Tial QR Recirculating Bypass Valve
This mod is a forced induction only mod. The Bosch bypass valve (henceforth, BPV) that came with the VF supercharger kit functioned fine but was completely silent. After taking delivery of my G-Power Z4M, I began to crave the open dump, blow off valve (BOV) sound that came from extra air being dumped. Even though the G-Power Z4M came with a BPV, it sounds like it has a BOV. I didn’t think this was possible. So, I bought the Tial QR BPV to try and recreate that sound.
In the sense of getting the BOV sound, I failed. The Tial QR is just as quiet as the Bosch BPV. This has to do with intake routing more than the bypass itself. The only way to get a BOV sound on a VF kit is to install a BOV.
The Tial QR is a high quality piece.
It’s a work of art that I’m disappointed I can’t see when I pop the hood, due to its location. The install itself required some custom work with PVC (painted black in the picture). The Tial QR is meant to be welded into place, but with the VF kit using molded plastic piping, we had to make an adapter to get it to work.
Overall, I don’t know if I would do this mod again, just because it didn’t accomplish what I wanted out of it (boost venting noise) while requiring some custom work. Great product, wrong application. The quality of the piece impressed me, so I will absolutely buy another Tial product – likely a Tial Q (BOV) for my ESS Z4M.
www.extremepsi.com has good technical support, and they answered my questions right away, even post-purchase. If I choose to upgrade the VF kit, then this piece would become critical, so it provides some peace of mind that it will hold together if I bump up the boost.