Originally Posted By: motor_oil_madman
I wonder how you guys get the tbn to last so long. My tbn is down to like 3 or 4 after maybe 6,000 miles.
Your engine has EGR, unless deleted. The OP's does not. EGR causes increased acidification of the oil even though tailpipe NOx emissions may be decreased.
Also he had 4qts makeup oil, about 1qt/5000mi.
Charlie