I just got the NGK iridium plugs that are one heat range colder from stock and I was wondering if they are supposed to be one ground or four ground. The plugs pictured on Mini-Madness are four ground NGK's but what I received are one ground NGK Iridium plugs part # BKR7EIX. The guy at Madness says that he thinks they no longer sell the plug pictured and have just recently switched to the plug I received. Anyone who has purchased the NGK, is this the correct plug?

 

The part number you have cross references from the Denso IK22 plug, which is the plug many people have and recommend for pulleyed MINIs.

You can see the chart here: http://www.sparkplugs.com/results_cr...CrossWarning=1

I use the NGK ZFR7F, V-groove copper plug in my MCS, which is further down that chart. Lots of experience with force inducted vehicles tends to make me prefer the copper ~$2 plug over the fragile iridium ~$7 plug. Copper survives minor detonation better in my experience, though everyone has their own opinion.

 

>>I just got the NGK iridium plugs that are one heat range colder from stock and I was wondering if they are supposed to be one ground or four ground. The plugs pictured on Mini-Madness are four ground NGK's but what I received are one ground NGK Iridium plugs part # BKR7EIX. The guy at Madness says that he thinks they no longer sell the plug pictured and have just recently switched to the plug I received. Anyone who has purchased the NGK, is this the correct plug?


Interesting. NGK is a big proponent of multiple electrode spark plugs, but it appears that their new Iridiums don't have the multiple ground spark plugs. It appears that they came out with an IX version. They are the right ones, just a different design. Mini-madness came on this site a while ago and had said that they had discussions with BMW stating that the 4-prong design was superior for the engine design. Now they are shipping other plugs and don't know why. This is very interesting and really makes me question there original push of the four prong design, as well as Mini-madness expertise in this area.

You can see the discussions here https://www.northamericanmotoring.co...mp;topic=22908

Mini-madness was pretty vocal about the 4 prong design and that was one of the specific considerations why they were selling that design over all the others. They said they were confident that this plug was more reliable and offered better performance than a single electrode.

I don't have anything against Madness, it was just that they were so strongly set on the 4-prong design and that they were basing it on their hard work and experience and now they are shipping a different plug, which is design differently and they don't know why. Either their original hard work and investigation was not so important to prevent them from selling other designs that they thought were inferior, or they had a botch up on their side with communication and a new product from the vendor. I am curious as to the reason it was shipped out.

 

I knew that they had pushed the four ground design, that's what confused me. However when I talk to madness they tell me they have switched to this plug since it is better performing

 

>>I knew that they had pushed the four ground design, that's what confused me. However when I talk to madness they tell me they have switched to this plug since it is better performing

Did they really say that they switch to a single prong because it was better performing? What a change in attitude. The single prong to me doesn't offer any advantage over the Denso IK22. At least with the four prong you could argue that the different design made a difference. I am really curious as to why they changed there stance, especially when they were so adamant on the four prong design. Doesn't give me a lot of confidence in their advice for products.

 

I think that the point has been made here numerous times that the 4-prong design doesn't help performance, but allows the plugs to last longer. For any given spark, the arc will exist between the center electrode and one of the 4 ground prongs. As the plugs wear over time, each of the prongs will likely wear at a different rate - but one will always be the path of least resistance to ground. With a standard,single prong plug when the ground electrode wears out the plug will require replacement.

BMW's strategy for supplying the 4-prong plugs probably has not so much to do with performance, but more with extending the maintenance interval for the plugs.

 

>>I think that the point has been made here numerous times that the 4-prong design doesn't help performance, but allows the plugs to last longer. For any given spark, the arc will exist between the center electrode and one of the 4 ground prongs. As the plugs wear over time, each of the prongs will likely wear at a different rate - but one will always be the path of least resistance to ground. With a standard,single prong plug when the ground electrode wears out the plug will require replacement.
>>
>>BMW's strategy for supplying the 4-prong plugs probably has not so much to do with performance, but more with extending the maintenance interval for the plugs.


I agree the 4-prong plug is only for extending maintenance interval. The single prong plug will be sufficient.

 

What is the advantage of using non-stock spark plugs? I have been running a smaller than stock pulley (first 15% then 19%) for over 18,000 miles in all sorts of temperature/driving conditions. The plugs appear perfect - no sign of detonation or discoloration.

 

>>What is the advantage of using non-stock spark plugs? I have been running a smaller than stock pulley (first 15% then 19%) for over 18,000 miles in all sorts of temperature/driving conditions. The plugs appear perfect - no sign of detonation or discoloration.


I don't think anything scientifically has been shown that a problem exists between the stock plugs and a pulley reduction. It is known that a colder range will help with detonation that may occur increased pressures from forced induction. The price of a set of plugs is pretty small (@$25) for people who are looking for increased protection and performance. JCW includes one range colder plugs with their JCW kit, but I have not heard anything on whether this is to correct any problem or just being cautious. People will spend $200 for a set of Nology's without much of a performance impact, so $25 doesn't seem so bad, especially when the BMW approved tuning package includes it as well. I would like to see someone test this more to see if they really are needed. I installed some IK22's with my pulley, but I can't say I noticed much, if any difference.