Description

VTT F9X M5 / M8

Blow-Off Valve (BOV) Kit — S63 Engine

Fits BMW F90 M5 & F91 / F92 / F93 M8 (All Trims)

Why the S63 Needs a Proper Blow-Off Valve

As capable as the S63 platform is in the F9X M5 and M8, one critical component is missing from the factory configuration: a true diverter valve (DV) or blow-off valve (BOV) to properly vent excess boost pressure during throttle lift.

From the factory, the S63 relies on Valvetronic to manage pressure relief. While this strategy works from an OEM drivability standpoint, it is not an effective method of fully venting boost pressure. Under higher load, rapid throttle closures, or tuned conditions, this can lead to compressor surge, increased stress on the turbochargers, and reduced turbocharger longevity over time.

The VTT BOV Kit adds the missing mechanical venting solution the S63 needs. By properly evacuating excess boost pressure during throttle lift, this system:

• Reduces compressor surge

• Protects turbochargers under aggressive driving

• Improves long-term reliability

• • Delivers some BOV sound, but volume varies by conditions (full boost lift = louder, light throttle = minimal or none)
  • Not designed for sound—that’s just a byproduct
  • Primary purpose is turbocharger longevity—the S63 HIGHLY benefits from a properly functioning BOV

This is a functional upgrade first—sound is simply the byproduct.

Kit Includes

• VTT CNC-Machined Billet BOV Adapter

  • Anodized in multiple colors available

• Turbosmart Gen-V RacePort Blow-Off Valve

• All required hoses, clamps, and mounting hardware

• Correct drill bit

• 1/8″ NPT tap

Everything required for installation is included.

Installation Requirement — READ CAREFULLY

⚠️ IMPORTANT — INSTALLATION NOTICE

This kit REQUIRES drilling and tapping the passenger-side intake manifold for a boost/vacuum reference port.

• You must drill a small hole and tap it to 1/8″ NPT

• This process takes approximately 10–15 minutes

• The modification is fully reversible by installing a 1/8″ NPT plug if the kit is ever removed

DO NOT purchase this kit if you are unwilling or unable to perform this modification.

Improper drilling or tapping can permanently damage your intake manifold. If you have any doubt about your ability to perform this procedure correctly, take the vehicle to a qualified performance shop for installation.

Fitment

• BMW F90 M5

• BMW F91 / F92 / F93 M8

• All trims (Base & Competition)

• S63 engine

Summary

The factory S63 boost control strategy was designed for OEM constraints—not long-term turbo health under performance use. The VTT BOV Kit corrects this shortcoming with a proven mechanical venting solution that protects your turbos, improves drivability during aggressive throttle transitions, and CAN add the unmistakable sound enthusiasts want under certain circumstances.

This is a functional reliability upgrade, not a cosmetic add-on.