The Mann OEM Audi filter question

[ZeeOSix]

The by-pass opening pressure of the filter is 43.511 PSI :
https://www.mann-filter.com/us-en/c...t.html/w930/21_mann-filter.html#technicalData

43.511 PSI is very high, wonder why. Too high a bypass setting could cause the oil pump to hit pressure relief earlier if the dP gets that high, and cutting back pump flow before the filter bypass valve opens.

They do show the 4.3511 PSI above in the bullet info. Slipped a decimal point.

 

[rollins.]

Here some more on the specs (they've probably changed something in the last two decades) :
https://www.audiworld.com/forums/12...-who-choose-use-mann-w940-25-instead-2592144/

 

[ZeeOSix]

Here some more on the specs (they've probably changed something in the last two decades) :
https://www.audiworld.com/forums/12...-who-choose-use-mann-w940-25-instead-2592144/

From link above ... not real efficient.

W940/25: efficiency (ISO 4548-12) 50% at 18 micron
W930/21: efficiency (ISO 4548-12) 50% at 14 micron

 

[rollins.]

Yep . Bumped into an older discussion :

C

Thread 'Finally found official Mann filter efficiency #'s'

Jan 30, 2018

https://oe-products.mann-hummel.com/fileadmin/user_upload/kataloge/MANN_HUMMEL_Liquid_Filters_EN.pdf

There are a lot of filter efficiencies listed here. Unfortunately, they don't include the microglass elements.

It was previously stated on this forum (many times) that the Mann W 719/30 spin on filter was 99.5% to 99.9% efficient at just 9 microns. This information apparently supplied directly by a Mann engineer.

Turns out that it, and many other Mann cellulose filters and elements, are 99% at 38 microns and 50% at 20 microns.

• CharlieBauer
• Replies: 25
• Forum: Engine Oil Filters

 

[ZeeOSix]

Yep . Bumped into an older discussion :

C

Thread 'Finally found official Mann filter efficiency #'s'

Jan 30, 2018

https://oe-products.mann-hummel.com/fileadmin/user_upload/kataloge/MANN_HUMMEL_Liquid_Filters_EN.pdf

There are a lot of filter efficiencies listed here. Unfortunately, they don't include the microglass elements.

It was previously stated on this forum (many times) that the Mann W 719/30 spin on filter was 99.5% to 99.9% efficient at just 9 microns. This information apparently supplied directly by a Mann engineer.

Turns out that it, and many other Mann cellulose filters and elements, are 99% at 38 microns and 50% at 20 microns.

• CharlieBauer
• Replies: 25
• Forum: Engine Oil Filters

The most efficient filters shown in that table are 99% @ 38u, and most show to be 99% @ 50u.