Got Boost?
KD Boost Valve for the 2001-2004 LB7 Duramax 6600

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By Jim Bigley

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There's an old saying that says "offer a great inexpensive part that installs in 5 minutes, and you'll sell a million of them." Well, the KD boost valve is inexpensive, installs in minutes, and offers a lot of bang for the buck. This simple device increases maximum boost pressure about ~5-8 psi, and makes the factory LB7 turbo a lot more responsive under all operating conditions. Combine this with any one of a variety of Duramax power mods, and you'll see an even bigger improvement in power than what a power mod by itself delivers.

To reduce smoke, most Duramax performance programmers and modules don't apply an uprated fuel curve till boost pressure rises to a predetermined level. A more responsive turbo will allow these performance products to begin adding fuel sooner than it might without boost enhancement.

The KD Boost Valve works by preventing boost pressure from acting on the wastegate actuator till a preset level has been reached. Then, that somewhat higher level of pressure is allowed to act on the wastegate actuator to limit peak turbo boost pressure. The result is a more responsive turbocharger along with a few more pounds of boost pressure. A bleed hole allows the actuator side of the boost valve to return to atmospheric pressure once boost pressure drops below the set-point.

The yellow arrow in the above photo points to an early prototype KD boost valve installed on our LB7 Duramax. Production versions include a black anodized finish with a white arrow etched into the aluminum to indicate airflow path (arrow points toward the wastegate actuator). Installation took only minutes, and there's no calibration required - it comes pre-adjusted to the correct pressure level. Our Banks Big Head turbo wastegate actuator would allow a maximum boost pressure of approximately 26 psi without the KD Boost Valve, and 32 psi with. Simple to install, inexpensive and works great.

Not wanting to leave anyone out, Kennedy Diesel also offers a simple to install plug-in kit called the Boost Stick that increases boost pressure for the 2004.5 model-year or newer LLY Duramax.    TDP