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Discussion Starter #1
hi guys im new here to this forum must say you guys really know these cars inside out just picked up 2005 fx45 must say its my favorite car ive owned to date the question i had was whats your guys input on ngk iridiums i've tried searching for opinions here but i cant seem to find anyone saying they really like them or not just woundering if anyone here has them and what their input on them is thanks.
 

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Platinums are more than adequate and should be changed at 50K v 100K..you will feel it
Do not recommend iridum for any car...GM Powertrain engineers are ademant about that...too harsh a firing plug
Go a range colder too
 

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brnjug said:
Platinums are more than adequate and should be changed at 50K v 100K..you will feel it
Do not recommend iridum for any car...GM Powertrain engineers are ademant about that...too harsh a firing plug
Go a range colder too
So what do you recommend? I'm about 60k miles - I should change my spark plugs out w/ new OEM plugs?
 

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Conrad wasnt there an old discussion on the fun of changing the plugs on the 45? This thread has got me thinking about changing mine (86k). I seem to remember there were some issues or difficult procedures, or basically just a PITA.
 

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As an aside,iridiums are very hard on cats

Cube and a couple of others have done their own...I think an hour or so effort if you have the tools
Do not remember the "fun" thread of this..if you have the manual CD you should be fine
Colder is just to move a step away from detonation,the spark is strong enough to fire a very cold plug
 

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Discussion Starter #7
so basically what you guys are saying is you dont like those plugs and dont recommend them,is that about right?
 

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Platinums are more than adequate
I noticed less than clean pulls up my test hill to my redline of 7300 in first and 7K in the other gears...fresh plugs,one step colder and it pulled to redline smoothly.As hard as I drive I want that improvement...
 

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Discussion Starter #9
perfect thanks 4 the advice im definitly going to buy a set platinums once again thanks for the input
 

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W/o checking,NGK come in the car and one step colder is stocked by the dealers...but a lot cheaper elsewhere
 

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Found this in another thread:

NGK Platinum Spark Plugs:
Gap (Nominal) : 1.1 mm (0.043 in)
Standard type - PLFR5A-11
Cold type - PLFR6A-11
Hot type - PLFR4A-11

NGK Iridium Spark Plugs:
Standard type - LFR5AIX-11
Cold type - LFR6AIX-11
Hot type - LFR4AIX-11

Denso Iridium Spark Plugs:
Standard type - IKH16
Cold type - IKH20

Surprizingly I found the Iridiums for $3 less than the Platinum. Aren't the Iridiums supposed to be "better"? I'm going to stick with the stardard temp, but do you recommend Iridium or Platinum?
 

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Would never try to explain pricing

GM Powertrain built my '98 3.8SC Buick and they were adament about not using iridiums(even though that car did not have cats and was also emissions clean-long story,but informative)
Yes,some believe they are great and better.I heed the engineers advice...they brutalize motors to find performance limits and to calibrate motors..They also preached synthetic oil and no need for overhead cams since they could out perform them with pushrods...it was a PR/sales hype,not performance...the more they preached,the more I listened...racing a turbo car,I knew synthetics were a must,but they said everywhere,trans,gears,rear.

Use them if you want to,there is no need,fresh plugs will gain you more...racers change plugs every race day at least...cheap predictable performance
 

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I run the copper NGKs in my '02 Trans Am LS1. I know you have to change them more often than the platinum or iridium but they are cheap, just as good, and I don't mind changing them.

Sounds like you are recommending some platinums for my 45? With the miles I put on it, I don't want to have the change them as much as the coppers require.
 

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I changed mine at 50K,now 71K and will probably change again before 100K...so not like copper in frequency
 

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Yes, should have made that more clear
 

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I run platinum,one range colder(our ignition is more than adequate enough to handle several ranges colder).I have always used the coldest plug available),but not here since MSD does not make anything for our ignition...part of my usual regimen
I do not know anything about the plug you mentioned from the list above other than it is seemly stock temp
 
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