The Most Fuel Efficient Spark Plugs
 

For awhile now, I've been attempting to deterime which company, by reputation or research, is reknowned for making the most fuel efficient spark plugs & wires. Now, just to be clear, I'm not expecting to get a drastic increase; however, I am looking to get a the best bang for my buck.

So far, I've seen everything from Iridium plugs(i.e. Denso & NGK) to platinum plugs(i.e. Bouch Platiniums, Platinum 4)to plantinum/iridium infusion, as well as something called the E3 sparkplug. I was wondering if anyone in the forum has had any experience with these along with any tips that could be offered.

Thanks.

first off... i have no idea if any of this is true, but heres my thinking on it

there is a problem with testing plugs, i think it would be difficult to test mileage gains of plug A vs plug B because the difference would likely only be few percent, maybe only 1 or 2% (new vs. new). just making test runs with a scangauge, the difference between runs without changes might be greater than the difference provided by the plugs. maybe if you did an A-B-A-B-A-B-A-B....... eventually you might have a significant result...

then i found this
https://www.sparkplugs.com/sparkplug4...Results&mfid=0
and there are other links on that page....

now heres my jump in logic.... i'd imagine the plugs producing the best torque, would provide the best mpg... whether it actually does... no idea

the best and 2nd best torque results went to 2 iridium plugs

the pulstar got best hp and 3rd best torque

the e3 wasn't tested with those plugs but on...
https://www.sparkplugs.com/files/SCRP-070700-UPGRADE.pdf
... the dyno chart which STARTS at 4400rpm, shows a loss of power from 4400-4800rpm, and a gain from 5200-6200... where i doubt i get very good FE

so anyways, the bang for the buck... i still wondered if those pulstars might be good... but theyre $25 a plug....

the ngk iridium looks like its $7-8 bucks

but for me, the 2 iridiums tested aren't available for my car, so heres jump in logic #2 the 2 iridium plugs had the best torque, perhaps all iridiums would have similar results... then just buy whatever iridium plugs you like for the best price.

There is only one problem with the tests sparkplugs.com did. They're all at WOT.

While you might think that doesn't matter, it does. At low RPM and throttle there can be massive gains had depending on your spark. There isn't as much air and fuel being compressed, velocities are down keeping the fuel from atomizing as well and a few other things like spark advance scheme and WOT enrichment tables.

We need some part throttle dynos to determine the best plug for FE.

I think there'd be more difference in mpg by changing the gaps rather than changing the brands. To change the gaps you have to upgrade to a stronger coil.

Wires definitely will make no difference. They either work or they don't. The best wires made are Magnecor, and only because you never have to replace them. And because they suppress interference.

Even when you change to a superior ignition system, ie. Coil-on-plug, you still really don't see much difference in mileage. Emissions maybe; but only under certain conditions. So there's not a lot a spark plug can do except last a long time, get a certain amount of heat out of the combustion chamber, try to get an even burn, and try not to get in the way of air flow.

Ignition timing on the other hand has a huge impact on mpg. But once you get it in the ballpark there is not a whole lot to be gained by getting it dead-on considering the cost of the dyno time to do so. When you look at the stock VX ECU calibration, you can see large blocks of the map are the same value. Theoretically ignition timing should change with engine torque and RPM but it doesn't seem to. Just load.

Interested to see if you get any results though.

Wires will make a difference. As they break down internally from carrying high voltage, the resistance of them increases. Over time they lead to misfiring. Which plug will yield the best MPG all depends on your goal. The best MPG from one tank or over the life of the plug? Platinum and iridium last longer than standard plugs. This keeps the engine running in tune for a lot longer, which is why you see many newer cars with 100K mile tune ups. Right out of the box, though, unless your current plugs are pretty worn its doubtful you'll notice anything at all.

One thing to be careful with is choosing the right plugs for your engine. There's been lots of problems associated with installing platinum plugs on engines that didn't come OE with them. Platinum and iridium are more durable but also have a higher resistance. A higher resistance will require a higher secondary ignition system voltage. Older ignitions and pretty well worn ones just don't have it. I've seen this happen when trying to run double plats in an engine OE equipped with single plats. The idling went to crap.

You can open up the air gap, but that leads to more stress and heat on the rest of the ignition components. Also, widening the gap can lead to cold start issues, as well as lower the power range of the engine. Take a spock plug and open it up .010" over stock and you'll notice top end power max out lower. Indexing the plugs is another useful item. Pretty common on racing engines and it involves using index washers to get the air gap of the plug so that it faces the intake valves.

I think with the higher resistance platinum plugs, there is also such a thing as "too much" secondary voltage... it's hard to find higher voltage output than on Ford or Mopar stock coils... and those are two of the brands that hate bosch plugs the most... what I think is happening is that the increased resistance at the plug is tending to force flashover and corona discharge further back in the wires, even when there's good wires on them. The set of platinums I had in made everything very sensitive to damp weather. These things are close gapped too... I think they are designed to maximise the spark duration of weak ignition systems.

Also, yes I've only just realised really that the claims of gas savings with these plugs are really just based on the "after 50,000 miles of no maintenance normal plugs suck" effect... and... I... just... can't.... seem.... to.... leave... my.... plugs.... alone.... for more than a year without pulling them, cleaning them and gapping them.

That is because you are someone who takes responsibility for making sure your car is in tune. Although every year might be borderline OCD by today's standards!

The only major difference a plug can make is for it to spark into the combustion chamber better to ignite the fuel more effectively. Like with the plugs that spark outwards from the end instead of sideways. Other than that, anything that ensures that they fire consistantly should result in consistant performance and if they can generate more spark energy via a bigger gap that doesn't stress the voltage limits of the electrical system providing the spark then that is good also. Usually a smaller diameter electrode made of a tougher material will do this i.e. irridium or platinum tip plugs as long as you increase the spark gap to take advantage of the small diameter electrode.

yup i agree with all of it.

wires are almost as important if not more important than the plugs.

it would be like having cloth covered frayed wiring in your house from the 40's and installing brand new fancy outlets. Doesn't make much sense.

yes certian plugs work best with certain engines. some of em run great on one brand and run liek crap on another.

like i do know that the 2.2L s-10 engine(same as you caviler guys) runs best on either the factory spec delco plugs ($6 a plug for some reason) or NKG plugs. BUT it runs like crap on the bosh plugs and autolites...

wires they aren't to picky on either delco wires or the next cheapest work good.

I beg to differ, I replaced my ex-g/fs 2.2 OHV cavalier plugs from new(looking) delco factory plugs to Autolite double platinums and had no issues for the 60k they were in there before the car got sold. My car used to have Bosch Platinum +2 plugs before i went with Pulstar plugs.

I think most of the issues people have with different brands of plugs is a lack of knowledge in gapping and such. Not every company is perfect. I've found NGK Iridium IX plugs(top of the line for them) that are +- .010" from the gap it should be set to(specified on the box), that's enough to cause problems in ESA equipped cars, reduced fuel economy and cause a rough feeling idle. I can explain why if anyone needs to know.