They do flow more air and give you a itsy bitsy boost in power. They are also excellent for sanding down the cylinder walls, valve stems, and bearing races.

 

Any problems with torque and throttle? Have you fixed the idle @ lights?

 

i think once i reset my ecu . everything runs better and makes enough torque and power . and the idle at the lights has happen twice were it just died out but after a couple of minutes still driving it goes back to normal

 

ok, IAC valve might be getting a lil dirty, clean it out and see what happens.

 

alright ill try and do that tomarrow and ill get back to ya

 

2.5 and up diameter pipes are really only needed for blown engines. unless you have a heavily modified engine 2" is quite good, 2.5 is a doable replacement when stock rust's out.

 

What do you mean by this? I haven't been able to locate any information about this. Could you provide a link?

 

sounds like his takes his stuff through the sand . lol . k&n air filter definitely adds power. i have one on my ktm, and i have one on my truck and it isnt no 2 hrp. its more like 10 or more
and if you don't want mud or sand in it,shouldn't a pre air filter cover dis prove sanding down the cylinder walls .

 

The only way to make an air filter flow more air, given the same surface area, is to make the holes bigger.

In your average K&N...the holes are so big you could drive a grain of sand through them...and that is what happens. They flow more air...and more dirt. And the dirt sands down your cylinders and every other moving part.

Their own advertising tells you that their "efficiency improves as they become more clogged with dirt". This blows me away...to ADVERTISE that your filter does not stop as much dirt when it is clean as when it is dirty.

If you pull the filter off your engine entirely you won't get 10 horsepower. The OEM paper filters are not that restrictive. Measure off a quarter mile and time your run. Just from a standstill, stomp on the gas pedal. Then pull the filter element out and do it again. You cant measure the difference.

Again...this is a huge marketing exercise on the part of filter makers like K&N. Under the hood of a Duramax or PS or Cummins truck there is a little gauge that tells you when your air filter should be replaced. There is even a reset button! It is there because people are freaked out about engine longevity and are changing out their filters when they don't need changing.

Nothing I say will stop people from buying K&Ns...and that's a shame because they are singlehandedly responsible for more worn-out motors than any other filter company out there. Just my 2 cents worth.

 

Good read.

http://www.dieselbombers.com/chevy-g...r-testing.html

Like CAEMI said, if it flows more air, it passes more dirt. The paper filter will flow more air than the 4.0L draws under 99.99% of driving conditions and do a better job of filtering out dirt. A cotton/gauze filter won't make 10hp over paper in the rpm range where 99.99% of every day driving is done.

 

I am a retired mechanic with, experience with 4by's stock cars & drag cars. I guess I am the link

 

If this was true you would see absolutely zero increase in power or gas mileage, correct?

Just because the k&n lets more air in doesn't mean the 4.0 will injest the extra available air.

 

Under 99.99% of normal driving conditions, the stock paper element will flow plenty of air......even the K&N dyno charts show 0-2hp increase from idle to 3000 rpm. The link I posted shows the K&N provided less filtration than paper.

Nobody admits that they spent X $ on a performance mod and then says the mod didn't work, so I sent it back, for a refund........it has to work, it cost more, marketing depts wouldn't lie.........would they???????????

 

i have a K&N, is there a filter like the K&N thats better? i have the stock air tube and the K&BN filter and filter heat shield. i dont have the stock air box anymore...and i need a new filter

 

dont you wash K&N's? Ive never had one but i thought thats what you do, or just leave it dirty to stop more dirt from coming in