NGK R7437-8 Equivalent. Denso Iridium Spark Plugs feature the world's
smallest center electrode, measuring 0.4mm in diameter. Because the
majority of spark is exposed to the air/fuel instead of the metal
surface, the fuel burn is greater (0.5 increase over platinum), which
ultimately improves gas mileage. The tiny 0.4mm tip doesn't get in the
way of the electrical current, which means less voltage is required to
create the spark. This lets the spark plug respond effectively to
greater extremes of driving conditions, assuring optimum performance all
Iridium is 6x harder, 8x stronger and could take
temperatures 1,200°F hotter than platinum. Iridium is so tough, that
Denso requires laser welding in order to join the Iridium tip to the
nickel base. The process provides 360° seal so reliable that the
electrode resists wear even in the worst conditions.
Denso Iridium Spark Plugs require on average 5,000 fewer volts to fire
than conventional spark plugs. Less power is required to fire Denso
Iridium Power Plugs, and coupled with U-Groove technology, the use of
Iridium alloy, the tapered cut, and the ultra fine 0.4mm diameter
electrode translates to increased horsepower throughout the dyno range.
To increase the gap size:
1: Use needle nose pliers or spark plug gapping tool to bend the ground
strap up to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL
TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN.
Step 2: Re-check the gap with a calibrated gapping tool.
To decrease the gap size:
1: Use the same method as above, however bend the ground strap down to
the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE
IRIDIUM CENTER ELECTRODE OR PORCELAIN.
Step 2: Re-check the gap with a
calibrated gapping tool.
WARNING: Failure to follow these directions may permanently damage the
spark plug. Note: Never use a round gapping tool to check the gap or to
increase or decrease the gap setting.