I just removed the AFM from my grey 300SDL and plumbed in a tubing section from an '84 SD air filter snorkel to replace it. I noticed correspondingly huge increase in blowby.

This has the same effect as plucking that breather hose away from the turbo compressor snorkel and venting it to the outside air. When I do so, there is no change in said emissions.

Why is this?

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)