Question of best flowing? Screen vs. Filter and Intake tube

[turboglenn]

okay..out of the two, on the dyno/at track which one would reign supreme?

I thought about this and haven't gotten it off my mind since getting the new turbo with 4" inlet, and I had to buy a filter and order a coupler and some pipe to make an intake since there's no room for the filter at the turbo it's self

Now i will be running a filter when my 4" pipe and coupler gets here in another day or two. in the mean time i'm driving very little on roads that are pretty clean (but i hate doing it cause i know what really gets in on DD driving) Mine is wraped over 6 times of fine aluminum mesh so i feel ~ok for now, but i'd rather have a clotch/paper element than none at all

but at the track would a longer tube or even just a 45" 12" bend and 4" K&N or just a Screen Clamped over the inlet make more power?

My theory is the K&N and tube .. i think the K&N would flow as much as it needed to for the probably small gain if any to effect power by much

plus the longer tube gets the air gathered and denser as well as increasing it's speed, so when the air rushes in it creates low pressure in the filter (measurable on a boost gauge) and there for the air flow is starting to perpetuate its self while allowing the charge to pick up velocity on it's way it. But this is theory cause i havne't done a "back to back" or anything. but Bernouli's principals say filter+ tubing (preferably at least a foot per2.5 - 3" diameter for best "speed increase")

I don't think the screen "restricts" air but it doesn't allow anything to help it gather and flow either.

Oh, and the reason i even bring this up is I love looking through pics and I see a good amount of people running screen only, but the majority are still using a tube and filter so i want to hear both sides..argue your point, debate club is open

 

[Aproductions]

Maybe there is a reason that some STM guys use the forward facing manifold that puts the turbo in the front with no filter. I think each setup has it's own purpose but would love to hear some detailed explanations/proof to which is better at what type of driving.

Good topic.

 

[turboglenn]

^^^^exactly what i mean on the forward mount none run filter and tube but face out in the least aerodynamic areas and get fed air in a sense. Although i have my own thoughts on the subject i'm just up for intellegent conversation or debate right now

 

[El Cuervo]

I say screen with a velocity stack. However, how many layers of mesh compose the screen. A filter is thin but dense. This will allow good flow and filtering protection. If the screen is very see through with huge holes where you can see the compressor wheel spin, then just don't run a screen at all.
I think there was a filter comparison where some company compared HP and filtering on various filters. One of these filters was a metal filter. I think it was k&n, greddy, apexi, and hks foam filter. You would think that the foam filter would filter the best, but I think it was the worse one. Also, you would say that the metal filter would have the best flow because of its metal screen. Well if I remember right, the apexi cotton filter showed the highest hp gains. I believe k&n followed second or third. Can't remember to well. Its been years.
So in this test, cotton filter ranked superior in hp as suppose to a metal filter. Granted its not a screen as it is a filter. However, it is a metal filter which could be closer to a screen as oppose to a cotton one.

 

[romeen]

I say screen with a velocity stack. However, how many layers of mesh compose the screen. A filter is thin but dense. This will allow good flow and filtering protection. If the screen is very see through with huge holes where you can see the compressor wheel spin, then just don't run a screen at all.
I think there was a filter comparison where some company compared HP and filtering on various filters. One of these filters was a metal filter. I think it was k&n, greddy, apexi, and hks foam filter. You would think that the foam filter would filter the best, but I think it was the worse one. Also, you would say that the metal filter would have the best flow because of its metal screen. Well if I remember right, the apexi cotton filter showed the highest hp gains. I believe k&n followed second or third. Can't remember to well. Its been years.
So in this test, cotton filter ranked superior in hp as suppose to a metal filter. Granted its not a screen as it is a filter. However, it is a metal filter which could be closer to a screen as oppose to a cotton one.

http://www.mkiv.com/techarticles/filters_test/2/

Not to stray off topic Glenn, but FWIW I have a Blitz stainless steel mesh filter and I agree with the conclusion of the that test that they do not filter out the crap very well.

 

[bastarddsm]

Ya know funny you ask. I found out the hardway, but if your turbo is mounted conventionally, run a filter in the stock location. Running open turbo cost me about 75whp, on a 520whp setup. My post I/C IAT's dropped 50*f just putting a tube and filter on my holset. I can't comment on the flow part of it, but sucking in air from behind the radiator is not good for power. And if you have even a super small exhast leak, it can really #### your day up.

 

[turboglenn]

wow..that's a LOT, thanks for the tech entry with the proven results!!!

 

[bastarddsm]

Ya no problem. Obviosuly tho, your results may very. But there is definatly no performance gain from running running open turbo.