Mustangdude281

Just wondered if a K&N filter yeilds any noticible results in terms of HP and feel.

Bender

Other than I won't have to buy another filter, no.

05BlkTL

I'm gonna say no

I hate cars

The only difference is it will let lots more dirt past it. The factory filter is always oversized to take into account the typical loading that happens over the filter change interval. On a nice car like the TL that's a daily driver I would never use a K&N. I used one on my turbo car for years but it had different requirements.

JTS97Z28

iTrader: (4)

No a K&N filter will not yield you any gains.

Izzy-Type-S

iTrader: (1)

I've never heard that they let in more dirt...but I trust your experience. Tell us more...

Jaco

iTrader: (1)

No more power but the car did get a little louder.

KN_TL

iTrader: (3)

There are a gizillion case studies about these filters.

They do let more air pass but at the cost of filtration and is only a benefit if you are looking for maximum performance.

tihomirbg

iTrader: (1)

Not really. I had it for like a year. Now AEM cai

Izzy-Type-S

iTrader: (1)

So more dirt particles are obviously not good...do u guys recommend I remove mine? ATLP recommended I NOT do a CAI with the system on order.

KN_TL

iTrader: (3)

What system do you have on order?

Izzy-Type-S

iTrader: (1)

ATLP cat back exhaust with J-pipe & High Flow Cat.

KN_TL

iTrader: (3)

Not sure why he would recommend against it.

Izzy-Type-S

iTrader: (1)

He didnt officially say "no dont get it" but with the sound I'm going for, driving clients around in the car & the raspiness I hear in the CAIs I opted out...for now. I also hear mixed reviews on loosing lower end power but gaining it on the upper end. IMO the TL cant afford to loose anything more on that initial kick, the mid-range is bad ass and once you're at the top end past 120mph it does fade out but then again, I'm not at those speeds daily. I'll still give it some thought since its something I kinda wanted but I want to hear the exhaust as it is for now. I'd love to meet someone or hear the ATLP with the CAI.

I hate cars

I'll help you out a little.

The stock airbox is the primary means of muffling intake noise, not the filter. With a K&N or no filter at all in the stock airbox, if you really pay attention you might be able to hear a subtle difference when vtec hits but passengers would never notice.

A CAI can not take away power anywhere in the rev range from idle to redline. Colder air will make extra power everywhere on the tach and less restriction will only show up once you've exceeded the flow of the factory intake system which the TL does not in stock form. In other words, if the stock inlet tract is not a restriction, how can a freer flowing one make more power?

So in short, as long as you have the factory airbox, nothing you do to it can make it too loud.

A filter or CAI can't take away bottom end. A filter by iteslf won't give you more power unless you're heavily modded. Cold air is always good.


What I did was remove the factory plumbing so that it retained the factory airbox but took in air behind the bumper. It sounded stock until you had your foot to the floor and vtec hit and then it was slightly louder than stock but not much.

I tried it with a stock filter and K&N (which I still have somewhere with 100 miles on it) with a vacuum guage on it and there was no measurable vacuum with either filter meaning no restriction.

nfnsquared

Anytime anyone tells you this, ask them to provide scientific proof or studies that prove this. So far, I haven't seen anything but WOM (word of mouth).

AckTL05

iTrader: (18)

Either or its a waist of money. Might as well get a cone for 15 bucks and connect it to your plastic tubing connected to the TB and take away stock airbox.

CubanLynx84

iTrader: (2)

yeah I can't really see the K&N filter letting in more dirt. that doesn't make sense to me. Aren't the oem filters paper material? whereas the K&N filter is made of a gauze type pattern to be able to trap in more dirt? Especially since they are also oiled?

You will not gain any power with the K&N filter oem replacement though, that I know is true. All you'll get is better filtration and a longer lasting filter.

KN_TL

iTrader: (3)

There are so many case studies that you could read forever...

nfnsquared

Would love to see such case studies....please post the link/s.
Thanks!

KN_TL

iTrader: (3)

I'm not going to hand feed you. Anyone can use Google.

I researched this a few years ago and there are a lot of people who took the time to do side by side comparisons of various filters and filter types. Unless they made huge changes in their technology, they are still valid comparisons.

From there you can make your own decision.

nfnsquared

^^^^Just like I said...The naysayers offer no scientific proof.

On the other hand, there is no proof the other way either.

I hate cars

There are many, many studies out there. Just take a look at a K&N then look at a paper filter it should be obvious. I've seen no less than 4 studies including my own. Arguing that a K&N does not let more dirt in is like arguing that the tires on your car are not round.

The oil is there as a bandaid because the guaze material is so open.

This is common knowledge guys, do your research.

KN_TL

iTrader: (3)

I don't need a person who has Dr in front or Phd on the end of their name to tell what is happening in real life.

If you look at the examples people have out there, it's really obvious. What ends up on the other end of the filter is what matters. Not rocket science.

nfnsquared

OK, guys. Don't get emotional on me. I'm not attacking your integrity or knowledge, I'm asking for proof of your claims.

I say again: "Where's the beef?" Give me a couple of links to some lab that's run some test on this that support your view. I'll tell you right now that I'm very happy with the K&N, but I can't prove to anyone that it works any better or any worse than other filters. We all can "Google" and find plenty of people opening their pieholes and making pro and con claims about K&N filters, but from what I've seen it's just a bunch of hot air and opinions not based in fact. Again, if someone has proof that I may be damaging my car or that K&N is the best thing out there, I'd be very interested in seeing it.

On a totally unscientific note I know the following from my experience (and I'm touting this as my experience only and not claiming that there are tons of studies out there that support my experience):

I ran a K&N cone filter on my Supra Turbo for 17 years and a 165,000 miles before I sold it (Damn, wished I had never sold it, but couldn't very well take to ND). During that time, it blew the head gasket twice (first time at 112,000 miles, second time at 144,000 miles, both times repaired by the local Toyota dealer). Both times I had the mechanics call me when the engine was apart. The head and valves were immaculate both times as was the whole intake system (and not that it really applies, but all six cylinder walls still had the factory etching visible).[Head gasket problem in Supras was theorized to be caused by insufficient factory torque specs on the head bolts, 57 ft/lbs if I remember correctly. A new set of high torque head bolts and a $50 tip to the mechanic to crank the bolts to 71ft/lbs solved the problem. I only wish I had found out about that the first time it blew).

I've run the K&N on my 04 TL since about 16,000 miles, now at 85,000 miles. All I know (from my experience only) is this:

My oil is never excessively dirty at oil changes (7500 miles)
I consistently get 31-33 MPG on the highway at 70MPH with A/C on (summer gas formula). Before the K&N it was 29-31.
The throttle body side of the air box is never dirty when I pull the air filter to clean it.
The throttle body has never fouled on me.
I can't tell any increase in HP or performance.

I hate cars

Alright, I'll keep this civil. My favorites got deleted so it will take a few...

I've posted on here the government study on the effects of a dirty filter, clean paper filter, and high flow (K&N) filter on fuel economy. I no longer have it but it's on Acurazine somewhere.

The results were exactly what I've been saying, on a fuel injected car it is 100% impossible to see a gain in fuel economy. Completely impossible. Your throttlebody restricts airflow to control power. Going by the logic that a high flow filter increases power, you would get better mpg at full throttle since the throttle valve is open all the way.

People get intake mods confused with exhaust all the time. A high flow filter can't affect mileage or low end power but exhaust mods can.

Your car runs at the same AF ratio no matter what. If the airfilter is super dirty all it does is cut back the amount of air that is available to the engine, reducing power. But it is no different than closing the throttle a little. The computer sees less airflow and matches it with the correct amount of fuel. Again, going by you logic would mean the car gets worse mileage at low throttle.

As for the filters, I have had problems with compressor wheel abrasion from dust intrusion past the filter. It went away when I installed one of Amsoil's high flow and high filtration filters.

The filter usually won't let enough dust past to notice prematurely darkening oil. And it usually won't make a dent in the life expectancy below 150,000 miles. But don't kid yourself, it does make a difference in engine life. The area the car is driven in makes a huge difference. Mine is a dusty area and I noticed it in the intake tract. Some areas that have very clean air don't rely on the filter nearly as much.

If you need proof right away that K&Ns let more air in, go to bobistheoilguy.com and look in the UOA section for people that are running K&Ns. They consistently show more silicone in the oil that goes away once the factory filter is put back in.

This is one thing you guys are really missing out on. Amsoil has a whole line of cone filters that filter as well or better than an OEM paper filter and flow as well as a K&N. It's a synthetic media which uses no oil and can be cleaned.

KN_TL

iTrader: (3)

I figured it was a case of using K&N and defending it.

It's like anything else, you use what you want and be happy. I'll do the same. But like IHC, I have read all the things like bobistheoilguy and others who have had analysis done after doing some inhouse comparisons and take that as scientific as it will get.

I hate cars

I do have one good test, probably posted on bitog also that I will try to find. Now that I think about it, my ban should be over today. I may have to go over there and stir things up.

thisaznboi88

iTrader: (7)

I was wondering when you remove the intake resonator and added the k&n did you notice a lost in low end tq? i removed it and now I ono. Car feels slower.

I hate cars

It's impossible for a filter or CAI or SRI or even an open throttlebody with no inlet tract to lower low end torque. The only thing it can do is increase power or do nothing but it can't lower it. Only certain exhaust mods can lower low end torque and that's more rare than you think.

princelybug

iTrader: (16)

It's not worth it.

thisaznboi88

iTrader: (7)

Thanks for the reply. I reset the ecu and now the car feels about the same. Removing the intake resonator didn't do smack for increasing sound. ON my I4 accord it make it deep and growly. One the V6 is still quiet as night.

Bender

Correct. In fact I didn't notice anything. But just sleep well knowing your car can breath better.

pimpin-tl

This is not correct. As many intake systems have been tested on the Z cars and other cars I have seen, that when at low rpms, the intake system will cause a car to lose power on the low end and dynos have proven this. Due to turbulence in the intake system mostly. As many notice going from a stock intake to a aftermarket your car feels a bit slower off the line, or not as quick, till the rpms climb some.

Many vendors on my350z have tested this and it's a known fact. It happens on other cars as well.

I hate cars

Now you're flat out annoying. Get an education!

Is is physically impossible for a car to lose power due to a decrease in restriction on the intake side of the throttlebody. Impossible. If this were true, flooring the throttle would cause you to lose power since the throttlebody is the largest restriction. Does this turbulence somehow get better at wide open and high rpms when airflow is at it's highest? You contradict yourself over and over in these threads. Just sit back and read until you have a basic understanding of these things.

CSWBiggs

go to library...

get books...Fluid-dynamics...thermo-dynamics...

digest...

shut-up...

there are "laws" that state what happens to matter in certain conditions...

Thank You

-Jason

Bender

Lmao, you don't see fighter jets with restricted intakes do you?

pimpin-tl

Turbulent airflow causes loss of power when the MAF can not read the a/f correctly. This is the reason for the baffles in the stock airbox. And yes the turbulence straightens itself out at higher rpms. www.my350z.com for more info and education that you obviously need.

Do you have PROOF that it doesn't?

http://www.cobbtuning.com/info/?ID=3223

Teach yourself something.

"Turbulence
In order to accurately measure the amount of air coming into the system, it is important for the air to flow smoothly across the MAF sensor. Any turbulence in this air flow will create errors in the amount of air measured versus what is actually entering the system.

In the factory air box, the Subaru engineers utilizes a smooth velocity stack style inlet and internal ribbing on the inner sections of the cases to dampen pressure waves and promote a laminar air flow into the MAF sensor housing. The MAF sensor housing itself is straight and smooth internally and positions the sensing portion of the MAF sensor properly in the air flow stream (ie: not offset to any angle left/right or up/down).

For aftermarket intake systems, turbulence across the MAF sensor is an all too common occurrence. Often times the MAF sensor is placed in close proximity to a bend, pipe joint, or weld. In the case of some hot air intakes (ie: Short Ram), the MAF sensor is mounted directly after a conical intake -- well before the air has a chance to smooth out.

When this turbulence occurs, the MAF sensor will suddenly see more or less air then it had previously. This will cause the engine management system to respond by making the engine run leaner or richer for as long as the error from turbulence occurs. The most noticeable driving characteristic associated with this would be a hesitation or flat-spot in the engine's power deliver. A worse case scenario would be the engine suddenly leaning out while under full throttle that resulted in engine damage.

Unlike the errors created by the different size of piping, there are no corrections one can make for an intake design that allows turbulence across the MAF sensor."

pimpin-tl

Since the forum wont let me post links to this other site, I will copy and paste here.

"In the most simplest form the narrower the runner the higher the velocity which in turn allows better filling of the cylinders at lower rpms, thus producing more power lower in the power band. Also, the narrower the runner the maximum air flow is reduced (if you could imagine breathing through a straw.)

So, which just this basic knowledge of IM tuning you could see how a after market IM with fatter runners would cause you to "lose power", albeit relatively speaking. You are essentially dropping you power numbers in the low to mid range to achieve higher power in the top rpm range. So if you cannot benefit from a higher rpm range you are not benefiting from a fatter runner IM.

Now, if you want more it gets much much more complicated then this. Runner length effects the timing of the velocity of air relative to the opening of the intake valve. To better understand this we need to understand that air actually has acoustic properties like that of a spring, and the air travelling through the IM has pulses(frequency) like that of a spring. This is referred to as a spring-mass system.

To better put this, the air actually compresses and expands inside the intake system causing a oscillation exactly like that of a spring.

When a piston is forced down from combustion it causes a depression in the cylinder ( negative pressure, vacuum). So our most basic filling of a cylinder is cause from this vacuum and the movement of higher pressure to lower pressure. Now, when the intake valve closes it causes the air still travelling down the runners to slam into the back of the intake valve. Now this air has to go somewhere, so the energy of the travelling air causes it to first compress against the valve. Then since the valve is going to exert an equal force the air effectively rebounds and goes back up the intake runner, thus producing our frequency.

Note that the higher the rpm the more energy, inertia, the travelling air has which in turn causes a more rapid compression and rebound giving a higher acoustic frequency, which now you may be able to see why depending on desired power curve we must tune the runner length. If the runner length is still hard to grasp keep reading and i will show you how by using this oscillating energy we can effectively add boost to the intake air charge.

So now the cam comes into the picture. While lift does have an effect on the velocity/volume of the air being delivered to the cylinder we are only going to look at duration and a little bit of phasing. Now that we know there is actually energized air oscillating in our intake system the final consideration is the intake valve. If we can match this frequency with the opening of the intake valve we can use the rebound of the air bouncing off the plenum back down the intake runner and help aid in cylinder filling. Now not only do we have the normal movement of high pressure to low pressure caused by cylinder combustion, we are adding to that with the oscillating energy caused by the air compressing and rebounding between the plenum and the back of the intake valve. This is effectively boosting our incoming intake charge and allowing us to put more air in the cylinder then just the piston sweep vacuum, allowing us to achieve greater then 100% volumetric efficiency, just like a forced induction system.

So to recap: Runner diameter effects the velocity and volume of air being delivered to the cylinder. Runner length effects where the oscillating air is going to be when the intake valve opens. If tuned properly the oscillating charge will be right back at the intake valve when it opens adding a pushing of air in to the cylinder on top of the sucking of air caused by vacuum.

Now with this basic understanding we can see how we "lose power" with an after market IM. These manifolds are built to deliver power in the upper rpm lvls with short fatter runners. When we optimize a runner we must do so at a certain frequency, which is pretty much directly related to rpm. With a runner set for a certain rpm we lose out on everything else outside of this picture, which is why we see dual runner intake systems which allow us to benefit from 2 different runner designs, given a broader more streetable power curve. Also note the fatter runner just makes sure we can supply the amount of air needed at that rpm, while making air velocity less at lower rpm range also negatively effecting cylinder filling.

Just to add to the complication all this is regarding a one cylinder application. More variables become apparent when we add 3 more cylinders to the picture. Now, just like exhaust header design we can not only sync the oscillation of one runner we can have 2 or more sync'd to add even more positive pressure to the charge. Granted, we can have the reverse effect with improper tuning, having one runner creating a negative pressure on another via the plenum while both of them need to have positive pressure going towards the intake valve...."

I hate cars

I'm headed to a meeting so I have one second to reply.


THE TL DOES NOT HAVE A MAF IDIOT.