Quote:
Originally Posted by krayzie
So it looks like walnut blasting service is still a thing with these newer BMW engines as they do not utilize port injection in addition to direct injection. Not like Toyota is ready to spill its engine technology to ze Germans other than the hybrid.
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It's no longer necessary. They mostly fixed the carbon buildup issues with the N55 by adding variable lift to the valvetrain (valvetronic). They essentially reduce the lift at idle so that the valve only lifts a tiny bit, forcing the air to squeeze by at much higher speed than normal. This blows most of the carbon off. My N54 needed cleaning every 30k. My N55 is sitting at 85k and the valves look fine (checked 6mo ago, never had a valve cleaning). Some cars still get it because different use cases I guess, but my mechanic told me he's never seen an N55/B58 that needed it, and he does about one N54 a month.