I changed the plugs on my '04 R50 about four months ago. I put the NGK BKR6EIX iridium plugs in because that was what everyone on the forum seemded to recommend.

Performance is outstanding now!! What I have noticed is that it now seems to run right at the midpoint on the temperature gague and if I am in traffic or have been just before shutting down the auxilary fan comes on for several minutes when I shut it down. It never seemed to do that before and I am beginning to worry!! Today it was under 60f out and it still came on when I shut down.

Did I make a mistake with the plugs? Should I have put a colder plug in (it called for a 6 series).

Any suggestions would be appreciated!!!

Bill

 

My 08 R56 does that, and I worried at first, because most cars do not run the fan after the shutdown, however, my 08 is designed to do it, to cool the coolant during heat soak. It even mentions it in the manual. Look at yours and see if it mentions it as well. Now that I know, I don't worry about it.

 

The wrong sparkplugs will not make a cooling fan run more....
No reason to run a cooler plug on a r50...you have not upped the compression or power output signifignatly....so keep tye same same range...check your coolant level though...
just a bit of history on the r50...

Some early r50's were deliveded with a different heat range plug...but mini then switched to the range you are using..being a r53 guy not sure of the specfics, but just stick yo the stock range imo.
you can tell if the plug is the right heat range by looking at it after it has been a run a bit...the colour and cleaniness of the plug tells the story....