Air filter - to change or not to change

[ljacko78]

howdy,

I always change my filter when changing oil and doing service. I also keep the cleanest second hand one I have for when i go on a long trip as a back up. Seems logical, cheap and takes bugger all time to do.

so then I stumbled onto this: (don't know why it says browser warning - link is ok for me)
Browser Warning

No change in pressure drop on dirty filter to new / clean filter. Interested in seeing what other people think.

Lj

 

[D21 dualcab Z24 4X4]

Woops. Think ive wasted a little cash over the years.

Can some navara owner with nothing better to do test this ?

 

[Old.Tony]

Doesn't sound right to me. Dirt particles sitting in the filter are going to block the filter they're sitting in. Blockage = flow restriction, it's pure common sense.

I'm not taking my snorkel off for anyone. It might be a minor restriction but I'd rather have that than the dusty, hot air or the excessive moisture caused by dunking it over the bonnet!

In my opinion they should have used the exact same gauge and sensors in both places to prove their point. They didn't, thus introducing some doubt about the accuracy.

And if his fundamental assumption is based on the fact that a dirty filter and a clean filter have the same flow rates, then the entire article is flawed.

 

[D21 dualcab Z24 4X4]

And if his fundamental assumption is based on the fact that a dirty filter and a clean filter have the same flow rates, then the entire article is flawed.

What if a clean filter has say, 60% greater flow rate than the induction system is phisicaly capable of, and a dirty filter is restricted by 50%. The net result would be no change in flow rate with a filter change.. Just a thought

 

[navman_dave]

genuine filters have improved over the years. the aftermarket industry has been using the same technology for 20 years now theres nothing performance wise in it. pod filters are a waste of money.

 

[UncySpam]

You guys are all interpreting this article in the wrong way.

This article is saying "don't bother with oiled filters, or special foam filters, they wont help"

not that you shouldnt change a filter, or that you shouldnt have a snorkel.

The point here is that the pressure drop from one side of the filter to the other is not changed by any noticable amount when ONLY the filter is altered (by cleaning or replacing with another type). The noticable (and therefore worthwhile changes) for performance come from changing the airbox or intake to allow that pressure differential to be reduced.

The ONLY reason to go to a different type of filter is if you are doing very specific things with the vehcile - I used to ride enduro bikes, and oiled foam filters are the go for them due to teh conditions they work in (better filtration is the reason to use oiled filters, not performance)

 

[Old.Tony]

Something tells me that because there's a difference between the flow rates doesn't mean we should inhibit the flow rate on purpose. It just means there's less capacity.

However, I see the point you're making, and it's entirely possible that could cause an apparent similarity in flow rates.

 

[ljacko78]

point - Its also reaching the max level of the gague so we can't tell if the dirty filter actually lead to 25 inch or 30 inch pressure change for example. Then a clean filter only 20. So there could be an improvement that this gague can't register.