Your OBP should activate about 16 psi, IIRC. I have run the old 300SD at 14.7 lbs maximum (wastegate controlled) for years and normal driving on the freeway at 60 mph will give 10-11 psi readings.

There really is no spec for boost at normal cruise, but 10 psi has been good for the past 100,000 miles or so...FWIW

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership