Air Filter Study for Diesel Engines

[Mark / Ohio]

This page shows the results of an independent study done on Light Truck Diesel Engine AIR Filters regarding efficiency and cfm restriction.

Air Filter Study (http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm)

[MowHoward2210]

Interesting. I had heard somewhere that those "performance" filters pass more air, as well as more dirt.

[glenn27]

Good Morning-
Has anyone tried one of these K & N Filters (reusable wash/reoil), and do you think they will do what is claimed? I buy my filters from NAPA for years-the company I work for has "fleet status", so I get a very good price, and they can get anything by the next day. I am just wondering about these K & N claims. My son and his buddies run them on 'yota mud boggers and off-road stuff.
Thanks for any opinions-daggone I like this forum!! :
:trink40:

[MowHoward2210]

glenn27, I think you are gonna find various arguments on these high performance filters, just like you'll find in the Synthetic vs Dino oil arguments. As for what is better, I think the answer lies somewhere in between.

Here is a link to some air filter tests. (http://www.bobistheoilguy.com/airfilter/airtest1.htm) Note this is a home-brewed test, so take if for what it's worth, and also note, it seems to mirror what memmurphys link concludes: Pass more air = pass more dirt, Restrict air flow = catch more dirt!

[Carl]

The ideal filter will capture all dirt, and have no pressure drop. However, that isn't the way it works. The finer the filter media (catch smaller particles) the larger the pressure drop.

The Delco filter has the highest initial pressure drop at 6 + inches water column. There are 27.7 inches water column per PSI. But it also has the best capture rate, total capacity, and lowest pass through rate of all the filters tested.

What it means to me is that if you want to be nice to your engine use a Delco air filter. I will have to find out what the specs are for my New Holland filters.

The oiled filters have the worst pressure drop when dirty, capture less, and need more attension. It would make a good prefilter, and that is usually the application that it is used for.

My hat is off to the guys that did the test. They are truly disel lovers, had access to the test equipment, and invested the time to run the test. I give them all the credit for a job well done.

[Mickey]

This study has been around for some time and I've had it bookmarked. There is info on filters like the K&N and they are not rated very highly.

I've had a couple K&N's, one for something I couldn't find a reg filter for and the other was a gift so sorta have to use it. The ones I've had a gaps in the media big enough you could call them pin holes. If I can see daylight through them then they are not filtering as good as they should and for something you use under dusty conditions like your mower in the summer time, I don't think you'd be doing your engine any favor.

[Michael]

The thing I have against the K&N is the fact that the filter medium is larger. With the filter medium larger you tend to have more air passage which will relate to more power but for a tractor engine I do not think that is a good idea. I personally think that with all the dust and dirt that a tractor (lawn and garden and regular sized tractors) stirs up that I want the most protection for the engines from getting dirt into them. I peprsonally have never used a K&N for just that reason. I tend not to buy new stuff but when I do I am a bit on the obsessive about maintenance and a good example is the car I have have. I have used nothing but NAPA (Wix) filters on it since it was new in 1994 and with 205,000 miles on it I have never touched the engine, I just passed emission tests (not required but it gives me the information that the car is running correctly for best econemy and gas mileage, the car is computer controled and the only way to know it is correct)

[HydroHarold]

So can we transpose the information from Memmurphy's test from light truck filter down to g/t filters? We would have to assume that the filter medium in g/t filters would be the same brand for brand. Would it be, or are the air passage rates/filtering rates different for lower volume applications?

[rwairforce]

I just wanted to share some feedback I got from my mechanic buddy and all around pretty smart guy concerning the filter data.....
Remember, I'm just sharing, for what it's worth. :hide:

Start..
That must have been one of those studies funded with tax dollars.

Let's review. The filter that did the best job of "filtering" is also the most restrictive.
I 'm thinking any 10 year old could have figured that out.

The testing was done at 350CFM flow rates. Well ****, if you are working with a 100 cubic inch engine that would be about 3/4 throttle and the data might have some relevance. If we're talking a 350 cubic inch or larger truck engine then 350CFM does not even equate to half throttle, so the data is relevant if you are simply cruising along under no load.

Now to say that the least restrictive filters like the K&N do not make additional horsepower unless other modifications are made to the engine I just have to say "NO SH$t SHERLOCK"!!!!!!!

What a stupid article that one is.

This ranks right up there with the company that made car oil filters that used full rolls of toilet paper as the replaceable filter. Man did they EVER filter the oil!!! Unfortunately they restricted the flow so much that the bearings were starved for oil and the engines blew up.
But it was one HELLUVA filter!!!!!! End...

[Carl]

rwairforce,
The test was done by a couple of guys that were interested in filter performance. The shop owner donated the machine time. One of the workers at the shop, and a friend donated their time to run the test. No tax dollars.

I am not familiar enough with different filters so don't know what these filters were for.

The filters were tested at 350 CFM. That doesn't mean that they were rated at 350 CFM. Of course the higher the flow the larger the pressure drop would be. What is an acceptable pressure drop?

The one thing that I see from the test is that the Delco filter was the overall best filter to use. It removed the most fine particles, and held the largest quantity of dirt. This works out to the cleanest air for the engine and the longest time between filter changes.

So the test wasn't all that bad.

[rwairforce]

Carl,
Possibly, I just don't know, I'm know expert. You said "This works out to the cleanest air for the engine and the longest time between filter changes."

I didn't really study the charts mainly because I don't care, I'm using what I use but.....does it also mean the the engine has the best supply of air flow, volume?? Not unlike the toilet paper roll would make a great filter but would have a real bad influence on oil volume.

[Mickey]

I'm with Carl on his response. RW you also need to get out more often, the tollet paper filter tech is still very much being used in some applications, you just don't see them on auto's. Just read something about these filter a few days ago.

[rwairforce]

I don't get out much....I also don't get sick often :eck16:

[MowHoward2210]

Keep the dirt out of your engine and it will last a lot longer. I had an old machinist who has seen just about every kind of internal combustion engine come through his shop over the years tell me that. No, he's not the first to make that observation, but it drove home the point to keep the oil and the air coming into your engine clean.

[HydroHarold]

Anyone doubting the restrict-ivity to liquid of a roll of soggy wet toilet paper, just dip one in the bowl and see whatcha got. How any oil could get THROUGH it I can't fathom... I'm betting the oil goes around it a heck of a lot easier than through it... I think the T.P. Filter is a "psychological savings" product like using old drain oil on a chainsaw bar. "Wow guys, I didn't need to buy any oil filters for Ol' Betsy this year!" "That bearing-like noise? Probably just a lifter or the fuel pump...."

Is it really worth the "chance" you take using "head tickets" instead of oil filters? How many guys are willing to try one on a nice shiney new F350 w/diesel and pull a loaded horse trailer between Grand Junction and Denver? Lemme know how it goes...