Hi-performance filter outlets?
04-10-2003, 08:08 AM
#1
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Hi-performance filter outlets?
Since I'm kind of unsuccessfully trolling on subjects that everybody already knows about, like pulling the silencer ring, 
, I thought I'd ask this.
Isn't the amount of air a BHAF or an AFE or K&N flow restricted by the four-inch outlet hole? And is it possible that the BHAF, the AFE and the K&N all flow more air than the outlet can handle? And if that's the case, wouldn't your turbo and intake receive the same air charge from all of these filters, so that other than temperature, it doesn't matter what you use? I asked Fleetguard about this regarding the BHAF, and they told me they didn't have those figures, but it was a good point.
Don't hurt me for asking! ;D
ascraeus
, I thought I'd ask this. Isn't the amount of air a BHAF or an AFE or K&N flow restricted by the four-inch outlet hole? And is it possible that the BHAF, the AFE and the K&N all flow more air than the outlet can handle? And if that's the case, wouldn't your turbo and intake receive the same air charge from all of these filters, so that other than temperature, it doesn't matter what you use? I asked Fleetguard about this regarding the BHAF, and they told me they didn't have those figures, but it was a good point.
Don't hurt me for asking! ;D
ascraeus
04-10-2003, 11:13 AM
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Re:Hi-performance filter outlets?
The amount of airflow through the 4 inch inlet hose would be dependent on the amount of restriction from the filter. A 4 inch pipe can flow a lot of air if it has no restriction.
04-10-2003, 05:27 PM
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Re:Hi-performance filter outlets?
But the more surface you've got on the filter, the more it flows, right? So if you've got a lot of surface, like the BHAF, or a lesser amount of less-restricted surface, like the AFE, much more than four inches squared worth, isn't it possible you'd reach the outlet restriction before you'd reach the filter restriction?
I guess my question is, has anyone ever tested the flow of a four inch outlet? And then compared the filter flow figures, to be sure? Somebody somewhere must have figures.
Just more science.
ascraeus
I guess my question is, has anyone ever tested the flow of a four inch outlet? And then compared the filter flow figures, to be sure? Somebody somewhere must have figures.
Just more science.
ascraeus
04-10-2003, 05:55 PM
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Re:Hi-performance filter outlets?
You're looking at it a touch wrong...It all adds up to a total pressure drop (or suction-how ever you want to look at it). The drop across the filter + the drop through the tube. I suspect the drop through the tube is pretty negligable when compared to the drop across the filter - even with a size huge filter. So...to answer your question (I think) you can't get a filter big enough to overflow the tube - I suppose if you had a filter that took up the size of the bed you might turn the numbers around to the point where the filter was negligable compared to the tube...But basically youre after the lowest restriction inlet you can get -which is the sum of the tube plus the filter....I sure hope that makes sense to someone else 
04-10-2003, 06:09 PM
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Re:Hi-performance filter outlets?
MisterKTM, "Suction, not flow", that makes sense. But as far as a filter being the size of a bed, have you ever removed the filter element from a BHAF and straightened out the pleats? Yup, you guessed it, surface area as big as a bed! ;D That's what got me thinking about this in the first place. (My dad has a damaged one he's replacing, so out of curiousity we cut it apart.)
And BigBlue, it takes more time for you to think up answers than for me to ask stupid questions!
ascraeus
And BigBlue, it takes more time for you to think up answers than for me to ask stupid questions!
ascraeus
04-10-2003, 08:05 PM
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Re:Hi-performance filter outlets?
Its not ONLY the size of the filter that is important. The filter material has a lot to do with the retriction factor. When K&N introduced its gauze design it revolutionized the way air filters where made.
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04-10-2003, 08:42 PM
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Re:Hi-performance filter outlets?
OK OK I admit I also have to much time on my hands!!! :
<br><br> This reminds me of a sale display I seen for K&N airfilters. They had a vaccum set up with a ball. They proved to me that sucking through their filter they could suck this ball higher up the tube than with my purolator. Proving to me they could flow more air. I sucked in. I bought one....and a boost guage....34 psi. with both filters and builds pressure just as quick....it seems. $69. filter vs. $6.90 filter.<br><br> My theory: If you produce the same boost wheres the gain? Air temp./ Air density. ??<br><br>I apologize for jumping in but I think it's sort of the same question...you can only flow as much air as she'll take..right? Anything past that would be boost wouldn't it?<br><br>
04-10-2003, 10:01 PM
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Re:Hi-performance filter outlets?
I don't doubt that those big filters are as big as the bed - there is a lot of pleats in them for sure. What I'm saying is the fact that you have losses from going through the tube doesn't have anything to do with the losses through the filter - The lower you can get the restriction through the filter the better - as they are both additive at the point it gets to the turbo inlet<br><br>As to seeing no gains with a low restriction air filter...the stock filter was probably doing just fine with no other mods to the motor- if you were to add fuel (fuel plate or chip) then you would need more air to go with the extra fuel and then you probably see a difference. The stock filter may not be able to supply air at the increased demand - compared to the K & N.
04-11-2003, 01:18 AM
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Re:Hi-performance filter outlets?
My theory: If you produce the same boost wheres the gain? Air temp./ Air density. ??
04-11-2003, 03:04 AM
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Re:Hi-performance filter outlets?
[quote author=Amish hauler link=board=7;threadid=13432;start=0#126708 date=1050025323]<br> My theory: If you produce the same boost wheres the gain? Air temp./ Air density. ??<br><br>I apologize for jumping in but I think it's sort of the same question...you can only flow as much air as she'll take..right? Anything past that would be boost wouldn't it?<br>[/quote]<br><br>You can only flow as much air as the truck wants, but the objective is to flow this air as easily as possible. So proper air system design is not just strictly related to air flow/air restriction of the filter on a bench. You want to allow the turbo to pull air as easily as possible (or ideally, push the air to it so it doesn't have to pull a doggoned thing) so you don't increase drive pressures, and pull the turbo out of its efficiency map. The harder the compressor has to work to get its air, the hotter that air will be after it leaves the turbo.<br><br>Rod
04-11-2003, 06:40 AM
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Re:Hi-performance filter outlets?
[quote author=Push Rod link=board=7;threadid=13432;start=0#126825 date=1050048267]
You want to allow the turbo to pull air as easily as possible (or ideally, push the air to it so it doesn't have to pull a doggoned thing) so you don't increase drive pressures, and pull the turbo out of its efficiency map. The harder the compressor has to work to get its air, the hotter that air will be after it leaves the turbo.
Rod
You want to allow the turbo to pull air as easily as possible (or ideally, push the air to it so it doesn't have to pull a doggoned thing) so you don't increase drive pressures, and pull the turbo out of its efficiency map. The harder the compressor has to work to get its air, the hotter that air will be after it leaves the turbo.
Rod
Which brings us back to removing the so-called "silencer ring" and the air flow effects caused by its "theft". . . . OK, I'll shut up.
ascraeus
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