im running nitrous on my car this summer so i was looking to find a cooler heat range of spark plugs. but when i look them up and find the heat range its all diffrent letters and numbers like C 5 9 8 D 4 2, so how do i tell what the stock heat range is and whats a heat range cooler?

 

Your plugs are some number like R45TS.

R = resistor
45 = the heat range
T = tapered seat
S = extended nose

lower number = cooler

In the example above, you might try R43TS for a cooler but otherwise identical plug.

 

Sofas right there for delco. I've attached a chart for delco and NGK. NGK is UR4 for the hot one, UR5 cooler, UR6 cold.

Champions equivalent to the R45TS is the RV17YC
The equivalent to the cooler R42T (non extended nose as well) is RV8C
So for champion
RV (heat range)8 (if you want the extended nose, Y) C

I like champion because they are silver, vs delcos black oxide. The silver is easier to read than the black IMHO.

 

so how would this one do?

http://store.summitracing.com/partde...5&autoview=sku

 

The R42's are great heck for the price i would run em. I think that is what you want if not a step colder with the right amount of timing. let me know what the timing is set at and what size shot you are shooting. War Eagle Racing

 

150 shot, not sure on the timming yet though.

 

The 42's should be fine. I run a R42T (no S). On f-birds recommendation. I can't tell you why (lest I have to kill you).

Stock motor otherwise? Ie, no other reason to go to a colder plug as well?

You should be able to get those at your local parts shop for cheaper than that as well.

 

sweet, well im just gonna get them on summit cause i have a **** load of other stuff to order on there anyway. thanks for the help though.