Nominal flow rate: Bigger = better ?

[finmile]

By looking Mann's oil filter cross reference table, they recommend Mann W67/1 filter for my Nissan Primera. That's not available at the local car parts store, but one inch longer version would be, Mann W610/3.

The two oil filters have the same specifications, except what is shown below:

Mann W67/1 (cross reference to the OEM oil filter):
- Height = 6.5 cm (2.56 inches)
- Nominal flow rate = 9.72 l/min (2.57 gpm)
- Filtration area = 486 cm^2 (75.3 in^2)
- Dust holding capacity = 4 grams

Mann W610/3 (oversized):
- Height = 9.0 cm (3.54 inches)
- Nominal flow rate = 16.24 l/min (4.29 gpm)
- Filtration area = 812 cm^2 (125.9 in^2)
- Dust holding capacity = 7 grams

The discussion about "oversized filter or not" has been talked through many times already and the conclusion is that it's a feel good modification, no benefits and no adverse effects can be shown.

In my case I would like to go for the feel good modification for sure, BUT ALSO the shorter version is not easily available.

So, to the actual question:

The longer oil filter has a bigger "nominal flow rate". I'm a little bit concerned about that and want to be sure.

The bigger flow rate is only a good thing, right? Oil flows better, and at winter time (-25C/-13F) there's smaller possibility for the bypass valve to open. Right?

 

[4wheeldog]

And more capacity that you can afford to lose, before the filter can be considered "Clogged".

The only downside, assuming that there is plenty of clearance, is if the filter mounts so that it drains, when shut off. That can allow a bit longer time without pressure on startup.

 

[finmile]

Yes, the filter is mounted sideways, so will probably drain empty overnight. But there's plenty of room for the bigger filter, so no problems on that.

The smaller filter is the Nissan 'shorty' with less than 2 dl (7 oz) of volume. And even the oversized filter is less than 3 dl (10 oz) of volume. So, probably doesn't take too long to fill up?

 

[Nate1979]

What does nominal flow rate mean?

 

[finmile]

Originally Posted By: Nate1979
What does nominal flow rate mean?


I don't know. That's exactly what they responded from the Mann by email.

By googling I found the definition below.

But what was the pressure they used, that's probably the real question...?

Nominal flow rate measures the volume of liquid passing through a system under specific pressure conditions. Depending on region, the nominal flow rate may be measured in gallons per minute, or GPM, or liters per minute, or LPM. High-volume applications may even be expressed in gallons or liters per second. Nominal flow rate calculations can be critical to successful operation, maintenance and design of many types of plumbing or industrial systems.

Read more : http://www.ehow.com/about_8091298_definition-nominal-flow-rate.html

 

[CT8]

Bigger is better ! Oh whoops never mind.

 

[ExMachina]

Good thing about bigger ones is that you can use it for 2 oil changes, not just one, since it takes a very long time to get the oversized one to clog. And don't worry about startup filling, as the ADBV prevents dry starts with this thing.

 

[4wheeldog]

Originally Posted By: finmile
Yes, the filter is mounted sideways, so will probably drain empty overnight. But there's plenty of room for the bigger filter, so no problems on that.

The smaller filter is the Nissan 'shorty' with less than 2 dl (7 oz) of volume. And even the oversized filter is less than 3 dl (10 oz) of volume. So, probably doesn't take too long to fill up?


In my experience, filters mounted on their side do not drain all that much. The ones mounted mounting plate down, can....Though they don't all drain, either.

 

[CT8]

Originally Posted By: ExMachina
Good thing about bigger ones is that you can use it for 2 oil changes, not just one, since it takes a very long time to get the oversized one to clog. And don't worry about startup filling, as the ADBV prevents dry starts with this thing.
Given enough time the oil leaks out of all the oil passages and bearings, and some times the filter depending upon where the filter is located and if it has a double anti drain back valves

 

[davison0976]

Originally Posted By: 4wheeldog
Originally Posted By: finmile
Yes, the filter is mounted sideways, so will probably drain empty overnight. But there's plenty of room for the bigger filter, so no problems on that.

The smaller filter is the Nissan 'shorty' with less than 2 dl (7 oz) of volume. And even the oversized filter is less than 3 dl (10 oz) of volume. So, probably doesn't take too long to fill up?


In my experience, filters mounted on their side do not drain all that much. The ones mounted mounting plate down, can....Though they don't all drain, either.


On Nissan's VQ37VHR engines where filter is mounted on its side if you are to change oil filter without draining oil, some oil continues to drain off the engine once you have the filter completely off. That means oil filter is located below the surface of the oil in the system and will never drain despite being mounted on its side.

 

[goodtimes]

Those Mann filters listed have low dust capacity. That would lead to more bypass the way I understand it. Then the flow rate is according to the size of the bypass and might as well not have an oil filter.