Looking For Colder Spark Plugs
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camthman
Dedicated LVC Member
mharrison
Dedicated LVC Member
What brand are you looking for? Here is some general Heat Range information followed by some brand specific info showing the cooler plug for an '03 LS V8.
Autolite
Autolite Suggested: 3924 So one range cooler would be 3923
Autolite Numbering System
Autolite® spark plug numbers indicate the heat range with the last number of the part number. Everything previous to that, regardless of the number of digits, can only be used to indicate a similar design (spark plug family). For example, a 23 is one heat range colder than a 24. A 3924 is one heat range hotter than the 3923. The 23 and 24 (full plug numbers, not just the end) will look exactly alike, but they will not look like the 3923 or 3924.
Some part numbers also use prefixes to indicate special features. AP as in AP24 indicates a platinum center wire on a 24. APP indicates a platinum center wire and a platinum ground (or side) wire. MP is for motorcycle platinum and WC is especially for personal watercraft.
Champion
Champion Suggested:RC12YC So one range cooler would be RC11YC or RC10YC
NGK
NGK Suggested:BKR5ES-11 So one range cooler would be BKR6ES-11.
AC Delco
As far as AC Delco goes it calls for a 41-629 stock, but finding a cooler one is a bit harder with Delco because in the early 1990s, an all-numeric, identification code was developed to ensure that the proper spark plug would be selected for replacement in specific engine applications. The numeric code does not in any way correspond to the heat range of the spark plug. Therefore, selection of a spark plug with a different code number is not recommended. The heat ranges may be drastically different between two different plugs, and engine damage or poor performance may result. See your local installer or retailer for details.
The prefix “41” stands for the manufacturer’s product line (e.g., 41 = spark plug)
Numbers after the prefix indicate the type of spark plug and also the specific application:
* 100 – 199 = Iridium
* 600 – 699 = Resistor
* 800 – 999 = Double Platinum
Autolite
Autolite Suggested: 3924 So one range cooler would be 3923
Autolite Numbering System
Autolite® spark plug numbers indicate the heat range with the last number of the part number. Everything previous to that, regardless of the number of digits, can only be used to indicate a similar design (spark plug family). For example, a 23 is one heat range colder than a 24. A 3924 is one heat range hotter than the 3923. The 23 and 24 (full plug numbers, not just the end) will look exactly alike, but they will not look like the 3923 or 3924.
Some part numbers also use prefixes to indicate special features. AP as in AP24 indicates a platinum center wire on a 24. APP indicates a platinum center wire and a platinum ground (or side) wire. MP is for motorcycle platinum and WC is especially for personal watercraft.
Champion
Champion Suggested:RC12YC So one range cooler would be RC11YC or RC10YC
NGK
NGK Suggested:BKR5ES-11 So one range cooler would be BKR6ES-11.
AC Delco
As far as AC Delco goes it calls for a 41-629 stock, but finding a cooler one is a bit harder with Delco because in the early 1990s, an all-numeric, identification code was developed to ensure that the proper spark plug would be selected for replacement in specific engine applications. The numeric code does not in any way correspond to the heat range of the spark plug. Therefore, selection of a spark plug with a different code number is not recommended. The heat ranges may be drastically different between two different plugs, and engine damage or poor performance may result. See your local installer or retailer for details.
The prefix “41” stands for the manufacturer’s product line (e.g., 41 = spark plug)
Numbers after the prefix indicate the type of spark plug and also the specific application:
* 100 – 199 = Iridium
* 600 – 699 = Resistor
* 800 – 999 = Double Platinum
SPSully
Dedicated LVC Member
didnt the guy who did your turbo set up give that info..... call him up. He has it!
camthman
Dedicated LVC Member
Well. Robert at KBX used champion plugs. Thats all I know.
mharrison
Dedicated LVC Member
Heat ranges are not equal between manufacturers (ie. NGK may be 10 degrees, Champion may be 5 degrees explaining why the numbers on the cross reference chart sometimes have a single range from one manu. and two from another.)
Champion Suggested Stock Plug:RC12YC
So one/two range cooler would be RC11YC or RC10YC
I would say try to 11's first then maybe the 10's.
97stscaddy
Dedicated LVC Member
Sparkplugs.com
mharrison
Dedicated LVC Member
That's actually where most of that information came from. You didn't think I just whipped all those charts up with MS Paint real quick did you?
97stscaddy
Dedicated LVC Member
Haha, no I actually recognized the charts, but I didn't see a link anywhere so I just threw it out there.
camthman
Dedicated LVC Member
I just got mine. Autolite 3923
SPSully
Dedicated LVC Member
think its the 10yc.... dont quote me on that
mharrison
Dedicated LVC Member
They'll both work, the RC11YC will just be a little hotter than the RC10YC, but still colder than OEM specs.
SPSully
Dedicated LVC Member
hahahahaha yeah but when he calls KBX, the 10yc is what hes gonna get for an answer
camthman
Dedicated LVC Member
Thats what I got. What are you gapping them at? Im thinking for my turbo setup Im going with .032 to .035.
SPSully
Dedicated LVC Member
mixed reviews on that. Seems like its not needed but a good idea. From what I can tell it reduces the chance of detonation. I gapped mine at the same .035 for the N20 and will run the same plug config for my turbo
.35 here