Hey Guys,

I have had a 15% pulley on my MINI for a while with the stock plugs. Now, I've been reading this forum a lot lately and most recommend a cooler plug for s/c's that have a reduction pulley (higher amount of boost?)

Is this necessary for high altitude MINI's? We are losing between 15-20% of air density anyhow being a mile high, I doubt the 15% pulley is bringing engine up to sea level air density. Any feedback is greatly appreciated. Doing a bunch of maintenance on my car and trying to cover all the bases. Thanks!

 

Correct, as combustion pressures are increased, the event of auto-ignition (where the fuel-air mix combusts before spark ignition) increases.

It highly recommended, but it's not because of intake density.
It's based on the increase pressure made by:
a.) the reduction pulley for a supercharger (boost is produced through engine speed, connected via a belt)
b.) turbocharger works harder make the same amount of boost at altitude, creating hotter air compressed

You'll see less knock and some better fuel econ with a cooler-temp plug.

- Erik

 

Forgive me if I am wrong (I am a pilot, so the forced induction systems may be different in planes than cars), but the supercharger is tied to engine RPM via the serpentine belt. It can't spin faster to make up for higher altitudes, unlike what a turbo does.

 

Nope, you're spot on.
My previous statement of "a supercharger works harder" is incorrect as you pointed out.

- Erik

 

Ah okay. So should we still get some cooler plugs? Or is it not necessary? Thanks!

 

One thing to consider...the JCW pulley is about 11-12%...so running a 15%, you are likely running the same boost as a JCW at sealevel...so IMO you still need the cooler plugs...the same ones as the JCW.
Be sure to use a tourqe wrench...tons of folks have blown plugs out..and check the tourqe in a few days.
You should be fine till spring though..folks generally have issues with the plugs causing pinging with warmer OAT's...so I don't think you need to rush.

 

Sounds good. I guess it couldn't hurt regardless of elevation. I'll probably end up making some road trips anyhow. Thanks for everyone's responses.

What is the NGK plug that the JCW cars use? Or is there a plug recommended for MCS's?

 

the OEM fitment for my Works car is NGK BKR7EQUP. These are reputedly one heat range cooler than the NGK BKR6EQUP which is standard for the "S".

 

NGK platinum or iridium plugs are good IMO...some folks like the Brisk plugs. A quick search will get you the plug numbers for a jcw, or a vendor can ship them....dealers charge about 2x-4x what they normally sell for.
One reminder...with the higher boost temps and pressures of a JCW, mini recommends changing the plugs much more often...every inspection that is..so about every 30k or so.

 

I have had the Brisk silver's that Alta used to have on their site, for about 2 years(only driven for a year of that) and I love them. I just need to watch them because the only torque spec I could find for the plugs on a MINI is 25 ft/lbs and after about 10,000 miles 3 of them backed out to finger tight.

 

mmm...

The spec is 19-23 lb/ft, and thanks for the heads up. I'll add that to the checklist even though it's never been a problem thus far. No harm in checking.

BTW (and sorry for the off topic) are you still in CONUS and how's your baby coming along?

 

Well I am back in Kuwait now but it wont be long until I am home for good.
I got way more done in the time I was home than I thought, I even got the Autopower roll bar in the night before I left. I couldent get any pictures of that up because of computer problems at home.

To get back on topic, there was a thread on here about the Brisk plugs backing out (thats why I checked mine ASAP) evedently it happens quite a bit. Brik has a couple different plugs out for MINI's but the only ones I have tried are the BR125's (I'm pretty sure) I installed them down in Tennessee on my last visit and they made a pretty good differance down there. When I got back to Colorado I did notice that quite a bit of the vibration at idle was gone, but not much else.
As for needing colder plugs with most of the basic power mods that we do, I would say it's a good Idea, but not an absolute necessity. The high altitude and our oxygen levels or lack there of around Denver dosent realy play mutch into an engine with forced induction's need for a cooler burn temp. Even at 10,000 feet our S/C engines are burning more air than a N/A car at sea level, so I would say go for it, the cooler plugs are about the same price, and it wouldnt hurt anything.

 

I put the e3 Spark plugs in mine, and I could tell a difference right away. They are much smoother then stock. Now I do a have a few mods, but not a ton, see my sig for them all.

The model for our MINIs is E3.48.
Also here is a link they have for torque
Applying the Correct Torque:


And here is a link at Sparkplugs.com for several vendors and prices
http://www.sparkplugs.com/results_ap...1&AAIA=1426564