The GFB DV+ T9388 is designed as a complete, drop-in upgrade for the OEM diverter valves found in late-model Mercedes vehicles. Unlike earlier Pierburg-made diverters, the newer AMG-branded OEM valves are not serviceable, so GFB created the T9388 with a low-profile integrated solenoid, offering an easy, direct replacement without clearance issues.

Key Benefits

• Enhanced boost holding for improved performance
• Sharper throttle response for better drivability
• Faster boost recovery after gearshifts or throttle lifts
• Built for longevity and backed by a Lifetime Warranty

Why Upgrade to the T9388?

While OEM diverter valves have become more reliable over the years, they still have significant limitations due to their plastic construction and operational design. During testing on a Mercedes C63S, GFB engineers found that the OEM valve leaked excessively—up to 28L/min at 1 Bar—because the diverter was mounted on a plastic intercooler tank rather than directly on the turbocharger.

Even with advanced sealing materials like Viton, the OEM plastic seat was too uneven for a proper seal. The T9388 solves this with an integral machined piston seat built into the valve body, ensuring a consistent, reliable seal even on imperfect OEM surfaces.

Smoother Power Delivery with Pilot Actuation

Factory diverters operate in a simple binary mode—either open or shut—which can cause abrupt power changes during small throttle movements. The DV+ "pilot actuation" system allows progressive valve control, smoothing power delivery and sharpening throttle response, especially when modulating the throttle through corners or during quick transitions.

Lifetime Reliability

Precision manufacturing, premium materials, and careful design mean the T9388 is built to withstand extreme conditions for the life of your vehicle. And it’s backed by GFB’s Lifetime Warranty, giving you complete confidence in your upgrade.