That's a good question, and I'll answer it in a bit, but first I've got a couple of questions for you. Did you read my calculations about vacuum being relative, and my conclusion that you can breathe in outer space? My answer to this question involves a similar concept of being relative. In the following, I'm not venting at you or trying to put you on the spot, I'm just asking for your inputs to help me better calibrate how and why my calculations are perceived here on FTE.

I'm wondering why people seem to accept my vacuum calculation, and my conclusion from it that you can breathe in outer space, yes, that's without a space suit for those who haven't read it, don't hold your breath and breathe normally and you'll be ok! On the other hand when I do a calculation showing that several gal/hr of water are being sucked through your air intake, and conclude that using a paper filter doesn't seem like the best choice, I get a response like Pocket gave..." However I can tell when something doesn't make sense and when something isn't relative. Like the other calculation at the beginning of the thread with humidity and the air intake."

So breathing in outer space makes sense, but concluding that sucking several gal/hr of water through a paper filter is a bad thing to do doesn't make sense? Then Pocket goes on to say that using a paper 6637 does make sense, because "Guess what? Stock trucks come with a paper filter." Well my early 99 had the air box that sucked damp air from the fender well, and I'll tell anyone who cares to listen to actual logic and common sense, that using any kind of paper filter on these trucks isn't a good idea period.

Now that I've vented, I'll get to your question regarding still air and a vortex. In my analogy, I talked about "still (relatively undisturbed) water is required on the surface above the drain." for a vortex to form, and then said "Compared with the direct RAM air flowing through an air box inlet, the air in the vicinity of an under the hood intake is relatively still because it's confined to the region of the firewall and fender wall." So there's two relative aspects involved here in what I'm calling still air, firewall and fender wall air vs RAM air, and still water vs still air.

First there's my comparison between 65 mph air that's being rammed down the throat of a cold air intake vs the relatively still air that's trapped in the firewall and fender wall area around an open intake filter. I had a setup with the inlet portion from my updated 99.5 air box feeding air from a Zoodad to my K&N cone. I found many bugs accumulating around the fuse box area indicating to me that the air was getting trapped back there and wasn't free flowing. So I'd consider that to be relatively still air compared to blowing a leaf blower back there which is about the same as the RAM air going into an air box!

In my breathing in space post I gave a number of calculations involving molecular densities, and the following are round numbers in molecules/ft3 to compare interstellar space=10^8, nominal atmosphere=10^24, water=10^27, and a solid=10^28. So the relative density between water and air is about X1000, and this factor applies to what's considered still water vs still air! In other words, you need to magnify the ripples on the surface of water which destroys the stillness there by X1000 to destroy the stillness in air.

This will be my last post on a vortex, at least for awhile, as that poor dog needs his rest, please, lets not kick him again!

 

I have no doubt that Gene has no intention other then finding out what is the truth. Paper filters i stopped using them Years ago. But While im not math Articulate, I have quite a few friends that numbers just flow to them and makes sense. And so imply that someone is fudging the numbers with fuzzy logic or otherwise is a pretty silly statement. people who crunch numbers know there is only one right answer. Heck i cant crunch numbers and i know that.

 

Just installed an aFe cold air induction about 20 minutes ago. I can tell that the truck was gasping for air before hand and now it, well lets just say wow, definately worth the $375 smackaroos. It has faster acceleration and the turbo is spooling a lot quicker. Next is the 5" exhaust....

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2000 Ford F-250 XLT SuperCab
aFe cold air induction

 

The following is a POSSIBLE interpretation of these results that's more consistent with the quote I gave from Tenn at the beginning of this thread about the dyno run at BTS which showed a 25 HP difference between the 6637 and no filter at all. Comparing the 2nd and 3rd set of runs you see about a 20 HP difference, which is about what was seen at BTS. I'm wondering what the results would've been if runs 1 and 2 had been done in reverse order? Test the AFE, then the 6637. Based on my experience at Smokin, I can make a case that if the AFE had been tested first it would've posted the highest HP.

During the Sat dyno runs at Smokin, things proceeded at a much more relaxed pace than on Sun when the crowed arrived, and then there problems with the dyno as well. Anyway, on Sat I got to make a number of measurements with my IR thermometer, and correlate those against the HP from the dyno runs. I had several conversations with the dyno operator, and he confirmed my findings. Namely, that the temp of the air intake is more important than turning up the fuel setting on the chip. He said he tells people that if they want to post their highest HP to go for it in the first run when their intake is the coolest, instead of starting with a lower fuel setting and working their way up to higher settings. He said that 95% of the time he gets the highest HP on the first run, even when he turns the fuel up on the 2nd and 3rd runs.

Now if anyone thinks I'm just making this up they can go back to my Smokin thread from 6 months ago and see that I posted about this effect of the 1st run being the best there. BTW, I've decided I'm no longer going to give links. It's a lot of work for me, hardly anyone bothers to read them anyway, and people can take what I post at face value as being my best, well intended effort, at accuracy, or go find the answers themselves without asking me to prove beyond a shadow of a doubt everything I post!

 

That’s an interesting tidbit of information on Dyno’s. I would agree that when doing a scientific study you must be able to replicate the results many times for validity. I would like to see other Dyno runs. These of course must be done under similar conditions. Using the same truck is not necessary. Mix up the order in which the filters are tested to eliminate any chance that another variable is affecting the results. This is what they refer to as causality. We are attempting to find a relationship between an independent variable (air filter) and a dependent variable (HP). To do this you have to be able to rule out that something else is causing the increase in HP. Gene, your dyno operator was stating an observation and while I would classify him as an expert some corroboration is still needed.


As I stated earlier mathematics and computations are great tools for developing a hypothesis, predictions, and even a plan on how to perform the study. It is however not the answer just a source of information. If the math is proven to be unreliable during the study then there is a problem somewhere. As a said before there must be a missing variable.
<O</O

Please continue with your efforts. It’s good to see amateur mathematicians like Gene out there discovering things through mathematics. While some would say it is good for old timers like Gene to exercise there brains I would counter that it’s good for everyone. If you have a problem with Gene’s math counter it with some of your own. There is more than enough room to do so. Gene is dealing with so few variables when doing his math he very well may be missing something. These trucks are complex machines with many things that can affect their performance. The number of variables is mind boggling. This is probably why Gene is only dealing with a few at a time when trying to identify relationships to determine causality. I would bet he would love your help.
<O</O

On a side note to Gene, I see you keep bringing up the leaf blower simulating a ram air system. Please tell me this is not going to be your next mod as a leaf blower sticking out of that hole in the front of your truck would be just God awful ugly.

 

This is meant as a serious complement! You make it very easy for me to respond to your rebuttal posts by stating your comments and issues with my posts in a clear, concise, and organized way. That's not to imply that I actually agree with your rebuttals, but it's easy to see point by point what they are. Keep up the good work, but stop disagreeing with me so often, you've probably got more important things to do! This # is from my best recollection, but the 6637 only has a 99.8% or a 99.85% (the # was different for different brands) capture efficiency compared to 99.99% for the AIS. It's interesting that you mentioned OA as being a benchmark for good air filtering, because I'm trying to do an analysis to see just how much dirt (grams per 1000 miles) gets sucked through an engine (into the intake and out the exhaust) before enough accumulates in the 4 gallons of oil to show up as a given # of ppm on an OA report. Surprisingly, I've found no references to any tests or analysis to determine this. On a recent thread, Strokin seemed very surprised when a truck he was working on which had an absolutely filthy intake system came back with a perfect OA report. I'm wondering how many miles you could run without an air filter and still get a good OA report? That will be one of my future calculations. Not if it goes through your turbo or comes loose and dusts your engine! I believe the old saying is something like "penny wise but pound foolish"! I'm glad you said apparently, see my post where I make a case that the AFE might've done better if it'd been tested on the first series of runs when the intake was the coolest. Well I'm not dead yet either! Does that mean I never will be? I can only hope that's the case. If it ever does fall off you might ruin your engine. I quoted a case where one fell off and went unnoticed for two days, but he had one of those protective covers to limit the damage. Well there's sure a lot of maybe's going on here that would tend to make me loose sleep worrying about them. Since all these maybe's concern a PAPER filter getting wet, maybe it's best to just not use paper filters of any brand if you really care about your truck!

 

I actually have a 1970 Cobra Jet Shaker Hood Scoop and air cleaner Assembly. I've been planning on cutting out the hood,and mounting it to the top of the motor and tie it into a Y in the Intake Tube, making it fully fuctional. Also having a shut off switch, so that in bad weather be it rain or dust you can keep the R/Air closed. Not to mention it would look awsome. Along with the CJ badges, Snake mounted on the Side under the F250 badges..What do yah think? Country. Sorry guys didn't mean to Hijack here. I do run the 6637, so I'm following this thread closely. I replaced the K&N Cone filter, with the 6637. I did leave the metal K&N enclosure in Place when I installed the 6637 for some added protection from heat, dust and water. Thanks Country

 

Gene,
Thanks!! Now you're on to something -- I'm very interested in the OA project. I'll be the first NOT to offer my truck up for that test!!

I'll keep this short, though. My point was there is no way to know if a filter (paper or otherwise) is going to fly apart while using it. I'm not sure how he ran the dynos, but it was interesting that all of them were much lower on the first run. Not sure why that was -- maybe there's a logical reason. I know just about squat about dynos, but I thought someone would have mentioned it before now. Can anyone enlighten me?

Oh, and believe me, I don't spend much time disagreeing with you -- it just flows...

 

For those who've mentioned the possibly of using dual air filters, this configuration might be adapted to a PSD.

 

Well i had put a neat picture with this.....however when i posted the thread went into moderation Im guessing they dont like outside pictures...

 

Now that Gene, would move some air! HAH HAH. I still think that a Black CJ Shaker sticking out of the hood would look awsome!!. It'll let the Dura-craps and the Cummins guys know yah mean business. Hey Gene I just started a Tranny Cooler thread. I would like your input. Thanks. Country

 

might i suggest, to improve overall performance... a turbo on either side of that setup...?

 

how about a cowl induction of only one reverse scoop right above and a little behind the filter... it would kind of look like the old in hood tachometer that some of the old GTO's used to have... one small reverse scoop on the hood right in front of the driver...

 

The way to keep the tube from falling off is simple. Use a piece of 4in stainless between the filter and the intake tube. This way you dont have to try to stretch the intake tube over the filter.

 

sorry, i got a little off topic with that last reply... i doubt the cowl induction hood has any negative effect on filtering ability, but i bet the actual temperature of the air you are sucking into you engine is higher than you want it to be... think about it... you are bringing air through the cowl right where the turbo is... that is probably the hottest place under your hood and the incoming air has to be absorbing at least some of that heat...