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Best Spark Plugs

Expert Reviews & Buying Guide

quadcopter reviewsBest Spark Plugs

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How to Choose Your Spark Plugs

What are the best spark plugs? Well, that depends on your vehicle, but iridium or platinum plugs are your best bet! We’ve researched and reviewed a range of best-selling spark plugs to provide you with an easy way to compare different options in an easy-to-read spark plug review. But there’s no need for a cold start--read up on the following specs we’ve included with each review to help you choose the best option!

Best Spark Plugs

Count - Some spark plugs are sold individually, while others come in multi-packs so you can easily replace everything at once.

Best Spark Plugs

Material - Copper, platinum, and iridium are common spark plug materials that affect price and durability over time.

How to Choose Your Spark Plugs

Corrosion Resistance - Nickel plating and materials like platinum and iridium help prevent corrosion, giving the plug a longer lifespan.

Best Spark Plugs

Hex Size - What socket do you need to install your new spark plugs? This spec will let you know ahead of time!

Best Spark Plugs

Thread Diameter - Measured in millimeters, thread diameter is an important compatibility feature of replacement spark plugs.

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Warranty - How long is the manufacturer warranty? This can be an indicator of product quality and give you peace of mind.

Top 10 Products

Now that you’re warmed up, it’s time to accelerate into our spark plugs review! Our top pick and budget pick compare what we found to be the best options on the market today. But you can explore a greater variety beyond that with our other eight spark plug reviews. Start your engines!

ACDelco Iridium Spark Plug

Top Pick
Our top pick in our best spark plugs review is this eight-piece iridium spark plug set from ACDelco. Why iridium? Because it’s awesome! Specifically, it’s one of the most advanced spark plug materials, with greater strength, hardness, and heat-resistance than platinum. The result: a smaller and more efficient electrode design, providing you with better cold starting and acceleration with reduced voltage demands on the ignition system. The center electrode features an iridium core and iridium tip, and the ground electrode tip is also made from iridium. It’s iridium all the way down! The integral suppressor seal has a one-piece design to provide a seal against compression leakage and improve the spark plug’s lifespan by metering energy. Iridium is an even more durable and corrosion-resistant material than platinum, making it a more durable and corrosion-resistant choice than platinum spark plugs. These plugs can last up to 100,000 miles, making them well worth the price!
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Denso Spark Plug

Budget Pick
Looking for the best spark plugs with a low price? The search is over! The Denso Platinum TT 4504 PK20TT plugs at an economical low price point. It features twin-tip technology with a fine wire platinum center electrode and titanium-enhanced ground electrode, plus a purified alumina powder ceramic insulator. A copper-glass seal provides a gas-tight seal between the center electrode and insulator for maintaining ideal heat levels without letting gas enter the plug. These plugs fit a wide range of vehicles from many different brands and have a preset gap of 0.040’’. It’s hard to find platinum spark plugs at a low price, but here they are! You can see improved fuel economy, acceleration, and start times. But that’s not all: these plugs are also designed to last 60,000 miles before needing to be replaced! When you’re looking to combine the superior design of high performance spark plugs with a low price, it’s hard to say no to the Denso 4504 PK20TT!
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NGK Platinum Spark Plug

Review
NGK spark plugs are widely regarded as some of the best spark plugs for performance, but what are the best NGK spark plugs? We think the NGK Platinum 3403 deserves the spotlight! The fine wire design features a small-tip platinum center electrode with a trapezoid-shaped ground electrode with a nickel alloy tip. It has a copper core and ceramic insulator, as well as trivalent metal plating to keep corrosion and seizing at bay. It’s a high-quality spark plug choice with a high value to boot! It has a factory preset gap of 0.060’’ and lasts 30,000-40,000 miles before needing to be replaced. The platinum center electrode design helps to improve ignitability for quicker starts and lower voltage requirements while preventing fouling. It can help improve fuel economy by encouraging more efficient fuel burning, and the trapezoid shape of the ground electrode provides improved flame reproduction.
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Motorcraft Spark Plug

Review
The Motorcraft SP515 spark plug is designed for Ford vehicles and recommended by the Ford brand as a replacement spark plug. With a fine wire design and nickel-plated shell with a platinum electrode, this spark plug delivers solid performance and has a long lifetime. It is designed to last 60,000-100,000 miles before needing to be replaced! Platinum is highly corrosion-resistant thanks to its hardness, strength, and high melting point. A copper-glass seal binding the insulator and terminal post center electrode together helps protect against misfires by ensuring the full required voltage at the spark gap. It’s a great replacement spark plug upgrade for a Ford, Lincoln, or Mercury vehicle to help it run efficiently and powerfully for as long as possible. They’re even easy to install! If your Ford F-150 or other vehicle is struggling with misfires or other issues, replacing the spark plugs with SP515 plugs can do a lot for its performance and longevity!
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Bosch 4308 Platinum Spark Plugs

Review
Also available in packs of one, four, eight, and ten, this six-pack of Bosch #4308 Platinum Plus 2 spark plugs provides an awesome service to you and your vehicle. The +2 plugs have a greater amount of platinum than other Bosch platinum plugs, so they’ll last a long time--definitely longer than standard copper-core plugs. The fine wire design has a platinum center electrode, yttrium ground electrodes, a nickel-plated shell, a copper core, and a ceramic insulator. The plugs come pre-gapped for fast and easy installation. They use a surface air-gap firing technology, which can help improve engine performance and fuel efficiency by providing multiple spark paths. You get a longer spark without increased voltage! The Bosch 4308 spark plug reaches self-cleaning temperature in just a few seconds, which also helps improve its lifespan. Give your vehicle the gift of a great spark with the Platinum +2 spark plu!
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Motorcraft Spark Plug

Review
When a platinum spark plug just isn’t enough for you, it’s time to go to the next level: iridium. Iridium is harder and stronger than platinum with a higher melting point--so it’s definitely a durable material for your spark plugs! The Motorcraft SP534 spark plug is recommended for Ford, Lincoln, and Mercury vehicles, but is compatible with other vehicles outside of those brands as well. It’s one of the best spark plugs for horsepower! A nickel-plated shell provides corrosion resistance, while an iridium electrode tip provides more heat-resistance and corrosion-resistance than platinum. The electrodes and side wire electrode have platinum pads and platinum ground electrode tip, with a copper core inside. These spark plugs come especially recommended for Ford EcoBoost trucks and are easy to install. If you’re looking for a high-performing replacement spark plug made to the same quality standards as the plugs your vehicle rolled off the factory line with, the Motorcraft SP534 fits the bill!
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Bosch Spark Plug

Review
The Bosch Original Equipment Double-Platinum Spark Plug is designed for BMW and Rolls-Royce vehicles. It starts off right with a laser-welded platinum-tipped center electrode with a core of nickel-yttrium, copper, and platinum and a ceramic insulator. This combination of materials and the fine wire design doesn’t just take ignitability to the next level--it also resists corrosion and has a longer lifespan than copper spark plugs. If your gorgeous car needs an equally gorgeous spark plug upgrade, the double-platinum spark plug will complement it perfectly! Although not from the BMW brand directly, these Bosch spark plugs are well-crafted to give your luxury vehicle the performance it deserves. If you’re looking for the best spark plug brand for BMW vehicles, Bosch is definitely one to consider for spark plug replacements and upgrades. It can be hard to tell the difference between BMW spark plugs and this option from Bosch--so don’t worry, you’re not betraying the BMW brand!
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Autolite Spark Plug

Review
The Autolite HT15 spark plug is designed for Ford 4.6L, 5.4L, and 6.8L three-valve engines and is the official plug of NASCAR. Why is that, you ask? Where do we start! First of all, it’s made with a platinum-nickel alloy and platinum-iridium alloy with a fine wire tip, a ceramic insulator, a carbon-based resistor, and conducting glass-seal terminations. The one-piece ground shield strap also gets the benefits of platinum alloy enhancement in the pad form, and the one-piece design improves heat transfer. The fine wire tip can help improve fuel efficiency and horsepower while reducing emissions, all with very little gap erosion. This plug has a 9/16’’ hex size and can be replaced with a special socket tool thanks to high-strength steel technology. It’s a sure-fire way to amp up the performance of Ford vehicles like the F-150 or F53. When you’re hauling heavy loads, good spark plugs are a must!
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Champion Spark Plug

Review
The Champion Spark Plug Copper Plus 985 is designed for use in small engines. Made to resist fouling and corrosion with increased conductivity and heat control, the result is an ultra-dependable, durable, and long-lasting spark plug for your engine. It’s made with copper core electrode and a corrosion-resistant nickel-copper alloy with a zirconia-enhanced insulator. The preset gap is 0.037-0.043’’, the hex is ?’’, 410cc displacement, and it has a gasket type seat. If your main concern when replacing spark plugs for a small engine is dependability, this spark plug from Champion is proven to perform. It’s a popular choice for other small engine applications, including backup electric generators--where dependability is crucial! The one-year warranty ensures you’ll get your money’s worth. Note that this is one of the highly recommended spark plugs for long-lasting performance and corrosion-resistance, but may not be for you if you’re trying to turn your small engine into a sports car!
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E3 Spark Plug

Review
The E3.54 spark plug can have amazing results on your vehicle due to its design optimizing spark and a more extensive flame with forced edge-to-edge spark discharge. The DiamondFire technology produces more localized pressure with each power stroke of your engine. The result? Better power output, better fuel economy, decreased carbon buildup, and even reduced emissions! The E3.54 is designed from top to bottom to provide a more complete burn, from getting the flame kernel to the piston faster and a “chimney” effect improving air/fuel mixture travel time to the spark zone. As for the specs, it has a corrosion-resistant nickel-plated terminal end, a taper seat, ?’’ hex size, and a DiamondFire fixed gap design. It has a lower self-cleaning temperature due to the reduction in carbon emissions and build-up. The five-year/100,000-mile limited warranty combined with the long-lasting plug design make this a great choice for your spark plug upgrade.
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