CAI Track Test Data From Last Nite

[motorhead]

And no, Mike, LC was selling a kit long before you ever rigged a cold air kit and so did ATR

I am not talking about a flex tube stuck to a restrictive can wrapped around a filter fed from an air dam, Steve.

[Steve Wood]

The ATR kit was a 14" KN that mounted in front of the radiator.  Was not restrictive, or canned....

Altho I recall the Tinman wars that claimed it's special filter put the KN filter in the ground....and then there was the Pete Tomka kit...I remember all the test claims but don't recall any actual data being provided....  Nor did anyone mention that the stock maf was the biggest restriction and yet cars ran tens with them

[Scoobum]

As I stated earlier I picked this CAI up from one of the locals in a package deal. He's beyond anal and did a masterful job of fabbing/polishing it. I'm a data hound...and don't believe anything unless I have track data to back it up. The numbers are all there...and whether a CAI would help without alky to cool it is up for debate. In a non alky situation...ma ybe. With alky as a cooling agent...then I doubt it. As Steve said...with the extra bend...you'd prolly break even...at best. Money would be best spent on an alky kit...or a IC upgrade. Ambient air temp was 91F with the CAI and 75 without it. MPH temp is when the temp dropped.

[Scoobum]

Steve, I have a question. Any truth to the bigger the air filter...the more CFM's can pass through it? I had a K and N filter on my car that was the size of a trash can. Got it from none other than...Norbs. I had to relocate the canister under the fender to get it to fit. Lol!

Any calculation I could do to work the size filter I would need for my engine at a given RPM?

[Steve Wood]

Absolutely!  9" filters are starting to be a drag on quite a few cars and some filters are more restrictive than others. I have the equation. I will find it

[Steve Wood]

Chuck Leeper posted this long ago and it was on my site...looks like I left it off the last version I put up.  There are some filters out there that claim to outflow a K&N but I don't recall if I have ever seen an independent test.  I like the filters with the inverted cone in the nose to give more filter area on a smaller filter.  Also, we used to be able to buy one that had a dome at the outlet end that smoothed air flow as it left the filter reducing turbulence that would actually try to block some of the flow coming out of the filter.  I think I may have those on both my cars.

The biggest help I have seen is from going to a 4" out from the normal three inch outlet and increasing the pipe size to three inches.  The longer the inlet pipe, the more important this is because air flow is reduced by the friction caused by the inside walls of the tube just as a water pipe does on water.  The longer the pipe, the more important this becomes.

Here is the formula from the K&N site.  If you have a cone filter instead of a cylinder, take the diameter of both ends and use the average of the two when calculating flow.



Use the formula below to compute the minimum size filter required for your particular application. The usable portion of the filter is called the EFFECTIVE FILTERING AREA which is determined by multiplying the diameter of the filter times Pi (3.1416) times the height of the air filter in inches, then subtracting .75-inch. We subtract .75-inch to compensate for the rubber seals on each end of the element and the filter material near them since very little air flows through this area.

A=(CID X  RPM) / 20,839
A = effective filtering area
CID = cubic inch displacement
RPM = revolutions per minute
at maximum power
 Example: A 350 CID Chevy engine with a horsepower peak at 5,500 rpm.
A=(350 X  5500) / 20,839 = 92.4 square inches
If you are sizing a panel filter, multiply the width of the filter area (not the rubber seal) times its length. If you are sizing a round filter, use the following formula to determine the height of the filter.

H=(A / D * 3.14)+0.75
A = effective filtering area
H = height
D = outside diameter of the filter
3.14 = pi
0.75 = the rubber end caps
 Example:
H=(92.4 / 12 * 3.14)+0.75 = 3.20 inches

[Steve Wood]

same thing, less words from GNttype   

http://www.gnttype.org/techarea/turbo/airfilter.html

[earlbrown]

As I stated earlier I picked this CAI up from one of the locals in a package deal. He's beyond anal and did a masterful job of fabbing/polishing it. I'm a data hound...and don't believe anything unless I have track data to back it up. The numbers are all there...and whether a CAI would help without alky to cool it is up for debate. In a non alky situation...ma ybe. With alky as a cooling agent...then I doubt it. As Steve said...with the extra bend...you'd prolly break even...at best. Money would be best spent on an alky kit...or a IC upgrade. Ambient air temp was 91F with the CAI and 75 without it. MPH temp is when the temp dropped.

I built this a couple years ago and still haven't put it on my car.  It started out wanting to get rid of my 14" K4N with a sharp edged 3" outlet   I found a 4" AEM 'no-oil' filter with a radiused outlet shaped kinda like a velocity stack...     Then just went all the way to the turbo with it...

I figure a 4" neck through a 3.5" pipe should have minimal pressure drop, even with the extra bend, since the actual inlet on my turbo is around 2 inches.

[earlbrown]

Any calculation I could do to work the size filter I would need for my engine at a given RPM?

More = Better

[Steve Wood]

Exactly, Earl!  LOL

S&B also makes some with the radiused base and inverted cone    http://www.verociousmotorsports.com/Shop-by-Brand/S-B-Inverted-Cone-Air-Filters/S-B-Power-Stack-Air-Filter-Inverted-Cone-Rubber-Cap

[earlbrown]

It's also interesting that K&N's own numbers ignore the pleats on the actual filter media.

I almost wonder if that's a way to 'trick' people into making sure they get minimal pressure drop.

[Steve Wood]

perhaps, the flow is not equal thru the vertical pleats as compared to horizontal pleats but is more an area as presented to incoming air flow?  Not sure. 

did you read the pm I sent you?

[Scoobum]

Wonder what the Canadian price is...

[Steve Wood]

I bet AEM has a dealer up there..look for one of theirs

[earlbrown]

perhaps, the flow is not equal thru the vertical pleats as compared to horizontal pleats but is more an area as presented to incoming air flow?  Not sure. 

did you read the pm I sent you?

I just went and found it (along with a lot of other PM's I've never seen).  I need to find a setting to alert me when I get a message.  I don't spend near the time on the boards that I used to.

I just went outside and measured my 14" K&N that came with the ATR 'ram' air kit from yesteryear...     If I were to wrap a piece of paper around the outside (basically K&M's math) it's 218.625 square inches of flow area....


In real life it has 59 pleats (the 60th's is the sheet metal clamp to close the loop) with  right at 1" of length between valleys.  Using that math the calc changes from 16.5*13.25    to 59*13.25   for a change to 781.75 square inches.


From looking at it, I really would have guessed the difference would be greater.


I would imagine the flow might be a little down where two pleats touch but not by that much.   With that much surface area compared to the 2.2ish inch turbo opening that's a pretty good difference.   Now I have 781 square inches feeding 3.8 square inches

  So that's roughly a 206:1 ratio of flow area between my filter and my inlet.  the air should be going pretty slow at the filter media that flow shouldn't take too much of a hit.

NOTE: The above math aaUmes that my entire filter surface is a flow area and it is not.  I have no idea the ratio of material .vs open area on K&N's cotton gauze.

Plus, as filters get used, they get more 'filtery' as the passages get debris stuck in them and turn one orifice into a few very very small orifices.  So flow goes down and micron ratings go numerically down.