I'm in need of new plugs for my '03 MCS, and I'm searching for the correct NGK like you mentioned. If I go on NGK's website they say the ZFR6FIX-11 is the correct plug for the MCS. If I go to some online stores and use their parts finder they recommend the BKR7EIX-11. Can anyone shed light on what should be used on a bone-stock MCS?

 

The two plugs you mentioned are different in two ways.

ZFR6FIX-11 is the stock heat range for the MINI, and factory-gapped at 0.044".

BKR7EIX-11 is one stage cooler than stock plugs, and factory-gapped at 0.030".

Seems that you should be using ZFR6FIX-11 if you're looking for OEM replacement plugs.

 

I've had my Denso IK22's for just over a year now and I want to change them. I was thinking about going down to IK24's or the equivalent NGK plugs. I haven't had any problems with my Denso's so I think I'm going to stick with those. However, would anyone advise AGAINST stepping down a heat range to IK24's. My mods are listed in my sig. I live in Miami wheres it gets REALLY hot... TIA

 

Go with the 24s. It's cold here & no issues. The 24s have been the best plug in this car. Had the 22s they were an improvment over OE. In the spring I'm going to try even colder, possibly an NGK, or not. The best plug is as cold as the ign will take. The Mini under hood is a furnace even when it's cold outside.

 

Are there any drawbacks going with colder plugs in the northern states? Should be fine for summer, what about winter?

 

the first year of my MINI's life it was in wisconsin winters. With the denso ik-22's my car would cold start stumble.

It would do this badly until the car was properly warmed up in anything less then 35 degrees.

Now that I live in Tennessee I have been running the colder plugs in the cooler weather. The car will still stumble a bit when starting from sitting for more then 4 hours. However it will only do it first heavy throttle. Not after that.

With my stock plugs this behavior is rare but still there to a much much lesser extent. Supposedly an ecu update will fix this but I have to see that.

 

I have another question along with what prime was stating. I'm going to change out my plugs soon, because I feel that I should be running colder. My mods will include intake, pulley, and header, including a cat-back later on. Should I run one step colder (NGK BKR7EIX)?

I live in Ohio, where winters are harsh, and last winter I had several very bad times where the MINI just didn't want to start, and ran very rough until the engine was warm. Would running one step colder improve or hurt this?

Thanks!
-Cody

 

I used to run two steps colder when the nitrous was still in and didn't experience any starting/running problems even as low as 14F...could be something else...

 

I haven't had problems starting, but same thing with the rough running/yo-yo last winter on my stock MCS when cold, so might just be a general temp thing (or if you buy the urban myth, the winter gas ).

I was planning on the Denso IK22s when I get pullied based on my perception that they were the plugs of choice from people's sigs, but if the NGKs are as good or better option, I'll be happy to save a few bucks.

Just to verify, the NGK part #s listed above (BKR7EIX for 1 step colder and BKR8EIX for 2 steps colder) are gapped correctly for the MCS out of the box?

Alta seemed to recommend one step colder for a 17% reduction and 2 steps colder for 19% in their Q&A thread. Are there any potential long term negatives (aside from possibly some issues w/ cold starting) to running two steps colder w/o the 19%? Seems like colder would be better...

TIA

 

Why do you need colder plugs?

 

Given the mods I will have, should I run one step or two steps colder? Every now and then, I'll hear and feel my MINI stumbling at a light, like it putts....almost as it wants to stall, but it doesn't. Is this due to the timing retard on my plugs? Would running colder plugs help with this? BTW: This has been happening on and off for about a year with the OEM plugs, with a M7 16% pulley and ALTA intake.

Thanks,
-Cody

 

I believe the idea of the colder plugs is to offset the effects of the additional heat from the faster rotation of the SC and added boost, but I'm no mechanical engineer so I couldn't say for sure...

 

I switched back from two ranges colder to one range in January of this year.

Car simply ran better.

Also, went to NGK for greater durabilty over the Densos.

Have to say that if I weren't doing track events on hot days here in the South, I'd want to try the stock range again, just to see what happens.

Might anyway...

 

I was running the Denso IK22 for the last year or so. Recently experiencing slightly harder starting than usual. Felt it was time for new plugs. I picked up NGK ZFR6FIX-11 (OEM match) at Summit Racing because they didn't have the next step colder available. Have to say the MINI starts up much faster now, but they are new so it should. I was a little concerned that the insulator/firing end was a little longer than the Denso's I removed but had nothing to compare against for the OEM length.

btw, the NGK website has a nice technical article on the spark plug and what colder plugs do.

 

what about stock JCW MCS's ?

would they use IK22/24 and NGK BKR8 and 7s as well?

 

Stock JCW's come with the NGK's BKR7EQUP (according to realOEM.com)

Stock MCS come with the NGK's BKR6EQUP (also according to realOEM.com)

 

Thanks....this has been an enlightening (and confusing!) thread, sooo many similar part numbers, but I think I have it now: (sorry if this is all buried somewhere in A FAQ that I missed!)

OEM in red (realOEM.com)

Cooper:
NGK BKR6EQUP Platinum+4, NGK BKP6EIX Iridium 0.030 gap
one heat range colder: NGK BKP7EIX Iridium 0.030 gap

CooperS:
NGK BKR6EQUP Platinum+4, NGK ZFR6FIX-11 (also BKR6EIX-11?) Iridium 0.044 gap; Denso IK20
one heat range colder: NGK BKR7EIX-11 Iridium 0.044 gap (no valid ZFR7FIX-11 part#), Denso IK22

JCW CooperS: NGK BKR7EQUP Platinum+4, NGK BKR7EIX-11 Iridium 0.044 gap, Denso IK22
one heat range colder: NGK BKR8EIX-11 Iridium 0.044 gap; Denso IK24

(these of course do not include R56 MINIs, or other vendors)