GFB SV52 Blow Off Valve

Strength is important!

Realizing that a high-flowing valve like this will see duty in some high-boost environments, GFB engineers made sure the SV52 tops the class in that category as well, giving it an astonishing boost pressure rating of 300psi!

The SV52 also includes 2 springs PLUS a spring pre-load adjustment system so you can dial it in for optimum throttle response and boost recovery after gearshift, without resorting to the costly hit- and-miss approach of purchasing extra springs.

! Suits engines with manifold vacuum ranging from 5-22inHg (17-74.5kPa, 2.5-11psi vacuum) !

» BODY

The SV52’s unparalleled pressure capacity starts with a monobloc body design, CNC machined from a single aluminium billet that ensures strength without adding unnecessary bulk.

» PISTON

The anodized piston bore creates an extremely hard and low-friction surface on which the single piece aluminum 52.5mm piston glides, and will continue to do so over countless cycles. It features an arrangement of Viton o-ring seals unique to GFB.

» DESIGN

Why do GFB valves use a piston instead of the more common diaphragm design?

Strength and reliability is the primary factor, something that a diaphragm simply cannot match in a high-boost BOV environment. Diaphragms have their place (e.g. in GFB wastegates), as they offer low friction and good sealing capability. However, a rolling diaphragm is only designed to receive a net pressure on one side, which essentially “inflates” it against the walls of the chamber in which it resides, exactly how it is used in a wastegate.

However, a BOV is exposed to frequent pressure reversals – every time you accelerate and lift off.
For a diaphragm, this means it is repeatedly collapsing on itself under boost, then inflating under vacuum. Eventually, this leads to diaphragm failure. A piston on the other hand is immune to this issue, and will continue to operate under the most extreme pressure, temperature, and cyclic conditions.

The unique mounting method of the SV52 is one of the ways GFB was able to save unnecessary bulk.
By eliminating the v-band style mount, the piston and its venting ports can sit much lower, which reduces the overall height to a number others can’t match.

Product specification:

• Pressure rating of 300psi
• Suitable for manifold vacuum 2.5-11psi
• Extremely hard and low-friction surface