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View Full Version : K&N filter system - did I do my math right?



keithshotrodshop
February 10th, 2007, 12:57 PM
Looking at a K&N Filter system for my Silverado - which costs $269.00. The website and several boards claim about a 2mpg increase with this kit. My truck currently gets 10mpg, so...

Before I put the system on, I burn 700 gallons of fuel in 7000 miles.

With the new system, I burn 583 gallons of fuel in 7000 miles (hopefully!).

Figuring the cost of gas around $2.25 a gallon for the 117 gallons saved = $263.00 in savings

That means that I will not see a return on my investment until after 7000 miles, and I will be approaching the time when the filter needs a recharge, which runs about 30 bucks.

This just doesn't sound like it's all that worth it, what do you think?

lgottler
February 10th, 2007, 01:34 PM
Recharge is simply some oil you spray on it. I have some from the first K&N I put on. Unless you run dusty areas, you shouldn't have to clean it but once 50,000 miles....and then you just wash it, dry it, oil it. You can borrow some of my oil if you want.....

joe_jeep
February 10th, 2007, 02:14 PM
k&n filters should be cleaned every 40,000 to 60,000 miles.
and a k&n recharge kits cost about 15 bucks last time i bought one and it will clean the filter 2 or 3 times. so no the math was slightly flawed. and i think 2 mpg increase is a little high expectation. mabey one mpg is possible. i got my k&n fipk kit totally covered in mud at the first doa. and talked to k&n about this they said no matter how dirty it looks its fine.
cleaning more than once a year would be dumb, even in the harshest conditions. i did like the k&n fipk system, good throttle response, nice sound, works pretty well.

keithshotrodshop
February 10th, 2007, 06:19 PM
So if I add only 1 mpg, I won't be looking at a return on my investment till over 14,000 miles! Probably not worth it.

lgottler
February 10th, 2007, 07:06 PM
I know with just the cheapy K&N drop in on the Suburban, I went from 7mpg to 9mpg towing up to Canada. Could be weather, humidity, speed etc... but something changed.

keithshotrodshop
February 10th, 2007, 11:11 PM
Could it be that the old filter was plugged? I picked up about 1mpg when I put a new stock one into my truck, so I am really leery as to how much I'll actually pick up with the K&N. I guess I could always try the drop in one first, and upgrade to the kit later if the drop in seems to make a difference.

lgottler
February 10th, 2007, 11:14 PM
Yeah, the filter that was in there was clean, I was just grasping at straws really, anything to get a mile or two better!

RockyTop
February 11th, 2007, 12:25 AM
K&N's have helped my 2002 and current 2004 Explorer to shift better. Also, the paper filters were black after 3000 miles. I swapped them when I got the 2004. I have a recharger as well. I've cleaned it twice since I bought it.

joe_jeep
February 11th, 2007, 02:13 AM
perhaps you could look at it as a slight performance upgrade.
and you only need to clean it every 50,000 miles or so, and you only buy it once, normally you would buy a factory style filter at least once a year. not to mention your not taking up land fill space and helping the environment. think about the tree not cut down to make your paper filter???i think its a wise investment on many levels.

keithshotrodshop
February 11th, 2007, 12:24 PM
So, do you guys think my better investment would be to get the 35 dollar drop in filter instead of the complete system? That's kinda what I am leaning towards.

joe_jeep
February 11th, 2007, 01:31 PM
i think the syastems work pretty well. but if money is the limiting factor the get the drop in.

RockyTop
February 11th, 2007, 02:07 PM
the Systems are great, I have only owned the "drop in's".

keithshotrodshop
February 11th, 2007, 11:14 PM
Money is not a factor with this, I just don't want to end up wasting money.

keithshotrodshop
February 12th, 2007, 11:48 PM
Ended up ordering the full system today. I possilbly will do a writeup on the affects, and the install.

So far, I think I'll calculate mileage 3 times and take the average.

I think I might also check the 0-60 time

Then I'll do it all again with the new system installed.



Do you think I should do the 0-60 with or without a loaded trailer behind me, since it is my tow rig?

joe_jeep
February 13th, 2007, 03:25 AM
i dont know about 0 to 60 times?? i do know when i did my system i had 33 inch tires and 3.07 gears. my truck would fall on its face even in 4th gear on the hiway. bout 65 was max spd! forget 5th at all! once i did the system it ran pretty good in 4th, and as long as the land was flat and was no head wind, i could even run 5th gear a little. could go as fast as i would dare go in 4th gear (33 in swampers and no front sway bar), no problem up to 80 mph. sure felt different! its not a big horsepower difference im sure(mabey 10hp tops). made a world of difference in my jeep with the wrong gears.
now with 4.56 gears, lockers, and 35's it runs sweet! can top out the top speed limiter no problem! sounds good too. i have a header, a cat back system, empty convertor, k&n fipk system, helix power tower tbi spacer, and a jet stage2 chip. it dont sound like alot but it will light up some 35's like you wont believe.
i cant imagine needing more power than this. wanting a v8 and more power sure. but needing it no! the k&n fipk kit was the biggest improvement ive seen in this motor. the factory air box is pretty restrictive!

keithshotrodshop
February 13th, 2007, 09:50 AM
I just want to take a scientific approach to the benifits of the system, and it is one of the ways I should be able to accurately measure improvement. The web is full of great testimonies such as yours, but in the long run they only come down to being a seat of pants measurment. I too have run K&N systems on other vehicles in the past, and have "felt" an improvement. But I am forced to wonder if I only "felt" that improvement because my wallet was lighter! This time I am going to test it out and find out if there really is a change.

RockyTop
February 13th, 2007, 10:11 AM
<div class='quotetop'>QUOTE(keithshotrodshop &#064; Feb 13 2007, 08&#58;50 AM) 22505</div>
I just want to take a scientific approach to the benifits of the system, and it is one of the ways I should be able to accurately measure improvement. The web is full of great testimonies such as yours, but in the long run they only come down to being a seat of pants measurment. I too have run K&N systems on other vehicles in the past, and have "felt" an improvement. But I am forced to wonder if I only "felt" that improvement because my wallet was lighter&#33; This time I am going to test it out and find out if there really is a change. [/b]



It isn&#39;t a "snake oil" if that is what you mean. Unlike most products "claiming better performance", K&N&#39;s are one of the few that deliver on their promise.

keithshotrodshop
February 13th, 2007, 06:35 PM
I&#39;ve had that feeling in the past, and have always been happy with K&N. I just wonder if their credit is really due. Nobody seems to want to take any sort of testing approach to their products. Every other part in the world they usually do dyno tests and all sorts of other stuff. K&N is claiming 28 horsepower and approx 2mpg better mileage. I just want to find out if they are full of it, or legit.

Part of my question is that if K&N truely makes more power and milage, how come the auto manufacturers don&#39;t run them from the factory?

lgottler
February 13th, 2007, 08:07 PM
Because on my TJ, after a dusty run, the intake tube had dirt in it.....after the filter&#33;&#33;

Roadhouse
February 13th, 2007, 10:24 PM
<div class='quotetop'>QUOTE(lgottler &#064; Feb 13 2007, 07&#58;07 PM) 22518</div>

Because on my TJ, after a dusty run, the intake tube had dirt in it.....after the filter&#33;&#33;
[/b]


with a K & N?

Jarhead
February 14th, 2007, 07:26 AM
<div class='quotetop'>QUOTE(keithshotrodshop &#064; Feb 13 2007, 05&#58;35 PM) 22515</div>

Part of my question is that if K&N truely makes more power and milage, how come the auto manufacturers don&#39;t run them from the factory?
[/b]
Asked and Answered. The Big 3 are not interested in our ability to get better gas mileage. There have been significant improvements in many, many areas (tires, paint, intermal combustion, etc.) that the Automakers claim are to costly to make available on every vehicle. The aftermarket exists because the automakers dial back and limit the true abilities of any vehicle in the interest of long term non warranty claims or issues. The military does the same thing with all the vehicles they utilize. If I run a vehicle at its peak performance it will wear down or break more frequently than if I dial it back and allow a safety margin that provides performance yet provides a reasonable degree of no work or warranty concerns.
K&N?
Cat-Back?
SuperChip?
The Service Parts and Operations leg of General Motors has gotten more involved in offering aftermarket components at the Dealership level in the last few years. It works a little different at each dealership, but they all have the ability of purchasing and installing the aftermarket accessories. The advantage of having the dealership install the aftermarket accessories is you get to have the cost of the aftermarket accessories rolled into the purchase price, plus they are covered by the very same warranty.

keithshotrodshop
February 14th, 2007, 10:02 AM
I am very familiar with the engineered suicide points (GM term, not mine, when I was attending the GM ASEP Program) of vehicles. However I disagree that the manufacturers don&#39;t want to get better mileage. They are penalized monetarily if they don&#39;t meet certain requirements, and get tax breaks if they get better mileage than is required. It is fully in the manufacturers benifit to get the best milage and power out of their vehicle as possilble. Sure, they want the thing to rust out in 9 years (GM&#39;s target point for having a vehicle go to hell) but in the meantime they want it to run as efficiantly as possible, at least till it drives off the lot.

95geo
February 14th, 2007, 01:12 PM
<div class='quotetop'>QUOTE(keithshotrodshop &#064; Feb 14 2007, 09&#58;02 AM) 22522</div>

However I disagree that the manufacturers don&#39;t want to get better mileage.
[/b]

you are correct keith, havent you guys ever heard of CAFE numbers? combined average fuel economy, its a big deal to the EPA

everything is a factor and you have to balance it all out.

on another note, i call bull**** on almost all of k&n&#39;s numbers. the one increase you will see is more air flow because the flow of the filter goes up, theres 2 ways to do this. one is create more surface area with the same micron filtering capacity or the other is to reduce its filtering ability and keeping the size the same (a drop in). i wouldnt meess with the intake/filter personally. i&#39;d rather the least amount of dirt go through my engine as possible.

i run 2x the actual stock horse power in my pickup and its through the factory box/filter.

exhaust will help more than an intake will unless the intake was designed like crap from the beginning.

lgottler
February 14th, 2007, 01:13 PM
<div class='quotetop'>QUOTE(Roadhouse &#064; Feb 13 2007, 09&#58;24 PM) 22519</div>

<div class='quotetop'>QUOTE(lgottler &#064; Feb 13 2007, 07&#58;07 PM) 22518

Because on my TJ, after a dusty run, the intake tube had dirt in it.....after the filter&#33;&#33;
[/b]


with a K & N?
[/b][/quote]

Yup, in dusty conditions you are supposed to use a Prefilter, I think K&N sells one actually. If I ever plan on running in dust, a vacuume cleaner foam thing will fit over my snorkle tower, thats my plan.

WhiteRhino
February 14th, 2007, 02:12 PM
I run the K&N prefilter on my drop in 14" K&N. It catches a ton of dust&#33; Wouldn&#39;t run without it. I have never had any dust get past my filter. But I keep it cleaned and oiled pretty well. I have no input on performance since I put it on the motor when it was installed.

As far as auto makers wanting improved mileage, I also believe they do. But they also have to weigh the improvement versus expense. Look at the splitfire spark plugs. Some say they work, others say they don&#39;t. But, if they gave enough improvement, I would be they would be standard issue. Unless......... they cost too much for the improvement they provide.

Jim M. was just discussing with me a couple weeks ago about an improvement on fuel savings on the new VortecMax 6 litre displacement on demand engine. They don&#39;t convert to 4 cylinders at idle because of vibrations. They have a vibration dampener but it would not give a good enough return on the investment. So they leave it out.

MuddyPaws
February 14th, 2007, 09:23 PM
Do the searches and read the research data. How does any filter like this flow better? By having bigger holes to let the air in. What comes in the bigger holes with the air? Bigger pieces of dirt.

I can&#39;t remember the university but somewhere like MIT has a whole scientific check of something like 30 different filters and the K&N scored very low on the particulat filteration test. Yes it flowed better then some, but let lots of dirt in.

This was not a Fram test, it was a objective test.

Food for thought.

<div class='quotetop'>QUOTE(WhiteRhino &#064; Feb 14 2007, 01&#58;12 PM) 22536</div>

As far as auto makers wanting improved mileage, I also believe they do. But they also have to weigh the improvement versus expense. Look at the splitfire spark plugs. Some say they work, others say they don&#39;t. But, if they gave enough improvement, I would be they would be standard issue. Unless......... they cost too much for the improvement they provide.
[/b]


Look at the new vehicle warranties...Split Fire plugs void almost every new vehicle engine warranty. It says so in the fine print. I know when I was with Mazda, we had a TSB and a dealer message out about this. Ford also had the same TSB and message out when I was with them.

WhiteRhino
February 14th, 2007, 10:48 PM
<div class='quotetop'>QUOTE(MuddyPaws &#064; Feb 14 2007, 08&#58;23 PM) 22555</div>

Do the searches and read the research data. How does any filter like this flow better? By having bigger holes to let the air in. What comes in the bigger holes with the air? Bigger pieces of dirt.

I can&#39;t remember the university but somewhere like MIT has a whole scientific check of something like 30 different filters and the K&N scored very low on the particulat filteration test. Yes it flowed better then some, but let lots of dirt in.

This was not a Fram test, it was a objective test.

Food for thought.

<div class='quotetop'>QUOTE(WhiteRhino &#064; Feb 14 2007, 01&#58;12 PM) 22536

As far as auto makers wanting improved mileage, I also believe they do. But they also have to weigh the improvement versus expense. Look at the splitfire spark plugs. Some say they work, others say they don&#39;t. But, if they gave enough improvement, I would be they would be standard issue. Unless......... they cost too much for the improvement they provide.
[/b]


Look at the new vehicle warranties...Split Fire plugs void almost every new vehicle engine warranty. It says so in the fine print. I know when I was with Mazda, we had a TSB and a dealer message out about this. Ford also had the same TSB and message out when I was with them.
[/b][/quote]

Did anyone ever give you a reason?

keithshotrodshop
February 15th, 2007, 12:36 AM
I don&#39;t know about the splitfires, but when I was working at the Chevy dealer back in 98, Slick 50 was in the vogue, and it voided your warranty with GM if you used it. It&#39;s been awhile, but I seem to remember a bulletin that quoted something like "Laboratory tests have shown that Slick 50, when mixed with certain synthetic oils, causes premature sludge buildup, and oil pump failure." Don&#39;t know if it was hype, but I know the voiding the warranty part was real.

MuddyPaws
February 15th, 2007, 10:24 PM
Did anyone ever give you a reason?
[/b]

Reason was a higher tendency for preignition and holes in the tops of the pistons.

WhiteRhino
February 16th, 2007, 09:48 AM
<div class='quotetop'>QUOTE(MuddyPaws &#064; Feb 15 2007, 09&#58;24 PM) 22576</div>


Did anyone ever give you a reason?
[/b]

Reason was a higher tendency for preignition and holes in the tops of the pistons.
[/b]

Okay...............

Not argueing here.......... :lmao: ....... but isn&#39;t preignition a condition of octane and compression ratio. A spark plug would only effect ignition due to timing???????????

MuddyPaws
February 16th, 2007, 10:04 AM
The reports said that a split fire plug ran "hotter" in the cylinder. Yes timing and octane play in that equasion but the problem was people not moving to higher octane fuel and only putting the new plugs in. Spark knock started and the computer did not have the ability to retart the timing enough to get rid of it, or if it did have the ability to retard the timing enough then performance and fuel economy suffered drasticly.

ganz
February 16th, 2007, 12:54 PM
Ok, Im putting my 2 cents worth in. for whats it worth.
I raced Short course off road race cars for 10 years and if your going to see dirt it would be in a pack of 20 to 25 cars at speeds of 20 to 100 mph.
i ran a K&N filter on my car. without any issues. when i did find dirt in the intake it could be traced to a point usealy near the mount surface.
I agree that the K&N filter is not as good as OEM for filtering in its store bought condition. but under the extreme conditions found in the off road area you really should have a PRE FILTER. usally made of foam that is oiled. also the proper care of the K&N its self is important. cleaning and reoiling. also the seal at the mounting surfaces. i used a foam oil filter oil made by Bel-Ray industrys and a white litho grease to seal the surfaces. had good luck with it.
Anyone who has a or has owned a dirt bike/ ATV, knows the type of filter and the maintance that is involved with the air filer. why not take care of the filter on your trail rigs the same way?

My 2 Cents?
Ganz.......

Creative Fab
February 16th, 2007, 07:45 PM
<div class='quotetop'>QUOTE(ganz &#064; Feb 16 2007, 11&#58;54 AM) 22597</div>

Ok, Im putting my 2 cents worth in. for whats it worth.
I raced Short course off road race cars for 10 years and if your going to see dirt it would be in a pack of 20 to 25 cars at speeds of 20 to 100 mph.
i ran a K&N filter on my car. without any issues. when i did find dirt in the intake it could be traced to a point usealy near the mount surface.
I agree that the K&N filter is not as good as OEM for filtering in its store bought condition. but under the extreme conditions found in the off road area you really should have a PRE FILTER. usally made of foam that is oiled. also the proper care of the K&N its self is important. cleaning and reoiling. also the seal at the mounting surfaces. i used a foam oil filter oil made by Bel-Ray industrys and a white litho grease to seal the surfaces. had good luck with it.
Anyone who has a or has owned a dirt bike/ ATV, knows the type of filter and the maintance that is involved with the air filer. why not take care of the filter on your trail rigs the same way?

My 2 Cents?
Ganz.......
[/b]

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