These plugs run 1 heat range colder than the stock plugs. This cooler range plug prevents early detonation and provides smoother running from your modified engine by allowing more heat transfer away from the cylinder to the cylinder head resulting in lower in cylinder temperatures; highly recommended for those running more boost via pulley upgrade.
Click this link to see what happens when a MINI runs too lean and has pre-detonation occur. Not a pretty site, this customer was running our competitors software, and STOCK replacement Denso plugs. We determined a combination of lean running and the STOCK heat range plug resulted in this damage. $1000 later this MINI was running again with Evotech software and NGK 1 heat range colder plugs.
Includes 4 pre-gapped NGK Iridium spark plugs.