Why does BMW recommend Walnut Blasting your N54 every 30,000 miles?

At Bavarian Auto Werke we use factory BMW tools to perform this job.  Factory tools ensure the job is done right the first time.  The intake manifold is removed and all ports are cleaned with BMW factory tools, utilizing BMW approved, walnut shell media.  In order to remove the carbon deposits an abrasive must be used, and crushed walnut shells provide a material that is strong enough to remove the deposits without harming the metal itself. The result is a smooth intake surface, allowing the intake air to smoothly move into the engine, without creating power-robbing turbulence. The manifold goes back on, with a set of new intake seals, and everything is tested. All BMWs with direct injection will have this very common problem, and the only solution is the have the experts at Bavarian Auto Werke perform this much needed service. Keep your BMW running like new by removing the buildup of carbon in your intake system.

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In order to remove the carbon deposits an abrasive must be used, and crushed walnut shells provide a material that is strong enough to remove the deposits without harming the metal itself.

This buildup can cause:

-driveability issues (stumbling, odd throttle response, etc…)

-loss of power

-inconsistent idle

-emission concerns