Reference number for spark plugs....Help!

[vetteboy86]

I bought the regular AC Delco plugs for my car, just to have them. Well the builder looked at them and said he would like cooler plugs. Does anyone have a reference number for AC Delco's.

Thanks,
Craig

 

[Mad-Mic]

I bought the regular AC Delco plugs for my car, just to have them. Well the builder looked at them and said he would like cooler plugs. Does anyone have a reference number for AC Delco's.

Thanks,
Craig

whats his reason for cooler plugs? are you running aluminum heads or iron?

AC Delco RAPIDFIRE TM Spark Plugs
For Corvette Engines

1986All Iron HeadRF#21986-1991Aluminum Head (VIN 8)RF#5

Whenever the RF#2 is specified, if a slightly colder plug is desired for racing or very aggressive street driving, the RF#1 can be substituted. Whenever the RF#5 is specified, if a slightly colder plug is desired for racing or very aggressive street driving, the RF#9 can be substituted.

http://www.idavette.net/tech/acplugs.htm

some more reading...

Certain running conditions, such as the length of the average journey, average sustained speed, altitude of operation, available fuel, ambient temperature, amount of engine wear, air/fuel mixture, or compression ratio may make a change to the recommended plug temperature appropriate.

Too low a plug temperature can result in a plug fouling, evident when sticky deposits are deposited on the plug rather than being burned off.

Too high a plug temperature results in pre-ignition and breaking up, with potentially dangerous consequences to the engine should the plug insulator material fall into the cylinder bore.

A "hot" high power engine requires a "cold" plug.
A low power engine requires a hot plug.

http://www.mgcars.org.uk/electrical/body_plugs.html

google is your friend
always check with the parts dealer to confirm what you are buying is what you need. IE this plug is colder than this plug and if so how many ranges ect?

BTW
Google Owns Me

 

[vetteboy86]

Thanks Mic, he said he thought they would be too hot. I have AL heads on my car. I do know that I will see better then a 10 to 1 compression ratio.

The hole reasoning for doing this is to prevent detonation correct? He said if the knock sensor picks up anything it will pull timing and the car will be a major dog. So I bought a new knock sensor, and I guess am going with a cooler plug. I ran the rapid fires on the stock motor though, and was impressed.

I guess I will call autozone, and find out what they have. I hate doing that, because most of the time they hardly know what I am talking about. So the reference number on the plug will change, but the rest of the part number will stay the same. Is this correct?

 

[vetteboy86]

Well I went to autozone, and the guy had no idea what I wanted. I asked for the Rapid fires, and all they have is the reference number 5. So I looked at the regular plugs, and he couldn't figure that out either. Gave me some, after calling a hot rod shop or something. I will post the number he gave me when I go get them out of the car.

 

[vetteboy86]

Okay guys this is the AC Delco plug number they gave me at autozone:

R43XLS

Anyone have an idea about this one, I am going to try to research it now. Found this link: http://www.crateenginedepot.com/sparkplug_chart.html

Unsure if as you go up the reference number you get hotter or colder. According to text in Mic's post, if you go from a 5 to a 9 you get a cooler heat range plug. Well they gave me a 4 so WTF does that mean.