Qingqi QM200GY-BA (Qlink XF200) Iridium spark plug

We hear alot of good things about these relatively new components, rave reviews in magazines and impressive dyno tests proving significant power increases. One magazine in the US got nearly 30 bhp more out of a supercharged Mustang with iridium plugs. Aparently they're specially good on supercharged and tuned motors.

I've always been a bit cynical about this type of claim, specially after the SPLITFIRE plug debacle, but it seems that people like Denso and NGK, both reputable manufacturers stand by these claims.

Claims on normally aspirated non-tuned engines add up to 1 to 3 % power increases, easier starting, reduced fuel consumption, smoother running and longer life. Good thing too, as they're up to 5 times more expensive...

I've fitted one to my Qingqi today and have to admit that for the first time ever it started from cold instantly as soon as I hit the button, and the choke could be retracted fully almost immediately and the engine settled to a steady tickover straight away. I'm impressed.

Normally the starter churns around for a bit, sometimes throwing the starter clutch out of engagement with a graunching noise, and the choke has to be kept halfway on for a minute or two.

Not really noticed any power increase. You normally need something like 5% improvement to be able to tell using the "butt dyno", but it does seem to run and respond better. Only subjective though.

The type used was a DENSO IRIDIUM IX24

The NGK equivalent would be the DR8EIX

Why/how are the iridiums supposed to be different/special? How do you figure that effected your startup?

CC

Quote:

---

Originally Posted by CrazyCarl

Why/how are the iridiums supposed to be different/special? How do you figure that effected your startup?
CC

---

It seems the precious metal can be formed into an extremely thin firing point, just 0.4 mm in the Denso Power types, and 0.7 mm in the long life version. They also boast a patented "U" groove in the earth electrode. This gives a much improved spark ideal for burning leaner mixtures more effectively, and the plug needs less voltage to fire properly. They say 5000 volts less.

DENSO dedicate an entire webpage to them:

http://www.densoiridium.com/

There's another factor that could have affected the starting: The Qingqi has a plug cap fitted with a 5 KOhm resistor in it for radio supression purposes. The original plug is also a resistor type, another 5 kOhm resistance in the ignition circuit. The "R" in the type designation shows that: NGK DR8ESL
The iridium plug has no resistor in it. Maybe this has improved further the voltage reaching the plug.

The only way to test this would be to either fit an unsupressed plug cap or an ordinary non-resistor plug. In our case the NGK D8ESL.

im agree with
forchetto
http://www.mychinamoto.com/forums/im...er-offline.png
and i have been using the denso ix 24 from first day and im realy happy with the performance ...