Performance Blow Off Valves (BOV) & Diverter Valves
A blow-off valve vents the pressurised intake charge between the turbo and throttle body when you lift off the throttle — preventing compressor surge and producing that iconic turbo "pssh" sound. SP Engineering carries the iconic BOV brands in atmospheric, recirculating, and dual-port styles, in sizes from 25mm to 60mm.
Top BOV Brands We Carry
HKS (SSQV4, Super SQV, SQV4 Universal), GReddy (Type RS, Type RZ, FV2), Tial Sport (Q, QR, QRJ, S-Series), Turbosmart (Race Port, Kompact, Dual Port Plumb Back), GFB (Deceptor Pro, Stealth FX, T9001 Hybrid, DV+), SARD R2D2, BLITZ Super Sound, Apexi SBV, Forge Motorsport, Synapse SS BOV, Tomei Type S, Cosworth, MAC, JBR.
Popular Vehicle Fitments
Subaru WRX/STI (recirc required for MAF cars), Nissan Skyline RB26/RB25, Silvia SR20DET, 300ZX, GT-R R35; Toyota Supra 2JZ-GTE, MR2, Celica; Mitsubishi Evo 4G63, Eclipse; Mazda RX-7 13B; Audi 1.8T/2.0T, RS3, RS6; VW Golf MK4–MK7 GTI/R; BMW N54/N55/S55/B58; Ford Mustang EcoBoost, Focus ST/RS.
Atmospheric vs Recirculating
Atmospheric (vent-to-atmosphere) BOVs deliver the loudest "pssh" sound — best for tuned cars with MAP-based ECUs (Subaru, Evo, Skyline, Supra). On MAF-based cars (most modern EFI), atmospheric venting causes idle fluctuation and fault codes — use recirculating or dual-port. Spring rate matters too: stiffer for high boost, softer for low boost. SARD R2D2 has the signature electronic note.
Free BOV Selection Help
Email sales@sp-power.com with your year/make/model and boost target. We'll spec the right BOV style, size and spring — plus any adapter flanges needed.
SP Engineering — Turbo specialists since 1996.
