I'm in the process of moving up (or down) to a 3.4"pulley on my blower, but I know I need colder plugs 1st. I'm leaning towards the NGK TR6ix Iridium plugs for the long life. I have heard the Autolite's just don't have any longevity to them. I want something that will last 50,000mi or more. I don't want to change plugs again. Is there a better plug than this. Is there an AC Delco platinum plug available?
Wayne

 

you dont want plat or iridium with the blower!

single plat might be ok, but the iridiums will increase Knock. the electrode is too small and will create a hot spot for pre-ignition.

the best plugs are still the copper core autolites. go with an additional range colder (104's) and you might get the plat to hold up a little better. but the high temps in a boosted engine dont like plat or iridium tips.

when you get into performance mods you need to be ready for more maintenace and sacrifices. personally i dont even trust platinum plugs for 50k miles.

 

No other opinions out there?
What is in there stock. Part no's?
I don't want to change plugs every couple of months. Platinums are fine, just not the copper cores.

http://www.cardomain.com/ride/2319272

 

with the 3.4" pulley i would use NGK IRIDIUMS part # 3692 (or TR65IX) they're colder than the stock ones...thats what i have for mine when i get my pulley put on

 

its been said iridiums can cause more Knock. i even saw more Kr in my NA motor from using iridiums. when it comes to performance mods i dont understand why people would want to spend more money on exotic plugs so they dont have to change them and spend more time on other mods. why not do the easy things first and do them right the first time?

 

X2. I tried the NGK TR6ix Iridium plugs and saw 2* more of KR than the Autolites I have. Went from 7 KR up to 9. Brought them back and gota refund after hitting them with rubbing alcohol and a Qtip.

AutoLite is a much better call.

 

What kind of life can I expect to see from the Autolite plugs? I drive 600mi/week commuting. Parents live 250mi away. Do the math. 38,000mi/year. Should I forget the pulley until it is no longer a daily driver?

http://www.cardomain.com/ride/2319272

 

You would need to change plugs maybe once a year or so. They are about 12 bucks for a pack and after you do them once aren't that hard to do.

 

I also found this write up on plugs and wanted to share it:


Give me a spark plug 101

A spark plug has two main tasks: to ignite the air/fuel mixture properly, and to remove heat from the combustion chamber to maintain an optimal temperature.

Platinum, some hear that word and think BAM these are premium plugs. What makes platinum different? Well the answer is in the design of a platinum plug. So lets start there.

A spark plug's firing task is to transfer electrical current or "spark" between a power and a ground electrode to ignite the air and fuel mixture. We want this spark to be powerful, to promote a nice clean burn of the mixture, as this will promote the best efficiency and therefore the most power. Now imagine two spheres electrically charged, hold them closely together and you'll see spark jump across it. Now try and separate them and you'll see the spark disappear. NOW try this with two sharp pointed electrical rods and you'll see you can hold them further apart and the spark will still jump between them. What does this mean? Sharp points will transfer the spark the most effectively. Ever notice the tip of the spark plug and how most platinum plugs are sharp tipped center electrodes?

Sharp tips are all well and fine, but thats a hot environment down there. Infact the biggest problem is withstanding the heat. A sharp center electrode will get very hot, this promotes easy ignition (less charge to spark the plug) and a clean running plug free of deposits, but try this with a standard copper plug and it'll melt! Platinum has a much higher melting point than copper which is used on the classic style spark plug, thus the tip can be sharpened like it is. Iridium is the new guy on the block; same thing, it has an even higher melting point, thus the tip can be sharp. Now a copper plug needs to have a wide body to disperse the heat over a larger area so its tip can run cooler. Now did that set off any light bulb on where that would be beneficial? If you said forced induction or nitrous applications, pat on the back! In applications where you want to minimize existing heat in the combustion chamber, platinum may not be a good thing.

Here is another stick in the spokes of the platinum bandwagon wheel: Platinum does not conduct electricity very well. Platinum was chosen due to its resistance to heat and erosion, however it conducts electricity about a third as well as copper. The new iridiums are an attempt to find a metal with similar heat and erosion resistance as platinum but better conductivity of electricity; however, iridium is still only about half as good a conductor as copper, iridium plugs are one of the best marketing tools for spark plugs today and nothing more in the authors opinion. Now this disadvantage of platinum is offset to an extent by the ease of firing that platinum plug design offers, with its sharp pointed tip. Whether a copper plug can produce as much spark energy with a smaller gap however, than a platinum counterpart with a wider gap, is a good point of debate. The author’s viewpoint is yes.


Before I read further, what plug do you recommend for my application?

My recommendation for GTPs is to use a copper Autolite plug whenever possible. Copper runs cool, will perform better than exotic metals in my experience, should last its user about 2 years, and best of all are inexpensive.

For a stock pullied car, if you are unmodified and looking for a maintenance recommendation for plugs rather than a performance one, look for Autolite platinums which are part number coded AP for platinum and APP for double platinum at the very beginning of the part number.

Non-intercooled:
3.8” factory: Autolite 605 @ .055-.057” gap (or AP605/APP605 platinums @.060”)
3.4-3.25” pulley: Autolite 104 @ .052-.054” gap
3.1-3.0” pulley: Autolite 103 @ .047-.050” gap
2.9-2.7” pulley: Autolite AR94 (4 range colder race plug) @ .044-.046”

 

I'll summarize all that stuff above.

Copper = better spark

Modding requires effort. you're already dumping money into mods... why not make it reliable power. All it requires is 30 minutes to change your plugs a little more often. 10k miles for 103s with heavy mods like me, 15-20k miles for cars with 104s mildly modded with 3.4" and 3.25" pulleys.

Effort pays off...