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?