JWT has pushed their VQ cam design program beyond what was possible even 5 years ago, along with required DLC coated lifters, a new valve spring design was needed. This new spring is designed to handle even the largest JWT VQ profiles (.600”+ lift) with about 3g less combined spring & retainer weight than the original VQ parts! Reliability is greatly improved by use of super clean wire material, followed by enhanced additional heat treating with a nano-peened and polished finish. The varied coil diameters of this beehive spring dampen harmonic resonance that can cause a conventional spring to surge at critical RPMs causing the valve to bounce on the seat or float. This spring uses the lighter 2013+ VQ retainer (ID 12.3mm) and needs to also be purchased if used in an earlier VQ engine with the earlier (ID 17.6mm) retainer. These springs are designed to be used with the original bottom spring shims. Fits VQ35DE, REVUP, HR, VQ37VHR (exh. only), VQ40DE, & VQ30DE.