Spark Plug Basic Knowledge (Denso)

Status
Not open for further replies.
Originally Posted By: PandaBear
http://www.globaldenso.com/en/products/aftermarket/plug/basic_knowledge/spark/index.html

Don't miss the video, it shows that sparks are generated at the "edge" of the electrode and not the center; that's why fresh plugs with sharp edges gives more "performance".


yawn...I could get 100K out of basic platinum plugs on almost any car. But marketing is freaking awesome and now I can get 2x the gas mileage out of any car with 3x the performance.
 
Originally Posted By: PandaBear
... it shows that sparks are generated at the "edge" of the electrode and not the center; that's why fresh plugs with sharp edges gives more "performance".

This is a good reason to go with platinum tipped plugs even if it's only one electrode. Small/sharp area that doesn't wear.
 
Originally Posted By: martinq
Originally Posted By: PandaBear
... it shows that sparks are generated at the "edge" of the electrode and not the center; that's why fresh plugs with sharp edges gives more "performance".

This is a good reason to go with platinum tipped plugs even if it's only one electrode. Small/sharp area that doesn't wear.

If you want a small sharp area that doesn't wear, you want iridiums. Both cars in my signature came with iridium plugs and the manual doesn't call for replacement until 100k miles due to their resistance to erosion. I recently put new plugs in the GP and most of the plugs looked good, despite it appearing that they were all original and had therefore been in the engine for more than 131k miles (bought at 131k). The only reason I found out that they needed to be replaced and were most likely the originals is that I got a misfire code.
 
Originally Posted By: NMBurb02
If you want a small sharp area that doesn't wear, you want iridiums.

The difference between iridium and platinum is very small but both are significantly better than the standard plug. You will find that iridium is usually priced significantly higher and this is usually only a single tip application. Dual-platinum should be significantly better than iridium but applications that would benefit are very rare I think.

What you'll also find is that the ceramic insulator gets layered with deposits that eventually will affect ignition performance. This can take a long while in a clean burning engine.

I find that the best value (by far) is a single-tipped platinum and I'd change those out every 2-4 years to keep the insulator and threads fresh. This will vary by application as I've found some OEM standard plugs that are $20 to $30 without a platinum option.

Quick example for one of my applications (RockAuto prices):

NGK 7133 $1.61 (std)
NGK 7084 $2.42 (plat)
NGK 3903 $6.45 (irid)
 
Last edited:
Originally Posted By: martinq
Originally Posted By: NMBurb02
If you want a small sharp area that doesn't wear, you want iridiums.

The difference between iridium and platinum is very small but both are significantly better than the standard plug. You will find that iridium is usually priced significantly higher and this is usually only a single tip application. Dual-platinum should be significantly better than iridium but applications that would benefit are very rare I think.

What you'll also find is that the ceramic insulator gets layered with deposits that eventually will affect ignition performance. This can take a long while in a clean burning engine.

I find that the best value (by far) is a single-tipped platinum and I'd change those out every 2-4 years to keep the insulator and threads fresh. This will vary by application as I've found some OEM standard plugs that are $20 to $30 without a platinum option.

Quick example for one of my applications (RockAuto prices):

NGK 7133 $1.61 (std)
NGK 7084 $2.42 (plat)
NGK 3903 $6.45 (irid)

I believe the main performance difference between iridium and platinum are the service lives of the plugs. Plats are meant to last 60k miles or less, whereas iridiums go as long as 100k. At the prices you listed, it doesn't make economic sense to go with iridiums unless the plats will only last 30k miles and you plan to keep the car for 100k+ miles.

That being said, spark plugs aren't a major investment, unless you replace them frequently or have an engine that requires a gaggle of them (like the '98 MB C280 I owned at one time - 2 plugs per cylinder, for a total of 12!).
 
Originally Posted By: NMBurb02
Originally Posted By: martinq
Originally Posted By: NMBurb02
If you want a small sharp area that doesn't wear, you want iridiums.

The difference between iridium and platinum is very small but both are significantly better than the standard plug. You will find that iridium is usually priced significantly higher and this is usually only a single tip application. Dual-platinum should be significantly better than iridium but applications that would benefit are very rare I think.

What you'll also find is that the ceramic insulator gets layered with deposits that eventually will affect ignition performance. This can take a long while in a clean burning engine.

I find that the best value (by far) is a single-tipped platinum and I'd change those out NGK 7133 $1.61 (std)
NGK 7084 $2.42 (plat)
NGK 3903 $6.45 (irid)
every 2-4 years to keep the insulator and threads fresh. This will vary by application as I've found some OEM standard plugs that are $20 to $30 without a platinum option.

Quick example for one of my applications (RockAuto prices):


I believe the main performance difference between iridium and platinum are the service lives of the plugs. Plats are meant to last 60k miles or less, whereas iridiums go as long as 100k. At the prices you listed, it doesn't make economic sense to go with iridiums unless the plats will only last 30k miles and you plan to keep the car for 100k+ miles.

That being said, spark plugs aren't a major investment, unless you replace them frequently or have an engine that requires a gaggle of them (like the '98 MB C280 I owned at one time - 2 plugs per cylinder, for a total of 12!).



Well in my eyes 6.45 per plug is nothing. I would rather get the longest lasting and not worry about it for alooonnnnnnnnnggggggg time. To each their own though. Any reason to work on your ride i guess!
 
Originally Posted By: NMBurb02
2 plugs per cylinder, for a total of 12!).

Yep! That sure is a bunch-O-plugs!!
 
Originally Posted By: Rolla07
I would rather get the longest lasting and not worry about it for alooonnnnnnnnnggggggg time. To each their own though. Any reason to work on your ride i guess!

I've had some rough experiences with OE plugs that were left in until the scheduled change. I like to swap them (or at least inspect) before going in for an e-test. Part of maintenance and easier than rethreading or swapping a head.
 
There's a 2010 Toyota Yaris with 200,000mi on it that comes by my place. It's a neglected officer patrol car. I'll see if I can pull a spark plug off that engine.
 
Originally Posted By: wirelessF
There's a 2010 Toyota Yaris with 200,000mi on it ...

How is that possible?
shocked.gif


I would think the plugs should be easy enough to get out as they're not even 4yrs old.
 
Originally Posted By: martinq
Originally Posted By: wirelessF
There's a 2010 Toyota Yaris with 200,000mi on it ...

How is that possible?
shocked.gif


I would think the plugs should be easy enough to get out as they're not even 4yrs old.


Must be owned by the same guy who owns the 2007 Yaris with 400k + miles. lol
 
Originally Posted By: NMBurb02
Originally Posted By: martinq
Originally Posted By: NMBurb02
If you want a small sharp area that doesn't wear, you want iridiums.

The difference between iridium and platinum is very small but both are significantly better than the standard plug. You will find that iridium is usually priced significantly higher and this is usually only a single tip application. Dual-platinum should be significantly better than iridium but applications that would benefit are very rare I think.

What you'll also find is that the ceramic insulator gets layered with deposits that eventually will affect ignition performance. This can take a long while in a clean burning engine.

I find that the best value (by far) is a single-tipped platinum and I'd change those out every 2-4 years to keep the insulator and threads fresh. This will vary by application as I've found some OEM standard plugs that are $20 to $30 without a platinum option.

Quick example for one of my applications (RockAuto prices):

NGK 7133 $1.61 (std)
NGK 7084 $2.42 (plat)
NGK 3903 $6.45 (irid)

I believe the main performance difference between iridium and platinum are the service lives of the plugs. Plats are meant to last 60k miles or less, whereas iridiums go as long as 100k. At the prices you listed, it doesn't make economic sense to go with iridiums unless the plats will only last 30k miles and you plan to keep the car for 100k+ miles.

That being said, spark plugs aren't a major investment, unless you replace them frequently or have an engine that requires a gaggle of them (like the '98 MB C280 I owned at one time - 2 plugs per cylinder, for a total of 12!).


That's it, only 12? I have 16 in my Hemi Magnum and I change them every 40,000km (25,000mi) whether she needs them or not, and I shell out the big bucks: either Bosch Platinum +4 or NGK Laser Platinum. Gran tit, I am running significantly higher horsepower and a turbo setup, but any spark plug SHOULD be a major investment.

And, if you have an S/C Grand Prix ('06 GT) which I think you have, then I would definitely suggest you run Autolite Iridiums or NGK Laser Iridium in that beast or you are going to have some issues later on down the road - I have one myself.
 
Originally Posted By: TheBig2003
And, if you have an S/C Grand Prix ('06 GT) which I think you have, then I would definitely suggest you run Autolite Iridiums or NGK Laser Iridium in that beast or you are going to have some issues later on down the road - I have one myself.

So what kind of problems 'down the road' are the sparkplugs going to cause?
 
I have special Denso iridium plugs in my Corolla. The plugs are a long reach spec or something that is not common. The manual specifies plug changes at 192,000 km or 120,000 miles. ...they cost $14 each.

I just use NGK platinum's in the GM products and will change them every 100K kms or 60K miles.
 
Originally Posted By: martinq
Originally Posted By: PandaBear
... it shows that sparks are generated at the "edge" of the electrode and not the center; that's why fresh plugs with sharp edges gives more "performance".

This is a good reason to go with platinum tipped plugs even if it's only one electrode. Small/sharp area that doesn't wear.
I believe these multiple ground electrode designs shroud the spark. I use single ground NGK platinums in my Toyota products as listed in the NGK application book for the car. This is despite a stealer droid telling me I had "the wrong plugs" during one of the few times I actually was forced to bring a car there. I asked WHY they were wrong ( How dare I ) since the plug is LISTED in the NGK book as an application for that engine and was told "they 'pull' too much". I said, "explain that to me in terms an Electrical Engineer might understand".... I got a blank stare but they REMOVED the 15 dollar replacement plugs they were trying to stick me with. When I "read" the plug they waived in my face telling me it was "wrong"....gap OK, color OK, electrodes not worn, they backed WAY down. That set of plugs has about 75K on it now, and the car just passed the California based emissions test my state uses. Go figure.
 
Status
Not open for further replies.
Back
Top