This might interest those of you who choose to use the Mann W940/25 instead of...
05-02-2006, 02:38 PM
#1
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This might interest those of you who choose to use the Mann W940/25 instead of...
the Audi-recommended Mann W930/21 oil filter.
I was wondering a couple things:
1. Is bypass pressure valve spec identical? Per the 2004 Mann book:
- W930/21: 3 bar
- W940/25: 2.5 bar
Is the 0.5 bar difference critical? I don't know, but I do know that the W940/25 will be at lower oil pressure in bypass mode, meaning the oil will then get only partially filtered.
2. The W930/21 is a LongLife filter, the W940/25 isn't. Which one filters better? Which one flows better. See down below.
3. How much more oil goes in the W940/25? Only 6.4 oz!
A few weeks ago I asked MANN USA for specs, besides the length of the filter assembly, in regard to filter medium specs and bypass valve pressure settings of the 930/21 and the 940/25. Today I received a reply:
<i>Please see the explanation below concerning our filter elements. Should you require more detailed information, please do not hesitate to contact Bruce Bounnakhom, Manager of Filter Development directly. Bruce can be reached at 269-329-7286.
These are oil filters
W940/25: efficiency (ISO 4548-12) 50% at 18 micron (flow rate of 36 l/m); capacity =29 g
W930/21: efficiency (ISO 4548-12) 50% at 14 micron (flow rate of 40 l/m); capacity =25 g no information in our database on bypass opening pressure.
Kind Regards,
XXXXX</i>
From this reply we see that the W930/21 flows and filters better than the W940/25.
The W940/25 can hold more particles than the smaller W930/21, but this is normally not an issue. You don't have a sludge monster, do you? ;-)
<b>All in all, I'd say 6.4 oz bigger capacity at the cost of reduced filtration, worse flow and incorrect bypass valve pressure spec doesn't make the W940/25 especially appealing. I'd stick with the proper W930/21.</b>
I was wondering a couple things:
1. Is bypass pressure valve spec identical? Per the 2004 Mann book:
- W930/21: 3 bar
- W940/25: 2.5 bar
Is the 0.5 bar difference critical? I don't know, but I do know that the W940/25 will be at lower oil pressure in bypass mode, meaning the oil will then get only partially filtered.
2. The W930/21 is a LongLife filter, the W940/25 isn't. Which one filters better? Which one flows better. See down below.
3. How much more oil goes in the W940/25? Only 6.4 oz!
A few weeks ago I asked MANN USA for specs, besides the length of the filter assembly, in regard to filter medium specs and bypass valve pressure settings of the 930/21 and the 940/25. Today I received a reply:
<i>Please see the explanation below concerning our filter elements. Should you require more detailed information, please do not hesitate to contact Bruce Bounnakhom, Manager of Filter Development directly. Bruce can be reached at 269-329-7286.
These are oil filters
W940/25: efficiency (ISO 4548-12) 50% at 18 micron (flow rate of 36 l/m); capacity =29 g
W930/21: efficiency (ISO 4548-12) 50% at 14 micron (flow rate of 40 l/m); capacity =25 g no information in our database on bypass opening pressure.
Kind Regards,
XXXXX</i>
From this reply we see that the W930/21 flows and filters better than the W940/25.
The W940/25 can hold more particles than the smaller W930/21, but this is normally not an issue. You don't have a sludge monster, do you? ;-)
<b>All in all, I'd say 6.4 oz bigger capacity at the cost of reduced filtration, worse flow and incorrect bypass valve pressure spec doesn't make the W940/25 especially appealing. I'd stick with the proper W930/21.</b>
05-02-2006, 05:37 PM
#4
Great info! I've been using the 930/21 simply because I bought a bunch of them at once but
was thinking about trying the larger one since I only have one 930/21 left but this makes me think twice.
Thanks
Thanks
05-02-2006, 09:49 PM
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Mann+Hummel and Bosch jointly bought Purolator earlier this year
You may want to read <a href="http://www.bosch-presse.de/TBWebDB/en-US/PressText.cfm?id=2617">this</a> and <a href="http://carolinanewswire.com/news/News.cgi?database=topstories.db&command=viewone&id =3973&op=t"> that</a>.
I can't tell you for sure if the MANN-made Purolator is identical to a MANN-made Mann.
I can also not tell you if the 0.5 bar difference in bypass valve pressure is a problem or not. Audi, for some reason decided the 12v required a 3.0 bar bypass valve setting. It may have to do with the oil system having been re-designed at some point.
I can't tell you for sure if the MANN-made Purolator is identical to a MANN-made Mann.
I can also not tell you if the 0.5 bar difference in bypass valve pressure is a problem or not. Audi, for some reason decided the 12v required a 3.0 bar bypass valve setting. It may have to do with the oil system having been re-designed at some point.
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05-03-2006, 02:07 PM
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I took a pic of the purolator filter (on the left) with the new 1.8t filter. The purolator filter
<center><img src="http://pictureposter.audiworld.com/17351/photo_050306_002.1.jpg"></center><p>says it's made in Germany. I have the filter on the car now. DO you think I'm causing any harm using it?
05-03-2006, 04:29 PM
#10
Necessity is the mother of invention....
I've been running the larger VW Diesel sized filter on all my Audi's, for many years. Long before Audi endorsed the practice.
Even now my 90 V6 has a much larger than OEM filter, and to date, never once any oil related issue, with any one of my Audi's.
While its always prudent to run what is recommended, often we strive to see if somethings better. ;O)
Even now my 90 V6 has a much larger than OEM filter, and to date, never once any oil related issue, with any one of my Audi's.
While its always prudent to run what is recommended, often we strive to see if somethings better. ;O)