My first post so go easy...

Ill list the cars ive owned since it will matter for my question

Current
2003 Maxima SE auto
2001 Sentra SE auto

Gone Cars
2000 Altima SE 5spd
1997 Altima GXE 5spd
1994 Eclipse GS 5spd
1991 Talon ESi 5spd

My question is when i first got my max I waited about 500 miles before I put in the K&N filter(wanted to feel the car without K&N filter)

Then I put the K&N in and right away I noticed a lack of power between shifts and overall feeling of it being slower. Since this is my first auto, is this because im so use to the feel of a 5spd? or something else.

After about 300 miles of this I put the stock filter back in and it feels so much better

Ive always felt the difference in my past cars using a K&N filter. Not so this time. Plus ive noticed the threads about the oily MAF.

 

i'm suprised... on my auto ... i actually feel more power with the K&N... a littel better pick up.... the stock sounds like its bout to die..

 

the filter adds .4hp with a 2001 maxima.....

 

I've never felt a difference either way with the K&N filter. I only put it in because I know it's a better filter than OEM and it's reusable.

 

K&N with GAB/CAI custom job = better MPG + nicer pickup

 

It depends... did you put on a cone-filter, or did you just replace the square element? If you put on a cone filter you may notice a difference in the low rpms when it's very hot... up to 2,500rpms maybe. But overall the cone-filter delivers more HP & torque when you need it most: as you're flooring your Max.

G

 

First off no way the stock filter is dying car only has 4000 miles on it.

Second it was Jan in NY when I had the K&N filter in.

And it is just the filter not the cone.

I find flooring an auto just gives you that lagged feeling, so im more a graduial pressure kinda driver.

Thx for the input.

 

I've felt no difference.

 

Who invented that anyway???

 

If you've never noticed a difference then I don't understand the last part of your post on the K&N being a better filter. The K&N filters are not very good at stopping dirt in comparison to other filters. The Nissan OEM filters stop dirt much better.

http://www.mkiv.com/techarticles/filters_test/2/

 

I hear Amsoil is supposed to have a good filter. Anybody use their filter?

 

Agreed and I tried it in my 97 and I didnt feel a difference at all at WOT.

 

[QUOTE]Originally posted by Virus
[B]

If you've never noticed a difference then I don't understand the last part of your post on the K&N being a better filter. The K&N filters are not very good at stopping dirt in comparison to other filters. The Nissan OEM filters stop dirt much better.

How can you say nissan's filters stop better than K&N, I didn't see it finish second place behind the Apexi. Your statement is pretty balsy.

 

Nissan's filters stop dirt better than the Apexi's. Hell, Fram stops dirt better than the Apexi's. Better dirt stopping mean less airflow. Paper filters generally stop more dirt than all other media types, but it comes at a cost of lower air flow.

I've used Amsoil foam filters is several cars. They are the best of both worlds. They stop dirt close to paper filters and keep really good airflow. That being said, they are a pain in the butt to clean and reoil and they are definately not a lifetime filter like Amsoil claims. The foam starts to break apart after 2 or 3 washings. I personally wouldn't use them in our cars with all of the MAF problems. The oil they use is really thick.

 

You're always gonna feel that lag with auto when you floor it..

You should have stayed in the 5spd family

 

I'm not sure that I understand your post or your link either. The link doesn't say anything about the Nissan OEM filter at all. So how do you know it stops dirt better? I just thought it was a fact that K&N filters were better than OEM. Maybe I'm wrong.

 

I've seen mag dynos of the K&N on a 5sp 2000 gain 4hp/6.1tq and withOUT any filter it was 0.4hp/0.2tq gain over the K&N.

It's good for a couple hp, but nothing you're going to be able to feel from a butt dyno.

 

Any paper media filter will stop dirt better than any K&N(or foam), especially an oiled one like the OEM.

You can SEE holes through a K&N, but you can't with a paper so what does that tell ya?

If it flows more air, then it's allowing more dirt through. That's a fact.

 

So it's bad to put a K&N filter in then?

 

Not if you change your oil regularly.

A K&N is the BEST compromise in my opinion. If you want more power then you have to sacrifice air filtration, that is part of the game. However, if you change your oil regularly and service the K&N filter accordingly, you won't hurt anything.

I've used both and the K&N flows more air, however keeps more dirt out than anything else I've seen.

 

I disagree with your last point. More air flow could be a factor of two things:

1. Increased pore size allowing less of a pressure drop across the filter membrane, resulting in larger and more numerous particle penetration

2. Increase filter membrane surface area that results in decreased pressure drop across the filter while maintaining particle efficiency


I have a feeling K&N gets more airflow through larger pore size. Probably not the best thing for your motor, but who knows. I'll never buy one...maybe the apexi...hmm

Do they publish efficiency and surface area numbers?



Bemis

 

Thanks IceY2K1. What do you have in yours now? Honestly I thought the K&N was a superior filter, period. That's why I put it in right when I got the car. But since I honestly didn't feel a power gain I might put the OEM one back in. I've only got 2k miles so far, but I changed the oil at 1k and will do it again this weekend. I plan on changing at 1k, 2k, 3k, 6k, and switching to synthetic at 9k.

Knowing this about the K&N just makes me want a Frankencar with Apexi filter that much more. Think if I order it today I'll get it by X-mas?

 

I have the Stillen POP w/K&N and I had a JWT POP w/look alike K&N(returned it) and I just bought a PR CAI w/K&N(used), but I'm currently running an OEM paper filter.

I used the Stillen POP for a couple thousand miles, otherwise I've always used a stock filter. I took the Stillen off for a dealer visit and once I did, I noticed the bottom end was back, but the top-end had lost a little. The difference between stock and POP wasn't much, but maybe with a Y-pipe and/or exhaust it would make more of a difference.

Honestly, the factory intake is pretty darn good and the minimal difference made me decide it wasn't worth putting back on the POP. However, now I'm going to try a PR CAI and see what I think.

 

As far as I know there isn't a way to increase the filter area of the stock paper element, so I still stand by my statement.

 

Same here.. i got GAB and it's just sounds better.. cant really tell on peformance.

 

The Apexi is the best filter out there for dirt stopping and flow. Many people stick by the K&N because it's a better price performance filter. It does an ok job at stopping dirt and lets alot of airflow in. I've had both and I personally prefer the Apexi, but I'm not saying you can feel a huge difference with the Apexi. I just like the looks and the dry filter as opposed to the oil treated.

 

I guess my point was that if you purchase an aftermarket filter you should look for one with the most filter element area. A cone filter may have more surface area than a stock box filter, but I haven't seen the numbers. THe only way to increase surface area in a box filter would be to have deeper pleats.

Increased filter surface area means that the mfg needs to use more material. I wouldn't be surprised if that is why apexi's cost so much

Cheers

 

Oiled filters will stop MORE dirt than an Apexi dry filter. However, most people are attracted to the Apexi dry filter because of MAF failure problems from OVER-oiled filters. Dry filters don't have that problem.

Apexi filters aren't a better DIRT filter than a K&N.

 

Jeez, this just keeps getting more and more confusing. So a K&N will stop more dirt than an Apexi? That goes against the link that Virus posted earlier in the thread. According to that the Apexi was the best.

 

That's only ONE test...probably biased or skewed.

Only way to know FOR SURE is to run them both ON AN ENGINE and get the oil analyzed several times, which will show silicon(dirt) levels.

I'm not saying K&N is the BEST, just that wet vs. dry, wet will win especially when it's a paper media barrier like the Nissan OEM.

 

OK, so bottom line and then I'll stop dragging this thread on...assuming you're not going to do alot of performance mods would you go with a K&N drop-in or leave the Nissan OEM filter?

 

IMO - Nissan OEM filter.

Why? The hp difference is minimal, your allowing more dirt into the engine for a negligible gain, and MOST importantly is that an OVER-oiled K&N is a quick death to an expensive MAF that could strand you on the side of the road when you least expect it.

These are PERSONAL preferences and everyone is different. Some people do it for the minimal gain, some do it for the $$$$ saved by cleaning the K&N vs. throwing away OEM filters, some do it for the wee bit more sound, some do it just to say they have one in their sig, and some JUST for the damn K&N sticker.

Your decision and I'm not going to make it for you.

 

I'm going to go one step up and try to use my 9 inch K & N cone filter I have and make a custom intake from PVC pipe. Should that not work, I'm going to get a frankencar.

 

Yeah I did it for the sound I hated the electrical noise of the engine so I got a little bit of a real car sound by dropping that stupid thing in. Maybe at WOT I get a 2HP difference but whatever it does last longer and it is only 34$$$$$

 

Yeah, if you seal everything.

 

Actually a while back there were at least 3 links to reviews all showing the Apexi stopping more dirt than the K&N. Steve Frankencar also had dyno's showing an extra 4 hp with the Apexi over the K&N, but we all know that dyno's can show 3 or 4hp difference each time. One thing I will also point out is that the construction of the Apexi is much better than the K&N.

 

I havent looked too closely, but I do notice a long metal tube coming off the midpipe on these intakes. What is the purpose of that long metal tube?

http://www.frankencar.com/stevepic/int1.jpg

Its the upper left of the pic

 

A dry Apexi filter will NOT stop more dirt than an oiled cotton, paper, or foam filter. The oil is a barrier that makes the difference.

Only an oil analysis will back up that an Apexi filters better.

 

okay, I guess the reviewers were wrong an purposely dirtied the material? Oil analysis is a very poor way of testing an air filters efficiency at stopping dirt. This has been discussed to death. If one so desires they can take the time to look up the info here on the org. Several months ago someone pointed out that if you read the K&N literature, they use totally different tests to show the efficiency rating of their filters. The test they use is of a lower caliber than others. Try to look through an Apexi filter and then do the same with the K&N. Look at the pore sizes of the K&N. They used to list on their site that they met the minimum standard for filtration. That doesn't sound promising to me.

 

Biased...yes. K&N is the "bar" all the others TRY to beat. Again, my point is NOT K&N are the BEST, but oiled vs. not, oiled will win. Apexi is no different than any other dry filter.

Oil analysis is the ONLY way to prove which filter is better.