Hi Folks,
I am new to this forum. I own a 2006 mini S hatchback. It has 83K on it and I decided that I would have the plugs replaced last week. I took it to a local garage and they installed what they said was an OE plug (NGK Iridium). After driving the car for a week or so, I must say that it seems that the car doesn't have the same torque that it used to. I would estimate 15-20% less power. I don't have any codes that suggest a bad plug and the car runs fine (check engine light is off).
I went back to the garage and they said that unless the check engine light is on that everything is good.


I don't have the old plugs so I cant change back. Anyone have advice they can offer or have you had the same problem?


Thanks in advance for any help you can give me.

 

Are you running a reduction pulley on the sc?
If you are, most folks run the jcw heat range plug...which is one step cooler than the stock S.

 

Hey Zippy,
Thanks for the response. To the best of my knowledge the car is stock. I have owned it for about 1 year and have driven it 32K. I am wondering if they just changed to winter fuel at my local gas station? Maybe that is it??? Anyways, I have never owned a car where you change the plugs and get worse performance.


Looks like you live in NH. Me too. I live near Portsmouth!!

 

If the pulley is black, steel (hot-pressed), no bolt holes, it is stock...
Reduction pullies are of various colors, but are usually unpainted, have 3 or more bolt holes....
Did they change the belt? Stock is 1388 mm length....
With a 15% or 17% reduction, most folks run a (us length, not metric) 535 or 532 belt...
Ngk's are good plugs...I run them...hear any ping? You should be running 91+ octane, 92+ if you have a pulley... Not as important in the winter, but a possible factor...
Pretty sure "winter gas" changed about 2 months ago.....
Welcome to Nam...maybe see you around in nh sometime! I live around the nushua area...
When I get something I don't want to or can't diy I bring my car out to Greasysgarage in Worcester mass...a bit of a ride, but they are real mini guru's and charge about half the dealers prices...well worth an hours drive for me (heck some folks from me and vt go there too).

 

The stock MINI plugs are Platinum not Iridium. We don't recommend the Iridium as we see them wear out much faster or often loosen up. I would verify what plugs they put in. Also did they gap them? If they did it is possible for them to have too small or large of a gap causing a power loss. Also did you get wires? Check the coil terminals too. #3 is the most common to be corroded and can cause less spark on that cylinder.
These are all just guesses as there is no way to say if there even is anything wrong without seeing it.

 

I would definitely remove the plugs to have a look at their condition and to see if they're loose. I'd also check the coil terminals and if all looks ok, I'd gap and pop in a set of inexpensive copper plugs to see if you notice any difference.

Greg

 

btw, welcome to NAM, and a fello n'amshireite, im in dover.... far drive away from ya bud =P

everything that i have read, irididuim is not a performace spark plug. quite the opposite, they actually last the longest

it could be the plugs, our cold air will help our cars now compared to a couple months ago, but super cold liek this morning you will see a minor decrease in performace. reset the ECU, theres a thread in here, go for a drive and see if it helps