I look up some oilfilters and with same dimensions,gasket,media
there are different BPV (BypassValve) settings like 10 psi or 16 psi.
Whats the BPV of the Mann/Volvo?
Anybody knows his/her BPV settings of your filter currently running?
Is it preferable to choose a 10 psi BPV filter with an older car,
since the oilpump might be worn out?
Would a lower BPV setting be called a 'Full-Flow'filter?
How much is the average oilpressure on a warm engine?

Thanks for all your infos.
The reason was, I got a Napa/Wix filter 51307.
Wix 51307 : Height: 3.81 in; 16 psi ByPassValbe
Wix has that one as a result of the carmakers searchengine.
But then I went back on the web and put in the competitors numbers
and the corresponding Wix filters were:
Volvo 35178573 = Wix 51311 Height: 3.37 in ; 16 psi BPV
Mann W917 = Wix 51521 Height : 3.79 in ; 10 psi BPV
OD and Gaskets are the same.

So now it keeps me thinking, why the corresponding filters
for the MANN and the Volvo filters have different pressures.
(www.wixfilters.com)
Maybe WIX have their database totally messed up?
Anyway I wanted to put your attention on the fact,
that it matters HOW you search. You get 3 different results.

The volvo filter seems too expensive, and I can't find a
retailer, who sells me single Mann filters in Los Angeles,
and if I buy a case of Mann's on the internet, I have a box
laying around for years, since I don't drive that much.
So I went with WIX.

Thanks for reading that far.
Thanks Al for the link!

Here is a site that should answer any and all questions you might think of.
http://www.bobistheoilguy.com/
There is a lot of info on Oil, oil filters, air filters plus there is a forum that you can post any questions you may still have.

Let's hope your bypass valve never opens regardless of the pressure setting. When it does, it will be pumping dirty oil around your engine.

From personal experience I would rather have a lower setting if the filter element is a cheap POS like in the FRAM. I used to think an oil filter is an oil filter. Not after the FRAM collapsed on my 960 while using synthetic oil! The filter element blew through and not only let dirty oil through but added pieces of the filter as well. So far after another 30K mikes or so using Mann filters it seems no significant damage was done. (Lucky?)

I don't think it makes a big difference what the number is, as it is there to prevent a plugged filter from instantly destroying your engine. Use a good filter with lots of filter area and it should never open!

All filters on modern cars are "full flow". Bypass filters are used as secondary filters to scrub the oil really clean and therefor can't flow fast enough to supply the engine. Amsoil sells add-on kits which they claim allow safe operation without oil changes for really extended intervals. (More than 25K miles.)

Somewhere on this site are links to some oil filter studies done by various people.
--
'96 965 with 16' wheels at 101K. Had '85 745 Turbo Diesel for 200K.

I think the bypass valve sometimes opens in the coldest weather when the oil is thick as molasses in January and it can't get through the filter media.

Anyway, we all change our oil so often that it NEVER gets dirty.

Right?

Fram filters do not deserve to be called "filters."

Oil filter study.

Another oil filter study.

Yet another study.

And another...(yawn...)
--
Don Foster (near Cape Cod, MA)