Air Filter Vacuum ?

[PP]

I checked the archives and couldn't find the answer, but I know someone posted the info here a year or so ago. What is the acceptable vacuum reading on the little guage connected to the air cleaner box? Mine usually  read 180 and is now up to 250, which is still a ways from the top. I reset it and it went back to the 250 reading after about 150 miles.
Any enlightenment on this will be greatly appreciated as I don't want to starve the poor girl for air if I need new filters. Yet, I don't want to replace the filters if 250 is normal.
Thanks, Will

I might have picked up a little dust while we were stranded in a dirt lot waiting for a new start battery. One of my 8D's lost a cell and she wouldn't start (and this after all the time I put into caring for my batteries I  get less than 7 years out of one)

[luvrbus]

Can you translate that for me in inches of water the 8v92 is 20 max H20 for a dirty filter and 12 H2o max for a clean filter,I am one of those guys that does not put a lot of faith in the filter minders JMO just another gimmick to me

good luck

[eagle19952]

if your fuel economy is dropping off...your filter is dirty....

[PP]

Sorry it took so long to get back here, but before I did I took a better look at the 'minder' and it reads in 'mm' and 'inches' of water. The 250mm is equivalent to 10" of H2O vacuum, so I will assume that is fine. Thanks Clifford.
As for the fuel economy dropping off, I kind of quit checking that after noting that a 5MPG estimate with the toad barely covers the actual usage. Last trip was just under 400 miles and I'm at right around a 1/2 tank (200 G tank). Of course that was all up hill, so I should be able to get twice that on the way back. Right? This last trip included a lot of city driving, and I'm sure that hurt. It takes a lot of fuel chasing people down sidewalks---
Thanks for the input, Will

[Ncbob]

The air inlet restriction test is done with a water (h2o) manometer between the air filters and  the roots blower. While most of us don't have them they aren't that expensive and can be purchased from WW Grainger (flexible type).  The Detroit Field Service Data Manual (available for your engine from a DD Dealer) will give you the standards for testing your engine and systems.

Bob