Best Spark Plugs

Spark plugs are a critical component of engine maintenance, yet many drivers remain unaware of this requirement. Old, worn, or dirty spark plugs will decrease your engine's ability to perform, as they will be unable to ignite the fuel/air mixture as efficiently as they should. Having good spark plugs will make your engine run smoother, cleaner, and consume less fuel.

These best spark plugs make use of the latest technology and materials, and can achieve both high performance and durability without compromise. While these highest-performing spark plugs may come with a higher price tag, their ability to increase your engine's overall performance will be worth the added cost.

Bosch Platinum IR Fusion Spark Plug

As the name suggests, the Bosch Platinum IR Fusion mixes two different materials together to increase performance. The center electrode contains a platinum/iridium blend, while the ground electrodes feature yttrium enhancements for better performance. Read Full Review

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    Why it's best:

    Iridium spark plugs may offer the best performance outright of any type of spark plug available, but the drawback is the high initial cost. To remedy this shortcoming, Bosch offers the Platinum IR Fusion spark plug.

    As its name suggests, this spark plug features a center electrode made of a Bosch-exclusive blend of platinum and iridium which is designed to increase performance over a platinum spark plug without demanding the cost of an iridium one. This is combined with four precisely gapped yttrium-enhanced ground electrodes for a more powerful spark, which allows more thorough ignition of the fuel/air mixture.

    These spark plugs are designed to last their entire life without needing gap adjustment or other maintenance. If you believe that the increase in performance and durability is worth the couple extra dollars over traditional spark plugs, the Bosch Platinum IR Fusion is your best bet.

    Bosch Platinum IR Fusion Spark Plug

    Denso Iridium Power Spark Plugs

    If you value increased performance, the higher price tag of the Denso Iridium Power spark plugs may be worth it for you. These spark plugs have an extremely high melting point and a fine-tipped electrode, allowing for precise and prolonged use. Read Full Review

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      Why it's best:

      One of the main benefits of using iridium in spark plugs is its extremely high melting point at nearly 2500 degrees Celsius. The Denso Iridium Power spark plug takes full advantage of this attribute by using a fine-tipped 0.4 mm diameter electrode in place of the more traditional wide-diameter offerings. A standard electrode of that diameter would more than likely melt after prolonged use, but the Iridium allows for a more precise, controlled spark-to-ignition process.

      Combined with Denso's exclusive U-Groove pattern ground electrode, this allows the Iridium Power to handily outperform its competitors. However, this performance comes with a premium price tag. At more than three times the price of a standard spark plug, it's hard to make a case for the average, casual driver. If you are a performance enthusiast or a long-distance commuter, the cleaner burning capability and potential for increased fuel economy with the Denso Iridium Power may be worth looking into.

      Denso Iridium Power Spark Plugs

      NGK Iridium IX Spark Plug

      You'll find NGK spark plugs under the hood of many cars as they leave the factory, which shows just how well these spark plugs perform. The Iridium IX spark plug are practically maintenance-free, and reliably ignite fuel/air mixtures within the engine. Unfortunately, these spark plugs are pricier than the alternatives. Read Full Review

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        Why it's best:

        NGK is a highly trusted brand among spark plug manufacturers, to the extent that the vast majority of automakers today choose to equip their cars and trucks with NGK spark plugs as original equipment. The Iridium IX is a good example of how well-sorted a modern iridium spark plug can be, with the small-diameter iridium electrode offering powerful yet controlled spark. This results in a more thorough ignition, and can reduce or eliminate surging and other ignition-related engine problems.

        As with many other high-tech modern spark plugs, the NGK Iridium IX is a low-maintenance design that you can install and forget, though it is prudent to check the condition of the spark plugs every once in a while. Though the NGK Iridium IX spark plugs are designed to last and perform well throughout their life, the high price tag is something to consider.

        NGK Iridium IX Spark Plug

        AC Delco Iridium Spark Plug

        These powerful spark plugs are rated to last a long time with minimal maintenance, making them an excellent overall choice. The AC Delco Iridium spark plug has a higher melting point thanks to its iridium electrode, and can offer clean and smooth performance from your engine. Read Full Review

        Why it's best:

        Aside from being an excellent overall spark plug, AC Delco Iridium spark plugs are used as original equipment in premium and high-performance products from GM. Thanks to the higher melting point that the iridium electrode offers, this allows a more powerful spark that would wear out standard spark plugs. The powerful spark ensures a thorough ignition of the fuel/air mixture, meaning your engine will run much cleaner and smoother.

        The AC Delco Iridium spark plug requires little to no maintenance, though it’s always a good idea to check gap spacing every once in a while if you suspect that the spark plugs are becoming worn. These spark plugs are rated to last 100,000 miles, and will offer substantial performance for the entire duration of their service life.

        AC Delco Iridium Spark Plug

        Bosch Platinum +4 Spark Plug

        For the excellent all-around performance it provides, the Bosch Platinum +4 spark plug is quite affordable. Whether for a high-performance vehicle or daily commuter, these spark plugs require almost no maintenance and offer reliable performance. Read Full Review

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          Why it's best:

          For the vast majority of drivers on the road today, the Bosch Platinum +4 can be considered the best all-around spark plug. The Platinum +4 achieves its high performance by employing four (as opposed to one) yttrium-enhanced ground electrodes. This creates a powerful, long-duration spark which is better suited to igniting the fuel/air mixture in any engine, high performance or not.

          This spark plug requires no gapping or maintenance - you can simply install these in the engine and 'forget' about them until the next time you need a tune-up. The price of the Bosch Platinum +4 falls neatly in between a traditional spark plug and Bosch's own Platinum IR Fusion model, meaning that these performance spark plugs can even be considered relatively affordable.

          Bosch Platinum +4 Spark Plug
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          11 comments
          • daniel.j.burdette daniel.j.burdette

          BOSCH=JUNK! Engine-killers!

          Posted on 5/9/2014 11:49 am | Reply
          • daniel.j.burdette daniel.j.burdette

          I have been selling auto parts since 1992. I would not nor will I EVER sell another Bosch spark plug to a living soul including my worst enemies! I have seen first hand the damage they cause, including destroying an engine in a Saturn of mine. The problem is, lack of quality control and cheap porcelain. The porcelain completely separated at the base of the threads of plug,and yep, you guessed it, electrode and all dropped into cylinder and rattled around,knocking a hole in piston and eventually shot through the side of the block. Junk! Junk! Junk! If you want good plugs, can't go wrong with NGK. I work in parts department at a Ford dealership,and of course, recommend Motorcraft for all OEM Ford applications, as well as AC Delco for GMs, Champion for Chryslers. NGKs will work in about anything,as I have run the V-Powers in my wife's Buick Lesabre 3800 V-6 for past 3 years,still running strong with excellent throttle response. Once again, I cannot reiterate enough...STAY AWAY FROM BOSCH IF YOU LOVE YOUR RIDE!

          Posted on 5/9/2014 11:47 am | Reply
          • dave.setnik dave.setnik

          I disagree with this list. While the Iridium Fusion type are much better than past Bosch plugs, they're still Bosch, and I will not use them. In my experience, Bosch platinums, plus-4, whatever, have been THE root cause of more driveability issues/check engine lights/poor fuel economy/etc than ANY other brand out there, period. They're always on sale, so people by them up like crazy. And I fill my trash cans in the shop with them. My choices are NGK, DENSO, AC/Delco, MOTORCRAFT. The ONLY time I will use Bosch or Champion, is when they came in the car from the factory. But there's a catch. You should buy them from your dealership, because the replacements, although the same brand, are NOT the same. Trust me on this. They always seem a little cheaper made to me, and most of the time have a different number or markings on them.

          Posted on 3/13/2014 10:21 am | Reply
          • dave.setnik dave.setnik

          I am a 25+year professional auto tech. I disagree with this lists order. First off, Bosch plugs (any type) have been the root cause of more driveablity issues/short life/check engine lights/etc than ANY other plug out there. Not my opinion...but a fact. NGK, DENSO, AC/DELco, and MOTORCRAFT plugs are excellent quality plugs that will go the distance. The ONLY time I use Bosch is when the vehicle calls for them. But you should buy them from your dealership, because the aftermarket ones, even though same brand, are different. Trust me, they are.

          Posted on 3/13/2014 9:50 am | Reply
          • pomysean pomysean

          Highly appreciated material about installation of spark plug.

          Posted on 4/27/2013 3:48 am | Reply
          • pat.treudy pat.treudy

          I think Denso should be #1 and Bosch #2, That's a OE Plug in most foreign car makes, Our 2006 Sonata still has the OE plugs in them and there Denso Iridium with 98,000 miles on them and the car still runs good.

          Posted on 3/20/2013 2:11 pm | Reply
          • ThinkingMan ThinkingMan

          Most all technicians tell me that the Bosch plugs have a short lifespan, and are the first to "foul-out". I put the E3s in my Van and they have performed excellently.

          Posted on 9/25/2012 8:37 am | Reply
          • pomysean pomysean

          please go to this site and choose the spark plug at your own choice.http://autoplicity.com/manufacturer/95-bosch-spark-plugs.aspx?categoryid=53

          Posted on 4/27/2013 3:50 am. In reply to ThinkingMan | Reply
          • motormax motormax

          I would have liked to know how the E3 spark plugs compared and if they lived up to the hype.. it doesn't look like they were even evaluated. I really don't like this site that much because they always include "value" as part of the testing criteria. To me when it comes to my 70k car the best value is the one that performs the best period and I NEVER get that with this site.

          Posted on 6/24/2012 8:49 pm | Reply
          • OilMan OilMan

          Try NGK Spark Plugs they are good plugs for the price and a good value. For more go to http://www.synthetic-oil-tech.com/1982486 to find more on NGK plugs and much more.

          Posted on 4/5/2012 11:13 pm | Reply
          • thegupta thegupta

          Hi William,I got a 99 Toyota Camry V6, and it's in a need of a tuneup. I read your list of "Best Spark Plugs", in particularly about the Bosch IR Fusion. However, in forums people say Bosch is not meant for Japanese cars. Thoughts? Should I go for the NGK or Denso?

          Posted on 12/17/2010 2:41 am | Reply