Koyo R1819 Radiator - R-Series Built with a robust 53mm core, the R-Core Series is engineeredfor the serious performance tuner. Increased capacity means bettercooling reserve when you need it. Intended for both circuit anddaily use, you may double your coolant capacity and see up to 35%increased performance over your stock radiator.All Koyorad R-Series All Aluminum Radiators are Nocolok brazed,designed as a factory fit, direct bolt in with no enginemodifications necessary, and retain mounts for the stock fanshrouds and fans.