Colder Spark Plugs

[crouse]

When should I change to colder spark plugs? I've got about 45,000 miles on the clock and I'd like to change plugs this weekend. I recently purchased the Granatelli coil connectors. I've got SCT XCal-2 and a tune from Dennis Reinhart, custom 2.5" exhaust (stock manifolds), JLT CAI and 4.10 gears. I drive a lot of short distances, 20 miles round trip per day to and from work. I want to use Motorcraft plugs. Should I stay with the stock temp range or go one range colder? And why? Thanks for the input.

[CRUZTAKER]

When should I change to colder spark plugs?

When you have a tune to take advantage of the cooler plug.

[Pat]

I think that a "generic street" tune such as installed by the X-cal's or other flash tuners would by itself not warrant a colder plug. There are different quality/design of plugs and brands in the OEM heat range. Motorcraft is a good plug, visit their site and you will see they make several different quality and styles that work on our car in the stock heat range.

It's my understanding that going to a colder plug is needed when combustion chamber temps are for some reason increased. Such as significantly more timing, supercharger or nitrous applications.

My plugs are one range colder because I run a 100 shot of nitrous from time to time.

[oldekid]

My plugs are one range colder because I run a 100 shot of nitrous from time to time.Pat, what plugs did you go with for your nitrous? I'm trying to decide between NGK-TR6 or possibly going with the ZEX plugs. I have everything I need for my install now except for the plugs.

Thanks!

[Pat]

Oldekid;

Presently I'm using Denso IT-20's. They are iridium and cost about $12.00 each.

There is an Iridium motorcraft plug, P/N 9204 (new number system) gap .054 that is only $8.00 each. Iridium is a material that can handle a great deal of heat. Platinum plugs are good for stock, but not recommended for nitrous.
My Denso's have been installled for several years and over 20K miles.

The TR6 you mention is also an alternative.

If you go with the iridium then you don't regap them, damage can easily result. They come pregapped and that should be enough. The center electrode is very thin and any scrape or nick ruins the plug. There may be others that can also advise you.

Also, a copper electrode is a good choice.

[oldekid]

Thanks for the info Pat!

[RF Overlord]

^^^what Pat said about not gapping iridium plugs^^^

and


^^^what CRUZTAKER said about when to switch to colder plugs^^^

You should probably ask Dennis about this as well...I know he used to recommend going one step colder with his tunes, but that was a few years ago.

[Black Terror]

I saw this on another board I frequent...thought this could be good info to have over here for someone SEARCHing...

MOTORCRAFT

PART# / HEAT RANGE
AWSF-32C / stock heat range - copper plug
AWSF-22C / 1 Heat range colder - copper plug
AWSFA-12C / 2 Heat range cooler - copper plug
AGSF-32C/ Recommended for FRPP heads(not sure on heat range)

NGK

PART# / HEAT RANGE
TR-55/ 3951/ Stock Heat Range
TR-6/ 4177/ 1 Step Colder
BP7EFS (PN - 3526) BR7EF (PN - 3346) two steps
R5724-8 (PN - 7317) two and a half steps
R5724-9 (PN - 7891) three steps
R5724-10 (PN - 7993) four steps

AUTOLITE

PART# / HEAT RANGE
764s / Stock
103s / 1 heat range cooler
AR94 / 2 heat range cooler
AR93 / 3 heat range cooler
AR92 / 4 heat range cooler

CHAMPION

PART# / HEAT RANGE
YS-59C / -3 or -4 below stock heat range

DENSO

PART# / HEAT RANGE
IT16 / stock heat
IT20 / -1 heat range
IT22 / -2 heat range
IT24 / -3 heat range
__________________

[RCSignals]

I saw this on another board I frequent...thought this could be good info to have over here for someone SEARCHing...

MOTORCRAFT

PART# / HEAT RANGE
AWSF-32C / stock heat range - copper plug
AWSF-22C / 1 Heat range colder - copper plug
AWSFA-12C / 2 Heat range cooler - copper plug
AGSF-32C/ Recommended for FRPP heads(not sure on heat range)

NGK

PART# / HEAT RANGE
TR-55/ 3951/ Stock Heat Range
TR-6/ 4177/ 1 Step Colder
BP7EFS (PN - 3526) BR7EF (PN - 3346) two steps
R5724-8 (PN - 7317) two and a half steps
R5724-9 (PN - 7891) three steps
R5724-10 (PN - 7993) four steps

AUTOLITE

PART# / HEAT RANGE
764s / Stock
103s / 1 heat range cooler
AR94 / 2 heat range cooler
AR93 / 3 heat range cooler
AR92 / 4 heat range cooler

CHAMPION

PART# / HEAT RANGE
YS-59C / -3 or -4 below stock heat range

DENSO

PART# / HEAT RANGE
IT16 / stock heat
IT20 / -1 heat range
IT22 / -2 heat range
IT24 / -3 heat range
__________________

the information is old

most of the Motorcraft numbers have changed.

[RCSignals]

Motorcraft AWSF-22C number is now SP-505

[fastblackmerc]

the information is old

most of the Motorcraft numbers have changed.

At least it gives you a place to start.