Premium spark plugs.

[radek22]

Curious of opinions about premium spark plugs. I've been using D8EA in my 1980 GS1100e, NGK apparently suggests DR8EIX (Iridium IX) as premium plug. Some reviews suggest improved start and fuel economy, wondering if they're worth the extra coin. Cheers

[fastbysuzuki]

I belive they are good but for me B8ES work fine so personally spending a lot extra makes no sense B8ES = £1-59 each
NGK BR8EIX = £8 each £32 for 4 no thanks 🙁

[Steve]

I have heard similar claims for easier starting, but I do prefer to actually push the starter button for that to happen.

With everything working properly, it only seems to take a stern look at the starter button to get the engine running.
If it started any easier, I wouldn't even have to look at it.

And since it starts that easily, why pay several times as much for "premium" (priced) spark plugs?

.

[Rust_to_Redemption]

The B8ES work perfectly for me; bike starts easy, cant really speak to fuel economy (its good enough), and at 1/3 the price of the iridium plugs, I can replace them 3x as often if I'm really worried about my plugs working optimally.

[Gorminrider]

So, go for it, radek, and report back! Maybe shop with fervour to get them a little cheaper if you can...?
I treated the Civic to fancy plugs once when they went on sale and it made me feel good...and it didn't do the civic any harm. It's hard to tell how much better they worked when the car's ICU was involved, and being a Honda, but the plugs lasted without any sign of degradation at the electrodes which is not so much the case with "base" plugs...

[LAB3]

The last four wheeled vehicle I owned, an Old van with a 3.8 V6 required the engine to be unbolted and tilted to get to the three plugs facing the firewall. At 125k miles the plugs where probably original and severely eroded, put in the four electrode top of the line platinum plugs and lifetime warranted plug wires. When I finally got rid of it with 325k miles the wires probably could have been replaced but the three plugs in front looked as good as new. As to my bikes, I've stuck with direct replacements since they're easier to get to.

[Rob S.]

My mechanic told me premium plugs were a waste of money.

I did, however, have to use special plugs years ago when my Z1 started fouling plugs (valve guides, probably) and I didn't want to sink any more money into it. The center electrode was just a thin strip of wire and they fired fine in oil.

[2BRacing]

I would much rather spend some time and money (if needed) to get the ignition system voltage drops/losses as low as possible, to ensure the (standard) spark plugs produce the strongest possible spark.

This will probably result in similar gains in fuel economy etc. than expensive platinum spark plugs can produce.

[radek22]

Thanks everyone for your input.

[bwringer]

Absolutely pointless on a GS. Just run the correct NGK plugs. From the factory, Suzukis used NGK and ND plugs, and nowadays NGK are a lot easier to find and very inexpensive.

Worse than pointless, actually, since fancy plugs take money out of your pocket that could be put to better uses. Like gas and tires.

And while the NGK iridium plugs are very high quality and wouldn't hurt anything other than your wallet, there are many stupid variants of turbo rocket jet blaster plugs that are very poorly designed and manufactured and will cause vehicles to run worse or can even cause damage. For example, most of these don't bother to make plugs in the proper heat ranges; they make a limited set of part numbers and cross-reference to anything with the same thread size.



All that said, I've found over and over again that modern fuel-injected vehicles also run best using the OEM plugs. Most cars and bikes use long-life iridium plugs nowadays, so don't just buy the cheapest thing the parts monkey says will screw in or the doofy plug-of-the-week he's pushing; figure out the OEM brand and part number, and use ONLY what the vehicle left the factory with. You'll avoid a lot of check engine lights and frustration.

[TxGSrider]

I have never seen any performance advantage to the Iridium plugs in real life applications except on vehicles that its hard to reach the plugs to change them (a v-6 fiero I once owned immediately comes to mind). They tend to last longer so I didn't mind spending the extra money with the idea that probably I wouldn't have to do it ever again. lol ...Stupid rear 3 spark plugs...

[Gorminrider]

From the NGK 2017 catalogue, the GSX1100 ET/X/Z/S/ESD,SZ ,SD (Katana) 79-85 wants
DR8ES-L
or DR8EVX (platinum)DISCONTINUED
or DR8EIX (iridium)

so, if you believe in NGK, any of these might be an "upgrade" from the D8EA you are using now. This is not a "resistor" plug I guess? but IMO ,givien the general trend of my reading, with any variety of electronic ignition, it's better to use a resistor plug.

[Steve]

From the NGK 2017 catalogue, the GSX1100 ET/X/Z/S/ESD,SZ ,SD (Katana) 79-85 wants
DR8ES-L
or DR8EVX (platinum)DISCONTINUED
or DR8EIX (iridium)

so, if you believe in NGK, any of these might be an "upgrade" from the D8EA you are using now. This is not a "resistor" plug I guess? but IMO ,givien the general trend of my reading, with any variety of electronic ignition, it's better to use a resistor plug.

With the nomenclature "DR8ES-L", I conclude that it is:
D - 12mm thread diameter
R - Resistor
8 - Heat range
E - 19mm thread reach
S - standard 2.6mm electrode
L - (not listed in the chart)

In just about any system, electronic or not, it is beneficial to have some resistance. There are three possible sources: wires, plug caps, plugs. You only need ONE resistor in the system. Most GSes left the factory with solid wires, 5kΩ caps and non-resistor plugs. If you have resistor caps, you don't want resistor or "suppressor" wires or resistor caps, as that would be two sources of resistance.

.

[Nessism]

On Kawasaki KZ bikes the factory often ran resistor or non resistor plugs in parallel, depending on year and market for the bike. For example, the 1982 KZ550 ran resistor plugs in Canada and Europe (except for Italian and Norwegian models) but non resistor everywhere else. I'm not sure exactly why, but bottom line is that using a resistor plug is unlikely to cause any issues even if you already have a sources of resistance in the system.

[Gorminrider]

You only need ONE resistor in the system. Most GSes left the factory with solid wires, 5kΩ caps and non-resistor plugs.

True...except I don't know which plugs it left the factory with.
My gsx400 shop manual allows for both types NGK D8EA or NGK DR8ES-L or (Nippon Denso) ND X24ES-U or X24ESR-U.
The Haynes manual, which covers the gsx400 up to 1985, has dropped the NGK D8EA from it's spec sheet.

Having tried both, I can't tell the difference. So why bother making resistor plugs at all?

I've done some online reading on this...From NGK, I read that the addition of an xtra 5k "resistance" has no consequence compared to the air gap of a spark plug, and that

Resistor plugs are used for two reasons --

1. They cut down electrostatic interference.

2. They provide a sharper "edge" to the voltage spike, making for
a stronger, shorter spark. On high RPM motors, this is important.

Of course they want to sell spark plugs, but for the paranoid out there, if they really wanted to rip you off, why not sing the praises of the (simpler?) D8EA and thereafter double the price?

however paraphrasing one author (Mike Nixon) ,discussing bikes "mostly older than 1979" (to me that implies bikes with points) partly considers that the resistance is a sop to AM radio AND that the benefit from reduced "resistance" is that you can increase the air gap for a longer spark. But he goes on to say much more...this should be taken in context with his whole article.

More from NGK

Many older ignition systems are based on lower voltage magneto set-ups. NGK resistor plugs use a high quality ceramic
material for the resistor construction, which provides a very stable resistance level, typically 5k Ohms. Even a magneto
ignition system can produce tens of thousands of volts, which is more than capable of running a resistor plug. The actual
level of resistance at the electrode gap under combustion chamber pressures is far greater than any resistor installed in a
spark plug. Resistor plugs can and are used by many owners with this system without any issues, providing the ignition
system is in good condition. Some owners successfully use the modern NGK Iridium 'IX' range of spark plugs in
conjunction with magneto ignition systems. One advantage of the 'IX' range is the use of a very fine-wire centre electrode
(0.6 mm diameter), which requires less voltage to create a spark, beneficial when using a low powered ignition system.