Austarion

I just pulled out some NGK Iridium BKR7EVX plugs instead of the usual NGK B7ES plugs.
I didn't measure the gaps but they were far wider then 0.7 ~ 0.8mm.

Some questions:

Are these of the same temp range as the standard plugs?
How wide should the gap be?
Can they be wider because they produce a better spark?
What's the optimum gap with these then?
Our plugs don't normally have a resistor but this one with the "R" does...will that cause issues?
Could it have contributed to wrecking my head gasket?

See other post for more info:
http://forums.austarion.com/viewtopic.php?t=14556

I run NGK iridiums R's with the gaps as supplied with no problems or missfires on 16psi boost.They produce a more concentrated, intense or powerful spark.IMHO they have nothing to do with your HG problems.
7 is the same heat range regardless of type of metal used in the centre electrode.

i have been advised to shy away from platinum plugs, as they are pricey, but actually worse at creating spark - marketing gimick apparently

I put $50 of fancy plugs in my car just prior to getting it tunned at JEM. The first thing he did was put them out and put a set of stock plugs.

Hope this helps

Oh...and iridium plugs last longer, that's why they are used so you supposedly don't have to change them as often.

From Denso website....

Q. What makes Iridium better?
A. Until recently, platinum was considered the best material to use on the top of an electrode because of its durability. However, Iridium is 6 times harder, 8 times stronger, and has a melting point 1200 degrees higher than platinum. Put that into a harsh environment such as an engine piston chamber, and you have a spark plug that can resist wear much better than platinum. Additionally, the DENSO Iridium Power alloy is so durable; it allowed our engineers to produce the world’s smallest center electrode (.4mm) which reduces the voltage requirements, concentrating its sparking power. Also, its smaller size, combined with the tapered U-Groove ground electrode, allows more room for the flame kernel to develop and produce a more efficient combustion.

Denso FAQ

I've heard both iridium and platinum plugs have a greater resistance than normal plugs so unless you have a C.O.P set up I'd steer away from them.

I fitted NGK Iridiums BR7EIX and got a nicer idle than I had previously with the Bosch Super 4's and standard NGK's.

vr4gone wrote:I've heard both iridium and platinum plugs have a greater resistance than normal plugs so unless you have a C.O.P set up I'd steer away from them.

Wrong...

Looks like a debate has started...I haven't replaced them yet so I'm interested in hearing more.

Fugazi, if you disagree with vr4gone regarding resistance with coil over plug setups, can you enlighten us?

And Al, thanks for the X-ref chart!

thrash wrote:i have been advised to shy away from platinum plugs, as they are pricey, but actually worse at creating spark - marketing gimick apparently

My understanding is that Platinum plugs were produced for longer life over std plugs and are mainly used in east/west v6 fwd motors where it is a major service to change the rear 3 plugs that are changed when the cam belts are changed as the inlet manifold has to be removed to be able to install new plugs.

Iridium plugs were brought in as platinum make less power than normal plugs, iridium make the same power as normal but last like platinum

IR's probabley last even longer than platinum.
Adding resistance to sparkplugs and/or cables does'nt realy effect the spark in a negative way...
The IR's are as close to a "perfect" plug as you can get.
The small size of the hook makes a very good/big plamefront (think of what a "super4" or HALO-plug does to the flamefront!)
The more pointy the better it transmitts the spark...

What I meant with "wrong" is when someone HEARD something from someone... BS! Stick to facts!

Just one example!

These are factory OEM spark plugs used in the 135i.
Their engine is a 3L, DOHC VV-T, Direct injection, high comp (11.0:1) Turbo straight six.

Bosch ZGR6STE2 Super Plus Spark Plug

Bosch Super Plus Spark Plugs deliver quality performance based on technology that is proven on racetracks around the world in the most sophisticated racing engines. Testing has confirmed the durability of yttrium-enhanced center electrodes which offer superior reliability and 50 percent longer performance life. Super Plus also features a tapered, v-profile nickel chromium ground electrode for improved starting in cold weather and increased fuel ignitability, nickel-plated rolled threads for complete anti-seize and corrosion protection, a metal glass fused resistor for maximum interference suppression, and angular, five-ribbed insulator design to prevent misfires due to current leakage.

* 50 percent longer life than traditional copper core spark plugs
* Exclusive Yttrium extruded copper core center electrode increases resistance to spark erosion
*Tapered, v-profile nickel chromium ground electrode for consistent performance and prolonged service life
* 12mm Thread Size
*Solid terminal nut, 0.7mm gap

http://www.boschsparkplugs.net/resultsA ... eID=1&pt=1

They do NOT use platinum or iridium. Other people might, but I don't question BMW's German engineering!
Take it which ever way you like, I stand but my previous comment.

Yep, won't argue about the german knowhow!
But, the plug you're refering to isn't the same I meant...
The multihooked ones are crap, imo. They just mess up the funktion of getting ONE good spark. Cu's you CAN NOT get more than 1 spark at the time (unless you have more than 1 plug of course!)

Meltingpoint:
Yttrium 1795K
Platinum 2045K
Iridium 2683K
(Copper 1356,6K)

Whatever do they mean by "yttrium-enhanced"? Plated with yttrium?

"Post subject: NGK Iridium plugs, are they suitable?"
Yes, absolutley!!!
But you dont need more gap to get a better spark, cuite the oposite. If you have to wide a gap the boost will actually blowout the spark!
High boost=>Less gap

I've had them in my car since they became affordable, probably 8 years+

The reason originally was because with little use the car would foul plugs, with iridiums its real quick and easy to clear them without removing them.

I can't fault them and won't be bothering to check them for quite a few years yet, that to me makes them worthwhile/ better than cheap ones.