I have seen that most vendors recommend upgrade to colder spark plugs if you have one modifications on your Mini. So I want to make sure I don't waste my money, also I want to see if I really need them. I am looking to get these One step colder NGKs (BKR7EIX-11)

http://www.jscspeed.com/mini/engine/mini_ngk.htm

Any improvements with those? any issues?
I have an '06 MCS with 15% Minspeed pulley, K&N-CAI and One ball exhaust. 33k miles.

Thanks!

 

I used that plug for about 2 years but noticed that the iridium tip is slowly eroding i.e. becoming finer / thinner from where it used to be but probably because of the detonation brought by the overly advanced ignition timing from my previous aftermarket ecu flash. Some members here have reported the same issue of tip erosion too whether NGK or Denso. I am running NGK BKR7EQUP now.

 

That was my second option, but I have read at several vendor web pages that the Iridium is the latest technology, so it is supposed to be better.
The BKR7EQUP you are running are the ones that come with the JCW, so I guess at least these are guaranteed from factory. what improvements have you seen running the BKR7EQUP?
Thanks!

 

This thing with the spark plugs is really confusing...

These are supposed to be the OEM spark plugs for the MCS
http://www.minicarparts.net/Parts/BKR6EQUPK.cfm
http://new.minimania.com/web/item/G2.../InvDetail.cfm

These are the JCW ones
http://minspeed.net/NGK7.htm

These are an other reference I found for stock MCS plugs
http://new.minimania.com/web/item/NM.../InvDetail.cfm

These are the New colder plugs several Vendors are selling for MCS
http://www.ngk.com/results_cross.asp?pid=6988&x=0&y=0
http://www.mini-madness.com/index.as...PROD&ProdID=71

So which is the right one?.... and what improvements would I see?

 

I did not notice any improvement between the 2. Both started well and idled well but I only used the JCW plugs 5 days before the RMW tune. Jan told me that one reason why my iridiums were eroding was due to my old software causing pinging.

 

The NGK Iridium plugs last much longer than the Denso Iridium plugs, FWIW. I've been using NGK Iridium's for the last few years with excellent durability.

You're really not going to see any performance improvement per se. What you're doing it matching the heat range of the combustion with the tolerance range of the plug. If you're running on stock plugs with a supercharger pulley and other bolt ons, it would behoove you to go to 1 range colder. If you track the crap out of your car and/or have more advanced mods [like cylinder head, 19% pulley, merge-collector header, cam] then 2 steps colder is wise.

 

Well, I installed the NGK BKR7EIX-11. Got them from Advance Auto Parts for $29 =P. First impression, I think the car has better response...maybe. Now my question is, after 15% pulley, K&N CAI, One ball exhaust and NGK colder plugs, do I need to re-program ECU? If so, what kind of improvements would I see and how much could cost?
Thanks

 

I just went back to the NGK BKR7EQUP after having the NGK BKR7EIX-11. 2006 JCW. Smoother acceleration. Im in the SoCal area. Hot temps. Runs great.