loveshandbags said:

You've correct on this. There's 3mm protrusion on the DCPR7E plugs so that comes to 2mm. Apologies for doubting you.

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Well I did actually measure them before posting .

RobW said:

check out for Denso equivalents

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The IXU22/VXU22's are a direct (but probably better quality) equivalent for the DCPR7EIX, ie 0.8mm gap & a 3mm tip projection. FIAT specify plugs with 1.0mm gap & a 5mm tip projection for the 169A4000 engine. AFAIK there is no equivalent Ir plug so it's necessary to trade off the extra 2mm tip projection for the benefits of iridium - hence my experiment to find out if it's worth it. For earlier versions of the 1.2 FIRE which use the DCPR7E-N-10's, the Ir plugs under discussion are a direct replacement apart from the gap.

Obviously the gap can (with care) be adjusted; easier on the NGK's than the Denso's since you don't have to worry about disturbing the V-groove alignment (the DCPR7EIX has a flat faced side electrode). For now I've left them at 0.8mm as that gives instant starting & good performance at low rpm. Folks with aspirations at the other end of the power curve might have more reason to open out the gap to 1mm.

However, inspection of the removed plugs shows there is an additional risk with a larger gap - it's much easier for the spark to mistrack horizontally to the base of the side electrode & this actually happens in practice with the 'approved' ZKR7A's. Not easy to photograph - you really need a magnifying glass to see it - but I'll try to put something up here if I can get a clear shot.

It's somewhat incredible that NGK claim it would take 4 years to develop an Ir version of the ZKR7A. Perhaps Denso might care to rise to the challenge?

It's interesting reading through this whole topic about plugs.

To be fair though, to save any real hassles, would it not just make life easier and be better practise to just replace the standard NGK plugs like for like at a maximum of 12k? 18k changes just seem daft to me. After all they only cost 12 quid for a set.

jrkitching said:

However, inspection of the removed plugs shows there is an additional risk with a larger gap - it's much easier for the spark to mistrack horizontally to the base of the side electrode & this actually happens in practice with the 'approved' ZKR7A's. Not easy to photograph - you really need a magnifying glass to see it - but I'll try to put something up here if I can get a clear shot.

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Have a look at this picture (click twice to enlarge). The green arrows point to the area on the electrode where the spark is supposed to track; the red arrows show two patches where mistracking has been taking place.

Strange that FIAT & NGK spent all that time designing a plug to put the spark 2mm closer to the centre of the combustion chamber & then make it out of materials which allow it to sometimes jump almost 10mm out of position.

Iridium plugs have a much finer central electrode & should be much more consistent in the placement of the spark.

frupi said:

It's interesting reading through this whole topic about plugs.

To be fair though, to save any real hassles, would it not just make life easier and be better practise to just replace the standard NGK plugs like for like at a maximum of 12k? 18k changes just seem daft to me. After all they only cost 12 quid for a set.

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that's what I do

306maxi said:

that's what I do

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:hug:

:yuck:

frupi said:

:hug:
:yuck:

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So where's all that support that was promised.

The 4 year lead time was what I deduced from speaking with the technical guy in NGK. I got to him after raising a lot of questions with front line support after a lot of to'ing and fro'ing. I mentioned this thread so I wouldn't be surpised if he's reading it. He maintained the NGK/Fiat would have developed the plug to deal with the ethanol content in petrol since they would have known that it was on the horizon. I'm not too sure.

jrkitching said:

The IXU22/VXU22's are a direct (but probably better quality) equivalent for the DCPR7EIX

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There's a good summary up on ebay of what's different about the Denso's here. It also explains that the test bed for the 5% improvement in economy was from a 50cc engine !

jrkitching said:

Obviously the gap can (with care) be adjusted; easier on the NGK's than the Denso's since you don't have to worry about disturbing the V-groove alignment (the DCPR7EIX has a flat faced side electrode).

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Denso describe it as a U groove and it's patented. Might explain why it's better.

jrkitching said:

For now I've left them at 0.8mm as that gives instant starting & good performance at low rpm. Folks with aspirations at the other end of the power curve might have more reason to open out the gap to 1mm.

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Some contradicting info in this clip which gives the pluses and minuses of a smaller / bigger gap. Big allows the fuel to run lean => better economy and easier starting but the downsides tie up with what you said earlier on in the thread about the strain on the coil, etc.

loveshandbags said:

Some contradicting info in this clip which gives the pluses and minuses of a smaller / bigger gap. Big allows the fuel to run lean => better economy and easier starting but the downsides tie up with what you said earlier on in the thread about the strain on the coil, etc.

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In an aircraft the pilot usually has control of the mixture & modern engines like the Lyco TIO-540-AE2A are designed to be run LOP for best economy. Plug fouling is also a big issue since there's about 4 times the lead in 100LL as there was in the old 98RON 4 star. So for applications like the one in that clip there may be good reasons to run with a larger gap.

In a car where the ECU is controlling the mixture, I'm not so sure whether or not a bigger gap will translate into better mpg. There's a risk when experimenting in changing too many things at once & I want to see some fuel figures from these plugs 'out of the box' before messing around further.

loveshandbags said:

He maintained the NGK/Fiat would have developed the plug to deal with the ethanol content in petrol since they would have known that it was on the horizon. I'm not too sure.

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Having seen what the ZKR7A-10's look like after 13k, I'm far from convinced that they were designed to run on E5 fuel.

loveshandbags said:

Denso describe it as a U groove and it's patented. Might explain why it's better.

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Might explain why it's more expensive.

But the price of Ir aircraft plugs is downright ludicrous. Remember you've got 2 per cylinder, so a plug change on a six can cost north of £1000 just for the parts .

:Offtopic:

jrkitching said:

In an aircraft the pilot usually has control of the mixture & modern engines like the Lyco TIO-540-AE2A are designed to be run LOP for best economy.

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Didn't know what LOP meant and had to look it up. For those who are interested here is an interesting clip (Click here) that explains it.

jrkitching said:

But the price of Ir aircraft plugs is downright ludicrous. Remember you've got 2 per cylinder, so a plug change on a six can cost north of £1000 just for the parts .

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If 'they' can afford to use on a small aircraft 20 gals of fuel an hour or 13 gals in 'LOP' mode I would imagine that the price of plugs wouldn't be a big concern.

jrkitching said:

In an aircraft the pilot usually has control of the mixture & modern engines like the Lyco TIO-540-AE2A are designed to be run LOP for best economy. Plug fouling is also a big issue since there's about 4 times the lead in 100LL as there was in the old 98RON 4 star. So for applications like the one in that clip there may be good reasons to run with a larger gap.

In a car where the ECU is controlling the mixture, I'm not so sure whether or not a bigger gap will translate into better mpg. There's a risk when experimenting in changing too many things at once & I want to see some fuel figures from these plugs 'out of the box' before messing around further.



Having seen what the ZKR7A-10's look like after 13k, I'm far from convinced that they were designed to run on E5 fuel.



Might explain why it's more expensive.

But the price of Ir aircraft plugs is downright ludicrous. Remember you've got 2 per cylinder, so a plug change on a six can cost north of £1000 just for the parts .

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True, but if you have issues with a plug in a car then the car doesn't fall out of the sky

I did a year of a Bsc Aviation back in 2001 and loved it, but just didn't have the money to go ahead with all the flying training

306maxi said:

True, but if you have issues with a plug in a car then the car doesn't fall out of the sky

I did a year of a Bsc Aviation back in 2001 and loved it, but just didn't have the money to go ahead with all the flying training

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I heard its a major problem trying to be a pilot as in expense. But i heard the solution was join the military as an air force officer get the training and the flight hours for free (i think you need to commit to them for a few years so they get some of their money back as you are useful to them), and from the military become a commercial pilot.

jrkitching said:

Fitting Ir plugs will technically void the warranty but if you've taken the car in for a replacement failed suspension bush, I can't realistically see any FIAT mechanic digging down & removing them to check. In the (very unlikely) event of an actual engine problem, you could always just refit the original plugs .

From personal experience, I'd say the factory fit plugs will be past their best by 12,000 miles.

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It has been 20,000 km so about 12,000 miles since my last plug change with the normal ghetto plugs and i can feel it being a bit annoying when pulling away in the low rev range. Of course, having AC on makes things worse. I think i will need to change the plugs to the ones you got for my 1.4, i will be out of warranty next service anyway!

I think i will get myself some iridums at the next service as after 20000 km i am getting the feeling that the plugs are past their best. Another question is how to bring them to Greece = )

ahmett said:

I think i will get myself some iridums at the next service as after 20000 km i am getting the feeling that the plugs are past their best. Another question is how to bring them to Greece = )

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Can they not be posted? A set of 4 in a jiffy bag weighs just under 200g - postage at cost from the UK would be £3.16.

jrkitching said:

Can they not be posted? A set of 4 in a jiffy bag weighs just under 200g - postage at cost from the UK would be £3.16.

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Should be. When the time comes i will ask the indie if he can source them from here, he gets special discounts on spare parts as a trader. If not i will order it myself.

ahmett said:

I think i will get myself some iridums at the next service as after 20000 km i am getting the feeling that the plugs are past their best. Another question is how to bring them to Greece = )

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I remember getting charged nearly €40 for OEM NGK spark plugs on a 500 service so the ones that JR has pointed out are a 'steal'.

I've had both the NGK Iridiums and the Denso Iridiums on the 1.4 and I felt the difference on the Densos. Realise that they are expensive at £40 compared with £26 on the NGK Iridiums but if you compare what I paid on the standard OEMs from the Fiat garage you could possibly justify them if you intend to keep the 500. The 'jury is out' on the benefits of re-instating the gap to 1.0mm from the preset 0.8mm. Note that on the 100HP for Panda members manual states 0.9mm.

loveshandbags said:

I remember getting charged nearly €40 for OEM NGK spark plugs on a 500 service so the ones that JR has pointed out are a 'steal'.

I've had both the NGK Iridiums and the Denso Iridiums on the 1.4 and I felt the difference on the Densos. Realise that they are expensive at £40 compared with £26 on the NGK Iridiums but if you compare what I paid on the standard OEMs from the Fiat garage you could possibly justify them if you intend to keep the 500. The 'jury is out' on the benefits of re-instating the gap to 1.0mm from the preset 0.8mm. Note that on the 100HP for Panda members manual states 0.9mm.

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How often should you change the iridums by the way? And what do you think of a K and N air filter? Do you have to maintain and clean the filter at all?

ahmett said:

How often should you change the iridums by the way? And what do you think of a K and N air filter? Do you have to maintain and clean the filter at all?

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https://www.fiatforum.com/500/293274-fiat-500-1-2-pop-spark-plugs.html?p=2958523

OEM NGK quote 18K in reality 12K cost £11
NGK Iridiums quote 40K-60K probably 30K cost £26
Denso IX quote c.30K probably 20K cost £40
Denso VX quote c.50K probably 30K cost £50+
[in miles]

K&N air filter costs £30 plus cleaners another £10. 30 minute job to clean whilst foam needs to dry overnight. Worthwhile if you really want the extra 1-2bhp and a little induction noise. Otherwise paper is fine.

loveshandbags said:

I remember getting charged nearly €40 for OEM NGK spark plugs on a 500 service

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Did that include fitting?

jrkitching said:

Did that include fitting?

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Sadly - it didn't.
I'd post the actual invoice but it's gone with the service records with the car.
Bought them directly off the Dealer.
I put them on myself to 'save' on an hour's labour but had to take off the NGK Iridiums to keep the car under warranty.:bang:
Needed a full fat service at 39K.
Still got charged the 2nd hour but got 'free' rear shocks on the 3rd year.
Swings and roundabouts.

loveshandbags said:

The 'jury is out' on the benefits of re-instating the gap to 1.0mm from the preset 0.8mm.

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I'd say it depends whether your priority is for performance or economy. The wider gap will give you a slightly bigger spark & a faster burn of the combustion charge; a good thing above 4000 rpm but below 2000 rpm the slower burn from a 0.8 gap works to your advantage & improves the bottom end flexibility of the engine. The smaller gap should also reduce the stress on the coil packs, perhaps improving their long term reliability.

I can vouch for the low power benefits (ecodrivers should leave the Ir's at 0.8) but will leave it to someone else to report on how this might affect the running above 2500 rpm.

I'd expect Ahmett will give 'em a good workout .