making sure that spark gets to the cylinder. Spark plug wires aren’t a part that you want to try and save a few dollars on due to this important job.
“When adding a turbo, the spark conditions change and with an increase in cylinder pressure and RPM, a loss in spark could be imminent if the right equipment is not used. As stated previously, spark intensity is affected by the plug wire, so low resistance is key. When resistance is down the conductivity is up. Also, by adding a turbo, engine heat is a factor, making a high temperature-rated wire a requirement. Our LiveWires are a prime example of a high-end plug wire designed to work with these factors, as resistance is a low 300 ohms per foot, and with the fiberglass sleeve we add to the wires, they will withstand temperatures up to 1400-degrees Fahrenheit,” Caruth explains.
Delivering The Power
Spark plug wires deliver the spark to the engine, but the coils are the stars of the show since they generate the spark. The coils have to provide adequate spark to cover the timing required to induce the combustion process. The more voltage that comes out of the coils, the larger plug gap you can run, and that increases the burn of fuel inside the cylinder.
Ignition coil selection for a turbo application is very important no matter how much horsepower you’re trying to produce. If you don’t have the right coil for your application you’re going to experience tuning and performance issues as you start leaning on the engine.
“As with having a good set of plug wires, good coils make all the difference in a turbo engine. Stock coils most likely will not handle the extreme conditions of a turbocharged motor, and you will need to make sure you have a coil strong enough to light the fire. Performance coils, such as our SOS Coils, are designed to produce a higher voltage, longer duration spark. What this does is increase efficiency in the combustion process, which in turn increases horsepower and torque,” Caruth says.
High-performance ignition coils come in all kinds of shapes and sizes. ECU manufactures have their own brands of coils along with your traditional aftermarket ignition brands. If you’re going to be running a wild combination that’s making a ton of horsepower, you’ll need a coil that can throw plenty of spark at the engine, but for an application like a street-driven turbo car, you don’t need to go that extreme.
Caruth shares some items to look for when purchasing ignition coils for your turbocharged engine.
“You want quality products from a reputable company that specializes in the ignition systems is number one. Next, you want to take into consideration the build of your engine and how it will be used. Finally, you want to look at the track record of the part and the warranty it offers. Our SOS and Screamin’ Demon Coils are designed to provide reliable performance for naturally-aspirated, supercharged, and turbocharged engines that are used on the street and the track. Our coils have been dyno- and track-tested with proven positive results.”
The spark created by a coil and carried by the spark plug wire is the final step during the combustion process. You’ll need a hot spark for any upgraded engine that’s using a turbocharger to produce boost if you want to avoid any issues. Make sure you continue to follow Project Red Dragon right here as we finish up the conversion to boost.