Summit Racing™ Blow-Off Valves

KEY POINTS SUMMARY

• Safety: A blow-off valve prevents damage to your engine and turbocharger by automatically releasing boost pressure when your throttle suddenly closes.

• Adjustable: Summit Racing Blow-Off Valves can be adjusted from 0 to 50 psi and come with two valve springs, so they’ll work with most turbo setups.

• Quality: Summit Racing™ blow-off valves are machined from aluminum and have a black anodized finish, so they look great while they protect your engine.

• Included: Vacuum fittings, aluminum weld flange, V-band assembly, and two springs (9 psi and 3.5 psi) are included.

Big boost is great, but when you’re banging through the gears and the throttle suddenly closes, all that boost has to go somewhere! A Summit Racing 50mm Blow-Off Valve works with any turbo system up to 50 psi, reliably venting boost into the atmosphere, preventing engine damage and maintaining performance.

Specs and What’s Included:

Our blow-off valve is machined from aluminum and given a black anodized finish, and it comes with vacuum fittings, a weld flange, V-band clamp assembly, and two springs (9 psi and 3.5 psi) that allow you to change the activation point.

FAQ Section:

Q: How much horsepower does a blow-off valve add?

A: A blow-off valve doesn’t directly add horsepower or torque, but it does optimize the performance of your turbocharger and engine by maintaining the momentum of the compressor wheel.

Q: Is a blow-off valve bad for your engine?

A: Quite the opposite! In a turbocharged vehicle, compressor surge occurs when you suddenly lift off the throttle, like when you shift gears during competitive driving. When that boost hits the closed throttle plate, it has nowhere to go but backwards into the compressor wheel. This puts damaging stress on the wheel shaft and bearings, and also causes the wheel to lose momentum, which results in lag and poor throttle response.

A blow-off valve (also called a dump valve or a compressor bypass valve) safely redirects that pressure. This minimizes stress on your engine components and allows the turbo to get back to full boost more quickly.

Q: What’s the difference between a vent-to-atmosphere and a recirculating blow-off valve?

A: A vent-to-atmosphere blow-off valve expels excess pressure out of the intake tract. A recirculating valve (also called a bypass valve) vents the excess pressure back into the unpressurized part of the intake tract, before the turbocharger. Choosing what’s right for your setup involves a number of factors, including tuning methodology and desired sound. Generally, if your vehicle uses a mass airflow (MAF) sensor, a recirculating valve is the way to go, while performance/competitive driving favors a vent-to-atmosphere valve.

Q: What size blow-off valve do I need?

A: Summit Racing 50mm valves can handle engines making up to 700 hp and 50 psi of boost. If you’re assembling a twin-turbo system, you’ll obviously need two BOVs—one for each intake tract (a typical twin-turbo street engine uses two 38mm valves, but a higher horsepower engine might use up to 50mm valves like these). For hardcore drag racing engines making more boost and horsepower, you may need 60mm, 70mm, or larger valves.

Q: Will I need custom piping or flanges to install a blow-off valve if I’m using an intercooler?

A: Summit Racing blow-off valves come with V-band clamps and an aluminum weld flange, which is everything you need for a typical installation, whether you’re using an intercooler or not.