are expensive spark plugs worth it?

[91LegLS]

I've searched this database on "spark plugs" before asking this question. Recently, I removed the Delco plugs and installed the NGK's recommended by the owners manual, and I'm averaging 22-23 mpg in city driving. Will making an investment in a more expensive plug that promises better performance be worth the time and money?

 

Are platinum, iridium and copper plugs worth the effort? Do plugs with split or multiple electrodes (the piece of metal that curves at the end that screws into the engine for you newbies) make a difference?

 

I guess this type of question is related to using higher octane than is recommended or the best type of oil to use in your engine, but I'm still curious.

[nipper]

I've searched this database on "spark plugs" before asking this question. Recently, I removed the Delco plugs and installed the NGK's recommended by the owners manual, and I'm averaging 22-23 mpg in city driving. Will making an investment in a more expensive plug that promises better performance be worth the time and money?

 

Are platinum, iridium and copper plugs worth the effort? Do plugs with split or multiple electrodes (the piece of metal that curves at the end that screws into the engine for you newbies) make a difference?

 

I guess this type of question is related to using higher octane than is recommended or the best type of oil to use in your engine, but I'm still curious.

 

Just go with OE plugs for subarus. Some cars will do better with upscale plugs, some do worse. Subarus are finickey and like the plugs that are recomended,

i had a motorcycle that i put platnum plugs in and it hated them. Switched to the regular plugs that kawi recomended and the bike ran like a top.

Remeber plug performance between brands, there is no true standard. There is a wide range of acceptable perfomance between plugs, this is what a champion vs a NGK can be the same heat range, but so differnt. One can be at the top of the heat range, one can be at the bottom, and hence have totally differnt performance. Stay within the recomended faimily of plugs.

 

nipper

[Setright]

Well, I fitted the NGK Iridium plugs in my engine, but the main objective was to avoid replacing the standard spec splugs all the time.

 

I was running into changing them twice a year to do mileage. Since gaining access involves removing the air intake on one side, and the battery/sprinkler tank on the other, I was getting fed up.

 

The Iridium plugs haven't given me any discernable advantages - you'd need a dyno run before and after to measure the minimal gains.

 

Fancy multide electrode stuff is often rejected by Subaru engines, so that's not worth any extra money.

[PetterFan]

Stick with stock plugs. It seems that Subarus dont like anything else other than the stock ones.

[nipper]

Well, I fitted the NGK Iridium plugs in my engine, but the main objective was to avoid replacing the standard spec splugs all the time.

 

I was running into changing them twice a year to do mileage. Since gaining access involves removing the air intake on one side, and the battery/sprinkler tank on the other, I was getting fed up.

 

The Iridium plugs haven't given me any discernable advantages - you'd need a dyno run before and after to measure the minimal gains.

 

Fancy multide electrode stuff is often rejected by Subaru engines, so that's not worth any extra money.

 

ok i need to ask, how many miles do you drive a year and what do you have under the hood. I dont know how good the fuel is over there, but here in the U.S. we run a long long long time with facotory plugs.

 

i am seeing mileage intervals of 30,000 miles or 60,000 miles with planum plugs on www.cars101.com. I personally drive the plugs till i need to replace them (a miss or something). I think subaru is way too conservative on thier plug mileage and can go much farther. A lot of cars go 100,000 miles before they need plugs.

Some maint intervals can be ignored.

 

nipper

[firstwagon]

Stick with stock plugs. It seems that Subarus dont like anything else other than the stock ones.

 

What brand is stock for Subaru?

 

There are no Subaru dealers near me and I don't want to go for a 1 hour drive to get a set of plugs.

[nipper]

What brand is stock for Subaru?

 

There are no Subaru dealers near me and I don't want to go for a 1 hour drive to get a set of plugs.

 

 

www.cars101.com , (maintanence or archive) see if your engine/model is there, If not it may be on a sticker under the hood. You can also call the dealer and he may tell you, that way you can buy them locally.

 

nipper

[Setright]

In Kilometers:

 

Standard copper core plugs are listed in the handbook as lasting 25,000km.

 

I was doing 45~50,000km a year.

 

 

Platinum would've been fine, but NGK seem to have gone off the idea in Europe and Iridium was the only choice for stretching the plug service interval to 100,000km.

[brus brother]

Once again, the Grand Poobah Nipper is spot on. I have been wrestling with pinging for many years and in an attempt to reduce it, I switched to a cooler plug. NGK wasn't available so I went with the cross referenced Autolite and wasted my money. The pinging was worse. As per Nippy's suggestion, I finally got the NGK cooler range plug and there seems to be some improvement but certainly better than the Autolite experiment.

Just go with OE plugs for subarus. Some cars will do better with upscale plugs, some do worse. Subarus are finickey and like the plugs that are recomended,

i had a motorcycle that i put platnum plugs in and it hated them. Switched to the regular plugs that kawi recomended and the bike ran like a top.

Remeber plug performance between brands, there is no true standard. There is a wide range of acceptable perfomance between plugs, this is what a champion vs a NGK can be the same heat range, but so differnt. One can be at the top of the heat range, one can be at the bottom, and hence have totally differnt performance. Stay within the recomended faimily of plugs.

 

nipper

[91LegLS]

What brand is stock for Subaru?

 

There are no Subaru dealers near me and I don't want to go for a 1 hour drive to get a set of plugs.

NGK is what my dealer stocked in Subaru boxes. My owners manual listed three manufacturers (NGK, Nippondenso and Champion) and the part number for each plug. It also listed the recommended spark plug gap.

[91LegLS]

Once again, the Grand Poobah Nipper is spot on. I have been wrestling with pinging for many years and in an attempt to reduce it, I switched to a cooler plug. NGK wasn't available so I went with the cross referenced Autolite and wasted my money. The pinging was worse. As per Nippy's suggestion, I finally got the NGK cooler range plug and there seems to be some improvement but certainly better than the Autolite experiment.

 

I thought "pinging" was related to the grade of fuel being used. Are you using the lowest grade available and does it meet the recommended octane rating listed in your manual? My book says minimum is 87 or mid-grade for me, 91 for turbos. I have tried using the lowest grade and I was pinging a little. I then dumped some octane boost in the tank and the pinging stopped.

[brus brother]

So do you add octane boost every tank??$? I am using 87 octane as spec for car. The cooler plug was a suggestion from the site and agreed upon by subaru tech who has tried every other trick in the book to remedy this pinging situation which existed from day 1 for the car. This included flashing the computer, new plugs, air and fuel filter, checked and replaced timing belts, changed knock and MAP sensor, head gasket and checked and removed any trace of carbon, cleaned throttle body and did upper engine cleaning with Subaru top engine cleaner and Seafoam.I've been using the new plug for less than a week but the pinging seems to be reduced. The problem is definitely related to ambient temp and humidity so I'll give it a little more time before posting the actual results.

I thought "pinging" was related to the grade of fuel being used. Are you using the lowest grade available and does it meet the recommended octane rating listed in your manual? My book says minimum is 87 or mid-grade for me, 91 for turbos. I have tried using the lowest grade and I was pinging a little. I then dumped some octane boost in the tank and the pinging stopped.

[nipper]

I thought "pinging" was related to the grade of fuel being used. Are you using the lowest grade available and does it meet the recommended octane rating listed in your manual? My book says minimum is 87 or mid-grade for me, 91 for turbos. I have tried using the lowest grade and I was pinging a little. I then dumped some octane boost in the tank and the pinging stopped.

 

ive explained this a few times. Octane has to do autoignition http://auto.howstuffworks.com/question90.htm . Now ping from too hot a plug is not autoignition, since the plug is setting off the charge. A spark plug has a heat range, and this heat range refers too directly how much heat a spark plug retains. You dont need a an electric spark to set the mix on fire, a hot spot will do. When its a plug that sets it off due to heat and not a spark, its ping. Octane can help with this, but since its not ignition form compression, it wont really help all that much.

 

nipper

[cookie]

All I have to say on plugs is that a while ago Jaime reccomended stock plugs and wires for my 99 2.5. I now have 128,000 miles on the engine, much of it in traffic. no pinging, no other odd problems. Friday it passed a smog test with numbers so low that the mechanic remarked it was exceptionally well maintained.

It has had the plugs, wires, air cleaner, PCV, and a front oxegen sensor in the last year.

Except for the air cleaner (Purolater) I'm using all stock parts as reccomended by many folks on this board. They sure seem to work. If I had pinging and it was not carbon I would try one heat range cooler plugs, but I don't so I won't.

[BigMattyD]

I am just posting my opinion, but I have used the cheap autolite plugs and had no problems with pinging, misfires, or performance. They also lasted quite a long time. I inspected them about once a year. My plugs are easy to get to, but if they were not, I would use the longest lasting ones possible.

 

matt d

[brus brother]

I didn't mean to trash Autolite plugs. What Nipper accurately pointed out to me is that though the cooler NGK plug was accurately cross-referenced to an Autolite plug, the issue of temperature range was better addressed by staying within a manufacturer since it is in fact a "range". The pinging issue was much resolved when I went back to the NGK series and experimented within their ranges. With some trial and error, likely there is an Autolite plug that would suit my needs but for the moment, I was able to eliminate one possible variable by staying within one manufacturer.

I am just posting my opinion, but I have used the cheap autolite plugs and had no problems with pinging, misfires, or performance. They also lasted quite a long time. I inspected them about once a year. My plugs are easy to get to, but if they were not, I would use the longest lasting ones possible.

 

matt d

[Commuter]

Back to the original question...

 

My 97 OB calls for platinum plugs every 96k km. Around the 200k km mark, I decided to try the TorqueMaster plugs. I found a reference to them on Magnecor's website. (They were the only brand of plug mentioned at all on the site.) I'm not sure what has happened to the company. They were in the States (Calif I think), but the website disappeared a while ago. It was very much a "ma and pa" operation. I spoke directly with the inventor of the plug several years ago. You can see some info on the plugs at this site. A very interesting design.

 

Long story short, I changed them out about 6 months ago at 470k km. Due to an engine change, the plugs were not in my engine for a brief period, but in all, I put around 240k km on the plugs. Upon inspection, they looked like they would have gone another 100k km! A couple were showing some wear of the center electrode. The other 2 had just a trace of wear.

 

Did I experience any increased performance, or gas mileage, or "something"? No. Did they 'feel' any different? Not that I could really tell. Perhaps just a hint smoother idle, but that might have just been me looking for something. Did they give me any problems, with that wide gap? No!

 

My interest in trying them at the time was due to my issues with some carbon build up in the engine. I thought that if this plug caused a slightly better burn, it could only help.

 

At the time I bought them, they were $14.50 US. When I changed my plugs recently, the dealer charged me around $23 Cdn for the platinum plugs! This is about double what I last recall paying.

 

If I had known that I could still source these plugs, or if I had been there to see just how the plugs were, I probably would have told them to put them back in. (I don't change my own plugs and I work a long ways from my dealer.)

 

So... something for people to mull over. I haven't read thru the site link I provided above. That is, I don't know if it is current, where it is, etc. I just found the link quickly and it provides a picture of the plug design. I just thought I'd pass along my experience.

 

Years ago, I also stumbled upon a web site with a "sonic plug". It had a tuned blind hole in the center electrode (I think) and another hole in the ground prong. The theory was that the explosion from the spark caused a sonic shock wave inside the combustion chamber, thereby further atomizing fuel droplets, helping to increase fuel burn, etc. I tried to contact them, but was unsuccessful.

 

Fun stuff out there. Someone is always trying to build a better mousetrap.

 

Commuter

[nipper]

looking at the charts, i dont see much of an increase. Also word to the wise, unless they specify the conditions and engines, fuel and ambient (temp humidity barometer) the test is not valid. Also it takes more thenone test to determine an increase. There is also a correction factor that is required to compensate for change in weather conditions from run to run. Also with such limited increase in performance, if it is a real increase, what works on car a may not work on car b.

Also if it was a tue valid test they wuld stae the location of the test, and the calibration date of the dyno, and the brand of dyno. Ive seen this all stated in other performance magazines when they do tests. You need a certin level of increase to get out the "error" zone to make it valid.

If i remeber correctly they were sold here as for afew years as oil burning plugs. If you had a tired engine that burned oil, they wouldnt foul (and they worked well that way).

Be very leary of dyno tests without the proper given info, otherwise they are just selling snake oil.

 

nipper

[Commuter]

I'm not proposing that the TorqueMaster plugs are going to increase your performance. I indicated that I did not find that to be the case personally. This is typical marketing people playing off any edge they can find.

 

However, if you want a plug that you can put in and forget about for a long time, it might be work pursuing. My experience is just that - my experience.

 

Commuter

[nipper]

PS

http://www.se-r.net/engine/platinum_copper_ngk.html

http://forums.nasioc.com/forums/showthread.php?t=518633

http://www.modularfords.com/forums/2003-2004-mustang-cobra/brusk-plug-spark-pattern-picture-14475-print.html (brings up an excellant photoshop point)

once the spark jumps to a ground, its jumped. Thst it, you wont get a multiple path of current.

i looked everythwere for a valid test for these things, i cant find one, so im calling it snake oil.

 

nipper

[cookie]

The stock plugs are a couple of bucks a plug. The phase 2 2.5 engine is easy to change plugs on. May as well stay with stock.

Now if I had a phase 1 2.5 that I've heard a number of you folks discuss the difficulty of changing a plug on, I would seriously consider a plug that lasted a long time. My BMW has 90,000 mile plugs and they seem fine at 7 years old.

Perhaps one should consider the individual car before selecting a plug.

[Commuter]

once the spark jumps to a ground, its jumped. Thst it, you wont get a multiple path of current.

i looked everythwere for a valid test for these things, i cant find one, so im calling it snake oil.

 

nipper

nipper, perhaps you can search for me? At the time I was investigating these plugs, I found an excellent article from one of the spark plug manufacturers (I forget which one) about the various phases a spark goes thru from its initialization, to the 'main' spark to its collapse. It all happens in a split second, but it is not as steady state as one might think. One of the things I remember reading, is that once the spark develops, the resistance along that path increases. The spark will look for the path of least resistance, so it may develop a new path to another ground. I believe this is the argument behind the multi-ground plugs. One can actually get multiple sparks during a single "spark". In the case of the TorqueMaster plug, with its continuous fully surround ground, the spark doesn't have to jump, but it 'shifts' sideways, and continues to do so, and hence, ends up spinning, creating that 'disk' of sparking.

 

Yes, a lot of things are snake oil, but in my experience, there is often some bit of science behind it all. Unfortunately, marketing and unscrupulous advertising usually blow it all out of proportion.

 

Happy searching.

 

Commuter

[Soutthpaw]

Found this thread as i was looking to see if people had specific issues with any plugs. anyhoo i looked on NGK's website and they say the Double platinum is the OEM plug for my 97 OB

http://ngk.com/results_app.asp?AAIA=1270022

 

If you want to understand more about their plug coding see this link

at the bottom of the sidebar is a link to their plug designations

http://ngk.com/sparkplug411.asp

Just about everything you ever wanted to know about spark plugs is here...

[jon38iowa]

ok i need to ask, how many miles do you drive a year and what do you have under the hood. I dont know how good the fuel is over there, but here in the U.S. we run a long long long time with facotory plugs.

 

i am seeing mileage intervals of 30,000 miles or 60,000 miles with planum plugs on www.cars101.com. I personally drive the plugs till i need to replace them (a miss or something). I think subaru is way too conservative on thier plug mileage and can go much farther. A lot of cars go 100,000 miles before they need plugs.

Some maint intervals can be ignored.

 

nipper

I agree on the longevity of the Subaru plugs, but I still recomend taking them out every 35k to clean and inspect, moreover, If left in too long the plugs might be very tough to remove.

John

[unobtainium]

Those Torque Master plugs look a whole lot like the Lodge plugs used in Alfas. http://www.international-auto.com/index.cfm/fa/p/pid/2527/sc/8140

 

Alfas, BTW, are where I learned to follow manufacturer's recommendations. The Alfa engine really wanted Lodge plugs, and tinkering with other ones was a waste of money.