Any spark plugs proven to improve MPG?

[Galane]

Just got a 1997 Taurus LX Duratech DOHC V6 with 91,000 miles. Red metallic with tan leather. Moo-yeah.

Looks like it was fairly well maintained. Some of the fuel pipework is bright and shiny, obviously recently replaced and I found some old oval gasket under the hood which matches up with one of the connections, bolstering the replacement theory.

Without any service records I've no idea when the plugs and wires were last replaced, if ever. Looks like the only way to get at the back bank (with the engine in the car) is to remove the upper intake manifold.

Soooo, before I take the plunge on yanking bits off the engine that shouldn't have been designed so stupidly, does anyone have any info on spark plugs actually proven to provide higher MPG? Especially if tested in a Duratech V6 in a 3rd gen Taurus.

I don't mean manufacture claims, I want real world tests by real world people.

Major, if any, aero mods not going to happen because 99.999% of my driving is in town at 20~35 MPH.

[niky]

Typically, with a stock engine, the stock plug will give you the best performance. Especially if it's an NGK. Aftermarket multi-points or platinum/iridium do nothing that a brand new set of stock plugs can't.

Most dyno tests show no improvement, and on those that do show a difference, the difference is so incredibly slight that it is below the run-to-run variability of the test itself.

Those of us who use propane in our cars play around with different heat ranges to prevent plugs melting, but that's a very different proposition from a basically stock gasoline car.

[ChazInMT]

If you don't want to have to replace them after 15,000 miles you will want the iridium plugs or something designed to last 100,000 miles.

NGK has kick @$$ educational pages. Rock Auto has good prices on premium plugs. (I'm not affiliated with either, they've just been the best deal 4 me, I could care less what & where you buy)

Don't let ANYONE say "The plugs are pre-gapped, just put them in" Total BS! Check the gap on whatever plug you buy to your cars specification!
NGK on Gapping Plugs

Since most modern engines are 99.5% efficient at burning the fuel in the cylinder, I don't think there's much yer gonna do to help that using a spark plug. Most claims are hype. Prolly why this thread is in the Unicorn Corral

Look into Ford forums for advice as well, I know for my Honda there were plenty of opinions on spark plugs. I was able to sort of weed out the riff raff on them and came to the conclusion that 1 brand really was the safest bet for my Civic, so I went with that. You'll have to do your own search and come to your own conclusion on that.

Here's the Technical Overview of plugs from NGK, look at the FAQ's too for a goldmine of info.
NGK Spark Plug Technical Overview
These pages are very generic, they aren't hard selling or specing NGK at all, just straight dope on spark plugs from the peeps that make em.

[ConnClark]

The only thing that would improve mileage as far as sparkplugs go is having more than one per cylinder. Ask any pilot of a piston engine plane that does a magneto check on warm up. They will tell you that they get more power running off both sets of plugs than they do running on one set using the exact same throttle setting. This is due to a faster flame propagation through the cylinder from sparks starting in separate locations. Note, multi electrode sparkplug (3 or more) do not have the same effect because the spark only goes between the center and one of the other electrodes.

[gone-ot]

ConnClark, please forgive the pun, but I couldn't resist:

"...there's no replacement for DISPLACEMENT..." (wink,wink)

...as in "...physical displacement.." between two spark-producing plugs in one cylinder!

[Galane]

Pulled one plug today to see what was in it and condition. Autolite Platinum with the gap burned out to over 60 thousandths.

Time for new plugs. Oh. Joy. I get to remove the upper intake and a ton of other stuff. Would plugs with a bit of platinum on the side electrode be more wear resistant?

[TheIVJackal]

Galane, why not just re-gap the plugs? Or do they look obviously worn? Too add to this discussion, does opening the gap a little more than OE increase FE(Fuel Efficiency) or should I just follow OE Recommendations?
- Aaron

[Galane]

The center electrodes look good but the side ones are quite worn. I'll replace them with some new platinums. Looks like the upper intake gasket is thick, possibly with a metal core like the reusable transmission gasket. (Stamped right in the pan that it's reusable.)

I changed the transmission filter and fluid and engine oil and filter yesterday. Ford says it can use 5W-20 for a slight MPG improvement but with 91K on it I decided to stay with the original 5W-30.

Trans has that issue where once in a while it doesn't want to engage then suddenly does. I put some Lucas transmission stuff in it, had good results from it in other automatics and it also works great to quiet noisy power steering. I'm hoping the problem was due to the filter needing changed.

I also got a new accessory belt, had to make a tool just for releasing the tensioner. Bent the head of a 9/16" bolt over 90 degrees then milled it to a 3/8" square. Then I faced off both ends of a cheap six point 15mm 3/8" drive socket to get it short enough to fit between the tensioner and frame rail. Could Ford put a bit of a dimple in the frame there for more room? Oh heck noooo! That'd be too smart. Just like how they routed an exhaust pipe directly under the oil filter so it's impossible to not dump oil on it when removing the filter.

Same goes for V6 and V8 engines in front drives where large amounts of stuff like half the intake manifold has to come off just to change spark plugs. Can't the people who design these things be smart enough to figure out how to position things so there are holes through all the stuff to access the plugs?

Yet another "Good grief why?!" is all the vehicles where there isn't a hole directly under the radiator drain. Nooo, can't have that. Must have it so the coolant runs onto things that make it spread out and dribble from everywhere.
Two I've had to work on recently, 1995 Buick Century and 2004 Dodge Dakota quad cab. Grab the person responsible for the structure below the radiator, hold their ears and make them look at that part - "PUT A HOLE RIGHT THERE DUMMY!".

At least I have a single post in ground air/hydraulic lift in this 1950's vintage garage.

[Ryland]

The SAE has a book published that is all about spark plugs and the tests that they have done to test every kind of spark plug that they could find, it boils down to the fact that a spark jumps between sharp points or edges best and has a harder time jumping to a rounded surface, that is why it's not a good idea just to regap a worn spark plug.
The larger the gap the more fuel the spark is exposed to and the faster the flame spread will be but to large and the spark gets weak and inconsistant, the smaller the gap the stronger and hotter the spark will be, so you want a gap in the middle, large enough that the spark is exposed to fuel but small enough that it's a nice strong hot spark.
Platinum is hard and resists electrical wear, it is also a poor electrical conductor and expensive so they only put a thin layer of it on, I've also heard that there is only a few cubic yards of platinum on earth, so because of platinum being a poor conductor you get a slightly weaker spark, but because platinum doesn't wear very fast a spark plug can last many times longer, so if a copper spark plug needs to be changed every 15,000 miles, it might be safe to say that a platinum plug will perform about the same as a copper plug that has 10,000 miles on it but the platinum plug will last 100,000 miles and the platinum plug will perform the same over most of it's life.

There are also silver core spark plugs, silver being a better conductor then copper and from what I've read they really are better, but they also cost a lot more so you might never see the return in your fuel savings but you might see a slight boost in Horse Power if that slightly hotter spark is what you need.

[ConnClark]

Originally Posted by Old Tele man

ConnClark, please forgive the pun, but I couldn't resist:

"...there's no replacement for DISPLACEMENT..." (wink,wink)

...as in "...physical displacement.." between two spark-producing plugs in one cylinder!

Forgiven