Qingqi QM200GY-BA (Qlink XF200) Iridium spark plug

[forchetto]

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