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FAQ: Spark plugs


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whats the difference between the 2 of these? NGK Iridium - BKR8EIX or BKR9EIX?

 

Coldness.

9 = colder than 8.

 

9's probably won't run very well in anything short of a built motor with a standalone ECU.

 

7's for BPU 7-8's for APU (Singles etc)

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Guest Marcus1

i have a built motor hks to4z and a hypertune 90mm intake well i was looking at making 600 to 700 rwhp wich heat range ngk iridium plug do you guys recon i should go for 7 or 8 i havnt got a cdi yet but looking at the HKS DLI are they any good?

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Why shouldn't iridium plugs be gapped, the manufacturers specify a gapping procedure, just because it isn't the same as a copper plugs doesn't mean it shouldn't be followed?

 

No they don't - Iridiums come pre-gapped.

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Guest Marcus1

what heat range would be best for say max 600rwhp single to4z and street driving/ idle quality. ngk iridium 7s or 8s

thanks

 

 

 

Indeed thanks Rob, IK24 is made by Denso. The BKR8EIX is the NGK equivilent.
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No they don't - Iridiums come pre-gapped.

Yes but where does this advice come from?

 

It sure doesn't come from the plug manufacturers as Denso advise the Iridium plugs can be gapped (just not in the same way as normal copper plugs).

 

With copper plugs you can put the gauge into the plug, tap the plug down then remove the gauge.

 

With iridiums they say that doing this can snap the electrode, hence you remove the gauge before gapping then re-insert the gauge afterwards (hence elliminating any chance of the fragile electrode being snapped while removing the feeler gauge).

 

So where does this "you cannot regap an iridium plug" rule start, surely an iridium plug can be used indifferent applications with different gaps and there's no way a plug manufacturer is going to make the same plug with different gaps (otherwise they would have the same serial number and just another number to identify the gap at which the manufacturer set them at)?

 

I will refer you to Denso's website where it states although there may be no need to gap the plug, it certainly isn't the "don't ever gap iridium plugs" bull that seems to be banded around here like gospel:

 

http://www.densoiridium.com/faq.php

 

So are you still telling me "Manufacturers Don't Specifiy A Gapping Procedure For Iridium Plugs" Brian?

Edited by jevansio (see edit history)
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So are you still telling me "Manufacturers Don't Specifiy A Gapping Procedure For Iridium Plugs" Brian?

 

For a start are you a politician putting words into my mouth? I never made that statement. I said don't gap iridium plugs!

 

Have you gapped plugs? Just putting a feeler gauge inbetween the very fine center electrode and ground electrode is likely to damage or break the center electrode on an iridium plug. Even with copper plugs I don't leave the gauge in whilst setting the gap - it's a little by little approach to set the desired gap. Hammering the ground electrode into the center electrode via the feeler gauge inbetween is not a good approach IMO :search:

 

The whole point of the iridium design is not to require a smaller gap than what they are set at (and indeed you do get different gaps which are tagged onto the end of the model code eg. BKR7EIX-11 indicating a 1.1mm gap). Gapping down a copper plug is done to stop the spark getting blown out with the increased cylinder pressures seen in modified applications - IE it's a bit of a fudge! It is however done by many with copper plugs without any real adverse side effects.

 

Still, if you want to burn me over it go right ahead. Hey.... your engine, your choice.

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Have been trying to find some NGK BCPR8ES for my T67 Supe when it is being mapped. But nowhere even has that part number on there database, the only only one close to it is BPR8ES.

Are we 100% sure that the listed number on here is correct?

 

:)

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For a start are you a politician putting words into my mouth? I never made that statement. I said don't gap iridium plugs!

Brian, it's in black & white further up the page.

 

I said "Why shouldn't iridium plugs be gapped, the manufacturers specify a gapping procedure".

 

You said "No they don't" This can only refer to "The manufacturers don't specify a gapping procedure" statement.

 

I'm not going to get drawn into an argument over this, I'm not saying we should gap the iridiums, I'm saying that to say they can't be gapped is untrue.

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Have been trying to find some NGK BCPR8ES for my T67 Supe when it is being mapped. But nowhere even has that part number on there database, the only only one close to it is BPR8ES.

Are we 100% sure that the listed number on here is correct?

 

:)

 

Hi Steve,

 

I think the BP range has a different fitment. The closest match I could find was these:

 

http://www.sparkplugsrus.com/shop/index.cgi?command=list&search=BCR8ES

 

They should be the same fitment with the only difference being the centre electrode insulator isn't projected. They should do the trick :)

 

I can still find supplies of BKR7E's and BCPR7ES's from a number of places online. Either of these would probably be OK but the colder heat grade is probably sensible.

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Hi Steve,

 

I think the BP range has a different fitment. The closest match I could find was these:

 

http://www.sparkplugsrus.com/shop/index.cgi?command=list&search=BCR8ES

 

They should be the same fitment with the only difference being the centre electrode insulator isn't projected. They should do the trick :)

 

I can still find supplies of BKR7E's and BCPR7ES's from a number of places online. Either of these would probably be OK but the colder heat grade is probably sensible.

 

 

Excellent, thanks for looking Brian :thumbs:

 

Edit: The local places have them in stock :yahoo:

Edited by Steve (see edit history)
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