ditto

 

This is good feedback (for me in particular, since I am also blessed with CA's octane-challenged gas). I wonder whether cooler plugs or a better I/C such as the M7 DFIC would be the ticket?

 

i just added the JCW MCS plugs to my 15% equipped car. only because the original plugs were in the car for 3 years now (2 years with pulley) and i figured that they could stand to be changed anyway. i see no real advantage to the colder plugs i now have i just figured a minor tune up with new wires and what not would be cool.

 

I ran 19% with stock coil, wires, injectors, ECU and plugs with no problems.

Now I have 19% with 8.5mm Kingsborne wires, IK-22 plugs, JCW injectors, GIAC ECU flash and still no problems.

 

Alta 15 with IK22 installed at same time, torqued to spec. No problems with backing out.

No other ignition mods at this time. Plan on GIAC very soon (unless a "better" ecu upgrade comes out before that time). This morning is my 40k-mile appointment, then I'm going to get the flash done as soon as $$ permit.

 

M7 - 16%
IK 24s

 

Did anybody switch to NGK's?

 

15% with IK22s by reccomendation of Randy Webb of WMS. Both installed @ 2500 miles.
Also have Kingsborne wires.

 

15%, stock plugs, about 7K miles since the pulley. No driveability issues.

 

Yep yep

 

Yeah, I think I'll try the NGK iridiums when I put in the 19%.

 

Same here.

 

Just replaced my oem plugs at 19000+ miles..Put in NGK Iridiums (same heat range) and no issues (smoother idle but that may just be the new plugs)..seems that Iridiums are the wave of the future!

I wonder if the dealer will try anything since they are not the OEM NGK /BMW Plats! I never put more than 20k miles on plugs no matter what they say and for under $30 for 4...why not! (100k on plugs...plz)

 

15% + Denso IK22s

 

17%, colder NGK's

 

Have a 15% pulley and use Denso IK22. Used the stock plugs for two weeks until I could obtain Denso plugs. Did not notice any problems of any kind with the stock plugs. Changed the plugs to cooler range because I live where it is very hot. Didn't want any long term problems.

 

!9% pulley, went to NGK BKR7EIX-11's, torqued to 23 ftlbs. Stock: ECU, Coil, Wires, IC. Next Mods will probably be Injectors and ECU.

 

Ha! That is like the lifetime a/t fluid....

 

Based on some of the posts and my own personal experience with a 17% pulley, barring something unusual (like a heat wave), it doesn't seem to be a requirement to swap plugs when only a s/c reduction pulley is installed. If the s/c reduciton pulley is part of a group of mods, there may be a good reason to go colder. One additional mod that could require a colder plug set would seem to be an ECU re-map.

Thanks again to all who have posted their experiences. I really am enjoying my journey into modding my MINI. Taking things one at a time is much more fun than taking the plunge all at once (my Corvette). Next up will be a Dinan CAI and I think a Milltek cat-back.

 

I have a 15% pulley and was running a screamin demon coil pack with 9mm wires and berua plugs. I recently switched to denso IK22s that are a colder plug and I think it improved my throtle response.

 

I have 17% and NGK one step colder.

 

17% and IK22's, then went back to stock after a week. Found the stockers performed better.

 

I had a pretty modified '03. The denso IK-22s went in at 30k.

Sold it at 84,000 miles.

Replaced them every 20K or so.

The car is still running strong.

Put 22s in my new, modifed '06 MCS at 1400 miles. Probably going to 24s soon.

But the reason to do it from my viewpoint isn't so much about slightly better performance (or not), but about running the car in a safer zone, (less chance of detonation, or for that matter, lower performance from timing being pulled back)...

 

Colder plugs are to avoid pre-detonation (knock/ping). They should enable you to avoid the loss of performance as the ECU retards the ignition to compensate for a pre-detonating engine. I have not had any issues with pre-det. in 50,000+ miles of 15% reduction pulley use. I ran stock plugs for the first 25,000 miles, IK-22's for the next 25,000 and have just switched to the NGK Iridium IX equivalent of the IK-22 (BKR7EIX-11). Extreme temps such as on a racetrack or in the Southwest desert might require the colder plugs, but as for street driving and the occasional auto-x, I think you can get by with stock.

 

Helix 15%, IK22 w/ JCW catback, CAI and JCW flash, run smooth as silk.