K&N Air Filter...worth the extra $$??..necessary??

[billhv]

l was thinking about getting this filter,
then yesterday l was told my truck already
has a high capacity air filter in the stock
model w/the 3500 series & the K&N wouldn't make any difference; only help in 2500 series
trucks. Dose this Gm salesman know what he's
talkin' about??, or does it actually improve
mpg, etc?? Thanx in advance, Billhv.

------------------
2002 Sierra SL Long Box 4x4 3500HD, Summit White
Duramax/Allison 5SPD Auto
Reg Cab,Fleetside dually.
Wiltsie mudflaps, Delta toolbox, Belore's 5th wheel ballhitch, GM bedliner.
Mobil 1 Delvac 5W40 SYN..
http://www.picturetrail.com/billhv
Mobil 15/50 SYN..go's in
99'XL1200C "H.D."

[SoCalDMAX]

billhv,

Salesman's full of caca. 2500's and 3500's have the same filter. Although GM thinks it's high cap., it's just a big wrinkled piece of paper. It filters out dirt very well, but doesn't flow as much air as a K&N or an Amsoil air filter.

Best bet, buy an Amsoil air filter from Greg Landuyt. It flows as much as a K&N, but filters as well as the stock filter. K&N lets thru too much dirt, BAD news for a diesel. Greg will give you great prices, including oil filters, Fumoto valve, etc.

Regards, Steve

------------------
'02 2500HD 2WD LS, grey, CC, SB, D/A, locking diff., alloys, trailer and towing pkg. Delivered 11/09/01
So far:
Bully Dog Max Power Plug, pillar mounted SPA Boost/EGT/oil press./temp gauges, CD/MP3 player, 4-6.5" component speakers, 2-10" subs,1200W of Visonik audio power, Valentine One, Invinca-shield, Bed X-tender, Line-X, Lucerix mirrors, DeeZee running boards, PIAA headlights, Husky flaps, Fumoto valve and tinted windows
Up next:
PS2000 propane, 4" exhaust, 255/85 tires, high idle, Jordan 2020 Ultima brake controller, Power Tailgate Lock, Allison deep sump, tranny oil temp., rear diff. oil temp., Mag-Hytech diff. cover, Spare fuel tank?

[billhv]

Just talked to my neighbour-he knows an Amsoil rep here in SW Ont., thanks Steve..you've refreshed my memory cause l'm
sure l've heard what you've said previously
about K&N letting in dirt w/ all that air.
Amsoil it is.
"You don't know if you don't ask"

...its 1:30 am, wife just walks in, looks
at the computer screen; "yup, just what l
figuired, the dieselpage"...lol


------------------
2002 Sierra SL Long Box 4x4 3500HD, Summit White
Duramax/Allison 5SPD Auto
Reg Cab,Fleetside dually.
Wiltsie mudflaps, Delta toolbox, Belore's 5th wheel ballhitch, GM bedliner.
Mobil 1 Delvac 5W40 SYN..
http://www.picturetrail.com/billhv
Mobil 15/50 SYN..go's in
99'XL1200C "H.D."

[DJ Max]

billhv,
Great question. As soon as I got my truck I changed to Amsoil engine oil and bought a K&N air filter thinking these were inexpensive things that I could do for my baby. Never owned a $40,000 vehicle before and thought this was the least I could do to increase perf and prolong life. Before I had a chance to install the K&N I stumbled upon this website. I quickly noticed that the vast majority were running the Amsoil filters.My K&N is still sitting here under the desk. Hate to put it in knowing that I would be better off with the Amsoil. Not that it is doing a lot under my desk. http://www.62-65-dieselpage.com/ubb/wink.gif

After three weeks of steady time on the diesel page, my wife said "what is on that site that you are ALWAYS on?" I said " knowledge Sweetie, knowledge."

[sonofagun]

Do what SoCalDMAX said.

Bob

------------------
2001 GMC 2500HD D/A olympic white, Manik SS brush guard and nerfs, Hella driving lamps, Velvet rides, HD Air Lifts and Compressor
Snugtop cover, Linex, Yakima rails on cover (mt. bikes), Amsoil 2 stage airfilter. XM Radio. ECM upgrades. One piece driveshaft,43 gal
across the bed aux. tank.
--------
1966 Chevelle convertible 396 4SPD (restored)
--------------
Working on EGT/Boost guage, Mag-Hytec diff cover,4" exhaust.
Wish list: Whatever MDRAG does!
GOD BLESS AMERICA and those who walk in harms
way to protect us all!!
http://www.PictureTrail.com/gallery/view?username=sonofagun

[xwing]

I use K&N filters on all my vehicles, including my 2001 DMax. It improved the quartermile performance by about .2 sec/1.2mph vs. stock airfilter.

There are claims of Amsoil filtering better, but if filtration was the only factor, then putting something so restrictive NO air or particles got in at ALL would be best; sure, NO hp but MOST important no dust??

I just don't believe K&N lets in significantly filthier air than Amsoil. I even saw a Japanese website testing around 8 different air filters, they showed pictures of the dirt let through of each, and rated flow. K&N had the best flow, and was around tied with one other for cleanest filtration.

I'm sure Amsoil's filter keeps out dirt; I am just as sure that K&N's does. Sounds like these companies don't want to get into battles with each other, but to find out their position I sent K&N a letter today about this, and they sent me a letter back the same day:
--------------------------------------------
Dear customer,
You nailed it...they SELL Amsoil. It is in their best interest to make
more money. Amsoil is sold like Avon and Amway, do you really want parts
for your car or truck that are not available from a regular auto parts store
or dealership? We do not actively show comparisons against our competitors.
You only do that when you have something to worry about, why give them the
free press? Lastly, I have heard from a converted Amsoil dealer that the
Amsoil "tests" of a K&N are made up, nothing more than a spread sheet; no
actual tests results are there!
Our filters are tested by an outside, independent laboratory. They
have been proven to stop at least 99% of particles on a SAE dust test. This
test uses particles as low as the 0 - 5 micron range and goes up to 20
microns. For comparison, a paper filter also stops 99% on the same test and
the OEM minimum standard is 96%. Foam is generally the worst media with a
typical efficiency rating of 75 - 85%. To get higher ratings, the foam must
be more dense and therefore way more restrictive. The "tack" characteristic
of a K&N allows for increase filtration without loss of flow as well.
The testing procedure used is SAE J-726 using ISO Test Dust. This test
is the standard of the air filter industry. The test procedure consists of
flowing air through the filter at a constant rate (airflow rate is
determined by the application) while feeding test dust into the air stream
at a rate of 1 gram per cubic meter of air.
As the filter loads with dust the pressure drop across the filter is
increased to maintain the prescribed airflow rate. The test is continued
until the pressure drop increases 10" H2O above the initial restriction of
the clean element (in this case .78" to 10.78" H2O). At this point the test
is terminated. The dirty filter element is then weighed. This weight is
compared to the clean element weight to determine the total Dust Capacity.
The amount of dust retained by the filter is divided by the total amount of
dust fed during the test to determine the Cumulative Efficiency.
The K&N filter achieved the following results:

Dust Capacity: 305 grams

K&N Cumulative Efficiency: 99.05 %

Holding the filter to the light is useless, pin holes are normal. That
is what makes a K&N filter. There are actually hundreds of microscopic
fibers that cross these holes and when treated with oil, capture and hold
the very fine particles. On the same hand, they allow the filter to flow
more air than paper or foam. The filter is 4 ply cotton gauze unlike some
competitors synthetic material filters. The synthetics do not have the very
small fibers that natural cotton does. Also, the oil can be pulled off of a
foam filter contaminating electronic sensors. It will absorb into cotton
and stay in the media.
We got started over 30 years ago making filters for motorcycles and off
road racers. The filters did so well that these guys wanted them for their
cars and trucks. We started making filters for these applications and here
we are today. If they did not work, we would not still be here and growing
every year.
We now make filters for Chrysler/Mopar, Ford Motorsports, Edelbrock,
Rotax Engines, and Harley Davidson. We come as original equipment on the
2000 Ford Mustang Cobra-R. We even made filters for the Apache helicopters
used in Desert Storm because of maintenance problems with the original paper
design. If they work in these conditions they will work for you. Links to
the filtration tests are on our web site at
http://www.knfilters.com/images/factstab1.gif and
http://www.knfilters.com/images/factstab2.gif
Thanks for writing, Rick

> ----------
> From: xwing
> Sent: Wednesday, January 09, 2002 4:06 PM
> To: tech@knfilters.com
> Subject: K&N vs. Amsoil Filters
> Dear K&N:
> I have used K&N Filters for many years in my street and raced vehicles, and I like your product.
> I would like you to give me some DATA showing the filtration and flow
> efficiency/quality between a K&N filter, and an Amsoil filter of the same application.
> Reason: on The Diesel Page website, for GM diesel trucks mainly, there are
> people who sell Amsoil and claim that K&N filters filter poorly compared to
> Amsoil, and so they convince others to buy Amsoil instead of K&N. I know
> you are a big company and have alot of data, so would appreciate some
> information to carry back to these people to show whatever differences there may ACTUALLY be.
> I have posted results on my Duramax diesel GMC Sierra, showing the K&N
> improved the quartermile from 16.71 @ 79.0mph to 16.60 @ 79.8mph averaging
> 3 passes; one pass on the stock filter was an odd outlier value, so if you
> take the average of 2 passes each subtracting out the best pass from
> before/after, it went from 16.815 @ 78.15mph to 16.60 @ 79.75mph.
> When they come on and say "sure, but the K&N lets in more dirt, so don't buy
> K&N, buy Amsoil instead" I have nothing to say, and diesel people do worry
> alot about longevity, so more dirt is a big issue.
> Please give me a true test between an Amsoil and a K&N filter regarding
> filtration and flow; I see you had some "independent lab" results on your
> page.
> Thanks,
> 2001 GMC Sierra 2500HD Duramax

[Lone Eagle]

JD, I think your K&N is the same as the new small blocks use. Sell it to someone that doesn't read this forum. Later! Lone Eagle

[xwing]

Well, that's it. I try to find data, and PROVIDE personal data on what a K&N filter does to make our trucks perform better, and yet another letter like this:

"JD, I think your K&N is the same as the new small blocks use. Sell it to someone that doesn't read this forum. Later! Lone Eagle"


I find the snobbish way some people talk about every Amsoil product under the sun as being the greatest, and everything else is for idiots who aren't "in the know", MORE AND MORE SUSPECT. Is Amsoil a cult or WHAT?

I sure don't sell anything at all. I sure give personally tested data, and try to find independent tests; and for this the actual COMPANY'S response, trying to find TRUTH.

How about we get the AMSOIL CORPORATE HEADQUARTERS response to this question within one day like K&N gave...NOT a local Amsoil dealer or their crony?

[SoCalDMAX]

xwing,

Thanks for the response you posted from K&N. I'd heard about the Apache filter story. IIRC, the military had arrived in Kuwait and was eating up turbines rapidly. They called up K&N, who whipped up the solution within a couple of weeks.

I run K&N filters on all of my gassers except the wife's beemer, it seems BMW wants all authentic everything. I was all set to get a K&N for the dmax, when I read of a dust test performed at the 2000 Diesel Page Rendezvous using the stock filter, K&N and Amsoil. IIRC, according to witnesses there, the Amsoil did measurably better at stopping the ISO test dust than the K&N.

I don't have anything against K&N and really don't think there is an amsoil cult here. Lots of people (including me) are running a variety of other oils and filters in their engines, trannies and diffs. To be totally honest, I'm using Hastings oil filters and amsoil diff lube because they meet specs and Greg gives a great discount to us members. I appreciate it, and that's the main reason I pass the info on.

I really think Lone Eagle's suggestion to sell it was directed to DJ Max (misspelled as jd) who said he had a K&N doing nothing under his desk.

Regards, Steve

------------------
'02 2500HD 2WD LS, grey, CC, SB, D/A, locking diff., alloys, trailer and towing pkg. Delivered 11/09/01
So far:
Bully Dog Max Power Plug, pillar mounted SPA Boost/EGT/oil press./temp gauges, CD/MP3 player, 4-6.5" component speakers, 2-10" subs,1200W of Visonik audio power, Valentine One, Invinca-shield, Bed X-tender, Line-X, Lucerix mirrors, DeeZee running boards, PIAA headlights, Husky flaps, Fumoto valve and tinted windows
Up next:
PS2000 propane, 4" exhaust, 255/85 tires, high idle, Jordan 2020 Ultima brake controller, Power Tailgate Lock, Allison deep sump, tranny oil temp., rear diff. oil temp., Mag-Hytech diff. cover, Spare fuel tank?

[a64pilot]

If anyone cares. The air filter was for the airconditioning system on the Apache. It did work very well. It did not replace a paper filter, there was no filter at all. The A model Apaches still have the K&N filter on their A/C system.
I too have used K&N filters on everything I have owned for the last 25 years or so. My little D***e Dakota has over 250,000 miles on it and burns no oil. IMHO the K&N filter works well as long as you keep it well oiled. The oil is what keeps it filtering ,also it's filtering ability seems to get a little better with a dirty filter. Dust will wick the oil out of the filter and the filter needs to remain wet to work.
I have no experience with the Amsoil filter.

------------------
2001 C3500 LT Charcoal Grey
CC/Longbed Putco boss boards,
virtual grill,mudflaps,sill protectors Rhino liner,
bug deflector. Looking into Boost/EGT gague

[Mic]

a64pilot,

You own one of them D***e dakota's as well?

Mines still a baby at only 220,000 miles though. (on the 318)

She drinks a little oil, but notjin too bad.

------------------

[LanduytG]

NOT a local Amsoil dealer or their crony

I guess I must fall under this category, but then again so what. 100's of my customers with the filter in question in every day use and NO complaints speaks for itself, and many are X K&N fans. If K&N does not want to give Amsoil free press then why even mention it in their response? Also go to several off road forums and see what they say about the K&N letting dirt through. If you have to use a pre filter on the K&N then you just as well keep the stock paper filter. But one good thing is we live in the good old USA and are allowed to have our opinion.

Greg

------------------
greg@lubespecialist.com
www.lubespecialist.com (http://www.lubespecialist.com)
1-888-306-4255

Greg A. Landuyt
99 VW Beetle TDI
Stock for now.
95 K2500 6.5TD
Phazer,ATS Exhaust,JK Inter Cooler,Gear Vendors, Cooling Mod, Espar Diesel Fired Engine Heater, FSD Cooler, Power Shot 2000, JK Head Light Booster, Amsoil Dual By-Pas Filter, Amsoil Fluids and Grease

[Tader Jack]

Lots of testimony and figures on whose air filter might be better. Sounds like the jury is still out unless you believe some of the "home-made" tests that have been done, I don't pay much attention to them.

I've used many filters in over 35 years of competitive racing events from dirt bikes, dirt track cars, drag racing, atv's, street bikes, trucks, cars etc., etc. I have never had an engine failure due to the filter that even remotely could have been caused by the filter. And, we have been using K&N's ever since they have been on the market. I'd put one on my Lawn Boy if they had one for it.

I also use Amsoil oil, so I happen to believe I'm using the best of both worlds. The name doesn't make the product work any better or worse, it either works or it doesn't. If I don't think it works good for me, I don't use it, period.

There are times when too much air flow is a bad thing since your engine will actually burn "more" fuel with the increased flow. I've experienced that a few times over the years. Street bikes in particular will require rejetting because of the increased flow. They make more hp and have better throttle response, but can burn as much as 1/3 more fuel than with stock jetting and filters. That may be fine on a sport bike, but on cruisers, it is not the way to go unless you want to pull into a gas station every 75 miles. The interesting thing about it, is that K&N will tell you that right up front. WE have "one" street bike that does not have a free flowing filter right now just for that reason.

I actually thought at one point that the K&N was causing my Dmax to get decreased mileage. It turned out to be weather changes and poor fuel on occasion.

So, that's my 2c worth on air filters. Let the battle begin.

Jack Schultz, McKean, PA
jackschultz@adelphia.net

http://photos.yahoo.com/bc/jack_schultz2001

2001 Chevy Silverado, 4-WD, 2500HD, Crew Cab, Short Box
LT Trim, Black Onyx w/ Tan Leather
------------------------------------------------
Beltronics 980 Radar Detector

[a64pilot]

Jack,
I would agree with everything you say except too much air causes you to burn too much fuel. You control the amount of air in a spark combustion engine with a throttle plate, therefore if the carbs are properly jetted there can not be too much air.
I too have a little experience building bikes, my current rides are a 97 CBR-1100XX and a little Suzook GS-500 that I race in WERA sportsman class.
I disagree because as long as you maintain the correct ratio (air to fuel) the same amout of fuel and air are required to make the same power, I.E. if 100 cu ft of air per min = 50 hp then that number will remain constant. These numbers are purely therotecial and come from nothing, just an example. Therotecially if you reduce restance to incoming air in a natrually aspirated engine and maintain all other variables constant you increase efficency and therefore mileage.
I would propose to you that the reason that you are seeing reduced mileage in your bikes that you are adding headers and reducing intake resistance is because you are jetting them to the correct mixture that they should have been all along. I do not doubt that your mileage is suffering.
What I am saying is that to meet EPA standards the bike manufactors are having to over lean their bikes. Everything but mileage and emmisions suffer. If you jet a stock bike properly, it will gain power, cyl head temps will drop and it will get poorer mileage.
Now how does this apply to trucks. What I am saying is that if we improved intake efficency we would see a very slight increase in mileage and a jump in horsepower output not a decrease in mileage.
Our Diesels are different from bikes in that there is no throttle plate and in this case a turbo, but the thermodynamic principles are the same.

------------------
2001 C3500 LT Charcoal Grey
CC/Longbed Putco boss boards,
virtual grill,mudflaps,sill protectors Rhino liner,
bug deflector. Looking into Boost/EGT gague

[DJ Max]

X wing, I appreciated your post. Thanks.

------------------
2001 2500hd LT cc D/A Loaded, pewter, K&N air, Amsoil, Line-x, Curt gooseneck, Access cover

[Lone Eagle]

Gee xwing! Lighten up. I was making a little joke. I guess I should have added " Ha! Ha! ". I ran K&N filters in my last two trucks and liked them both. Later! Lone Eagle

[JoeDeisel]

Amsoil still seems to be a cult thing. I have seen their phoney "tests" on the web. Until their products are marketed normally, I will avoid them.

------------------
2002 Silverado 2500HD XCab SB D/A

1982 Jeep J=20 3/4 ton, 360 V8

[xwing]

I would just like to see an independent test of K&N vs Amsoil for flow in CFM at a specified pressure drop (probably would have to use a flowbench, at a pressure drop adequate to flow around 500cfm VERIFIED by flowbench)...

and filtration efficiency also AT high flow. Filtration is more difficult to quantify and set up a true/reproducible test for. You'd have to premeasure a weight some dry dust (?flour or a black very fine powder) and find a way to suspend it in air the same way from test to test, and (unfortunately) "see" how much dust shot through onto a tacky surface. Problems abound because at those flows, who knows how much is really sticking to tacky surface, vast majority will escape undetected; maybe small particles got through but large MORE VISIBLE ones were stopped etc.

It sounds like the SAE test cited by K&N's "99.05% efficient filter" uses a premeasured weight of a specified size "dust" and they weigh the filter before and after to see how much was captured; the rest got through; giving an "efficiency percent" You'd have to have an extremely accurate scale, and be very careful about any possible unmeasured dust losses.

I'm not saying K&N filters are better or worse than Amsoil. I do have data on my truck that K&N helped performance significantly in back to back testing vs. STOCK filter. The fact that the Amsoil vs. K&N test cited on the Diesel Page says 'there is not a significant flow difference' between K&N and Stock is shown to be INaccurate by the fact that in the real world, performance was improved. This throws the REST of the "conclusions" into doubt as well...doesn't say they are WRONG, just that if the FLOW side conclusion is inaccurate, why should we suddenly trust the FILTRATION conclusion?

For instance, a "fan rated at 540cfm" is rated in OPEN AIR, NO restriction. Fans are not able to generate PRESSURE well, so putting ANY restriction on it reduces flow A LOT! THAT may be why the tester didn't think there was much flow difference between the 3 filters tested, yet in the real world the K&N significantly improved performance.

I think it is great to run scientifically designed tests to look for TRUE DIFFERENCES, but THEN ya gotta be ready for scientific scrutiny and skepticism when you draw conclusions! I don't think filtration has been adequately tested.

[xwing]

OK I found the airfilter test!
It is on the Mark 4 Supra page. The test is from 1999, a Japanese Revspeed magazine test of 5 different filters. The (1) page is the Japanese but when you click on each filter you get its results; at the TOP of each filter's section it gives in English the horsepower gain vs. stock in "PS", which equals about 1 hp; and "filtration efficiency" along with a PICTURE of the white filter so you see how much dirt passed through.

You can EASILY see differences in amount of dirt on their test; K&N came in 2nd best in filtration, and essentially they all gained 13-14hp vs. stock filter. The FOAM filter in the group is the green HKS; it had the POOREST filtration, but it flowed well.

The hp gain is similar in proportion to what I saw with my DMax truck K&N, vs. stock filter. Now if only they did Amsoil... http://www.62-65-dieselpage.com/ubb/smile.gif

http://mkiv.com/main/index.html

goto the "Tech Articles" section, then scroll down to "Cone Filters Test Results"; (1) is original Japanese with some English words too; (2) is English interpretation/critique, left out the SARD filter though (worst filtration).


[This message has been edited by xwing (edited 01-11-2002).]

[hoot]

I thought this site did some sort of article/test and came out with the Amsoil on top.

Also, they say the K&N doesn't hold up well physically over time. It is said to lose fibers and develop holes.

------------------
Mike (dmax) DP Member #2429
2001 2500HD GMC Duramax/Allison Summit White CC/SB Loaded
Amsoil Air Filter, Straight Piped PIC (http://uscom.com/~hoot/cars/duramax/gmc/exhaust/jvn03.jpg)
PS2K Propane, 22 Gal. LP Tank PIC (http://onramp.uscom.com/~hoot/cars/duramax/gmc/propane/bigtank1.jpg)
Allison Deep Pan, Transynd Syn ATF PIC (http://uscom.com/~hoot/cars/duramax/gmc/allison/allis10.jpg)
SPA DG-111 Boost/EGT, Nordskog Digital Fuel Level PIC (http://uscom.com/~hoot/cars/duramax/gmc/allison/allis11.jpg)
VentShades, Husky Mudflaps, 255/85-R16 Dunlop Radial Rover RV's
Kennedy Headlight Booster Kit TRUCK PICTURES CLICK HERE (http://onramp.uscom.com/~hoot/cars/duramax/gmc)
1994 K1500 Blazer 350 Loaded, Flowmaster duals

[Tader Jack]

a64pilot --

I'm just stating actual occurrences that we have found over the years. We even talked extensively with the folks at K&N who verified our finding on a '01 Yamaha V-Start 1100. Their experience is that by adding the K&N filer along with rejetting, cruising mileage drops anywhere from 25-40%. This also occurs on several atv's that we have installed K&N filters and jet kits. Yes, more power, but also more fuel. This is not the case with "every" application. In fact, you could add a pipe with no change in power of mileage on these cruisers.

We personally experienced a 30% drop in cruising range and thus went back to the factory stock jetting on the V-Star. Several other street bikes are experiencing the same and many cruiser owners who ride any distances at all are going back to stock filters and jetting.

I'm convinced that the K&N did not help mileage one bit on the Duramax. I'm not knocking the K&N, just stating what we have personally experienced.

[hoot]

Tader Jack,

I'm not so sure you can compare the results of a gas motorcyle to a diesel truck.
I'm not disagreeing with your conclusion, just the method you used to come to it.

Most of us are using high performance products like air filters and freer flowing exhaust for just that, higher performance. They also say propane gives you better fuel economy. I don't use it for fuel economy so consequently my mileage has been the same and even dropped. I can tell you for sure that I do have higher performance.

Usually more power is at the expense of fuel economy with the exception of engines that have been redesigned and have more power plus better mileage. Example: Corvette. I think it gets highway mileage in the upper twenties? It's gas, has more hp than the Dmax and gets better mileage. Stock.

------------------
Mike (dmax) DP Member #2429
2001 2500HD GMC Duramax/Allison Summit White CC/SB Loaded
Amsoil Air Filter, Straight Piped PIC (http://uscom.com/~hoot/cars/duramax/gmc/exhaust/jvn03.jpg)
PS2K Propane, 22 Gal. LP Tank PIC (http://onramp.uscom.com/~hoot/cars/duramax/gmc/propane/bigtank1.jpg)
Allison Deep Pan, Transynd Syn ATF PIC (http://uscom.com/~hoot/cars/duramax/gmc/allison/allis10.jpg)
SPA DG-111 Boost/EGT, Nordskog Digital Fuel Level PIC (http://uscom.com/~hoot/cars/duramax/gmc/allison/allis11.jpg)
VentShades, Husky Mudflaps, 255/85-R16 Dunlop Radial Rover RV's
Kennedy Headlight Booster Kit TRUCK PICTURES CLICK HERE (http://onramp.uscom.com/~hoot/cars/duramax/gmc)
1994 K1500 Blazer 350 Loaded, Flowmaster duals

[xwing]

Tader:
It sounds like you know this, but the reason for your MPG drop was NOT the K&N, but the jetting change.

Jetting IS fuel, and usually stock stuff runs nice and lean for MPG and emissions purposes; for max power and fatter torque curve rejet kits usually fatten up the midrange etc; so more power, but less MPG.

MPG is mainly a function of CRUISING fuel efficiency. CRUISING is a relatively LOW HORSEPOWER, LOW AIRFLOW situation where the airfilter is nowhere near being taxed to its limits, so even a lower flow airfilter won't have a big difference (cruising at 55mph in a car takes about 35 hp or so...it does not take much airflow to make 35hp, and nowhere NEAR our car/truck's maximum airflow/horsepower).

SO, airfilter does not change MPG much IN AND OF ITSELF. If it is a gas/carbuereted engine and you go from a clogged/very restrictive filter to a highflow filter, you could lean out the engine some and have to make adjustments. Our trucks are injected, and have NO throttle plates, are turbocharged, so the LESS restriction pre-turbo the better.

[Tader Jack]

I'm completely aware that the jetting change is what did the mileage in. But, without the jetting change, there was "too much" air for the amount of fuel taken in and the bike would hardly run.

In our diesels and other fuel injected vehicles, the sensor will detect that increased air flow and adjust the computer to add the proper amount of fuel needed.

Hey, I'm a believer in K&N's. I just don't believe they help in all situations. I think the jury is still out on this and how much it actually helps these particular diesels.

Like I've said before, there are lots of opinions based upon hearsay whenever aftermarket speed merchant products are involved. Everyone likes to "think" they have made the correct decision themselves, and rarely admit that some of this aftermarket stuff does not work in all situations. There is an upside and downside to each situation. I have used K&N's with success in many situations, but there are some, where they have had a bad end result.

One thing I've stated before, they do help make more hp and I've never had an engine failure due to one.

[Durwin]

I'm glad to see that people are concerned enough about their vehicles to generate this much controversy over an air filter. I do have to say that I have never heard of the K&N loosing fibers and developing holes over time. I've had the K&N on my Mustang for awhile now. I bought an Amsoil for my 2500HD (on order). Can't wait to try it out.
Durwin

[KompressorMan]

I have a K&N filter on my 2001 D/A. The Banks sidewinder turbo kit I bought for my 1985 F**D 6.9 came with a K&N filter. I HAVE NOW DECIDED I DO NOT LIKE THE K&N FILTER.
Here's why... Look at the stock GM filter on the D/A. It is paper, and although it is the same size, it has an order of magnitude more surface area. NOW, look at the stock filter vs. the K&N on K&N's own test. The small fan blows air though the stock filter to barely raise a ball in a column. Now put in a K&N, turn on the fan, the ball rises to the top of the column. THINK, Less surface area, more flow=Less filtration. I don't know a thing about Amsoil's filter, but the K&N is coming out.
Herb

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2001 SLT DM/Allison CC 4X4 SB White/Charcoal

[fredwe]

great comments, i have a story of my own, on my 94 chev i went the hole amsoil way from new, i was working in a oil refinery operations and would do 10000 mile oil analiasis test, they were comming back with high dirt content, took to a local service center and had a look for where my dirt was comming, they could not find any where but seen that the inside of the throttle body was very dirty, they cleaned and i left again, after 10000 more miles i checked again with same results as before, now contacking amsoil they said their must be a leak and looked at it them selves, replaced my airfilter for me and put me on my way, one month later i went back same findings but now my vortec was using about a liter of oil per 2000 miles, there answer was, their must be another leak,and had all paper work from their factory to so call prove it, at that time i sold the truck and have not used their products since, beaware on all these toys for our duramaxes, a new motor is about 15000cdn and air filters are about 60.00, i would as well like to go to a performance airfilter but have my worries about less restrictions and more airflow, thanks fred