K & N air filter

[megatexture]

They do say 350cfm for the testing but Isn't this about the filter media filtration/airflow not the induction system? I wouldn't be changing the setup it would just be an easy replacement of the filter job so I'm more interested in the filter itself.
sure they are all within 3% in that one of 7 graphs I put up but what would that 3% add up to over 300-500,000km surely that would affect longevity?

[nissannewby]

They do say 350cfm for the testing but Isn't this about the filter media filtration/airflow not the induction system? I wouldn't be changing the setup it would just be an easy replacement of the filter job so I'm more interested in the filter itself.
sure they are all within 3% in that one of 7 graphs I put up but what would that 3% add up to over 300-500,000km surely that would affect longevity?

This is what im trying to say. You have more air requirement and restriction than what is in that test. So while the paper element in that test does well thats all they are testing is the element. So in an application like the zd30 and most airboxes fitted to a patrol k&n will filter better.

That 3% is only in those test conditions in real world with our zd box as an example the paper element will struggle to remove particles as small as the k&n will.

[megatexture]

I've been looking around just now and this fella has done a bit of real life testing that has me thinking also.
http://www.bobistheoilguy.com/airfilter/airtest1.htm

[megatexture]

Also I wouldn't have thought a zd30 would be that much higher than 350- 450 maybe. if a non turbo 2ltr 4cylinder uses around 141 cfm at 4000rpm (from the little reading I've done) I know at 15 psi would be compressing the air a bit but I've not looked at how dense it gets to work out the real volume but it can't be that much more.

[nissannewby]

I've been looking around just now and this fella has done a bit of real life testing that has me thinking also.
http://www.bobistheoilguy.com/airfilter/airtest1.htm

You have just found why the induction system makes a difference to a paper filters ability to filter.

[nissannewby]

Also I wouldn't have thought a zd30 would be that much higher than 350- 450 maybe. if a non turbo 2ltr 4cylinder uses around 141 cfm at 4000rpm (from the little reading I've done) I know at 15 psi would be compressing the air a bit but I've not looked at how dense it gets to work out the real volume but it can't be that much more.

A diesel of the same capacity requires twice as much air as a petrol and at far less rpm due to a diesel peak torque rpm. So your example of a 2 litre petrol requiring 141 would mean a diesel of the same size would require atleast 282cfm. Then more is required for a turbo. Not to mention the 142cfm is probably free flow or with very little to no restriction.

I dont doubt the paper elements in your examples offer better filtration at reduced flow but this is not in our application with a patrol.