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Thread: Best Spark Plugs for Fuel Economy?

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    Senior Member Gnestovia's Avatar
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    Lightbulb Best Spark Plugs for Fuel Economy?

    Hey what's up guys, so I've been experimenting to see what could be the best spark plugs for my 2015 Mirage to get the best fuel economy. Now I do live out in the country and with what I have been getting depends on the driving (more likely nice and easy), I average around 50mpg. That with Denso Iridium Power Spark Plugs. Now I got to looking around and seen that NGK 5018 Platinum Spark Plug could do better. Not the case. Same driving conditions and nothing different my car dropped to 45mpg. So now I'm wondering, if maybe there is something better or should I just put the Denso Iridium Power Spark Plugs back in? But still, if appreciate any thoughts or ideas. Thank you!



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    Administrator Daox's Avatar
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    The big OE spark plug makers don't even claim any MPG gains from changing to this plug or that. If they could, I got to believe they would. The different 'grades' of spark plug are mostly about how long they last. Copper plugs live the shortest, platinum is next, followed by iridium which I've found will go over 100k miles typically.

    There are a few specialty plugs out there like Pulstar. I tried these about 10 years ago. They sent me a free set for evaluation. I keep track of my gas mileage a lot closer than most, and I didn't notice any difference. I ran those plugs for about a year until one died on me. I then swapped in my old plugs, and again I noticed no difference at all.

    Personally, I typically stick with NGK or Denso plugs unless I find something else cheap.
    Custom Mirage products: Cruise control kit, Glove box light, MAF sensor housing, Rear sway bar, Upper grill block

    Current project: DIY Nitrous oxide setup for ~$100

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 47.2 mpg (US) ... 20.1 km/L ... 5.0 L/100 km ... 56.7 mpg (Imp)


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    Senior Member Gnestovia's Avatar
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    Thank you very much! Well since there isn't any difference and Iridium last the longest, I'd just put them back in and leave it. I've read about Pulsar plugs as well. Lots of reviews stated they fail often. I've checked on E3 and they don't currently make them for the Mirage. Now for my Neon, a small difference. Nothing really worth boasting about lol.

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    Senior Member stevedmc's Avatar
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    Quote Originally Posted by Gnestovia View Post
    Hey what's up guys, so I've been experimenting to see what could be the best spark plugs for my 2015 Mirage to get the best fuel economy. Now I do live out in the country and with what I have been getting depends on the driving (more likely nice and easy), I average around 50mpg. That with Denso Iridium Power Spark Plugs. Now I got to looking around and seen that NGK 5018 Platinum Spark Plug could do better. Not the case. Same driving conditions and nothing different my car dropped to 45mpg. So now I'm wondering, if maybe there is something better or should I just put the Denso Iridium Power Spark Plugs back in? But still, if appreciate any thoughts or ideas. Thank you!
    OEM NGK plugs are the best for our cars.

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    Senior Member Mitz's Avatar
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    NGK's new Ruthenium HX .. anyone?

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    Senior Member stevedmc's Avatar
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    Quote Originally Posted by Mitz View Post
    NGK's new Ruthenium HX .. anyone?

    Name:  NGK Spark Plugs.jpg
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    The OEM NGK plugs are old fashioned style plugs that can be gapped. I don’t know anything’s by about rutinium but anything other than an old fashioned plug is just snake oil. Those platinum plugs that are gap less such as the ones sold by Bosch are garbage. If NGK is making a high dollar gapless plug than it is garbage as well.

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    Senior Member stevedmc's Avatar
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    Quote Originally Posted by stevedmc View Post
    The OEM NGK plugs are old fashioned style plugs that can be gapped. I don’t know anything’s by about rutinium but anything other than an old fashioned plug is just snake oil. Those platinum plugs that are gap less such as the ones sold by Bosch are garbage. If NGK is making a high dollar gapless plug than it is garbage as well.
    Please excuse my rant about those Bosch 4 prong platinum plugs which are garbage. I just did a google Search for the Ruthenium plugs and they actually look ok. I still wouldn’t recommend anything other than our OEM plugs though. I change mine every 100k miles and each time I’ve bern amazed at how nice the old plugs look. I feel stupid for replacing plugs in such good condition but I do it anyway as preventive maintenance.

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    Moderator Eggman's Avatar
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    Quote Originally Posted by stevedmc View Post
    I still wouldn’t recommend anything other than our OEM plugs though. I change mine every 100k miles and each time I’ve bern amazed at how nice the old plugs look. I feel stupid for replacing plugs in such good condition but I do it anyway as preventive maintenance.
    What brand fuel do you use?

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)


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    Senior Member stevedmc's Avatar
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    Quote Originally Posted by Eggman View Post
    What brand fuel do you use?
    I was using Racetrack and Walmart fuel for my first 200k miles. Eventually one of my fuel injectors got dirty, so I suspect. The car had a pretty bad loss of power upon accelerating.

    Now I only use top tier fuels such as Shell. I do a Techron treatment every time I get my tires rotated. Fuel problem is gone now and the car runs perfect.

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    Quote Originally Posted by Mitz View Post
    NGK's new Ruthenium HX .. anyone?

    Name:  NGK Spark Plugs.jpg
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    Interesting. This is the first I've heard of them. This is NGK's site on them:

    https://www.ngksparkplugs.com/ruthenium-hx

    They make quite a few claims.

    Today's technology allows for efficient designs that create more power while using less fuel. This has shortened the life of traditional iridium and platinum spark plugs. In response, NGK has created NGK Ruthenium HX, a high stability spark plug with twice the service life of NGK Iridium.

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    Some very interesting claims there. As far as ignition speed, thats basically what Pulstar says is superior about their plugs. They do claim an improvement in acceleration, but they don't say to what speed! Is that 0-60? 0-100? Is it 10 accelerations to 100 mph? Who knows. Its largely marketing gimmick unless we know the scale of that chart. That said, I think the main benefit of these ruthenium plugs would be their claimed twice the service life. This would make them basically good for the life of the vehicle.

    I would be willing to give these a shot, BUT I can not find any place selling the LFR5AHX plug which is the one that fits our Mirage 3A92 engine. So, nobody is selling them quite yet, and we have no idea what the price is.


    Custom Mirage products: Cruise control kit, Glove box light, MAF sensor housing, Rear sway bar, Upper grill block

    Current project: DIY Nitrous oxide setup for ~$100

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 47.2 mpg (US) ... 20.1 km/L ... 5.0 L/100 km ... 56.7 mpg (Imp)


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