The Best Spark Plug Wires and Everything You Need to Know
You’re likely aware that in order to keep your vehicle running in great shape, you’ll need to replace the spark plugs from time to time, but what about the spark plug wires? These wires are responsible for transferring high voltage pulses between the distributor and the spark plugs in order to ignite the air/fuel mixture in the corresponding combustion chamber. Some modern vehicles have distributorless ignition systems, which have the spark plug wires connecting each coil pack directly to one or more spark plugs, whereas others are of a coil-on-plug design that removes the need for wires entirely (but that’s another story).
Much like other components that are inside your engine bay, spark plug wires will eventually wear down and need to be replaced. While many will be quick to just purchase OE replacements straight from a dealership or your local auto parts store, there are several aftermarket offerings available that can boost the performance if your ignition system. In this article, we are taking a look at some of the most popular, and best spark plug wires you can purchase, sticking to reputable brands that offer a variety of applications across multiple vehicle makes and models.
For more information on spark plug wires, refer to our table of contents.
Table of contents
1. Editor's Pick: ACDelco
ACDelco offers a variety of spark plug wire sets for a wide range of applications and vehicles. One of its most popular line of products is the Professional Spark Plug Wire Set, which is engineered with strength enhancing fiberglass, and high temperature silicone insulators. ACDelco says its Professional Spark Plug Wire Set covers of 96% of domestic vehicles on the road today, including models from Chrysler, Ford, GM, Honda, Nissan, and Toyota.
For the Professional Spark Plug Wire Sets, each wire conductor, wire length, and diameter have been designed to provide maximum spark delivery and protection. The spark plug distributor boot shape and materials provide proper fit, installation, and water-tight seal, while the terminal design improves spark plug retention and assists installation with excellent corrosion resistance. The insulator on these spark plug wires also employs high dielectric materials. Lastly, a coil retainer helps prevent fretting and micro-arcing.
The company also offers original equipment spark plug wire sets for various makes and models.
Pros | Wide range of OE applications, water-tight seal, excellent corrosion resistance, high dielectric materials |
Cons | Fitment is so tight that removing them could be problematic |
2. NGK
NGK is one of the largest OE suppliers and manufacturers of spark plugs, oxygen sensors, and air/fuel sensors in North America, so there's little surprise the company's spark plug wires are also one of the most popular. The company offers a wide variety of applications, and its spark plug wire sets are designed specifically for noise suppression and superior conductivity. NGK says the durable materials it uses in the manufacturing process enhance the overall strength of the wire, providing a "super strength backbone" on which the various layers of the wire assembly are formed.
Most of NGK's spark plug wire sets use high quality EPDM and silicone coverings to resist heat, oil, and chemical damages for increased durability. Each spark plug wire features a positive locking, corrosion resistant stainless steel terminal end, ensuring tight fit and maximum resistance to vibration and separation.
For easy installation, each wire is numbered with cylinder identification and the coil wires are color-coded.
Pros | Reputable manufacturer in the ignition industry, superior conductivity, high quality EPDM and silicone, tight fit |
Cons | Some applications have short wires, double check when ordering that you're getting the correct product for your vehicle |
3. MSD
MSD is another highly respected company in the ignition industry, offering a wide range of products from ignition boxes to distributors and coils. The company's comprehensive lineup of spark plug wires include the Extreme 9000 ceramic, 8.8mm, Super Stock, ThunderSport, Spiral, Ferro-Spiral, graphite, and stainless steel wire sets in both universal and custom-fit lengths.
There is also the popular 8.5mm Super Conductor Spark Plug Wire Set, which features snap-lock plug grip, separate crimp tabs for the conductor, large crimp tabs that grip the sleeve, 8.5mm jacket that protects against high heat while resisting tears, extra heavy glass braid, high dielectric insulator, ferro-magnetic impregnated center core, and helically wound copper alloy conductor.
These spark plug wires are highlighted by dual crimp terminals and as their name suggests, these terminals feature two crimps: one for the sleeve of the wire and another to grasp the conductor. The separate crimps ensures the conductor doesn't need to be bent 180 degrees and get squeezed between the terminal and sleeve. This individual conductor crimp results in a more secure crimp so there's less chance of spark arcing to the engine block or exhaust manifold through the boot.
Pros | Well respected company in the ignition industry, variety of product choices, dual crimp terminals on the 8.5mm Super Conduct model |
Cons | A little short on some applications, online fitment guide isn't accurate |
4. JEGS
Often seen on domestic vehicles are JEGS' spark plug wires, with three of its popular models being the Ultra Pow'r Wires available in red, yellow, and black. All three models have a wide range of applications, so if you're shopping for these, make sure a particular product fits your car prior to purchasing.
The JEGS Red Hot Pow'r Wires are considered performance plug wires at economical prices and feature a spiral core design that begins with a strand of Kevlar wrapped 32 times per inch with a fiberglass strand coated in a stainless alloy and then conductive latex. The special wire composition lowers resistance to about 350 ohms per foot, while RFI suppression is equal to that of OE carbon conductor wire, but with four times less resistance. The spark plug boots and outer jackets on these wires are separated by fiberglass reinforcing braid for added pull strength, while the EPDM/silicone jacket helps resist high temperature, fuels, and oils.
Both the Yellow and Black Ultra Pow'r Wires are ultra high-performance silicone ignition wires, with their core design starting with a strand of Kevlar wrapped 57 times per inch. The coils are first coated in a stainless alloy before a conductive polymer latex is added. These spark plug wires greatly exceed OE specs for RFI and conductivity and feature spark plug boots and outer jackets made of high-tear, heat-resistant silicone. In addition, the two outer jacket layers are separated by nylon pull tape for added pull strength and terminal retention. Lastly, these wires are equipped with stainless steel terminals connected using fold-over crimping, which won't vibrate loose like core crimping.
All models of these JEGS' spark plug wires include wire separators, numbered wire markers, and dielectric grease. Sets will also include the coil wire, unless noted otherwise.
Pros | Price, high-performance spark plug wires, EPDM/silicone jackets, stainless steel terminals, fold-over crimping |
Cons | Some complaints of wires being too short, discoloring if near a heat source |
5. Denso
If you're looking for a product that's more similar to an OE application, Denso's spark plug wires are your recommend choice. These feature identical OE end caps, designed to "click" into place for easy installation and a secure fit. Denso says thanks to a patented process, the terminals on these wires are attached to provide an extremely strong connection, so that the cable and boot will not separate during removal and installation. These wire sets are precut to exact lengths, so they're ready to install right out of the box.
The 7mm and 8mm ignition wires are SAE J2031 Class E rated, which is the highest quality wire used in the industry. They are able to withstand temperatures from -40°F to 428°F, passing all the tests covering everything from electrical properties to shrinkage to chemical resistance and accelerated life testing.
Other special features on Denso's spark plug wires include the high temperature "Class E" silicone jacket, which can withstand heat, cold, chemicals, and moisture; a reinforcing member for added strength and terminal retention; silicone insulation for superior dielectric and heat performance; a conductive silicone layer for high temperature performance and EMI/RFI noise suppression; fiberglass braid for maximum strength; carbon impregnated fiberglass core for superior support conductivity; a core reinforced with Kevlar; a layer impregnated with Ferrite; and a wire-wound layer to suppress EMI/RFI noise.
Pros | OE look and application, SAE J2031 Class E rated, silicone insulation, carbon impregnated fiberglass core, Kevlar-reinforced core |
Cons | Some complaints that the wires aren't a tight fit, no "click" |
6. Bosch
There's a good chance you have heard of Bosch products if you ever shop for any sort of automotive part or accessory. The company is well respected within the automotive industry and often supplies OE components to automakers. The company offers a few premium spark plug wire sets for various applications, all designed to deliver maximum voltage to the spark plug for a hotter, more powerful, and longer spark. This helps result in optimum engine performance while reducing the chance for misfire and eliminating radio static.
One if its more popular wire sets on Amazon feature 100% pure silicone jackets, helping resist oil penetration. Bosch also offers a lifetime protection against wire set failure due to these pure silicone jackets. The wires also have an EPDM inner insulation that stops power-robbing voltage leaks, while "snap lock" terminals or OEM-style connectors ensure the wires are tightly crimped to the connectors, exceeding OEM standards.
Bosch also backs its spark plug wire sets with a "no hassle" lifetime guarantee.
Pros | OE products, 100% pure silicone jackets, lifetime protection, no hassle lifetime guarantee, EPDM inner insulation, snap lock terminals |
Cons | Price |
Are High-Performance Wires Always the Way to Go?
You may be tempted to invest into a set of high-performance spark plug wires, believing they will improve the performance of your car. While this may be true for some applications, high-performance wires tend to sacrifice certain aspects that could affect the operation of electronics in your engine bay by not containing radio waves. These may work great for racing cars, but they're not ideal for some daily drivers.
Do I need OEM Wires?
Generally speaking, OEM products are the ideal way to go when you're replacing components on your vehicle. But when it comes to spark plug wires, many aftermarket offerings will do the job just fine while saving you some cash. In fact, some of the products listed here are just OEM products without the automaker's branding. With some research, you can likely find out what company makes the factory spark plug wires for your vehicle and you can purchase the same set at a reduced cost compared to buying them straight from the dealership.
What to Look for When Shopping for Spark Plug Wires
The most important aspect you need to pay attention to when shopping for spark plug wires is that they are an engine specific part. Before purchasing any set of spark plug wires, make sure they are designed to work on your vehicle and will fit with no issues. The connection from the spark plug to the distributor is extremely important in making sure your vehicle runs efficiently, so an incorrect spark plug wire can cause misfire or even worse conditions.
Once you determine which products fit your vehicle, you'll need to narrow down your choices to the best product for your budget. Generally you will want to stick to an OEM-type spark plug wire, unless you're confident a high-performance product won't affect your vehicle negatively. Another key important factor is to always purchase new spark plug wires, as you'll never know how used second-hand parts are. And given the price of spark plug wires, you won't be saving much purchasing used ones.
Since most spark plug wires are sold as a set and specifically for your vehicle, you'll likely not have to worry about getting the wrong number of wires. Still, it doesn't hurt to make sure you are getting the correct number of wires for your vehicle, which will be how many cylinders your engine has. The easiest way to determine this is to simply count how many wires you currently have and making sure what you're purchasing has the same amount.
Equally as important, make sure the wires you are getting are long enough to make for a secure installation. Once you have received the product, you'll want to make sure the wire lengths are similar to your factory wires before installing the new ones. Simply lay out your old wires, remembering which one went where, and measure up the new wires. Once you've matched them, you'll also know how to easily install them.
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Photo credit: TANAPAT LEK.JIW / Shutterstock.com
Jason Siu began his career in automotive journalism in 2003 with Modified Magazine, a property previously held by VerticalScope. As the West Coast Editor, he played a pivotal role while also extending his expertise to Modified Luxury & Exotics and Modified Mustangs. Beyond his editorial work, Jason authored two notable Cartech books. His tenure at AutoGuide.com saw him immersed in the daily news cycle, yet his passion for hands-on evaluation led him to focus on testing and product reviews, offering well-rounded recommendations to AutoGuide readers. Currently, as the Content Director for VerticalScope, Jason spearheads the content strategy for an array of online publications, a role that has him at the helm of ensuring quality and consistency across the board.
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Doing a 4.8 LS with a coil location under the dash on a '54 Corvette Restro. Thinking Ceramic boots. Building for dependability, economy--not speed, high HP, or torque...Entire project is DIY*, and I know I will need to make up the wires. Suggestions and thoughts, for instance will 7mm be adequate? * Building chassis, upholstery, paint and fabrication myself.
Magnecore