Anybody beside BillionPa use Iridium Spark Plugs? [Archive]

gale

12-02-2006, 08:34 PM

I ran the original Denso Iridiums in my Toyota 4.7 V-8 for 100k miles and they looked to be in very good condition when I replaced them. I did remove them at 31k to put a slight bit of anti-sieze on them so they would still come out at 100k. I replaced them with the same plug. Autohaus AZ had good prices. I got mine at our local Checkers for about $1 more. Do not try to gap them, the tip is really skinny & is harder than a feeler gage and can dig in and snag and snap the tip off. They should come with the correct gap for your engine. I'm thinking iridiums should do very well in most modern engines as long as there is a direct part number for a given application.

Eric540i

12-03-2006, 02:06 AM

Apart from their longevity, are there other benefits such as significantly reduced fuel consumption and perhaps some extra oomph?

BillionPa

12-03-2006, 03:12 AM

yes.

BillionPa

12-03-2006, 03:13 AM

TC535i

12-03-2006, 03:40 AM

I use em in my supercharged 318, cuz it's the only plug I can get in a colder heat range than stock. Happy with them there, but I like stock range replacements in my stock cars.

Boom n Zoom

12-03-2006, 06:12 AM

Yes, have them onboard, better burn with the 98 octane BP Ultimate that I use (Australia)

In cruise mode on the freeway I get around 8.4 L/100kms this is with the cruise control, but I have been able to get it down to 7.9 if I take the throttle.

Before with the Bosch standard plugs it was reading 10.3 L/100kms on the same trip from Brisbane to the Gold Coast (about 100kms one way) A/C on (set at 21 degrees C) in drive, two adults and two kids, 80+ litres of BP Ultimate (98 octane) no luggage, average temperature day (28 degrees C), reasonable traffic never dropped below 100km/h, mostly sat on 115kp/h. Cruise control on the way down and all me on the way back.

Yeah the fuel economy increase is a very pleasant surprise, the 'seat of the pants' o meter indicates that above 3500/3800 (indicated rpm) it is stronger than before and it wails up the the 7000rpm limiter very easily (Yeah it's chipped)

I personally think it is well worth the cost of putting the Iridium IX 's in. 100K (kms) of trouble free cracker life for AUS$187.00 well worth it in my book.

Your mileage may vary :)

Eric540i

12-03-2006, 07:08 AM

Do you notice much difference burning the 98 octane?
I treated myself once to the stuff (Shell optimax - or something like that) and found little difference. May be a few tank fulls are necessary?

A few years ago I used the premium stuff in an older car (a Mitsub. Magna, when I lived in Aus.) and its cleaning agents were so effective that the car ran like a dog thereafter. Apparently accumulated gunk that had successfully sealed various leaks and such in the fuel system just got cleaned out.

I best I've managed to extract from my 540i is 8.2l per 100km. I was mighty impressed. It was hot (30°C), I was carrying a passenger with our bulky luggage, a/c use was intermittent and I was cruising at 120km/h with short burst exceeding that for 600km. Indeed I find that the M60 uses less fuel at 120km/h than 100km/h.

Boom n Zoom

12-03-2006, 08:03 AM

Do you notice much difference burning the 98 octane?
I treated myself once to the stuff (Shell optimax - or something like that) and found little difference. May be a few tank fulls are necessary?

Oh yeah!

Shell Optimax, bad, bad stuff here in Oz. Has such a high detergent level that Ducati Australia 'recommend that you avoid using Shell Optimax in their entire range of motorcycles'

I ran it a couple of times in my '93 Ducati 888, not very good wouldn't rev cleanly, guy I was riding with (on a '02 800 SS) dropped a cylinder on the highway cruise home. Needless to say he was not impressed. EDIT: That is to say it fouled the plug up so much that it stopped fireing on one cylinder..........of two, for those who are not bike heads :)

I have since sworn off the stuff and will never fill with it again.

The BP Ultimate advertises 'Up to 43kms per tank extra range with constant use' I currently fill once every two weeks (75 Litres approx, some weeks its a little more some weeks a little less) but I get an average of 480kms per tank every fortnight running in peakhour stop/start traffic everyday and occasionally (call it once a month if I'm lucky) a bit of a run through my favorite twisty's on a sunny Sunday.

Good gear the Ultimate, swear by it, brilliant on long trips.

Have a write-up in the back of a bike mag (somewhere here) that I will scan and post sometime about the quality of BP's Ultimate fuel and what goes into producing it, great article.

Cheers! :)

BigKriss

12-03-2006, 08:18 AM

Where is the cheapest place to purchase the iridium spark plugs? A quick look through google resulted in usd$10 each for product number: IW16 for the m30.

Eric540i

12-03-2006, 10:43 AM

Boom 'n Zoom: thanks for info, I shan't Shell out for some Optimax.
I hadn't realised there was such a difference between fuels. How much is BP Ultimate in Aus.? In Europe premium fuel commands a premium price.
BigKriss try www.sparkplugs.com or on eBay the seller daveknowsdeals - both ship to international destinations and they're the cheapest suppliers I've found.

Jon K

12-03-2006, 11:31 AM

well, not significant fuel consumption. if you make use of that extra oomph, then the fuel consumption will go up. there is only about a percent or 2 extra torque, but the more efficient electrode design smooths out the curve.

I am sorry to rain on this parade. You are not getting any more power from sparkplugs. What you're doing is comparing new spark plugs to used spark plugs. Saying "I used to get x mpg with my old boschs and now I get y mpg..." would happen if you just put new stock spark plugs in! Iridium is not recommended because the only way they last a long time is if you never have a problem with your engine enrichment - meaning if your O2 goes bad, or something causes the engine to run the slightest bit rich, you will foul those electrodes in no time.

Please do not say that you gain 2% torque by using different spark plugs. They do not do anything different than ordinary plugs. You're saying a small electrode is smoothing out your torque curve?!

The only purpose of iridium plugs is to prolong the life. The iridium metal wears less than copper. That's it. However, if you can't take the time to change your plugs every 30k miles, I think it's time to re-evaluate your maintenance! Some people run the iridium (like Tim) because they come in a heat temp they need while the copper do not - thats not to say copper can't, the manufacturer just doesn't offer one (supply vs demand).

Spark is spark. If you're getting enough spark to fully ignite your mixture, then you're fully igniting the mixture. If you're not getting enough to be efficient (old grosssed up plugs...) then that's your problem and the "performance boost" you feel is due to an improper burn to begin with. I have tested about 10 or 12 different plug combinations on my motor (being turbo it can be finicky) and have finally found the perfect match: NGK BKR7E's copper V-groves, $1.7 ea locally.

Bill R.

12-03-2006, 11:45 AM

Think again Jon. Denso has it well documented by published labs and dyno testing on their plugs. just going to their tuners tales pages i found these dyno tests
(http://www.densoiridium.com/tunerstales.php)
And somewhere on their website they had posted their original lab testing which did verify a slight increase in power and efficiency over standard plugs. I didn't spend any time hunting it down but i saw it a couple of years back and posted it on here when i first got interested in trying iridium plugs.

I am sorry to rain on this parade. You are not getting any more power from sparkplugs. What you're doing is comparing new spark plugs to used spark plugs. Saying "I used to get x mpg with my old boschs and now I get y mpg..." would happen if you just put new stock spark plugs in! Iridium is not recommended because the only way they last a long time is if you never have a problem with your engine enrichment - meaning if your O2 goes bad, or something causes the engine to run the slightest bit rich, you will foul those electrodes in no time.

Please do not say that you gain 2% torque by using different spark plugs. They do not do anything different than ordinary plugs. You're saying a small electrode is smoothing out your torque curve?!

Jon K

12-03-2006, 11:54 AM

Think again Jon. Denso has it well documented by published labs and dyno testing on their plugs. just going to their tuners tales pages i found these dyno tests
(http://www.densoiridium.com/tunerstales.php)
And somewhere on their website they had posted their original lab testing which did verify a slight increase in power and efficiency over standard plugs. I didn't spend any time hunting it down but i saw it a couple of years back and posted it on here when i first got interested in trying iridium plugs.

Bill we've dyno'd cars back to back without any changes and they'll be peaky just like those (fake) dynos on Denso's site shows. 1 ft lb torque on an SAE corrected graph is considered variance in the hardwares ability to meter. Being heavily involved in BMW forced induction forums, if these plugs were free "13.5 hp" as claimed by the Denso site, a lot more people would be using them. The truth is though the small 0.4mm electrode fouls real easily. I don't see how they can consider 1 ft lb difference justifiable to publish. I bet they had numerous other dynos that dyno'd lower.

This is funny: This stock Civic Si experienced a 4 horsepower gain with the help of DENSO Iridium spark plugs!

then above it reads:

99 Si Stock, 2-1/4 inch exhaust, Random Tech Hi-Flow Cat, Mill 0.040

So its got exhaust and hiflow cat plus raised compression... stock :)

I just don't want to see people run out and drop close to $70 on sparkplugs and thinking their getting cheap horsepower. I know Qube is the type of person to test stuff - someone should put brand new NGK copper stock temp spark plugs in. Drive. Come back, swap in Iridium stock temp plugs and drive. I am willing to wager NO difference.

Montreal525

12-03-2006, 12:44 PM

I've been using NGK Iridium for the past month now and apart from the obvious better efficiency feeling you get from new plugs, which is now gone, Iridium spark plugs ARE NOT WORTH IT... I've been monitoring my consumption for the last 5 fill-ups, driving highway and city, using 91 octane and it's all the same. So, unless you need them for special applications, ie colder operating range or whatever, you don't need Iridium's plugs. It's the same results as with my old Bosch twin tips and now I feel that even that was overkill... No more for me, next time, I'm going back to stock... My 02 cents...

Jeff

632 Regal

12-03-2006, 01:00 PM

screw that noise:
Platinum plug, 14mm, 3741 PZFR5F 0.032 $11.71

Bill R.

12-03-2006, 02:33 PM

claim less than 5% increase in mileage on their testing. Let me see.....
Your in Montreal.... you changed them one month ago, weather started cooling off.....hmmm one month ago or so.. Gas mileage drops in the cooler weather as compared to summer. Montreal is running oxygenated gas in the winter months too aren't they? which also is a big drop in gas mileage...

Then again you had those huge cracks in your rubber boot creating vacum leaks causing your motor to run lean all the time which had to have improved your gas mileage until you replaced the boot at the same time that you changed the spark plugs.

On my own car which i can keep track of in the middle of summer i changed the plugs which weren't very old ngk stock plugs and replaced them with denso iridiums that i paid less than 5.00 each on the internet for. I posted it on here when i changed them. I noticed an immediate increase in idle rpm with no other changes, which i also mentioned on here. Enough to the point that i had to reset the idle adjusting screw to bring it back down to my normal idle. My previa typical gets right around 18 mpg consistently in the city with the A/C on. I noticed a change of just under 1/2 mile per gallon average. Denso claims a typical mileage increase of 2 to 4% which isn't much but at they price i pay for them and how well they work for me,its a win/win for me.

If you have been on the board for very long you'll notice that i don't jump on the bandwagon for new and improved things...Usually if i mention something here i've tried it on my own cars or put it on many customers cars before i make a mention on here.

I've been using NGK Iridium for the past month now and apart from the obvious better efficiency feeling you get from new plugs, which is now gone, Iridium spark plugs ARE NOT WORTH IT... I've been monitoring my consumption for the last 5 fill-ups, driving highway and city, using 91 octane and it's all the same. So, unless you need them for special applications, ie colder operating range or whatever, you don't need Iridium's plugs. It's the same results as with my old Bosch twin tips and now I feel that even that was overkill... No more for me, next time, I'm going back to stock... My 02 cents...

Jeff

Jehu

12-03-2006, 02:40 PM

So what about Jon's point that they will foul easier becasue the element is smaller so easier to gunk up limiting the available surface area to deliver spark?

Bill R.

12-03-2006, 02:52 PM

To put it mildly lets just say the Jon's point is hyperbole...or as we greasemonkey's like Winfred and myself prefer to call it B.S. I haven't had any
problems with fouling on these on any cars i've installed them on, unlike the bosch platinums. Iridium requires a lower firing voltage so they can handle a larger gap which means a larger flame kernel. If your fouling them then you have other problems which need to be addressed, little details like getting your a/f ratios correct and actually having a crankcase ventilation system that works and not burying your spark plugs in oil.

I personally haven't seen any of the numerous problems with the small center electrode on the iridiums that i see all the time on the bosch platinums with the small center electrode.

So what about Jon's point that they will foul easier becasue the element is smaller so easier to gunk up limiting the available surface area to deliver spark?

gale

12-03-2006, 03:32 PM

Part of the "hype" about iridium plugs came about from OBD-2 requirements that all emissions related equipment be good for 100k miles. The iridium electrodes will go that distance without ablating away, enough to satisfy OBD-2. Now marketing in Detroit grabs onto this and makes a big deal about "no tune-up required for 100k miles" and pitches it as a feature in their sales brochures.

Regardless, the porcellan will show signs of needing replacement. Personally, I wouldn't leave any plug in for that long without at least removing it periodically for some fresh anti-seize on the threads. It's a b*tch removing plugs that have locked up. Good time to do a visual inspection & "read" the porcellan for mixture/burn issues & verify the gaps & determine if the plugs can be re-used or replaced.

Montreal525

12-03-2006, 03:37 PM

Wow Bill, you sure keep track, good memory. I'm impressed... You have to know that we went below zero just 2 days ago and we have had unusually warm weather for November. It is true that from now on, MPG will drop du to cold weather and winter driving, it's already begun. I didn't factor in the cracked boot, could be a factor... At least it tells me my repairs are holding up for now...:)

But I'm not saying Iridium plugs are not good, only that it's probably overkill for most of us under normal driving conditions for the price they command. Price for price, I'd take them over Platinums but at twice the price...not so sure...

Again, it's my 02 cents...

Jeff

Jon K

12-03-2006, 04:39 PM

One other thing to keep in mind is that Advanced Auto and Autozone have NGK plugs in stock and have a 2 year warranty on them should they fail. Obviously we drive less than 100,000 miles in 2 years, but should you pull your plugs and inspect them (which I would expect every person to do at every oil change) and notice electrode wear, take them to advanced auto and get another set under warranty for your $11 investment.

Bill R.

12-03-2006, 07:09 PM

Sorry Don but thats not correct. Obd II requirements are for 8 years 80k miles on 2 components, the catalytic converter and the powertrain control module, or ecm or dme or whatever your make of vehicle calls it. Everything else got rolled back to 2 years 24kmiles when it was previously 5 years 50k miles on most emissions related components of which the spark plugs have never been included. Any normal wear items aren't included on the emissions warranty. This was in 95.

Many long life platinum plugs were already around at this time and Cadillac was already touting the 100k mile tuneup on the northstar in 92. My 92 previa came from the factory with ngk platinum long life 100k mile plugs because of how much trouble it was to change them and toyota put the 100k plugs on many models destined for taxi duty.

Iridiums are now used by the factory in all the hybrids, in fact the iridiums used in the honda insight are indexed and have a different part number for each plug, with a a,b, or c marked on the boss on the head where the corresponding spark plug goes on the insight's 3 cylinder motor. The primary purpose that the hybrids use them is the increased mileage capabilities and the ability to light extreme lean burn mixtures with the iridiums.

Edit, all of this aside i agree that i would never leave a plug in for 100k miles and usually won't leave them in for 20k miles... too used to the old days when plugs didn't last 15k miles when lead was king.

Part of the "hype" about iridium plugs came about from OBD-2 requirements that all emissions related equipment be good for 100k miles. The iridium electrodes will go that distance without ablating away, enough to satisfy OBD-2. Now marketing in Detroit grabs onto this and makes a big deal about "no tune-up required for 100k miles" and pitches it as a feature in their sales brochures.

Regardless, the porcellan will show signs of needing replacement. Personally, I wouldn't leave any plug in for that long without at least removing it periodically for some fresh anti-seize on the threads. It's a b*tch removing plugs that have locked up. Good time to do a visual inspection & "read" the porcellan for mixture/burn issues & verify the gaps & determine if the plugs can be re-used or replaced.

BillionPa

12-03-2006, 09:25 PM

i stand behind my argument for iridium plugs. i dont give a rats ass about how long they last, i care that they require less voltage to generate the same spark power as a "standard" plug.

also if you modify your ignition system with a coil booster or high output coils, the plug will hold up a lot better.

less voltage = more power available for other systems AND/OR less drain on the alternator (minimal)

larger gap with more concentrated energy release = better flame front generation = more of the fuel combusted = more power OR less fuel consumption to generate the same amount of power (minimal)

less electrode in the combusion chamber = displacement increase (very minimal)

stronger electrode material = longer plug life

single ground electrde = ability to use plug indexing not available with dual or quad ground plugs (any single electrode plug can do this)

blah blah blah, etc, etc.

Jon K

12-03-2006, 11:52 PM

Bill - the reason many people do not use the iridiums from a "performance" side of things (performance meaning higher horsepower, typically forced induced) is because while iridium allows for a gap to be larger, that doesn't help cars like mine because it just means we're more likely to blow the spark out. Gapping plugs down to 0.022" is pretty common for high horsepower FI cars. NA cars don't need to worry about it quite so much. But, guys have tried iridiums on their cars on bimmerforums in the FI section and had nothing but mediocre results at best. It seems as though even though its a better conductor, the spark is blown out more often.

As per the hybrid thing - my thought would be that maybe they use them because they do require less energy and thus less strain on the charging system which means the hybrid concept works better. Just my thoughts.

Bill R.

12-04-2006, 09:54 AM

Kenny Duttweiler has no problems with them running 40lbs boost as seen here
(http://www.advanceautoparts.com/english/youcan/html/pht/pht20010101ds.html)
Edit, also seems strange that the Bugatti 1000hp quadturbo w16 motor also comes from the factory with iridium plugs too....

Bill - the reason many people do not use the iridiums from a "performance" side of things (performance meaning higher horsepower, typically forced induced) is because while iridium allows for a gap to be larger, that doesn't help cars like mine because it just means we're more likely to blow the spark out. Gapping plugs down to 0.022" is pretty common for high horsepower FI cars. NA cars don't need to worry about it quite so much. But, guys have tried iridiums on their cars on bimmerforums in the FI section and had nothing but mediocre results at best. It seems as though even though its a better conductor, the spark is blown out more often.

As per the hybrid thing - my thought would be that maybe they use them because they do require less energy and thus less strain on the charging system which means the hybrid concept works better. Just my thoughts.

Martin in Bellevue

12-04-2006, 11:06 AM

Bill we've dyno'd cars back to back without any changes and they'll be peaky just like those (fake) dynos on Denso's site shows. ...
Does this mean there is a dyno sheet to be posted of your ride? Was there a dyno sheet to support the 340hp claim with your car before ya ruined the supacharger?
Is there any foundation to your claim against Denso's posted results?

Jon, do you read your posts before you hit the enter key?

WillDV

12-04-2006, 11:07 PM

Edit, also seems strange that the Bugatti 1000hp quadturbo w16 motor also comes from the factory with iridium plugs too....

:) lets not forget though, that when you have 16 sparkplugs to change, you wanna make pretty sure that you don't have to yank them out that often. Granted, its better than even money that a Veyron will never see 100k km's. I'm thinking though, that the reason for the iridiums in the Veyron is partly because when a car costs 2.5 mill, you don't wanna find bottom of the line NGK's, and partly because the cars whole philosophy is TECHNOLOGY. So I would assume that they would use the most technologically advanced materials available. This is purely an uneducated guess, please don't flame me too much, I get mad. :D

Jon K

12-05-2006, 12:13 AM

Does this mean there is a dyno sheet to be posted of your ride? Was there a dyno sheet to support the 340hp claim with your car before ya ruined the supacharger?
Is there any foundation to your claim against Denso's posted results?

Jon, do you read your posts before you hit the enter key?

I have not dyno'd my car - once I get my clutch in (its ordered woo) I'll hit the roller in February to see whats going on. I have helped buds tune several cars at this point - the one I am speaking about is a '99 Mitsubushi GSX on DSMLink. My buddy was running standard NGK's and then decided to put in Denso Iridiums within the same dyno session (operator even recommended him not change plugs since it can move the tune around) or about 30 - 40 mins of the first "best tune" pull and no difference (he thought he fouled plugs) with the iridiums in. His car made the same ~260 awhp before and after - I don't have a sheet print out of his runs but I can get him on here to vouch.

Edit:

Martin - the reason I called the Denso dyno's fake is because I've been around VW's a fair amount to know that any VR6 NA stock dynoing 164 (even corrected) is amazing - not happening. Also '97s are 12v motors and their peak horsepower falls of well before the point they display assuming they took it to redline.

My 2 cents.

Jon K

12-05-2006, 12:21 AM