Air filter
 

I've heard about some people removing the air filter and then replacing it with some kind of cloth and supposedly they get better fe. Does anyone know what the cloth is? And why does it increase your fe over an air filter? Is the cloth still ok to use instead of an air filter?

Some aftermarket filters use an oil soaked foam or cotton filter media. However, aftermarket air filters do nothing for fuel economy despite their advertisements.

If you want a low flow filter buy one, don't throw a sock (cloth) over the intake and call it good. You will run into problems with crap going into the fuel system and engine.

I think you're confusing filter vs cloth with paper filter vs cloth filter. They are both air filters specifically designed for your car, but one is disposable and one is cleanable. Don't buy a cleanable one. I'm an idiot for buying one. They don't pay themselves back for a long time (since you have to buy cleaning and oiling pack) and they sure as hell don't make your car any more powerful.

I saw an improvement with my k&n drop in filter. Yes they are expensive, but for my 03 civic it works. My escort rarely went over 2k and never over 3k so the engine never really pulled enough air for a better breating filter to be effective(65mph is at 3.5-3.6k on the civic). I also like the convenience, yes you have to clean them(eventually) but i don't drive that much so it will be a while. Do not try to make your own filter, anything that accedentally gets into the engine is a bad thing. Get one that is made for your car...and don't get a sponge one as they don't filter for very long.

air filter
 

while there is much hype about aftermarket air filters,there is no laboratory evidence to confirm advertized claims.K&N was tested against factory micronic paper element filters and found to filter less effectively,foul the soonest.Don't know about "fabric" filters.Air filters are a dead end with respect to improving mpg.They provide virtually no restriction to the intake flow,and consequently have no effect on volumetric efficiency of the engine,even at wide open throttle.There surface area is carefully computed to do exactly this.Spend your money elsewhere.

I prefer a clean engine and only use quality filters. I use Baldwin and no other brand. I am not going to get into statistics about filtering or argue on who makes the best filter because I already answered that question.

i put a k&n on my 2006 malibu and it gave me 2mpg's right out of the box

I tried a K&N on my 6000 wagon once. I did notice a bit snappier throttle response, but no better mpg. I could also buy a lot of stock paper air filters for I paid for the K&N.

Has anyone ever thought about putting a bigger box and filter into their car? Maybe there would be a bit less resistance. Just a thought

Let's get a little pedantic just for clarification, shall we?
IMHO, it's a bit of a stretch to say that a free-flow filter will have no positive effect on fuel economy without tests on a lot of different vehicles. It's probably generally true and most true in the modern era where it's easy to compute airflow needs and design a system to match. But if you want to go back to the days of oil bath filters and the first cellulose filters, well, some of those were restrictive enough to be a MPG issue. There are probably some poorly designed intake systems out there these days too but I don't know of any really bad ones. Basically, unless and until you run out of airflow capacity, the intake system is not a negative factor. Considering that hypermiling is all about low revs, even a system that's might be restrictive in a high-revving performance situation has plenty of capacity. A more useful pursuit would be velocity tuning for the most economical rpm range but that's pretty hard for the average person to do

I had a 98 Neon 5 speed that I drag raced....I put just over 147,000 miles on it and te very first mod was to get rid of the entire air filter system and put a fine wire mesh screen over the throttle body opening. That mod picked up very nearly 2 mpg and the car ran from .20-.23 of a second quicker in the 1/4 mile. I had the same mod on a 3.0 Sundance for over 100,000 miles with the same results. No troubles with this method, but I would not do it in a desert or dusty enviroment. K & Ns never werebeter for me and sometimes were the same as stock. I eventually was getting 46 mpg in that Neon with EOC and 41 without it...which was the EPA rating. The car had 180 hp on motor and 305 hp with NOS in use.....for you gear heads it ran 14.8 in the 1/4 on motor and 12.17 at 117 mph was its best time with NOS. In front wheel drve cars I have 33 NHRA & IHRA drag race championships and 1 IHRA championship with a rear wheel drive vehicle.
I used that Neon to win Car & Driver magazine's 50th anniversary drag race.....they had limited it to 500 entries!

so what about aftermarket intakes with smooth flow to the intake

I get better fuel mileage with a Fram paper filter, but the K&N cotton filter gives a noticeable improvement in power and response.

There was a study done about the effects of dirty air filters (can't remember the source, but it was posted here somewhere), and the conclusions were on fuel injected vehicles, lower airflow=less gas used=better FE, but lowered performance. On carburated cars, the lowered airflow altered the air/fuel ration and degrated both performace and economy.

My K&N filter gave me slightly better FE. But not much.

clogged air filters do NOT affect FE on Fuel Injected engines
 

http://www.fueleconomy.gov/FEG/pdfs/...02_26_2009.pdf

sorry people
this is the latest of three sets of test results that all show the same thing

clogged or restricted air filters have ZERO affect on fuel economy

quoted from the EPA TEST RESULTS Feb 26 2009
"Despite the filter restrictions, however, no significant changes in fuel economy were observed. Each vehicle was run through at least three rounds of FTP, HFET, and US06 tests with the new air filter, and the same protocol was repeated with the clogged air filter. The tests were conducted on consecutive days for each vehicle. This format was used to allow for the required soak time to perform a cold FTP each morning. The resulting fuel economy data for the vehicles are shown in Figs. 3.8, 3.9, and 3.10. Range bars in the figures show the minimum and maximum of the tests for each case, while the columns show the average. Test-to-test repeatability is within about 1.5%, and all of the variances between the new and clogged air filter cases are similarly within about 1.7%. The baseline fuel economies for the vehicles were all within 0–6% of unadjusted EPA certification database values (US Environmental Protection Agency) for similar vehicles.
The changes observed by clogging the air filter produced no significant effect on the fuel economy of the vehicles tested, when tested over these three standard cycles that represent a wide range of driving conditions. It is possible that there may be some isolated operating conditions under which the fuel economy may be more susceptible to a clogged air filter. However, such operating conditions are not likely to be consistent from vehicle to vehicle. The three driving cycles used here are representative of a wide range of driving conditions, as described in Sect. 1."

read this if you want ,
believe or not - as you choose -
see section 3.1.3 for test results and discussion on FE

Here's my two cents: After reading the following article I threw my K&N filter out and replaced it with a regular paper filter. That tiny bit in performance that is to be had isn't worth the extra junk flying into the engine possibly shortening the life of the engine.

Browser Warning

Just look at a K & N filter next to a paper filter. you can almost read through a K&N while a paper filter is lucky to let a lot of light through.

Dust is very small, so why would a filter with obvious gaping holes be a good thing?

The car they used had a MAF (Mass air flow) sensor and a turbo. My car has a MAP (Manifold absolute pressure) sensor and is naturally aspirated. Results vary.

Overly simplified, on most fuel injected engines, if there is less air flowing in, there is less gas going in. Sticking with overly simplified thinking, gas mileage should stay the same with a clean or dirty filter. So, more fuel is used with a clean filter, but less pedal is used to keep going a certain speed. A dirty filter will cause you to use less fuel, but more pedal to stay at a certain speed. Again, overly simplified but I can see why there would/should be no difference in fuel consumption with a clean or dirty filter.

K&N vs. paper. This has been debated on all different auto forums and nobody has ever proven to me beyond a doubt there is one filter that dominates all others. It all comes down to personal preference. I kept my K&N's clean and had oil samples of my truck tested and it showed that the K&N filtered just as well as a paper. Some people may have different results.

can a paper filter clean down to X microns? Sure, and there's years of experience to prove it.

can a reusable filter clean down to the same x microns? theoretically yes. Will you gain power? maybe. Will it be more economical compared to a new paper filter? doubtful.

And what is most likely to fetch the most consistently high quality filtration, replacing a good quality paper filter or cleaning and reoiling the cotton filter? And what is the likelihood of getting oil on the hypersensitive MAF sensor?

Here's a discussion from a corvette forum on the issue. To be quite honest, a paper filter is inexpensive and nearly guaranteed to work 100% of the time, while the cotton filter requires maintenance to keep it working correctly.

Worst case scenario with a paper filter if you're a couple thousand miles behind on replacement is that the acceleration is less peppy. But with the cotton filter, you risk damage to the engine.

I personally don't like to take such chances with a good engine.

I just put the K&N back in my car, and I'll see what the mileage is. I have several tanks with the Fram to compare it with.

By the way, reuseable filters help add less to landfills. There's eco for you. XD

It does add less to landfills, but what about when people degrease them in their driveways and the old oil runs off into the street?

speed density
 

I can often extend the life of a paper filter simply by knocking off the loose dust from the exterior of the filter. (There's a lot of dust in my area.)

Has anyone messed with cyclonic dust removers? (I'm referring to a device that removes dust from the air like a Dyson vacuum.) I've heard of them, and seen some examples in heavy equipment, but not in passenger vehicles. Using a device of that sort before the air filter would certainly extend it's life, or even using a foam filter in front of the paper filter.

Reuseable filters are a good idea, but they need to be a bit more sophisticated than a porous collection of cotton fibers. I've seen some reusable filters in vacuum cleaners that are reusable, but look very similar to a traditional paper filter. I would love to have a reusable filter that i could trust, but the K&N variety is a type I don't trust.

check out the links in my next post they show some facts about filters and there is an informative video in the second on....

a bit more sophisticated than a porous collection of cotton fibers


little video for ya'll

Nice video link!

Funnily enough yesterday I took mine out, knocked a load of dust out of it and then stuck a hoover (vacuumn cleaner) nozzle over it and it looks almost new. I'm hoping that reduces the recent smoke under full throttle issue I've been having, otherwise its the turbo. Maybe.

I actually have a copy of an SAE paper somewhere detailing and testing various air filters cleaning procedures. Tapping on a flat surface and vacuuming works, but tapping on a flat surface then blowing air from the inside out works even better.

I sucked (well the cleaner did) from the outside so I hope that is the same thing. My one spot of 'fun' on my journey to work tomorrow will prove if this has worked.

Hello guys,

I reviewed the links and I think I must agree with you guys.