The Great Filter Debate

[Funny]

Originally Posted by metromizer

hey Funny, the information you just provided should be bolded and capitalized. It's always great to hear from someone with such expertise. As a result, I'll choose my filters a little more carefully now. thanks!

I appreciate the flattery, but seriously, I just want to make sure people get the information straight. There is a good chance that someone with a grudge or agenda would spew misinformation in order to further their cause. I want people to know the truth, so you can make an informed decision. We ecomodders live for and survive on DATA. This subject has such a lack of truthful, objective observations that it makes me sick. Please help to keep people informed about how important regular maintenance and upkeep is on vehicles.
*steps down off soapbox*

[trebuchet03]

IMHO guys like to obsess over oil and filters, and many of them think they are doing their engines such a huuuuge favor by changing oil and filters at premature and excessive intervals.

Frank, I'm totally with you as far as engine oil is concerned. I run 10K+ mile service intervals on ye olde dino oil.

I can tell you from experience, because my company sells almost all of the filter makers the filter paper that they pleat and put in these filters, there is a difference in filters.

Funny, I'm also with you - no doubt the materials and construction makes a big difference in the filter.... The root question is, however, does that difference in filter make a difference with respect to the engine. I'll leave that as a rhetorical question...

I too buy the cheapo filters - but I also send used oil samples to blackstone for analysis (my choice is super short service intervals or, for the same price, oil analysis with longer intervals)... To date, I haven't gotten any ill reports about excessive solids, silica, etc. etc. in my oil (other than copper - but that's another story with '00 2.0 Jetta gassers). Perhaps it's causality, but I'm confident that the cheap filters I'm using are doing their job as a filter.

[Unforgiven]

Well from personal experience and some minor training, I simply just stick with Fram filters for air and oil. Never have had an issue with them, and considering only a few companies make all the dozens of "named filters" out there, it is not too hard to get the same filter innards with a different "can" around it. I also agree and recommend testing in doubt, and changing oil more frequently than the standard service interval. Having said that, please note that many quick lube places are actually quoting severe duty intervals as the standard interval. 3 months or 3,000 miles is a good old choice for carb engines, and for cabs or other severe duty vehicles. Common standard duty intervals are often double or even triple the severe duty cycle. Ford/Lincoln often recommends 6,500 miles between oil changes. GM often states 5,000. Toyota for a while was claiming 7,500 which can still be done depending on a lot of variables. My personal vehicle gets changed every 3,000 miles with Valvoline DuraBlend 5w30 (personal choice) while an old 68 Plymouth Fury II received Quaker State conventional 10w30 every 3,000 miles. The Fury I sadly no longer have, but at 183,xxx I pulled the venerable 318 out and replaced seals and did not have to deal with any sludge (ha, take that you Caker State whiners) lol. Reset the engine and it drove for another 100,xxx before selling off.
The Impala, well I dont drive it much currently, so I am keeping a check on the oil when I do get home to make sure it is not acting funny. Now for the Freightliner Columbia ( I had seen someone ask about heavy duty truck engine oil interval ) Detroit Diesel recommends oil changes between 20,000 to 30,000 miles. 20k during breakin, and 30k for normal. Sadly the company I work for wants to stretch this out to 40k, which is against Detroit Diesel recommendations. Now please also remember, while the car is holding 5 quarts of oil, the Detroit in my tractor-trailer holds 12.5 gallons of oil... big difference and with the larger filters, its easier to go a bit longer between oil changes...lol.

[Funny]

Originally Posted by Unforgiven

Now please also remember, while the car is holding 5 quarts of oil, the Detroit in my tractor-trailer holds 12.5 gallons of oil... big difference and with the larger filters, its easier to go a bit longer between oil changes...lol.

Unforgiven is spot on if you are going to have short interval drains on the engine you are using, because the oil doesn't have time to get enough particulates to fill it to capacity. However, manufactures like VW are going to LONG drain interval (more common in diesel, as Unforgiven also mentioned) as the recommended oil change (15 or 20K, if I'm not mistaken). So people that wish to follow the manufacturer's recommended interval, will need to find filters that are long drain interval, that's all I'm driving at.

BTW the majority of the particulates (dirt) that you find in the oil are attributed to your air filter not catching them. If you can, get a filter with a larger surface area, this will reduce face velocity of the intake air and the particles will be trapped easier by the filter. If you acquire a filter that is larger than your vehicle takes, see if it will fit under the hood with some modifications. A bigger filter really is better.

Feel free to wing questions my way, I'll try to answer them as I can, I'll be in the lab all day today.

[tasdrouille]

BTW the majority of the particulates (dirt) that you find in the oil are attributed to your air filter not catching them. If you can, get a filter with a larger surface area, this will reduce face velocity of the intake air and the particles will be trapped easier by the filter. If you acquire a filter that is larger than your vehicle takes, see if it will fit under the hood with some modifications. A bigger filter really is better.

To elaborate on that, people usually change their air filters way too early. As air filters accumulate dirt, they also filter better. So do yourself a favor, get an air filter service indicator and only change your filter when you need to.

[wagonman76]

Originally Posted by tasdrouille

To elaborate on that, people usually change their air filters way too early. As air filters accumulate dirt, they also filter better. So do yourself a favor, get an air filter service indicator and only change your filter when you need to.

They do filter better when dirty, because the pores get smaller. They are also more restrictive when dirty, hurting mpg. I am not familiar with an automotive filter service indicator, but where I work we deal with industrial filtering and use a differential pressure gauge spanning both sides of the filter to monitor filter restriction.

[Funny]

Originally Posted by tasdrouille

As air filters accumulate dirt, they also filter better. So do yourself a favor, get an air filter service indicator and only change your filter when you need to.

Tas is correct.
This phenomena is called initial blind-off. It happens when the largest pores in a filter fill up, or blind-off, leaving the smaller holes to filter the incoming air (or oil). This increases efficiency as the particulates accumulate on/in the filter media. So having a dirty (not ridiculously dirty, we all know what a reasonable about of filth is ) filter is actually more efficient than a brand new filter.

The only thing that changes with the filter is the differential pressure. As holes in the filter blind-off, it becomes harder to get the air (or oil) through the filter, thus pressure goes up. This is compensated for in newer cars with ECUs by using the Lambda (O2) sensor behind the catalytic converter to adjust the stoichiometric mix. It is a big problem with carburetted vehicles because as differential pressure goes up, more gas is added to the mix and stoichiometry is not maintained. That is why you still hear people saying that a dirty air filter is bad for gas mileage, because it used to apply to cars. It no longer has much of an effect on newer vehicles , though it still applies to older ones.

So change your air filter when it is damaged or too dirty to see sunlight through. Otherwise it is a waste of a perfectly good filter. And everyone knows how ecomodders feel about waste .

[Funny]

I love how wagonman and I posted at the exact same time, saying basically the same thing .

[dremd]

Originally Posted by wagonman76

They (air filters) are also more restrictive when dirty, hurting mpg.

I disagree; that was true with carburetors, but with FI (any type I can think of) it should just cause you to run the throttle plate a little more open.

Here is the air filter minder (brand) I run in the TDI Filter Minder, Automobile Parts, Air Filter, Fuel Monitor, Car Accessories, Engineered Products I got it because they were common on 7.3 PSD's when I toyed with them.

[Zukibot]

I like the Wix...

It uses a silicone ADBV over the nitrile, and has 8 inlet holes instead of the standard 6.