Kia 2004.5 Spectra Service Technical Training page 134

2004.5 Spectra Technology
SPARK PLUGS
The SULEV engines use Iridium tip spark plugs. These
plugs have more stable ignition during cold starts with
a leaner air/fuel mixture, and longer durability. Federal
emission vehicles (ULEV) use Platinum Plugs.
The very thin 1.1mm diameter center electrode tip on
the iridium plug is a hard and strong alloy of Iridium
and rhodium for increased oxidation wear resistance.
This Iridium tip is melted to the nickel base of the plug
with a 360-degree laser welding process for a reliable
seal. The 0.4mm Iridium alloy tip has a very high
melting point. The spark plug has a U-groove tip
design that gives the flame a groove to grow in for a
more complete combustion even in case of lean air-
fuel mixture.
Driveability
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