Dinan High Performance Heat ExchangerThe factory B4x B58 heat exchanger is not built to cater to the rigorous demands often associated with a modified build. The thin core is easily overwhelmed with IAT's rising dramatically once pushed beyond a few successive WOT pulls or even a few minutes at the track. This elevation in temperature gives way to the factory ECU fail safes pulling timing and reducing overall power in order to keep the system from overheating to the point of permanent