Thermoplastic vulcanisates (TPVs) are a special class of thermoplastic elastomers, produced by simultaneously mixing and cross-linking a rubber with a thermoplastic at elevated temperature. As a result a typical morphology is formed, where the cross-linked rubber particles are generally finely dispersed in a continuous matrix of thermoplastic. High performance TPVs or super TPVs are a new class of TPVs which exhibit high heat resistance as well as excellent oil resistance properties suitable for automotive under-the-hood applications. In the present work, a new super TPV based on carboxylated acrylonitrile butadiene rubber (XNBR) and polyamide (PA12) has been developed. TPVs of three different blend ratios (50:50, 60:40, 70:30) of (XNBR:PA12) have been prepared at an elevated temperature in an internal mixer by using a fixed concentration of Trigonox 311, which is a novel cyclic mono-functional cross-linking peroxide. The final morphology of the TPVs varies from a co-continuous to a dispersed one depending on the blend ratio. TPV of 50:50 XNBR-PA12 shows the best mechanical properties and the superior thermal stability amongst all TPVs. Detailed thermal characterisation through DSC and DMA and rheological characterisation have been performed. The lowest tanδ of the TPV with a 50:50 blend ratio of XNBR-PA12 indicates the highest degree of crosslinking and this is also well supported by the overall crosslink density value of that TPV. Heat ageing and oil resistance studies have also been carried out to demonstrate the performance of these TPVs. Keywords: TPV, XNBR rubber, Polyamide 12, dynamic cross-linking, peroxide, morphology