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Discussion Starter · #1 ·
This is a good area for debate, does anyone have any specific spark plug manufacturers with plugs that work well with fiesta mk6's?

I have an MSD uprated coil, and magnacor leads. Currently have NGK iridium plugs with a gap of just around 9mm. I hear that haynes say 1.3mm is a good gap for Fiestas.

The iridium installed is a hot plug, would a cooler copper core plug be more suitable for the engine? I have noticed the engine bay is getting fairly warm recently, as the radiator fan turns on more frequently.

Any comments are welcome. :L
 

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Unless you have added a turbo or increased the compression ratio then the standard 1.3mm

gap is probably right.

Qute common for people to have misfire issues and close the gap which can often sort the

problem even though that was not the original issue. Faulty coil pack or a breakdown of the

ignition system. Firing a smaller gap is easier on the system in general.

Hot / Cold plugs just fit whats standard unless your into crazy tunes or have an issue like the

plugs fouling badly or melting.

Closing the gap too much could have a smaller spark which may not give a complete burn and

actually losing power.

Unless its highly modified its hard to go wrong with a factory spec off the shelf item these days.

Cars have got far m,ore efficient the old school tuning methods have often already been done.
 

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Discussion Starter · #3 ·
Thanks for your comments, I have an aftermarket fuel pressure regulator, and read that smaller gaps would produce a stronger spark as it has less distance to travel, but I am thinking because the ignition coil produces a hotter spark anyway, perhaps, a larger gap might be an advantage, giving it a larger surface area to theoretically burn a larger amount of fuel.

I will be putting a small 500cc supercharger onto the intake soon so will more than likely use a smaller gap when that happens. Also a few stages of engine remaps are on the books, I will probably ask the tuner for their recommendations also. More opinions, and sources of information the better.

I was thinking what are the standard type of plugs for the mk6 fez?
 

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Original plugs would have probably been bog standard Motorcraft items.

Nothing special at all. Which plug depends on which engine you have.

More power you need to get more air/fuel into the engine.

Lots of variables with the supercharger. Pulley size / engine rpm can be altered a lot.
 

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Discussion Starter · #5 ·
Original plugs would have probably been bog standard Motorcraft items.

Nothing special at all. Which plug depends on which engine you have.

More power you need to get more air/fuel into the engine.

Lots of variables with the supercharger. Pulley size / engine rpm can be altered a lot.
I think the motorcraft were set at 1.3mm gap size if I am right?

I have the yamaha tuned 1.25 16v style, I had the throttle body bored by a machine shop who were good sports, did a brilliant job, cost £35 for the boring.

The supercharger I have is the amr500. positive displacement roots double lobe SC, AMR 500 Supercharger | Hyde Motor Works Shop.

I bought some champion, copper core, eon4 from ebay, 4 in the pack for a bargain price of less than £10 including postage. These plugs are pre-set to 1.0mm gaps. will see what they are like after using iridium for a while, should be interesting how copper differs with performance and heat dissipation.
 

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On a standard engine I would expect virtually zero difference.

I think its funny that the same plugs are sold in different gap sizes, what happened

to setting your own plug gaps. :D
 

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Discussion Starter · #7 ·
On a standard engine I would expect virtually zero difference.

I think its funny that the same plugs are sold in different gap sizes, what happened

to setting your own plug gaps. :D
I would hope the extra bore on the throttle body would be a good starter when adding the supercharger, induction kit and high flow 200cpi sports cat, rising rate fuel pressure regulator, engine mapping.

Yes it is rather strange how the same plugs are sold in different gap sizes, you would have though a certain engine would have a sweet spot at which it runs best with, and that everyone to follow suit in keeping the gaps the same.

I guess the issue with setting the gap sizes yourself would be not knowing exactly how much to set them by. I changed the gaps on the iridium to 1.3 originally, and then to just below 1.0, I think that the smaller gaps seem to make the engine heat up much quicker.
 

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Discussion Starter · #8 ·
I bought some cheap champion, Eon4, copper plugs from ebay and installed them into the engine. I thought they were quite good really, except on idle the car seemed to "bounce" or, something like, it while idling. It was slightly strange I thought, so I took them back out again.

on further inspection I cannot be 100% sure that these plugs are legitimate champion plugs as they look a little cheap, and do not seem to have a quality build you would expect from the champion brand. There were some NGK platinum plugs that were left from before the iridium were installed, so i re-installed them, and surprise surprise, no strange idling behaviour.

Must have bought some dodgy plugs, needless to say next time I will buy from somewhere other than ebay. :p
 
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