K&N AND OTHER OIL TYPE FILTERS:BEWARE

[Brody]

Ok, I have known about this for years and years and just about everyone I know that is into performance mods is also aware of this: K&N and other oiled cotton element filters are just about the worst thing you can put on any vehicle with EFI and a MAF sensor. Why? Well the main thing is that the oil ends up covering up the MAF sensor wires that send signals to the ECM. When the wires get crud on them, they can no longer read the air coming in correctly and send false signals to the ECM that usually results in poor performance and an over rich fuel situation.

There are no horsepower gains to be had per se, and many tests have shown that the bone stock filtering systems, especially on Toyotas, ends up producing more horsepower than any after market air intake, with or without any deck plate mods.

This is not just my own opinion, but the opinion of many performance oriented people who deal with all makes of vehicles. The general consensus is to NOT spend the $300 or so on an after market intake and spend it on something that will do the most good as far as performance and power gains go. Also to NEVER, EVER oil that crapola filter on your heap if it has a MAF sensor. Ever priced one of those? Roughly $300 a pop or more and the oil will jack them up to the point where they get ruined. I have cleaned out many totally crudded out MAF sensors where people were running K&N style oiled filters. My suggestion to these people: Clean out the filter with degreaser, rinse it with water and let it air dry. Reinstall it and never oil it. After all, they wasted a perfectly good $300 and the filter set up is OK, so why not continue using it? (See post #7 and #9. This isn't a good idea....)

This is a reply to an after market air intake question on another forum that pretty much sums it up:

I would have replaced it with the stock box and deckplated absolutely, but the KN being my first mod back in the day when I had a single set of 12pt sockets and one 3 inch extension, and little patience, I decided to break the box into pieces as it wasn't coming out otherwise. If you look at Gadgets dyno sheets on his site you have un-biased proof that the KN in most areas is increasing loss of hp. In the few areas were its helping you to restore some power its still only half that of the deckplate mod on stock box. The more I think about this, the more Im starting to get pissed off. K&N is advertising false gains and they know it! Gadgets/URD has absolutely no reason (even unconciously) to discourage those open filters-they don't sell them. I really think I should sell the KN or possibly trade it for stock, I'm sure someone would jump on that, I would have 5 yrs ago.

Where do I stand with my heap? Well, having been fooled into thinking that I could actually gain some horsepower from absolute crap like throttle body spacers, Hurricane inserts, and K&N style filters, I have had/tried them all. Did I ever achieve any additional horse power? Never that I could feel. I currently have an after market intake on my heap now. I put it on before I did more research into performance mods for the Yota thinking that with bigger exhaust and headers, I might as well increase the air flow. Wrong. I should have stuck with the stock box, did the deck plate mod and called it good enough.

Hope that this saves everyone some grief and dollars. I have been meaning to post this up for a few years and forgot about it until I ran into something on another forum.

Of course, the after market filter set ups have a certain amount of 'bling factor' to them if nothing else, and, after all, it is YOUR money that you are spending, not mine....

[4finger]

so--- im gonna go out and look into the truck. lets go ahead and show my stupidity- does my 3.4L have a MAP? im assuming it has something to do with Mass Airflow. i will also be looking into the haynes and chiltons and various online stuff. just figured id ask cause Brody can answer my question before i can even find a site that MIGHT answer my question.

question #2--- i have an oil needing K&N, do they make dry type cone filters to fit my application. since ive got a 95 engine in an 87 truck- the batterybox got moved to the other side of the truck and some things have been moved to fit the new location of the airfilter. so im thinking i need to stick close to this setup DESIGN. not nessasarily the K&N itself. i dont notice any power loss. the filter was on when i got ahold of the truck. i think my bro in law put it on. plus i only remember to clean and oil it once a year- so one less thing to remember will help me remember something more imprtant later.

[ROKTAXI]

AMSOIL makes cleanable dry filters. Just blow them out (gently) and you're good to go.

Shameless plug: www.lubedealer.com/martyavalos

For more info, go to the AMSOIL home page and click on filters, then choose air filters.

[4finger]

can i guess im looking for this version but for the 3.4L? "the ea universal air induction"??? is it a "direct bolt on replacement" to the K&N setup?

and do you have a stor in Moab or are you out of your home???

[Brody]

Thanks Marty! For those that don't know, Marty is the rep for Amsoil. If you have any questions about Amsoil or need a catalog PM him and he will answer the questions.

Thomas, you made me reread my post. I had to change all the MAP to MAF as there is a big difference. First of all the MAP sensors are voltage based whereas the MAF sensors are frequency based. They are also visually different with the MAP sensors having an obvious 'vane' in the front and the MAF sensors are open with small wires showing towards the back. The older EFI engines use the MAP sensors and these aren't nearly as sensitive to the crud that the newer MAF sensors are. If you have the 3.4L, then you have the same sensitive MAF sensor that I have....The wire is barely visible behind the 'bullseye' front piece. This is the wire that needs to be hosed down with MAF Sensor Cleaner to clean it.

Just clean the K&N and run it as an oil free after market unit. (See post #7 and #9.This isn't a good idea....)I went with the after market intake for the same reason that you did: everything flip flopped on the engine swap..

Also, for anyone running an older MAP sensor, you can wire in a pontentiometer with an in cab dial control so that you can fine tune the MAP sensor's air fuel ratio....not bad for a less than $10 mod...

[4finger]

Just clean the K&N and run it as an oil free after market
cool- thanx Pete. now-- i was told not to run an oil filter dry. the internal fibers get dry and brittle faster and can dislodge into the engine under hard gas situations. i will try the dry technique Pete, soon i may wanna change over. like i said- i have only cleaned it and oiled it 4 times in the 4 years its been running. so ive probably clogged some of the element. i am kinda embarassed to open my hood when people are around- it looks like someone took a big plastic cup and covered it in glue then rolled it in the sand- THEN installed it in my truck.:redface:

[SubaCool]

where people were running K&N style oiled filters. My suggestion to these people: Clean out the filter with degreaser, rinse it with water and let it air dry. Reinstall it and never oil it.
Wrong! If you're not gonna oil a K&N type filter then you might as well run without the filter altogether and go back to your OEM paper filter (or as Marty suggested, get a special dry cleanable filter). DO NOT USE A K&N FILTER WITHOUT OILING IT!! K&N type filters are typically made with a cotton gauze type element which microscopically is much more open than your standard dry paper element filter (that's why they claim "hp gains over OEM"). As a result, more air flow is achieved. The downside to that is that it also opens up to more dirt intake (less filtration). This is where the "oil" comes into play. It serves as a bonding agent that traps the dirt too small for the cotton fibers. <<<That is the simplest way I can explain it. For a more detailed version, read this: http://www.knfilters.com/filter_facts.htm

I completely agree with you about the oil possibly harming MAF and MAP sensors IF used in excess. Most "uneducated" consumers wash the filter, let it dry (or not), and spray gobs of that oil onto the filter (sometimes even using WD40 <<bad!). THAT'S how their sensors crap out. The biggest selling pitch at most autopart stores about these filters is that they are washable and reusable. YES! But what most customers don't learn is HOW to properly service these filters. And that's why they are crapping out their Mafs and Maps...

I'm not affiliated with K&N or any other brand, business, or whatever else to "promote" these types of filters (nor do i get anything for this), I'm just speaking from my short (5-6year) experience. I've been using these types of filters on all my cars and I haven't had ANY problems resulting from using these. I've always applied just enough oil to color the gauze and wiped off and dried any excess before installing back into the car. Would I use them for all types of driving/racing? No, especially if there's too much dirt/dust involved. Then you need prefiltering and relocating filters, etc, etc (I've toasted one engine to learn that the hard way :redface: ) But for regular driving, i'll use them again and again :thumb:

[ROKTAXI]

do you have a stor in Moab or are you out of your home???
I'm just a dealer / representative for AMSOIL. I don't stock any products. I just have a few quarts of stuff that fits my application. You can order it direct from AMSOIL or I can order it for you. I offer a 10% discount to all FR4x4. Depending on the item, it takes about 3- 4 days to get an order delivered to your door.

If you can put an order together with others that want a few items, it can be combined and I can sell it to you at MY COST! Usually takes an order of over $100 to make it work out. I'll explain how it works if any of you are interested.

[ROKTAXI]

DO NOT USE A K&N FILTER WITHOUT OILING IT!!

X2!! K&N makes a spray oil you can use to VERY LIGHTLY oil it until you decide on a dry type filter. Gauze filter material has to be oiled or else it will allow dirt to pass!!! Most issues with K&N are from people over oiling it. However, it is a proven fact that with even oiling it as per instructions, it will still allow more dirt to flow past compared to an OEM paper filter.

When I bought a new Jetta TDI I was warned to NEVER use an oiled gauze filter. $200 to replace the MAF, not to mention throwing CEL.

[Geno]

I have a K&N in every truck i own including a 2006 Toyota and have never had any kind of MAP/MAF sensor problem. I clean them when they are dirty and re-oil them as per the instructions and they work fine for me. I do have a 3.4 in my 01 taco with with a K&N drop in thats has been in there since 2003 when i bought the truck. The only issue I have really had is the K&N Cold air system( installed 6 months ago /removed 1 month ago) which leaned out my air/fuel too much because of the super charger. URD sold me a MAF piggy back to help my air/fuel mixture and when i took off the cold air system ( its for sale on CL) and re-installed the stock set-up with drop in K&N filter everything seems to work pretty good , still have some knocking and mid-throttle 4-6 lbs of boost going up a grade though. It is a challenge to get it all back into Tune for the ECM with the Supercharger and underdrive pulley. But I do not believe it has anything to do with the air filter,

[Brody]

Well, like anything 4x4, people have had both good and bad luck with the oil type filters, so I did expect some controversy (kinda like stating that skinny tires rule over big fat ones any day of the week....)....I should have mentioned that OVER OILING the K&N filters is USUALLY what causes all the problems, but still, the general consensus is to not run them...One of the things I did find out (and this is from doing a mess of research into getting my truck re tuned), is that relocating the MAF sensor or adding an after market intake screws up the air flow from the factory settings that the ECM reads from. Sometimes quite a bit and a lot more than what you would expect. Using a plastic intake tube does the same thing due to variances of the inside dimensions of the plastic during the casting procedure.

What the information that I researched led me to find out was that any modification, whether an after market air intake, headers, exhaust mods, etc, usually do not work quite as well as advertised simply because the rig needs to be 're tuned' so that the benefits can actually be realized. Most of my experience with engines have been with older engines, mainly Ford, Jeep and Chevys, without all of the computer stuff. Simpler stuff to be sure, so a lot of this information is new to me.

For those of us with Toyotas, here is a little more information. According to a quoted Yota tech, Toyota builds in a +-4% factor into their MAF sensors which will also affect tuning. Yota also pre programs all their ECMs so that they all run towards the rich side at higher rpms. This is mainly done as a 'safety' feature to protect the engine, hedging their bets, so to speak. In other words, in basic stock trim, without any 'go fast goodies', there is a consistent 10-15 hp to be gained on stock Yotas with a proper tune (read: recalibration, not plugs, air filter, etc...). And one more tidbit for the Yota folks: Toyota has, in the newer (what years they started in, I don't actually know, so I am going to say post 2000) ECMs started issuing ECM updates for the newer reprogrammable ECMs. If you take your rig into a dealer to get it tuned, Toyota will install the ECM updates with or without the customer's approval as a matter of course. This will overwrite any custom maps that you have written to your ECM and you will be back to square one with the ECM tuning....:D

Is it worth taking the rig down to get it dyno tuned for every mod you do to it? Probably not unless you are swimming in money. I am on a not too pleasant learning curve working with the R4 software and a Br-3 scanner so, theoretically (HAHA....and again: HAHA), I have the capability to do this....sans dyno dollars, of course...:D

As an aside here, before you spend any time trying to re tune your rig using software such as R4, your engine needs to be pretty well dialed in with new plugs, PCV, air filter, good O2 sensors, good engine temperature coolant sensor, etc. One of the things that I have found out (and this is mainly because this is my first experience trying to do this...) is that any leaks in the exhaust system before the O2 sensors will totally jack the readings that you are trying to work off of. Common sense to people who have been dealing with custom tuning of newer EFI/ECM engines, I am sure, but like I said, most of my experience fine tuning engines is pre computer BS where I just had to deal with mechanical or vacuum spark advance, weights, rejetting carbs, etc.

I was getting some major fluctuations in my fuel trims and was trying to find out what was causing this, so back to research. I found a sentence that said "any exhaust leaks before the O2 sensors will throw the readings off". Really? Made sense when I thought about it, so I took a very careful look at my entire exhaust system. I found numerous small leaks, mainly some cracked welds and resulting hairline cracks around my headers, worn collector gaskets which leaked and leaks on the very top of the joints where it is hard to get the welds right. I took my entire exhaust system apart, replaced all the gaskets, re welded all the headers joints, welded up all the hairline cracks, re welded all the other joints on the exhaust and re installed the system. A PITA for sure as the headers were initially installed with the 3.4L swap on the engine and taking them off was a Chinese puzzle. When I took the new readings, my fuel trims were now stable and not jumping all over the place like they were. Just another thing to keep in mind....


I found this information to be pretty informative, especially since there is never anything wrong with more hp and if it there for the asking, then why not?

Geno-One of the things that you might be dealing with tuning with the after market filter/air intake is that the actual MAF sensor gets relocated which will cause the air flow to either be more or less that what the ECM 'expects' to see.

How are you coming along on the tuning, anyway? R4 software, URD preloaded map, etc, etc? I have the same set up on mine plus the URD fuel upgrade kit and have never done anything like this before. I am using the Split Second FTC and BR-3...Doing some more research on that bumped me into all the posts on various threads about the K&N, air intake relocation, how it affects tuning, blah, blah...


Thanks Kubo and Marty! This is coming from someone who races cars and has more experience with the filters than I do, obviously. I will stop suggesting the cleaning of the K&N and running it as a regular filter. I went back through and referred Kubo's post #7 and Martt's post #9 on my posts so that this information is cleared up....Thanks again.

Wrong! If you're not gonna oil a K&N type filter then you might as well run without the filter altogether and go back to your OEM paper filter (or as Marty suggested, get a special dry cleanable filter). DO NOT USE A K&N FILTER WITHOUT OILING IT!! K&N type filters are typically made with a cotton gauze type element which microscopically is much more open than your standard dry paper element filter

[SubaCool]

You're welcome. We all learn something new every day :thumb: I bow down to your automotive knowledge every time I read something you post and I don't know nearly as much as you do. After all, you do have a few more years off experience on me ;)