Fortunately our TJ engines don't use a MAF sensor. I've learned to hate them on my daily driver cars though. If our engines did have MAF sensors you can bet there'd be fewer K&N air filters on them.
Is one air filter better than the other?
- Thread starter fourpointzero
- Start date
Hmmm seems as though Wix rated high on the provided chart, 2nd to AC delco.
Delco in all my vehicles. Relatively cheap and readily available. The only exception is my Harley which has the K&N knock off.
Rock auto is $11.....order a few at a time and the shipping doesn't hurt as much. I've also noticed shipping many times is a dollar or two less than the initial quote on RA.
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Ok I guess it's time the below chart and data gets thrown out here...
There was an exhaustive ISO 5011 lab test conducted several years back which just further reinforced my belief that K&N's filters are POS's indeed.
" (quoted)
ISO 5011 Test:
The ISO 5011 Standard (formerly SAE J726) defines a precise filter test using precision measurements under controlled conditions. Temperature & humidity of the test dust and air used in the test are strictly monitored and controlled. As Arlen learned in attempting his own tests, there are many variables that can adversely affect filter test results. A small temperature change or a small change in humidity can cause the mass of a paper filter to change by several grams. To obtain an accurate measure of filter efficiency, it’s critical to know the EXACT amount of test dust being fed into the filter during the test. By following the ISO 5011 standard, a filter tested in Germany can be compared directly compared to another filter tested 5 years later in Rhode Island. The ISO 5011 filter test data for each filter is contained in two test reports; Capacity-Efficiency and Flow Restriction." (end of quote from the lab test)
The below just one chart & comment copied verbatim from the multi-page lab test. The only thing the K&N topped the charts with was air flow... which is nothing, a screen door has great air flow through it.
View attachment 15745
In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574 gms of dirt and passed only 0.4 gms. After only 24 minutes the K&N had accumulated 221 gms of dirt but passed 7.0 gms. Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt. (The lab's words, not mine)
If someone doesn't care how much dirt gets passed into their engine, the K&N would be a good choice.
Anyone seen tests for Bosch or the Hastings filter above?
Bosch usually makes a good product.
I can't help but think that foam pad helps in filtration. Foam pads are used extensively in heavy off road applications....motorcycles and some heavy equipment.
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See, he does speak gospel.Ok I guess it's time the below chart and data gets thrown out here...
There was an exhaustive ISO 5011 lab test conducted several years back which just further reinforced my belief that K&N's filters are POS's indeed.
" (quoted)
ISO 5011 Test:
The ISO 5011 Standard (formerly SAE J726) defines a precise filter test using precision measurements under controlled conditions. Temperature & humidity of the test dust and air used in the test are strictly monitored and controlled. As Arlen learned in attempting his own tests, there are many variables that can adversely affect filter test results. A small temperature change or a small change in humidity can cause the mass of a paper filter to change by several grams. To obtain an accurate measure of filter efficiency, it’s critical to know the EXACT amount of test dust being fed into the filter during the test. By following the ISO 5011 standard, a filter tested in Germany can be compared directly compared to another filter tested 5 years later in Rhode Island. The ISO 5011 filter test data for each filter is contained in two test reports; Capacity-Efficiency and Flow Restriction." (end of quote from the lab test)
The below just one chart & comment copied verbatim from the multi-page lab test. The only thing the K&N topped the charts with was air flow... which is nothing, a screen door has great air flow through it.
View attachment 15745
In the chart above it’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574 gms of dirt and passed only 0.4 gms. After only 24 minutes the K&N had accumulated 221 gms of dirt but passed 7.0 gms. Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt. (The lab's words, not mine)
If someone doesn't care how much dirt gets passed into their engine, the K&N would be a good choice.
I think K&N type filters do have a place. For racing, where you want that extra few horsepower to scream through the quarter mile, and you don't mind giving up longevity for horsepower, any other situation where the motor is going to be rebuilt, or replaced in a relatively short time. They do breath a little better, but they let more crap enter the motor. Think of screen vs. chicken wire. My Jeep had a k&n on it when I bought it, and the inside of the intake tube was covered in fine dirt. After as many miles with an AC Delco element, the tube is still clean, and there was no noticeable decrease in power, or fuel economy.
X2 on all that. The very nice thing about our TJ air intake systems that not many are aware of is that it's not restrictive in the least. It was specifically designed to be able to flow more air than the engine can demand at WOT and redline RPMs. That is right from Jim Repp's mouth who was Jeep's senior-most engineer at the time I spoke to him years ago.
https://blog.jeep.com/news/executive-interview-jim-repp-jeep-brand-engineering/
Jim is also known as the 'father of the Rubicon' as it was his idea and his creation. Very nice guy to speak with, he emailed me out of the blue to ask about a problem my TJ was having back in 1998 or 1999. What brought the air intake up was there were a lot of discussions going on about getting more performance out of TJs with K&N filters so I asked him which I was (naturally) arguing against. He explained that while some vehicles were purposely designed with restrictive air intakes, like the Camaro Z-28 and Mustang 5.0L, their goal with the TJ was zero restriction... a large enough surface area air filter and air intake tube to not be restrictive. Jim also explained the trumpet's function at the opening of the air filter box serves to speed up the incoming air velocity to help quiet the intake's sound.
We spoke many times after that, he started 'leaking' Rubicon information to me before its introduction to help keep the rumors from getting too outlandish. We haven't spoken in 10+ years, I'm sure he must be retired by now. Nice guy.
Well as you can see, bought my Rubicon with K&N installed by PO.
I've cleaned it extensively and re-oiled much more then required hoping to reduce it's shortcomings.
I will say i live in a damp region so dusty trails aren't an issue, mostly.
I've also seen those charts previously when K&N's were at there peak in popularity as i ran them in all my 5.3's.
Wonder if ACDELCO makes a conical that i could just plug in where the other filter is now.
I've cleaned it extensively and re-oiled much more then required hoping to reduce it's shortcomings.
I will say i live in a damp region so dusty trails aren't an issue, mostly.
I've also seen those charts previously when K&N's were at there peak in popularity as i ran them in all my 5.3's.
Wonder if ACDELCO makes a conical that i could just plug in where the other filter is now.
badlieutenant
TJ Addict
Wildman Wells
New Member
While we are on the topic of breathing - how does the high volume cold air kit from K&N on the stock factory air filter box work? Or is it just hype?
Looks like it opens up the air intake side of the filter box to allow more air flow. Quadratec part #17014.000
Looks like it opens up the air intake side of the filter box to allow more air flow. Quadratec part #17014.000
Jp Magazine tested a bunch of cold air kits a few years ago. The best one added about 2 horsepower at redline. All you get is an inferior filter, and lighter wallet. I took the Volant CAI off my Jeep, sold it for 150.00, got a used stock box for 35.00, an AC Delco element, pocketed 100.00. Jeep didn't run any different.
I would (and did) add a pre-filter over the top of it. K&N sells them, they were forced to add prefilter covers years back due to it getting out how poorly their filters filter.
https://www.knfilters.com/search/wrap.aspx?pkid=4481365&rw=1
I actually added two prefilters over the top of my K&N filter before I was able to go back to the OE air intake and AC-Delco filter years back. The first prefilter ("PreCharger") from K&N didn't fit well enough to keep the dirt from entering from the side so I added the foam Unifilter over the top of it to better seal it against the filter body. This is how mine looked with it's two prefilters...
Hype. While it's technically true cold air is denser which can hold more gasoline, it doesn't do anything for a Jeep in reality other than to the butt-dyno some people believe they have. It's definitely louder which some believe must mean it's making more power which isn't true.
My second TJ came with that exact K&N "cold-air" air intake in your photo. It lasted 3-4 weeks until I was able to replace it with the stock factory intake obtained from forum guru @mrblaine. Zero felt difference in performance after going back to the OE air intake system which I am still running. I sold the K&N intake in about an hour after posting it on Craigslist.
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You have to wonder much restriction all those pre filters create. You're probably back to square one.
I would (and did) add a pre-filter over the top of it. K&N sells them, they were forced to add prefilter covers years back due to it getting out how poorly their filters filter.
https://www.knfilters.com/search/wrap.aspx?pkid=4481365&rw=1
I actually added two prefilters over the top of my K&N filter before I was able to go back to the OE air intake and AC-Delco filter years back. The first prefilter ("PreCharger") from K&N didn't fit well enough to keep the dirt from entering from the side so I added the foam Unifilter over the top of it to better seal it against the filter body. This is how mine looked with it's two prefilters...
View attachment 15858
Hype. While it's technically true cold air is denser which can hold more gasoline, it doesn't do anything for a Jeep in reality other than to the butt-dyno some people believe they have. It's definitely louder which some believe must mean it's making more power which isn't true.
My second TJ came with that exact K&N "cold-air" air intake in your photo. It lasted 3-4 weeks until I was able to replace it with the stock factory intake obtained from forum guru @mrblaine. Zero felt difference in performance after going back to the OE air intake system which I am still running. I sold the K&N intake in about an hour after posting it on Craigslist.
True, which just goes to show how a 'naked' K&N air filter isn't really adding performance to a Jeep. I detected no performance difference after installing those two pre-filters.
Replacing the factory air intake system can definitely help performance on engines the factory installed restrictive air intakes on. A couple with restrictive air intakes include the Camaro Z-28 and Mustang 5.0, a non-restrictive air intake can really wake them up. Just not on our Wranglers whose air intakes are not restrictive.
If it's going to see any dry dusty conditions at all, stick with the A.C. Delco. The K&N filters are not a good application on a Jeep, primarily because low restriction high flow air filters only offer a performance advantage in the higher RPM ranges , which definitely isn't what were using.
So this morning I read through all the threads and grafts. Then I went out to my Jeep and truck and looked at what I had. Well as luck would have it, i have a k&n filter in my ford f150 , it was dirty, so i ripped it out and threw it away. I figure no filter is better than that thing. So I drove down to O'Reilly's and bought a STP cone paper filter (because they didnt have an AC Delco) filter. I do have a new paper filter in my Jeep, but next oil change ill change it over to an AC Delco.
thanks for the info.
thanks for the info.
Aviatortroy
TJ Enthusiast
Yes that's the right part # and that's a great air filter. Good choice.