K & N Air Filters

[camlex]

Hello,

I just ordered K & N filter from O' reaily for $44.00.

Will I see any improvements in performance?

Thanks,

[amf1932]

Hello,

I just ordered K & N filter from O' reaily for $44.00.

Will I see any improvements in performance?

Thanks,

←

Only in your mind.

[ford212.809]

I didn't "notice" a performance difference with the K & N's that I have

owned in the past. However, they are nice in the fact that with proper care

that you will NEVER have to buy another air filter for that car. ;)

[camlex]

Hello,

Buying filter and replacing them isn't that hard task. After i bought, I was also thinking it's doesn't matter which filter you have, because MAF control the % of flow.

Am i thinking right? Please correct me.

Thanks,

[lexusk8]

Be cautious about purchasing your K&N filter. I installed one long ago in my '01 ES, and about 15,000 miles later, that led to a malfunctioned IAC valve and a dirty throttle body, causing startup failures and low idles. Had to ditch the K&N filter soon afterwards as that unfortunately allowed more air and dust particles to flow into the intake and the TB

[SKperformance]

I don;t think you iacv and tb problems where caused by the filter but the normal way the engien does it to everyone.

[steviej]

I have to concur with SK.

Doug, I tend to think you may have had a coincedence and the K&N was the most likely candidate for blame. But one will never know.

I had one in my SSEi for almost 75k miles before selling and never a problem (washed and reoiled 2 times).

I have had one in my ES for over 40k miles now and no problems (even after the first wash and reoil).

The key to the oiled filters is the washing and re-oiling.

The savings will be in the lack of yearly replacement of the standard filter but only if you extend this to over 5 years of replacements. Any gas savings varies greatly between users.

As for performance as in increased pickup or hp............none here.

steviej

[Lexusfreak]

I have to concur with SK.

Doug, I tend to think you may have had a coincedence and the K&N was the most likely candidate for blame.  But one will never know.

I had one in my SSEi for almost 75k miles before selling and never a problem (washed and reoiled 2 times).

I have had one in my ES for over 40k miles now and no problems (even after the first wash and reoil).

The key to the oiled filters is the washing and re-oiling. 

The savings will be in the lack of yearly replacement of the standard filter but only if you extend this to over 5 years of replacements.  Any gas savings varies greatly between users.

As for performance as in increased pickup or hp............none here.

steviej

←

Agreed sk & steviej! B) I noticed about a 1 - 2% increase in fuel economy but hardly anything to write home about. Never had a problem with any of my K & N filters I had for my last 3 vehicles & I'd buy one again. ;)

[jragosta]

Hello,

I just ordered K & N filter from O' reaily for $44.00.

Will I see any improvements in performance?

Thanks,

←

This has been discussed ad nauseum. To summarize:

1. K&N filters require maintenance - cleaning and oiling them. A little too much oil and you can damage your engine. A little too low and you will not be getting good filtration - and risk damaging your engine.

2. K&N makes claims that their filter is 'better' than OEM filters. Unfortunately, the test they're using is the wrong test. They measure dirt holding capacity - which is rarely an issue. They specifically fail to measure filtration efficiency as a function of particle size. By its nature, the K&N filter is likely to allow many small particles to get through.

3. In principle, a K&N filter will give you less pressure drop and therefore more air flow into the engine. That allows your engine computer to use more fuel to maintain the same ratio when you really need the power. You can therefore expect SOME increase in horsepower. However, unless you're on a drag strip using a digital timer, you won't notice it. In real life, the difference is miniscule.

4. Replacing OEM filters on a normal replacement schedule isn't that expensive.

5. If you are living in very dusty conditions where you'd have to replace OEM filters more frequently, it might be tempting to use K&N for cost savings - but don't. Those are precisely the conditions where you don't want particles getting past the air filter.

Bottom line is that I would never do it. The benefit is tiny and you run the risk of ruining your engine. I realize that lots of people will tell you that they've been using K&N for years with no problems. The difficulty is that you'll rarely hear from the ones who ruined their engine to save $10. Also, the damage is likely to be long term. I would never expect a catastropic failure. Rather, you'd expect an engine to last 150 K instead of 200 K miles (or whatever). If the engine fails early, no one blames the air filter.

My credentials on filtration? Doctorate in chemistry and 7 years as VP of Technology for a filtration company.

[jragosta]

I don;t think you iacv and tb problems where caused by the filter but the normal way the engien does it to everyone.

←

This is the kind of thing I mentioned in my earlier post.

While poor filtration most certainly CAN cause throttle body and IAC valve problems, when it happens, people who buy K&N tend to immediately blame something else.

Without extensive testing you can't say for sure that the filter caused the problem, but it's equally foolish to just assume that it didn't - particularly when the failures happened shortly after installing K&N filters.

Toyota spends billions of dollars on car design - including things like filtration. Stick with what the manufacturer recommends.

[bartkat]

K&N filters are just fine as long as you clean and oil proplerly, which you don't have to do very often. I got the TRD filter for my IS300 since it's engineered for Toyota and has a really good fit. It's been on there now for 2 years. I had a K&N drop in filter on my '94 Firebird LT1 for 10 years and it was still on there when I sold the car. The very fact that you have a lower pressure drop across the filter improves the dirt holding and the filtration ability as well. I've had this type filter on 4 different cars now, with nary a problem. Add it to a good intake pipe and you will actually gain some noticeable HP.

The best way to get whatever performance or mpg gains there may be is to reset the ECU after installation, so it learns the "new" airflow right away.

[mburnickas]

Based on my old diesel truck and the sensors that failed due to oil-glazed filters, I would stay with OEM or paper. My truck had a BARO sensor go and an air temp sensor go due to these filters. Never mind the higher then normal Si levels in oil tests.

Went back to paper and had zero issue (in all area). Stayed with paper since then. Now my bike is a different animal plus I had benchmarked the levels. No sensors either!

[amf1932]

The very fact that you have a lower pressure drop across the filter improves the dirt holding and the filtration ability as well. 

←

I would assume that a lower pressure drop has absolutely nothing to do with the filtration efficiency. So, I consider this statement incorrect! <_<

[bartkat]

The very fact that you have a lower pressure drop across the filter improves the dirt holding and the filtration ability as well. 

←

I would assume that a lower pressure drop has absolutely nothing to do with the filtration efficiency. So, I consider this statement incorrect! <_<

←

Why would you assume that?

[amf1932]

Any kind of filter creates a restriction to the flow of either air or liquids in a system, therefore a filter that creates less of a pressure drop will not filter as well.

When a filter is designed the amount of restriction is taken into consideration and other factors in this chain are adjusted to work in a satisfactory manner, ie: fuel - air mixture.

I would say, the more pressure drop, the more the filtration.

[bartkat]

Any kind of filter creates a restriction to the flow of either air or liquids in a system, therefore a filter that creates less of a pressure drop will not filter as well.

When a filter is designed the amount of restriction is taken into consideration and other factors in this chain are adjusted to work in a satisfactory manner, ie: fuel - air mixture.

I would say, the more pressure drop, the more the filtration.

←

You left out the effective filter area. Start with a media of the same porosity, and make one filter with deeper pleats, and more area, and you get less pressure drop. Higher pressures, will sooner or later result from filter blinding, and particles will be pushed or pulled through the filter. The wider area filter will go much longer before it starts to blind, therefore making it more efficient. If you check, you'll find that K&N, and others of that type have more filter area via more depth of media plus a bigger filter area. That's how you get the lower DP in the beginning and how you also have a lower DP after the same amount of use.

[amf1932]

OK, then to cut this short.....you continue using your aftermarket filter, and I'll continue using an OEM filter. I sorta trust what the engineers at Toyota figured what would be the best balance in air filtration. :)

[camlex]

Hello,

Is any filters (Toyota or After markets)mention how many micron bag(Paper) they use. Either your Delta P is small or big, MAF controls how much air needs to burns fuel correctly.

Please correct me if i am wrong.

Thanks,

[bartkat]

OK, then to cut this short.....you continue using your aftermarket filter, and I'll continue using an OEM filter. I sorta trust what the engineers at Toyota figured what would be the best balance in air filtration.  :)

←

I do hope you understand the concept of filtration, filter area, porosity, and pressure drop now, at any rate.

I'm not trying to sell you or anyone else on anything, but after 35 years working with and doing research on improved filtration, I don't take it kindly when someone tells me I don't know what I'm talking about.

[jragosta]

The very fact that you have a lower pressure drop across the filter improves the dirt holding and the filtration ability as well. 

←

I would assume that a lower pressure drop has absolutely nothing to do with the filtration efficiency. So, I consider this statement incorrect! <_<

←

The statement is incorrect, but not exactly for the reason you stated. First, be careful not to confuse dirt holding capacity with filtration efficiency. They're very different concepts. That's one of the things K&N uses to mislead people.

There is a relationship between filtration efficiency and pressure drop, but it has a lot of other variables and is not something that can easily be used by the layman.

[jragosta]

Any kind of filter creates a restriction to the flow of either air or liquids in a system, therefore a filter that creates less of a pressure drop will not filter as well.

When a filter is designed the amount of restriction is taken into consideration and other factors in this chain are adjusted to work in a satisfactory manner, ie: fuel - air mixture.

I would say, the more pressure drop, the more the filtration.

←

You'd be wrong.

There is a relationship between filtration efficiency and pressure drop but it's not anywhere near as simple as you're making it. It's also a time-dependent equation. Before trying to define the relationship, you need to consider:

1. Filter area

2. Fluid flow per unit area

3. Viscosity

4. Flter pore size distribution (a filter usually does not have a single pore size)

5. Contaminant particle size distribution

6. How heavily loaded the filter is (under some scenarios the pressure drop increases quickly, in others, the pressure drop increases slowy)

7. Time

8. Concentration of contamnants

And many more

Believe me - I use to do this for a living. Filtration is not as simple as everyone's trying to make it out to be.

[jragosta]

Hello,

Is any filters (Toyota or After markets)mention how many micron bag(Paper) they use. Either your Delta P is small or big, MAF controls how much air needs to burns fuel correctly.

Please correct me if i am wrong.

Thanks,

←

Can you please write that in English?

[Lexusfreak]

OK, then to cut this short.....you continue using your aftermarket filter, and I'll continue using an OEM filter. I sorta trust what the engineers at Toyota figured what would be the best balance in air filtration.  :)

←

Dosen't Toyota (TRD) also offer a K & N type of re-usable air filter? B) ;) You can check it out at www.trdusa.com :whistles: Not sure of the prices however. ;)

[amf1932]

OK, then to cut this short.....you continue using your aftermarket filter, and I'll continue using an OEM filter. I sorta trust what the engineers at Toyota figured what would be the best balance in air filtration.   :)

←

Dosen't Toyota (TRD) also offer a K & N type of re-usable air filter? B) ;) You can check it out at www.trdusa.com :whistles: Not sure of the prices however. ;)

←

The price is: $54.21 !!!

For that amount I can buy enough OEM filters to travel about 50K + miles. :D

[timothy]

Good info here. My 2004 es gets the air filter from the dealer. I'm sick of working on cars, let the dealer do it. If I pay more, oh well. My Lexus dealer has been very good so far. Very happy with the car and service.

Timothy