I/C R35 VR38DETT GT-R (DUCT LESS)13001 AN014 Cooling performance The performance of intercooler of stock is fine for normal stage, but for the tuned car of 1. 2k boost up (GT570, GT600 kit) can reach high temperature rapidly because of near flow capacity limitation of turbocharger which is that the stock core size is small capacity. To improve the cooling performance, more core capacity is required but a little bigger intercooler than the stock could not provide enough cooling