Independant Consumer Study
of the
K&N Filtercharger
Update Log:
07/20/2006: I have been running the truck with the paper element and flowmaster exhaust with the catalytic converters still intact. I was consistantly around 18 mpg depending on traffic. The catalytic converters went out, so they got replaced with empty ones (this is an off road vehicle so it is legal). I reinstalled the K&N thinking since I had the exhaust it would improve gas mileage and maybe performance, I was wrong, I lost gas mileage and nothing noticable with performance. I trashed the K&N. The truck is running great with the paper element, I just got a 19 mpg average on a recent tank! It runs very well, and with the cats removed I did notice a little more pep (but I think I was just use to the hp decrease from the cats being clogged for a while).
04/25/2006: So I installed a 3-chamber flowmaster in place of the stock muffler
I am currently working on a new MPG average for this new change
03/01/2006: K&N test #3 complete, results posted
No significant deviations from the current statistics shows a computer learn issue
02/24/2006: Paper test #3 complete, results posted
Beginning K&N #3 study tank
02/17/2006: K&N test #2 complete, results posted
Beginning #3 Paper study tank
02/01/2006: Paper test #2 complete, results posted
Beginning #2 K&N study tank
01/27/2006: K&N test #1 complete, results posted
Beginning #2 Paper study tank
01/25/2006: Cleaned out the truck, found some more Dirty K&N slips and also took a picture of the slips (also note that the average did not even change when I added three more mpg studies)
Tank #1 Study almost complete
01/21/2006: Tank#1 Paper test completed check results
Beginning #1 K&N study tank
01/19/2006: Website Created, Pictures taken, K&N Filter cleaned, Dirty K&N mpg stats entered
Beginning #1 Paper study tank (almost complete)
Internal Page links:
IMO Statement:
I believe that the K&N filter is a profitable marketing ploy aimed towards owners of stock vehicles and will have no adverse positive effect on performance or gas mileage. A performance study is on hold since the drag strips are currently closed. If I prove otherwise, I will apologize to the people (ehem AOD) I may have upset arguing about this filter and start praising this "miracle" filter.
Introduction:
This is Part 1 of a K&N vs. Paper Filter in regards to Miles Per Gallon.
A 1999 Chevrolet Silverado 1500 4.3V6 will be used as the test vehicle. The vehicle is completely stock running new 255-70R16 Toyo Open Country A/T tires (size meets mfg specifications). Completely stock means no modifications to any of the powertrain parts, in other words there are no aftermarket or custom parts on the vehicle and no parts have been removed. Overall the vehicle is in good working order with all emission systems intact. The gas tank capacity is 25 gallons. One exception is the plastic air spoiler in the front has broken off, but since it will be defaulted for both tests it is not relevant.
The paper filter being used in this study is a NAPA brand factory replacement filter unit.
Test Methodology:
-Every full tank the K&N and paper filters will alternate (be swapped out)
-90 miles per weekday (80 miles freeway, 10 miles city):
45 miles occuring at 7:00 AM to 8:00 AM and 45 miles occuring at 4:30 PM to 5:30 PM
-Moderate to Agreesive driving style
Passing cars, Accelerating onto freeway, Positioning in traffic, rarely "Hotrodded", Freeway averaging 60-75mph
-Traffic enviroment very stable
Typically same transit times
-Gas Mileage Calculation
Determining the gas mileage using the the marks on the gas guage are grossly inaccurate. To obtain a good indication of gas mileage, you need to fill the tank completely and reset the tripometer, drive until the tank is near empty, then fill the tank completely, and record the miles driven and the amount of fuel it took to refill the tank to full again. Then just take the total miles on the tripometer and divide that by the total gallons it took to refill it.
The reason you need to drive until the tank is almost empty is to utilize the greatest overall average, it will almost eliminate the error when refilling to exactly what it was filled the first time. So the bigger the tank, the more accurate it will be.
-Fuel Quality
87 Octane non-alcohol fuel or gas-o-hol
Typically BP, Mobile, Marathon, Shell fuels (even though all of its shipped in from the same pipe)
Statement:
This study is unlike any controlled test in a test lab (dynamometer cell). Like many (all?) cars driven on the roads, they are not driven in a controlled enviroment. Many variables work in conjunction with creating the final result. If there is any consistancy with the results, they should be regarded as good statistics. If the results are not consistant, this test may very well be invalid.
The Test Vehicle 1999 Chevrolet Silverado 1500 4.3V6
The air filter units
The size of the filter unit's air seal are identical
Physical Comparison:
NAPA's filter is 1.80 inches tall with 80 pleats each pleat at 11.50 inches long
Find the area of one side of one pleat, there are two sides, and 80 pleats:
Filter surface area = 80 x (2 x (1.80in x 11.50in)) = 3,312 in2 = 276 ft2
K&N's filter is 0.81 inches tall with 34 pleats each pleat 11.5 inches long
Find the area of one side of one pleat, there are two sides, and 34 pleats:
Filter surface area = 80 x (2 x (0.81in x 11.50in)) = 1490.4 in2 = 124.2 ft2
The total surface area of the K&N is less then half that of the Paper (45%)
Since the K&N Filtercharger unit is reusable, the filter that will be used during the test will be a used consumer cleaned unit per a K&N Recharge kit following the instructions. The unit has been in the vehicle for approximatly 12,000 miles untouched.
Cleaned the filter per K&N's instructions:
-Lightly brush off debres
-Spray cleaner on liberally and soak for 10 minutes
-Rinse with low pressure tap water and air dry
-Oil each pleat individually
The OEM replacement filter fits the air box perfectly
STATISTICS:
Dirty K&N Filtercharger unit:
Tank 1: 370.2 miles traveled using 22.789 gallons
Resulting in 16.2 mpg
Tank 2: 391.3 miles traveled using 22.711 gallons
Resulting in 17.2 mpg
Tank 3: 347.0 miles traveled using 20.274 gallons
Resulting in 17.1 mpg
Tank 4: 400.8 miles traveled using 23.377
Resulting in 17.1 mpg
Tank 5: 367 miles traveled using 22.215 gallons
Resulting in 16.5 mpg
Average: 16.8 mpg
See slips HERE
New NAPAGold Paper unit:
Tank 1: 426.0 miles traveled using 23.96 gallons
Resulting in 17.8 mpg
Tank 2: 428.5 miles traveled using 23.99 gallons
Resulting in 17.9 mpg
Tank 3: 418.5 miles traveled using 23.11 gallons
Resulting in 18.1 mpg
Average: 17.9 mpg
Flowmaster Upgrade:
Nothing drastic changed using the paper unit and the stock muffler replaced with a 3-chamber flowmaster and the catalytic converts intact. My torque curve was shifted, I know this because I am shifting from 4th to 3rd back and forth cruising at about 1800-2000 rpms, it never did that before. It pulls good at high rpms, but I cannot say there was a performance increase until I take it to the track.
Cleaned K&N Filtercharger unit:
Tank 1: 346.5 miles traveled using 20.959 gallons
Resulting in 16.5 mpg
Tank 2: 360.8 miles traveled using 20.834 gallons
Resulting in 17.3 mpg
Tank 3: 378.3 miles traveled using 23.203 gallons
Resulting in 16.3 mpg
Average: 16.7 mpg
CONCLUSION:
The K&N Filtercharger in its "clean" or "dirty" conditions shows no significant improvement to gas mileage. Actually the K&N Filtercharger decreased the average gas mileage.
IMO: I predicted that the K&N vs. Paper would reveal no difference, I am quite surprised that it decreased the mpg.
CONCERNS:
With the K&N filter installed after 8,000 miles, my throttle body began to stick at closed throttle and was difficult to reopen the throttle plates. After inspection of the throttle body, it was "gummed" up with a black sticky resedue. A solution of carb cleaner and a tooth brush aleveated the problem. I also inspected the MAF sensor and the resistors were not dirty.
I assure you the information published on this website are unbiased facts. Test results are subject to weather and traffic conditions but should not be invalidated because of a long term study that will help eliminate error and the fact that seasons do not change instantly week to week. This study is sponsered by a non-profit consumer and developer of this website. In no way will this study generate relationships with automobile air filter marketers or manufacturers.