by hotmetal1000 on Sat, 23 Jun 2018 5:37 +0000
Old thread I know but I have found the following information and might be helpful to someone else.
The IKH20 spark plugs are iridium power.
The VKH20 spark plugs are iridium tough.
From Denso's website,
"The IRIDIUM POWER, with its 0.4mm iridium center electrode and U-groove + tapered cut ground electrode, is a high performance plug providing ultimate running results.
The IRIDIUM TOUGH, with its 0.4mm iridium center electrode and platinum ground electrode, is a high performance plug with an emphasis on longer life.
The ground electrode of the IRIDIUM POWER has a tapered cut and a U-shaped groove on its underside, reducing the quenching effect during flame formation and providing exceptional ignitability.
The ground electrode of the IRIDIUM TOUGH has a platinum at the discharge point, suppressing electrode wear at discharge and providing the working life of a platinum plug."
Both plugs are listed for the 1GR-FE NA and supercharged by Denso.