Air Filter Tests '80 300SD
 

With my philosphy of "If it Ain't Broke, Don't Fix It" I was wondering if I was replacing my air filter when it wasn't needed. So I thought of a test that might give me the answer.

So I made 3 runs each of about a mile up hill with the old filter, no filter and a new filter. I started at 50 MPH and ended up at about 57 MPH and also timed the runs with a stop watch.

Without listing all the data there was virtually no difference in either the top speed or the elapsed time of any of the conditions that would would show any difference.

Checking the mileage for the last 1200 miles, I got 30 MPG.

Conclusion: Air filter did not have to be replced. So I gave it a good blow job with an air hose nozzle and reinstalled the used air filter. I'll check it again in about 25,000 miles. The test car is rarely driven on dirt or dusty roads so your results may differ if you drive in dirty or dusty conditions.

P E H

The airfilter in our Jetta is on a 20,000 replacement by VW spec's and they could probably easy do 30,000 miles in our driving. :D I don't know about the 240D, but it could probably go 20,000 in our driving conditions fairly easy.

Maybe I should just weld the hood shut.:D My friend gained a few mpg when he changed his old airfilter, on his E300D. Remember these are turbo charged engines so the filter would have to be very bad to affect performance. But if the turbo has to work harder mileage will go down. I will change mine every 2 years with one cleaning in between.

Oldnavy,

How can anyone write a spec for air filter replacement if that person doesn't know the conditions in which the filter is used.

So they probably specify replacement for worse case conditions. They also make more money if you replace your filter more than necessary by selling you more filters.

However, even their worse case conditions would not apply to an OK duststorm where a fiter could be plugged in a few miles.

P E H

I change mine every oil change (or every other, depending on my mood), and these days that either four or two times a year. I live in an agricultural area, and right now everyone is taking advantage of the nice dry weather to combine soybeans and corn -- dust EVERYWHERE. I washed the cars last weekend and they are yellow now.

Air filters are cheap, change often. On the turbos, you will notice more than normal turbo lag and higher idling tubo "whine" (if you can hear it -- the Volvo sounds like a police siren a block or so behind you!). More dirt will make it thorugh a dirty filter than a clean one, reguardless of blockage, they are "depth" filters.

Peter

I'm going with PEH on this one. Too many filters , spark plugs, distributer caps, and many other things are replaced needlessly, because there is a dollar to be made. When I ran my shop I never replaced these items unless they were due for replacing. I'd rather spend my client's money on preventive maintenance where it was really needed. The commercials tell you to get your car tuned up to improve fuel mileage and performance. Years ago I had a 79 Toyota that hauled ass and sipped the fuel. One day it started to die on me and was hard to start. I decided to check the plugs which was something I had not done in years. The gap was about 95 thousanths. It was time to replace the plugs. Now I'm not suggesting you run your car til it dies, but I'm saying that a good mechanic knows when it is time. Remember wax on wax off.

Peter

I thought that's what I said. :rolleyes: The spec is just a figure the engineers came up with some way. I just visually check mine an on ocassion and replace if I deem it needs replacing. Car has 42,000 miles and is on 3rd filter and 4th oil change. If I changed by oil sample report I would still be on third oil change for another 8,000 miles. But if I go too long at my age I might forget how to change the oil & filters.

Here's an idea for the experimenters in this forum.

Install a vacuum gauge between the air filter and the turbo inlet.

I expect the vacuum level to be too low low, in the "inches of water" category, for a regular gauge to be effective, but have no other guess.

Atmospheric pressure = 1 Bar = 30 inches of mercury = 14.7 psi = 33.9 feet of water

So, 1 psi = 27.7 inches of water. A water column makes a very sensitive gauge.

I expect pressure fluctuations, so a mechanical gauge might not be the best, unless properly damped.

(I just pictured someone driving around with a water bong on their hood.. ;) )

Record the vacuum with a new filter. I would expect to find a range of vacuum readings, depending on RPM and load and boost.

Put the 'dirty' filter back in and record again. I expect the dirtier filter to result in higher vacuum readings under all conditions.

P.E. Haiges, you would then be able to decide, based on a vacuum reading, that the filter is dirty. Also, you could see if cleaning is as good, for practical purposes, as a new replacement.

Ultimately, replace the gauge with a vacuum switch and warning light.

Best regards,
Jim

Air filter intervals really depend on conditions where you drive. In some areas, with a good amount of rain, air filters are probably changed more often than necessary.
If you do much driving in areas like west Texas it becomes more critical. They use an extremely hard caliche clay to surface dirt roads there. When it breaks down it is like talcum powder and gets into everything. Most of this damaging "grit" cannot be seen very well.
I have heard from several Powerstroke mechanics of "sanded" turbos due to owners not changing air filters because they did not appear dirty.
If you have been driving in dusty conditions, it really makes more sense to me, to change the air filters even more often. Air filters are much cheaper.

What are you doing?
 

OK, P E H, you hit another hot button, nothing personal....
I have no issue with how or if ever you change filters, it is your car.
I do have an issue with people who try to create their own pseudoscience.

This is not a test; it is a placebo with an opinion.
Air filter testing generally costs $3 - 7 million dollars and consumes 18 - 20 vehicles on three continents.
Do you have a calibrated flow stand?
Do you have calibrated particle detectors?
Can you give me the particle density incoming to the filter housing?
What is the particle density entering the intake manifold?
Do you have a mechanically - electrically perfect, thoroughly instrumented, calibrated, blueprinted and wind tunnel tested vehicle?
I have built them and run a durability fleet; there are many professional durability drivers in the Detroit metro area because of the OEM durability fleets running 24 X 7 X 365.
The specification for replacing air filters is a compromise, based on the theoretical average driver and geographic location.
The OEM's count on people not following the listed maintenance to void warranties.
I will not go into the 1200 to 3000 data points needed to certify just air filters and set durability change intervals.
I could arrange for your car to be instrumented properly for the type of data you seem to want, cost would be $185,000.00 - $268,000.00 and would cover only one hundred twenty eight channels with no video, UV or thermal imaging.
For minimum data to be valid, you would need 900,000 miles or nine duplicate vehicles run to 100,000 miles.
Data acquisition and record keeping must be Legal court ready at every moment, with no breaks in the evidence chain.



FYI:
For those who may not know the term pseudoscience.

http://skepdic.com/pseudosc.html
pseudoscience
A pseudoscience is set of ideas based on theories put forth as scientific when they are not scientific.

Scientific theories are characterized by such things as (a) being based upon empirical observation rather than the authority of some sacred text; (b) explaining a range of empirical phenomena; (c) being empirically tested in some meaningful way, usually involving testing specific predictions deduced from the theory; (d) being confirmed rather than falsified by empirical tests or with the discovery of new facts; (e) being impersonal and therefore testable by anyone regardless of personal religious or metaphysical beliefs; (f) being dynamic and fecund, leading investigators to new knowledge and understanding of the interrelatedness of the natural world rather than being static and stagnant leading to no research or development of a better understanding of anything in the natural world; and (g) being approached with skepticism rather than gullibility, especially regarding paranormal forces or supernatural powers, and being fallible and put forth tentatively rather than being put forth dogmatically as infallible.

Some pseudoscientific theories are based upon an authoritative text rather than observation or empirical investigation. Creationists, for example, make observations only to confirm infallible dogmas, not to discover the truth about the natural world. Such theories are static and lead to no new scientific discoveries or enhancement of our understanding of the natural world.

Some pseudoscientific theories explain what non-believers cannot even observe, e.g. orgone energy.

Some can't be tested because they are consistent with every imaginable state of affairs in the empirical world, e.g., L. Ron Hubbard's engram theory.

Some pseudoscientific theories can't be tested because they are so vague and malleable that anything relevant can be shoehorned to fit the theory, e.g., the enneagram, iridology, the theory of multiple personality disorder, the Myers-Briggs Type Indicator®, the theories behind many New Age psychotherapies, and reflexology.

Some theories have been empirically tested and rather than being confirmed they seem either to have been falsified or to require numerous ad hoc hypotheses to sustain them, e.g., astrology, biorhythms, facilitated communication, plant perception, and ESP. Yet, despite seemingly insurmountable evidence contrary to the theories, adherents won't give them up.

Some pseudoscientific theories rely on ancient myths and legends rather than on physical evidence, even when their interpretations of those legends either requires a belief contrary to the known laws of nature or to established facts, e.g., Velikovsky's, von Däniken's, and Sitchen's theories.

Some pseudoscientific theories are supported mainly by selective use of anecdotes, intuition, and examples of confirming instances, e.g., anthropometry, aromatherapy, craniometry, graphology, metoposcopy, personology, and physiognomy.

Some pseudoscientific theories confuse metaphysical claims with empirical claims, e.g., the theories of acupuncture, alchemy, cellular memory, Lysenkoism, naturopathy, reiki, rolfing, therapeutic touch, and Ayurvedic medicine.

Some pseudoscientific theories not only confuse metaphysical claims with empirical claims, but they also maintain views that contradict known scientific laws and use ad hoc hypotheses to explain their belief, e.g., homeopathy.

Pseudoscientists claim to base their theories on empirical evidence, and they may even use some scientific methods, though often their understanding of a controlled experiment is inadequate. Many pseudoscientists relish being able to point out the consistency of their theories with known facts or with predicted consequences, but they do not recognize that such consistency is not proof of anything. It is a necessary condition but not a sufficient condition that a good scientific theory be consistent with the facts. A theory which is contradicted by the facts is obviously not a very good scientific theory, but a theory which is consistent with the facts is not necessarily a good theory. For example, "the truth of the hypothesis that plague is due to evil spirits is not established by the correctness of the deduction that you can avoid the disease by keeping out of the reach of the evil spirits" (Beveridge 1957, 118).

See related entries on ad hoc hypothesis, cold reading, communal reinforcement, confirmation bias, control study, Occam's razor, pathological science, the placebo effect, the post hoc fallacy, pseudohistory, science, selective thinking, self-deception, subjective validation, and testimonials.

further reading

Dawes, Robyn M. House of Cards - Psychology and Psychotherapy Built on Myth, (New York: The Free Press, 1994).

Gardner, Martin. Fads and Fallacies in the Name of Science (New York: Dover Publications, Inc., 1957).

Um... politely speaking, the vacuum gauge is a tried and true indicator for the equipment operator, and a good investment if your diesel is high value (trucks have them on the dash). Then call the filter manufacturer and talk to the folks that designed the thing, not the salesman. They've already spent the coin to do the testing and know at what differential pressure the filter should be changed. This all assumes the filter doesn't leak or get crapped up with oil (not an issue with daBenz's oil bath filter).

air filter replacement
 

last time i replaced mine my daughter said "gee dad, that's like REALLY GROSS"

and it was.... :o

not exactly a scientific test but nonetheless the truth!

Vacuum gages for air filters are supplied on Freightliner MT-35, MT-45, MT-55 chassis, they are also now on Dodge Cummins diesel trucks and are used by many turck company's for monitoring the air filters.

Little colored thingies?
 

Anyone seen those things on some newer autos, heavy trucks, etc? Perhaps the vac gauges everyone is talking about, I have never taken a close look at them. They have some colored plastic in them and say when your filter should be changed, vehicle specific I assume. They seem to be pretty inexpensive looking (hah) and could probably easily be added to a stock air cleaner setup if someone was truely afriad of clean, easy flowing air problems.
When mine (air cleaner) changes color...I replace it. SImple enough.
(shug) :rolleyes:

Thanks for the enlightenment on vacuum gages, maybe not such a wild idea after all.

Now, aren't diesels an "excess air" combustion, where there is always more air than needed to combust the fuel injected? If so, how dirty would the filter have to be to drop airflow until performance loss was noticeable? :confused:

I guess I'll just change mine at suggested intervals.

Best to all,
Jim

Whunter,

I still think you are way too young and too technical. Wait, my son, and you will see the light. Although PEH and I have done battle on many grounds, I'm still hanging with him on this one. I still say stick with a good quality filter which by the way does not include Bosch at the moment in my opinion. I recently put a Bosch in my wagon and will probably change it soon, because I'm not sure of the micron rating. It looks like a cheap piece of **** from a discount chain. I yhink Bosch is cutting corners. Some major supply chains are rating Bosch as a second choice.Remember I have been at this professionally for 30 years. I change my filters when it looks like they need changing. I guess it is possible I'm killing my engine. I probably shouldn't expect an engine with 340,000 miles to last much longer. That is sad, because it doesn't use oil, starts well in cold weather, has plenty of power, and doesn't smoke. I still don't see how a properly sealed filter can allow dirt to enter the combustion chamber even if it is plugged.

Peter

I was going to say something like what you've said, with less proof. Mine went like this- I once saw a brown cow- now I know that all cows are brown.
PEH, I believe you've done a test no one can rely on.

I have seen those vacuum gauge indicators on some Ford air boxes at work. There is a green and a red area. Replace when in the red.

Thank you for the compliment.
 

I contest his presentation of testing; arguing opinion is a waste of my time and his.

I know Bosch is cutting corners, more like third rate product quality, and I keep looking for their stuff to show up in the dollar store.

Hmmm, I started working on cars in ____, and was employed in ____, lets leave that subject alone, it reminds me of how age is creeping up.

My filter change interval is personal, like the brand of under shorts I prefer, does it really matter, would knowing that someone changes filters every week or never in the life of the vehicle really change your mind?

I never said that a properly sealed filter can allow dirt to enter the combustion chamber even if it is plugged, that would be 180 wrong.

Impressive Treatise
 

WH that is an immpressive discussion of Psuedoscience. I will save for future reference. Have you ever heard of Bicom 2000 or the therapy known as Bioresonance? Add that one to your list. My wife is a practitioner by the way. Sorry for the off topic post.

I am not sure PEH intended his test to be science tho. Other practitioners run index type test to get an idea of the performance of certain materials. As a geotechnical engineer I can tell you that most of the earth structures in the world have been installed with great reliance on these type of index testing. Simple field type tests performed by specific techniques and that are repeatable are of great value. They may not be considered pure science.

Cheers!

Almost a fellow old gizzer, I'm with you on this one also. I just had a friend ask me yesterday if I wanted him to bring one of the gages to install in the Jetta airbox. I passed saying that I will just change them once a year wheather they needed it our not. It gives me something to do, and keep me from forgetting how to do the job. I second everything you posted above, hell of a good post. :D

I think I have proved my point that a new air filter is not needed. NO significant performance differences in using a new filter, old filter or even no filter and 30 MPG is all I need to know to prove to me that a new filter is NOT needed.

You guys can come to your own conclusions, replace parts unnecessarily and waste your money. But not me.

P E H

30 mpg?
 

PEH, are you getting 30 mpg with one of the 617's or with the 603?
If it is with one of the 617's, I would sure like to know the secret, if it is anything other than driving under 60 mph. :D

I don't think that the resolution of your measurements is fine enough. You really need to measure air flow and fuel delivery accurately as well as speed, acceleration and distance. You also need to look at and particle infiltration that each filter may be letting through.

Brian,

30 MPG on the 617 engine. Its more than I get ona trip at higher speeds. The driving was a combination of rural and city driving, but mostly rural averaging less than 50 MPH. Maybe its because I mix used engine oil in the fuel.

P E H

mplafleur,

I wasn't trying to evaluate the air filter as to quality or particle infiltration.

I was just trying to determine if there was any difference between the old filter and a new filter and if a new filter was required. I think the no filter test showed that the filters used by MB are adequate, at least for my use. It might be as different story in a high dust area.

P E H

How 'bout a positive idea? I live in a high dust area and used to have vehicles with expensive air filters (trucks). All paper filters get cleaned unless they're oily (worn out old cars and pickups). Here's how for the round filters: two pieces of sanded and painted plywood bolted over the ends with ready rod. One (in)side hooked to the shop vac running backwards (as a blower), with a bypass valve in the line, and a pressure gauge mounted to the plywood. Hit the on button and close the valve (keeping the pressure under 3psi). Keep it going until the filter blows clean. The paint helps keep the seal.

Wow 30mpg with a 617! The best I can get out of my 603 is 25mpg.

I've seen that 30 MPG figure floating around but I've never got it- but driving 75mph down I-95 will not get it no matter what I do I guess. :o

I drive 75 once in awhile. I tend to drive kind of fast, but even when I slow down it doesn't seem to make a difference. I do a lot of stop and go driving though, I will be lucky to get 20k miles out of my front pads. Most of my coummute to school is on Ell Grasso bulivard(sp?) in New Haven, their is a lot of sudden stops. :rolleyes: Why does everyone have to get in front of the s class?

I thought I taught you how to drive that thing. I can get 30 mpg IF I keep it down to 65 mph from here to Newington, CT and back. Getting it on a 617 is a whole different ballgame. I could do it, but, I'd have to keep the speed down to 55 mph. The shi*boxes would blow my doors off.

p.s.: Bet I get 50K out of my pads :D

Hatterasguy,

Yes a true 30 MPG It was right on 600 miles and 20 gallons filled it both times. I was surprised because I usually get 28 MPG. I have never done anything to the engine except valve adjustments and replacement of the water pump, V belts and front oil seal. You know me, "if it ain't broke, don't fix it".

I got 31 MPG once time but was at 50 to 55 MPH for about 450 miles with no stops.

You will cry when I tell how many miles are on my front pads. They were on the car when I bought it 138,000 miles ago. Odd though, I just had to replace the rear pads this week. But they were pads with rivets holding the friction material in place and they don't last as long. You can't use the friction material above and below the head of the rivet.

25 MPG sounds low for a 603. Maybe you need a tune up. LOL What kind of driving do you do? Pedal to the metal operation doesn't yield good fuel mileage nor does a lot of stop and go.

I Read Consumer Reports and there are very few cars that get an actual 30 MPG overall in their tests. And the ones that do are some little piss ant cars I wouldn't want.

P E H

I do take off slower from stop light's and time my moves better, but I always seem to need to use the brakes. For example I'm going 40-45 down the Bulivard getting passed as usual, and the light in front of me goes from green, yellow, red. For some reason the yellow seem's to be extremly short. :confused: So now I need to stop. I also do a lot of around town driving and again always seem to give the brakes a good work out. My front wheels will turn black in 300-400 miles.

As far as the highway, it is a Merc, the W126 comes together on the highway. With that turbine smooth 603 pulling and pulling, 100 comes up kind of fast.:D But mostly I cruise around 70 or slower, because of traffic, lots of traffic to fight. I only get to run her up once in awhile.

P.E.Haiges if I drove 55mph on long trips I bet I would get 30+ to.

30+?
 

I bought a container of "Power Service" conditioner at a truck stop in Ohio when I was out there. 12 oz. in 20 gallons will raise the cetane level by 6 points. I'm going to run six tanks of it and see how it does. The first tank yielded no benefit, but, I was stuck in stop and go traffic for at least 90 minutes. The second tank, presently, will also yield no benefit because I ran around Manhattan for two hours today in stop and go traffic. But, I am hoping for a return to 30+ even when running at 70 mph from here to Newington, CT and back. That would be quite something if it can do it.

I have been running Power Service since I bought my car, I just stopped this tank full and tried some ATF. The power service seems to make it respond better, I feel like I am pulling an anchor without it. But the ATF does make the engine run smother. Maybe I should try an ATF/Power Service cocktail this tankfull? :D Then I will throw in a 1/4oz of Biobar for good measure.

So, Hattie, how much Power Service did you put in for every tank?

Have any back to back comparisons on fuel economy?

I don't remember! :D I figured it out once and found a container that holds the right amount, I just fill it and dump it in the tank. I'll have to check.

Hatterasguy,

Doesn't power service have a biocide in it? Adding Biobor won't make any mileage difference but it will keep you running because it will keep the fungus from pluging up your filters.

Do you put the ATF in the fuel tank? I've been adding used engine oil to my tank. Only about 2% but I can't tell any difference.

I had a fungus problem in my 300SD so I put in Biobor and so far no more plugged filters. That was the only time I had a fungus problem in 35 years of driving Diesels. Some place I got contaminated fuel and the fungus kept growing. Should all be dead by now, I hope.

P E H

Ive been using PowerService Cetane booster (6 number increase) and their Bio Kleen biocide for years. They are two seperate additives. I bought a 16 oz bottle of biocide about 3 years ago for $12 and finally used the last of it about two weeks ago.

Here is a link to PowerService with a listing of all thier products. :D

With six points on Cetane, I would think you could document some fuel economy gains. Have any back to back data for the 240?

I'm going to try and make a case for using it with the SDL, however, my data on the first two tanks is compromised.

Last time I was on a trip in the Ozark Hills (elev 400ft to 1200 ft) and these are sharp angle up hill roads and I was foot to the floor about half the time keeping it at 65 to 70 mph and I averaged 31 mpg for the trip. I am averaging 27 mpg around town and I drive foot to the floor till I get to the speed I want to go. :D Also the fuel I use is B2 & 49 cetane with 10 micron final filters on the pumps. I also have access to 50+ cetane fuel if I wanted to drive 50 miles one way to get the stuff, I do drive 25 miles one way for the B2 49 cetane fuel.

Are you starting with 49 Cetane fuel and adding the Power Service for another 6 points on top of that?

I am adding 8 oz's Brian with every fill up.


P.E.Haiges I got the Biobor cheap and have been adding a little less than a 1/4oz every fill up. Just in case. The reason I tried a quart of ATF last fill up was because some of the 603 experts were saying it would clean things out real well; and since I am always fighting a skipping problem I figured I might as well give it a shot. It did seem to make the engine run a little better. However it didn't give it the little extra punch that the power service does. I swear my engine spools up faster with that stuff.

Yes, and I'm adding enough for the 6 points so as to get as far past 50 Cetane on the fuel I can. When these engines were designed the average cetane value of the fuel in the US was mid to upper 50's in cetane value. Now the average cetane rating is 42 in the US. Currently in western Europe the cetane rating is running mid 50's and is much cleaner then our fuel.

Higher cetane = higher BTU= more HP= better MPG= less smoke= longer lasting engine

Isn't this thread way off topic. :D

Whoops
 

How did that happen?:rolleyes:

Uhh, what are we talking about here??? :confused: :eek: :D

air filters
 

air filters. air filters. We were properly talking about PEH's air filter comparison. Somebody got us off topic. :o

:eek: Not me. :D