Hotter or Colder Spark Plug
 

Now that I am turbocharging my 3L and am going to replace the plugs. Do I want a hotter or colder plug.
The plan was NGK BPES (copper) but I was not sure what heat range I should buy them in.

ThanksSmileWavy JC

I had the denso IK22s in my car but then switched to NGKs. Im not sure what range but take the manufacturers recommended range and go down 1 or two ranges and start from there.
depending on boost I would gap them between 22 and 25 as to not blow the spark out.

So even though factory reccomends a gap of 70-80. You think I should go down to 22-25?
Thanks for the info. I think I will buy in the 7 range for temperature.

Are we talking standard or metric? You want a small gap when high cylinder pressures are introduced so you dont heat everything up and/or blow the spark out.

The 930 should have used a colder plug than the 911.

The correct factory specified plug is the Bosch W3DPO although people say they are too cold really for the street.

Factory gap is 0.024"

You are right, I was talking in millimeters. Back cover of Bently says 0.028-0.032"
I went with the NGK BPR7ES

I use one step colder on a bosch plug, that's wr6dc, stock is wr7dc.
lower number is colder for bosch
lower number is hotter for NGK

I started with sevens, went to sixes, and ordered fives. But the sixes look good, just looked at them this morning, 300 miles on them.