Drop in K&N

[Justin]

I realize this may be a redundant question, however I have the impression that many of the individuals on this site have already gone through the "dos and don'ts" when it comes to vehicle modifications.

My question is what effect does the drop in K&N filter have on the Mass Airflow Sensor? Do the benifits outway the risks? It seems fair to assume that an over oiled filter would eventually draw in some amount oil into the the intake. With that said, can I lessen the chances of that happening by putting a minimal amount of oil on the filter? Or, should I just stick with the stock Toyota paper element? Thanks in advance for the feedback.

 

[asteffes]

I've used K&N filters on other vehicles before purchasing my Tacoma. I'm of the opinion that there is no real benefit to using a K&N. Here's a list of my thoughts:

1. Cleaning a K&N periodically doesn't cost much less than buying replacement paper filters. The cleaning kit is about, what? $20? If you off-road a lot you'll probably be cleaning it often and go through a couple kits in the filter's lifetime. I also think that cleaning these filters is generally a pain in the butt and no more environmentally friendly than tossing a paper filter in the trash (you're using another chemical to clean it, one more to oil it.) I totally don't buy the idea that K&Ns are all that easy to deal with.

2. K&N filters allow more dirt through the filter media. I think this is simply the compromise you make to get more air into the engine. I've found a slimy film of dirt and grit inside the intake tubing of both cars with which I used a K&N filter. I can only extrapolate that this would be even worse with an off-road vehicle.

3. K&N filters provided no noticeable or measureable improvement in power in my experience. I dyno-tested my previous track car with stock, K&N and ITG filters and found no differences at all.

I would really just suggest carrying an extra paper filter off-road with you and count on the fact that you're getting the best filtration possible. Amsoil has released a new design for their air filters, but I have not personally tested one. It's sort of a hybrid between paper and gauze media, and while I won't suggest it will create massive horsepower improvements, it may filter a bit better than paper. (Disclaimer: I'm a registered Amsoil dealer. I'm not trying to sneak in a sale here. My truck has a factory Toyota filter in it and will at least until the service plan runs out.)

 

[Ursidae69]

I like the increase in HP and mileage from the drop in. I've used it for years in this truck and my last, never had any problem with the sensor. As long as you follow the re-oiling instructions explicitly, there should be no problem.

 

[Justin]

2. K&N filters allow more dirt through the filter media. I think this is simply the compromise you make to get more air into the engine. I've found a slimy film of dirt and grit inside the intake tubing of both cars with which I used a K&N filter. I can only extrapolate that this would be even worse with an off-road vehicle.

I often speculated that more dirt would most likely make it through the K&N... On my 94' p/u I used the Downey intake for the 2.4 and I too would find a thin layer of grit/grease inside the intake tube and around the enterance to the throttle body. I have also heard reports of people's oil looking much dirtier when running a K&N vs. the stock element. I have not experienced that however due to my nuerotic oil changing routine. For the time being I'll probably stick with the stock filter unless something really jumps out at me.

 

[Brian McVickers]

I have heard people either swear by them or against them.
The most often problem being a fault with the MAF as you mentioned. I have decided to not use them since a new MAF is more expensive than changing a paper filter more often. That doesn't mean I know anything, it's just my own comfort level!

 

[asteffes]

I guess I'm one of those people who swears at them.

My thinking is that the filter is there to *filter* dirt so use one that filters most thoroughly. I'm really surprised when people mention a noticeable improvement in horsepower or fuel economy. My butt dyno is not accurate to within five horsepower, and I think a one or two miles-per-gallon difference in efficiency could be attributed to many factors besides a filter change.

I also wouldn't want to have to change my oil more often because my filter is allowing more dirt in. If it was a racecar and I wanted maximum horsepower at the known cost of durability, sure, but not in my supposed-to-outlast-me Toyota.

Maybe it was just that the stock filter was clogged before switching to the K&N and a new stock filter would have a similar result in some of those cases? Who knows. I guess I just play it safe.

 

[flyingwil]

If you are opting for a K&N I would recomend an AMSOIL filter. The reason is that it is easy over oil the filter, then in intake can suck it up and the oil residue could clog your MAF. With the Amsoil filter or other foram type you blot off the excess and it is hard to over oil.

K&N's can be used but with care, and most people just perfer the good old 'yota brand. How ever I am running a AMSoil foam Filter with the deck plate mod and haven't had any MAF issues yet. I did try the K&N and noticed oil spray up the intake shaft, thus it ended up in its new home... the trash can. I haven't had this problem with the AMSOIL, and have clean and "recharged" it 3 times now, and each inspection shows up clean.

WIL

 

[Justin]

I have also heard good things about the Amsoil. I suppose it just boils down to where & how you use your truck and how long you want it to last. My father took the, "Toyota Genuine Parts" road with all of his past vehicles and they lasted a very long time with very hard drivers. However, my butt dyno noticed an improvment in throttle response on my 2.4 so it was mildly justified then which is why I am inquiring about the Tacoma now.

 

[gjackson]

I've had a lot of luck with K&N airfilters. IMHO if you are getting oil and dirt after the filter, then you are WAY over-oiling the filter. If you oil it properly you don't get oil deposit on the intake. Also, K&N (and other oil based filters) get better as they gey dirtier (to a certain extent). Of course I have a low horsepower engine and no MAF, so I don't have those issues.

I do have to say that the cleaning kit for the K&N takes up *much* less space than 3 paper filters for my truck. But then the paper filters for the 300tdi are huge!

I just have to make it clear that this is just my experience so may or may not have any relevance to your situation.

cheers

 

[Jonathan Hanson]

The answers on this thread are typical of what I've heard and experienced with K&N filters. Normally I wouldn't contradict Graham's wealth of experience, but my own with K&N has been less than satisfactory--although I've never had a problem with the mass airflow sensor, and from what I know of MAS design and the computer parameters a difference in air filters couldn't possibly affect it.

However, I find it hard to fault the quality of stock Toyota filters at least, which appears much better than K&N's. A mechanic friend, probably the finest Toyota mechanic in Arizona, refuses to install K&N filters. He says he has seen many that don't fit properly and actually allow completely unfiltered air into the intake.

Anytime I see reviews of a product divided so completely, my reaction is "Eh, probably not."

 

[BajaTaco]

Yea, "probably not". That's me too. I keep using the genuine Toyota paper filters on mine. I don't feel comfortable with the K&N, based on much of the same or similar comments expressed herein. I have used K&N filters before, but decided not to with my Tacoma. Plus, I like to just drop a new filter in as needed - you gotta admit, it's highly convenient, especially when you are crunched for time before leaving on a trip (as I often am).

 

[gjackson]

I do some things with my K&N that K&N says not to. They say don't use grease where the filter meets the filter housing, that the rubber on the filter will provide an adequate seal. This is not true! Every time I have not used a thin film of grease, I have found a nice dust trace under the seal. So I do use a thin smear of grease.

There may be something to the shape of the filter as well. The 300tdi filter is a cylinder, not a flat filter. It is held in by a wing nut that you can torque down to get a good seal.

On our off-road buggy we used K&N filters after we had used ITG foam filters. The ITGs had a huge problem with leaking around the base. Not so much with the K&Ns, but that's where I learned the grease trick.

Again, just my exp.

cheers

 

[erin]

I think if you are looking for improvements, your best bet would be to remove the intake suppressor to make for smoother air flow and less restriction. I installed an Air raid intake and noticed much smoother throttle response thru out the rpm range. I choose the Air raid because I felt it was a better filter than the KN, due to an extra layer of filter element and I believe smaller micron filtration. Overall I'm very pleased with this unit. Plus it adds alittle growl to the engine under throttle.

 

[Justin]

Anytime I see reviews of a product divided so completely, my reaction is "Eh, probably not."

Very true... I would like to think I am the same way. With so many mediums for comparing products, it makes sense that your research would influence your decisions.

Also, as BajaTaco mentioned the crunch for time aspect is a good reason to go with the factory element. I am heading out of town tomorrow and instead of bothering with the messy clean up, I am just going to swing by the Toyota dealer for a new filter, drop it in, and heed out!

 

[Brian McVickers]

How often do you all change or clean your air filter?