does a cold air intake really make a difference?

[PLoAudi]

does a cold air intake really make a difference? performance wise?...i have a awe quad tip...would it make it sound diff 2?

[NorcalPB]

No, pre-turbo temps don't make a difference, your main concern with an intake should be air flow. Short Ram works the best.

[audidrver]

No, pre-turbo temps don't make a difference, your main concern with an intake should be air flow. Short Ram works the best.
aaaaaa????? No. My intake adds about 42.5hp. Clown.

[greddy15]

aaaaaa????? No. My intake adds about 42.5hp. Clown.

that doesnt sound right, unless its with a chip

[Dan[FN]6262]

No, pre-turbo temps don't make a difference, your main concern with an intake should be air flow. Short Ram works the best.

so true [up]

[vagebadger]

http://www.audizine.com/forum/showthread.php?t=257109&referrerid=37776

The answer is...kinda

There are a few tests showing the difference between stock and a complete intake. The test results showed an increase in airflow (assuming more air = more power) it works...but simply replacing the stock paper filter with, say a K&N shows a comparable increase.

Price per HP is what you have to calculate. $300 bucks for an intake that gains a few HP v.s. a $40 K&N that may gain a few as well.

If you are looking for sound... A replacement filter or an intake with let you hear the turbo more...and an intake looks great.

read the pages on the thread above...good stuff any way you slice it.

[paulk11087]

aaaaaa????? No. My intake adds about 42.5hp. Clown.

42.5hp?!?!?! i highly doubt that... if thats the truth i want to see some dyno's and i want to know where you got this damn intake lol

[Charles]

No, pre-turbo temps don't make a difference, your main concern with an intake should be air flow. Short Ram works the best.

According to APR, pre-turbo air temps DO matter.

[CBRmatt600]

42.5hp?!?!?! i highly doubt that... if thats the truth i want to see some dyno's and i want to know where you got this damn intake lol

Some people are really awful at detecting sarcasm. Like, shamefully awful.

[9Hooker]

According to APR, pre-turbo air temps DO matter.

they do look to make a hefty sum by selling them.. so they would say so. if i had an all out car i would get one. why? because every little bit helps. until then i'll keep my k&n drop in.

[DELUX]

No positive difference performance-wise. In most cases you actually lose a little bit of hp and torque. You gain a sound which is what some people are after though.

Stock airbox is the way to go. Some of the fastest Audis in world are using the stock airbox assembly. Engineered properly to deliver air to your motor in the best possible way. Don't buy into the hype of cold air intakes.

[harryd14]

yeah, gains with a CAI are very minimal with our car. the stock airbox already has a very good amount of air flow into the engine which is why the aftermarket CAI's don't really improve performance as much.

One nice side to the CAI's though is the more audible turbo and woosh sound when you release the gas pedal

[EuroA4]

Some people are really awful at detecting sarcasm. Like, shamefully awful.

[hail] indeed

[Slo.Mo.Shun.]

Im going to do a small test with logs ( As soon as I get brake pads ) with my stock air box and my carbonio. Im currently getting up to 260gs on the MAF on with my carbonio.

[NastyNate]

Some people are really awful at detecting sarcasm. Like, shamefully awful.

I wonder if it hurts to be so smart and so cooler-than-thou... [hail]

[Grishbok]

I wonder if it hurts to be so smart and so cooler-than-thou... [hail]

it does.

[B7 Projectile]

I just swapped out my Carbonio for my old K&N +heat shield setup.. Lets put it this way, I can defn feel my fuel cuts now compared to the Carbonio. Regarding intake temps, I must saw that when I was in florida in true 101* @ 65mph, I could defn feel the heat in the bay at throttle. I am planning on fabricating a cold air which would fit down where the right intercooler had sat before the FMIC was added, I hope to reduce the heat a little more for this summer by using the stock ducts for the intercooler to redirect the fresh air.

Again, my $.02, my K&N is better than the Carbonio on the performance side with the exception of the above mentioned florida trip, then again, I have no reason to disregard the fact that the Carbonio might also suffer the same fate in that situation.

[CBRmatt600]

I wonder if it hurts to be so smart and so cooler-than-thou... [hail]

I think it hurts worse to be a complete rock head.

[ataylor]

Some people are really awful at detecting sarcasm. Like, shamefully awful.


Seriously!

anyway..
SEARCH

it's been MORE than discussed already.

but here, by all means, let us do the research for you, that's what we're here for: CLICK (http://www.audizine.com/forum/showthread.php?t=257109&highlight=cold+air+intake)

[paulk11087]

Some people are really awful at detecting sarcasm. Like, shamefully awful.

oh little did you know i was playing along with it... come on now... seriously?[:p]

[NastyNate]

I think it hurts worse to be a complete rock head.

That's almost definitely true...

No hard feelings Matt, but there's room for everyone here, right?

[A4ringedONE8T]

Intakes are overrated in general [:p]

[audidrver]

Intakes are overrated in general [:p]


[cool]..

[9Hooker]

words

assumptions:

your intercooler reduces intake temps 50% (from 400 to 200 say)

a CAI gives you a 5 degree intake temp difference

pre intercooler your temp is 4x your intake temp


air density = absolute pressure / (gas constant * absolute temp)

density post intercooler with CAI (400 F intake temp, 200 after intercooler, 1 Bar pressure):

x = 200000 / (287.05 * 375.35) = 1.8562kg/m3

density with CAI (395 deg f, 197.5 after intercooler)

x = 200000 / (287.05 * 373.95) = 1.8632kg/m3

1.8632/1.8562 = 1.0038. that's a .38% increase in density. so instead of making 230 whp, you make 230.87 whp. congratulations. lowering your PRE turbo intake doesn't do shit. lower your post compressor temps. i.e. make your intercooloer operate more efficiently to see ACTUAL benefit.

[Grishbok]

thats exactly how the Cry02 intercooler spray works :) increasing the efficiency of your intercooler significantly.

[audidrver]

Im going to do a small test with logs ( As soon as I get brake pads ) with my stock air box and my carbonio. Im currently getting up to 260gs on the MAF on with my carbonio.

I'm peaking only 210. Your car must be fast. Please do intake and ambient as well.

[Alkemix]

assumptions:

your intercooler reduces intake temps 50% (from 400 to 200 say)

a CAI gives you a 5 degree intake temp difference

pre intercooler your temp is 4x your intake temp


air density = absolute pressure / (gas constant * absolute temp)

density post intercooler with CAI (400 F intake temp, 200 after intercooler, 1 Bar pressure):

x = 200000 / (287.05 * 375.35) = 1.8562kg/m3

density with CAI (395 deg f, 197.5 after intercooler)

x = 200000 / (287.05 * 373.95) = 1.8632kg/m3

1.8632/1.8562 = 1.0038. that's a .38% increase in density. so instead of making 230 whp, you make 230.87 whp. congratulations. lowering your PRE turbo intake doesn't do shit. lower your post compressor temps. i.e. make your intercooloer operate more efficiently to see ACTUAL benefit.

hmmm... your calculations don't seem relevant, but we all know your conclusion to be true.

Why I think it's irrelevant: A good CAI should reduce more than 5 degrees and I'm pretty sure FMIC isn't efficient enough to reduce temps by 50% and also, 400 degree under the hood ambient temps are pretty outrageous.

You'd burn your face off when you open the hood after driving.

All of these assumptions lead to the 0.38% increase in air density over intercooler alone.

I can't recreate your calculations, but maybe you should try with CAI reduce temps by 15 degrees (outside air is MUCH colder than under the hood). Intercooler reduces temps by 20%, Starting intake temp is 185 degrees F without intercooler, or CAI.

Plus you haven't even considered the increased volume of air flow.

Just saying, but I like how you think.

[jmw241]

I think it hurts worse to be a complete rock head.

HAHA!


A Cold Air intake aka a hot air intake, seeing that it's going to be right above the turbo/down pipe[headbang] (even with a heat shield) will add a very small ammount of power. However if your going for looks/sound you will get alot of both if you do it right [cool].

Best bet is to make your own, for around 60-100 dollars. Upwards of $200 if you use a NICE HKS filter [hail]

Parts list:

-90 degree 3" aluminum intercooler pipe
-3" to 2.5" straight silicone reducer
-3" 45 degree silicone coupler
-(3) 3" T bolts
-(1) 2.5" T bolt

Going to go with red couplers with most likely black t-bolts and a black intercooler pipe. The T-bolts and Intercooler pipe will be powder coated black, with heat resistant paint :-). I might try to get creative with the powder coating and put some red camo or strip pattern on it as well or a "DOPE" audi symbol.

Mine will look similar to this:

http://i42.tinypic.com/168vg8y.jpg

[9Hooker]

volume flow increase from what? the temp decrease increases air density.

i think that 400 is not too crazy wrt non intercooled intake temps, neither is 50% decrease... maybe 30% or so.

here is a representation of some temps. they are liquid to air, but using a 100 degree liquid, it does better than 50% cooling.

http://www.racetep.com/tneticatolic.html

how are my calculations irrelevant.

i think this is more simplified formula, used for %-age increase/decrease:
density is in kg/m3
pressure is in Pa and is absolute
temp is in K
R= 287.05

first find a reference density:
air density = pressure / (gas constant * temp)

then play with

density1 = [(P1 * T2 ) / (P2 * T1)] * density2

[9Hooker]

Why I think it's irrelevant: A good CAI should reduce more than 5 degrees and I'm pretty sure FMIC isn't efficient enough to reduce temps by 50% and also, 400 degree under the hood ambient temps are pretty outrageous.

assumption:
pre intercooler your temp is 4x your intake temp

i was assuming either 100 or 95 degree underhood temps. multiply by 4 (just a guess to get to 400 deg F) and you get those numbers AFTER the compressor section. this is what the intercooler needs to cool down.

without scientific evidence I'm just throwing numbers up there wrt actual temp decreases from CAI alone. i.e. what the temp difference is the moment it hits the compressor.

[quickaudi07]

http://www.audizine.com/forum/showthread.php?t=257109&referrerid=37776

The answer is...kinda

There are a few tests showing the difference between stock and a complete intake. The test results showed an increase in airflow (assuming more air = more power) it works...but simply replacing the stock paper filter with, say a K&N shows a comparable increase.

Price per HP is what you have to calculate. $300 bucks for an intake that gains a few HP v.s. a $40 K&N that may gain a few as well.

If you are looking for sound... A replacement filter or an intake with let you hear the turbo more...and an intake looks great.

read the pages on the thread above...good stuff any way you slice it.

I love my turbo wine.. you cant beat it !!!
go with cold air and you be happy,

[Slo.Mo.Shun.]

I'm peaking only 210. Your car must be fast. Please do intake and ambient as well.

The car hold 257 and more all day long, but as soon as I pass 260 the car freaks out and drops the boost to 15psi. Ill definitely log charge temperatures to demonstrate how efective the AWE FMIC and the water meth are.

[Grishbok]

my air intake is smaller than everyone elses :(

[melloyelloguy]

my air intake is smaller than everyone elses :(

girls like a4's with big air intake

[4ty-phive]

Well, doesn't having a cai paired with a good aftermarket exhaust cause the engine to "breathe" better.

[9Hooker]

yes, but... we're not talking about flow rate. we're talking about effect of temp on power production. get at least SOME type of free flowing filter element, it will breathe easier.

has anyone considered that any increase in the CAI could be due to an increase in surface area of the filter? larger surface area given the same filter element will produce a lower pressure drop over the filter.. thus flowing "freer".

[audidrver]

my air intake is smaller than everyone elses :(

edit* I just looked up my logs and I only peaked at 199, and hold 190 [:(]

[9Hooker]

what numbers are these?

[Zebman]

what numbers are these?

MAF readings said HID in one of his first posts.

[B7 Projectile]

assumptions:

your intercooler reduces intake temps 50% (from 400 to 200 say)

a CAI gives you a 5 degree intake temp difference

pre intercooler your temp is 4x your intake temp


air density = absolute pressure / (gas constant * absolute temp)

density post intercooler with CAI (400 F intake temp, 200 after intercooler, 1 Bar pressure):

x = 200000 / (287.05 * 375.35) = 1.8562kg/m3

density with CAI (395 deg f, 197.5 after intercooler)

x = 200000 / (287.05 * 373.95) = 1.8632kg/m3

1.8632/1.8562 = 1.0038. that's a .38% increase in density. so instead of making 230 whp, you make 230.87 whp. congratulations. lowering your PRE turbo intake doesn't do shit. lower your post compressor temps. i.e. make your intercooloer operate more efficiently to see ACTUAL benefit.


CAI would reduce intake temp much more than 5*. My gains are from an increase of surface area. Coupled with a CAI, I would expect to see much more than a .38 difference holding the cone filter constant. but what do I know.... [rolleyes]

[p1nk50ck]

HAHA!


A Cold Air intake aka a hot air intake, seeing that it's going to be right above the turbo/down pipe[headbang] (even with a heat shield) will add a very small ammount of power. However if your going for looks/sound you will get alot of both if you do it right [cool].

Best bet is to make your own, for around 60-100 dollars. Upwards of $200 if you use a NICE HKS filter [hail]

Parts list:

-90 degree 3" aluminum intercooler pipe
-3" to 2.5" straight silicone reducer
-3" 45 degree silicone coupler
-(3) 3" T bolts
-(1) 2.5" T bolt

Going to go with red couplers with most likely black t-bolts and a black intercooler pipe. The T-bolts and Intercooler pipe will be powder coated black, with heat resistant paint :-). I might try to get creative with the powder coating and put some red camo or strip pattern on it as well or a "DOPE" audi symbol.

Mine will look similar to this:

http://i42.tinypic.com/168vg8y.jpg

that engine bay looks awfully familiar [:D]

[A4ringedONE8T]

lol @ this thread still

I made something for you guys, and yes I am an asshole, sorry [:p]

http://i19.photobucket.com/albums/b156/a4ringedone8t/Misc/Intakes.jpg

[Hyphy]

lol @ this thread still

I made something for you guys, and yes I am an asshole, sorry [:p]

http://i19.photobucket.com/albums/b156/a4ringedone8t/Misc/Intakes.jpg

:D

my intake better. soz

http://img20.imageshack.us/img20/302/intakee.jpg

[chrisrjs]

lol @ this thread still

I made something for you guys, and yes I am an asshole, sorry [:p]

http://i19.photobucket.com/albums/b156/a4ringedone8t/Misc/Intakes.jpg

love your setup [up] [up]

[9Hooker]

but what do I know.... [rolleyes]

exactly. i'm glad you're using the seat of the pants feel instead of math.

[B7 Projectile]

exactly. i'm glad you're using the seat of the pants feel instead of math.


Really dude,

1) Since when is 1 bar = 200,000.0 Pa??
According to this number, well... we should be a few miles under sea level...

Pa or absolute pressure at sea level is 101,325 or 1.01325 bar.

2) You don't know the difference between Kelvin and Fahrenheit.

375.35* KELVIN=216.23* F
373.95* KELVIN=213.71*F

3) WTF were you thinking..

Holding the assumption that the change (or delta) in HP is directly (I don't assume to know what I am talking about, if someone would like to give some input..) proportional to the change in Density, hp2 = hp1 * (d2/d1)

Lets use your example at sea level... 216.23* without CAI, 213.71* with the CAI. Fahrenheit. 375.3, 373.9 K.

D1=101,325/(287*375.3)
D2=101,325/(287*373.9)
D1=0.940585535 Kg/M3
D2=0.944106914 KG/M3

HP1=230
HP2=230.86
.373% difference over 3*.. sweet!!

I just threw together a quick excel sheet for % density change in 20* increments.... Fahrenheit.

60-80=3.850%
80-100=3.451%
100-120=3.806%
120-140=3.574%
140-160=3.480%
160-180=2.986%
180-200=3.125%
200-220=3.041%
220-240=2.944%
240-260=2.859%

[9Hooker]

Really dude,

1) Since when is 1 bar = 200,000.0 Pa??
According to this number, well... we should be a few miles under sea level...

Pa or absolute pressure at sea level is 101,325 or 1.01325 bar.

2) You don't know the difference between Kelvin and Fahrenheit.

375.35* KELVIN=216.23* F
373.95* KELVIN=213.71*F

3) WTF were you thinking..

Holding the assumption that the change (or delta) in HP is directly (I don't assume to know what I am talking about, if someone would like to give some input..) proportional to the change in Density, hp2 = hp1 * (d2/d1)

Lets use your example at sea level... 216.23* without CAI, 213.71* with the CAI. Fahrenheit. 375.3, 373.9 K.

D1=101,325/(287*375.3)
D2=101,325/(287*373.9)
D1=0.940585535 Kg/M3
D2=0.944106914 KG/M3

HP1=230
HP2=230.86
.373% difference over 3*.. sweet!!

I just threw together a quick excel sheet for % density change in 20* increments.... Fahrenheit.

60-80=3.850%
80-100=3.451%
100-120=3.806%
120-140=3.574%
140-160=3.480%
160-180=2.986%
180-200=3.125%
200-220=3.041%
220-240=2.944%
240-260=2.859%

it's late, but i'm going to have a LOT to say to you tomorrow AM. your above is incorrect.

[ray-ray]

there are little to no gains on an intake. when people do dyno runs and say an intake gives gains, do they ever consider that dynos vary in HP with the OEM airbox even at times 5+(-) hp? its all sound for our cars on our tiny turbos. i have one, no gains. its got a cool little "whoosh"..that is all

if there is a 5hp gain, its not even going to be a consistent enougn gain due to the heatsoak factor, you will eventually lose that minimal HP gained.

[FLAudiMotion]

when talking about CAI it is also very important to remember it is not just the temp of the air you intake, but its starting pressure as well. AUDI engineers spent a long time in the wind tunnel determining the best location to tap the intake. That spot at the top of the grill just so happens to be the highest pressure point on the front of the car as it moves through the air. By circumventing that, or moving the tap off location completely you are definitely doing yourself a disservice.

[9Hooker]

1) Since when is 1 bar = 200,000.0 Pa??

Since we're using absolute pressure, not gauge pressure.

~1 Bar is where we are right here at sea level.
1 Bar ~14.5 psi, about what the K03 does.

So using ABSOLUTE pressures in the equation, we get 2 Bar, or 200kPa.

According to this number, well... we should be a few miles under sea level...
If we were under water, we'd only be 32 feet down for 1 Bar.

2) You don't know the difference between Kelvin and Fahrenheit.
I made everything into C first.. so there's a conversion error because i used X instead of XX significant digits.

We said the intercooler lowers temps 50%.
Let's say that the turbo imparts 300 degrees in the ambient air before intercooling
CAI pre turbo - 95 deg F, or 308.15K
CAI post turbo - 395, or 474.82K
CAI post intercooler - .5 * 395, 197.5F, or 365.093K

NO CAI pre turbo - 100 deg F, or 310.93K
NO CAI post turbo - 400F, or 477.59K
NO CAI post intercooler - .5 * 400, 200F, or 366.48K

let's use those numbers then.

air density = absolute pressure / (gas constant * absolute temp)
R = 287.05

CAI
200000 / (287.05 * 365.09) = 1.9084


NO CAI
200000 / (287.05 * 366.48) = 1.9012

1.9084/1.9012=1.0038, or a .38 increase.

your 250 whp with a CAI goes to 250.9 whp

now let's do it with 55% reduction of heat by intercooler, simulating an intercooler upgrade.

old intercooler
pre turbo - 100 deg F, or 310.93K
post turbo - 400F, or 477.59K
post intercooler - .5 * 400, 200F, or 366.48K

new intercooler
pre turbo - 100 deg F, or 310.93K
post turbo - 400F, or 477.59K
post intercooler - .45 * 400, 180F, or 355.37K


old IC
200000 / (287.05 * 366.48) = 1.9012


new IC
200000 / (287.05 * 355.37) = 1.9606

1.9606/1.9012=1.0312 a 3.12% increase.

250whp is now 257.8whp.

questions? an IC does better than a CAI, which really does nothing.

PRE TURBO TEMPS PLAY HARDLY A ROLE IN MAKING POWER!

[FLAudiMotion]

your assumption for this whole thing is seriously flawed. You appear to assume the vehicle is not moving, hence absolute pressure of 2 bar. if this is the case, the intercooler is hardly cooling anything, and in fact if it is a FMIC, may actually be receiving radiated heat from the radiator.

If the car is moving, as i stated above, your tap off pressure would be larger due to its location on the front of the car. Unless you have the wind tunnel data Audi used to determine that location for varying speeds, these calculations hardly make sense. I applaud your math though, because it is correct.

[B7 Projectile]

Ok, I can see what you are doing with the 2 bar Pa.

There is a reason I didnt say underwater.. I used the proper term sea level because of its significance in the measurement of 1 Bar of pressure.
(Denver) Above sea level<1 Bar<below sea level(death valley)

I dont like the post turbo figure of 395, maybe 300.... Post intercooler 120 ish which might be on the high end. 5* reduction in temp.. I would expect more as well, especially with my setup, which is why I want to go with CAI. Currently there is 8" and a heat shield separating my intake from the Cat. As you can imagine, it can get very hot in there.

Just to throw my point around, if a 5* change warrants a .9 WHP gain, then using the same figure against a 25* change would give 4.5 WHP, or 5.75 crank(=4.5/.78)... and that was using a change from 395 to 400... I dont really have the time to go through the numbers right now, but if someone is willing to get 14 HP (crank) off a 1100 dollar intercooler, why would that same person not be interested in close to 6HP+ from a CAI along with the perk of increased volume from the Cone filter VS Carbonio/OEM...

I didnt loose HP when I added my Cone filter, making this CAI instead of having it in bed with my CAT will make a difference.

[B7 Projectile]

your assumption for this whole thing is seriously flawed. You appear to assume the vehicle is not moving, hence absolute pressure of 2 bar. if this is the case, the intercooler is hardly cooling anything, and in fact if it is a FMIC, may actually be receiving radiated heat from the radiator.

If the car is moving, as i stated above, your tap off pressure would be larger due to its location on the front of the car. Unless you have the wind tunnel data Audi used to determine that location for varying speeds, these calculations hardly make sense. I applaud your math though, because it is correct.

Great point.. but the car had been designed around the 200 HP/TQ requirements.. What happens when more airflow is provided by a cat back, and an intercooler slapped on in addition to a chip... I dont disagree with you, but, I trust the difference I can feel between the setups... Like I said in an earlier post, there is a reason I sold my Carbonio intake and put the cone back on... Now I want to either find a way to create a CAI, or even channel some fresh air to it through brake duct tubing.

[9Hooker]

i stated what my assumptions were, flawed or not, because i don't have the data. i am merely plugging in numbers to see their effects. feel free to do the same with your own numbers and post your conclusions.

my outcome was correct i believe using the assumptions I had.

the stock airbox is essentially a CAI because of where it draws air from in the first place.

I don't see what the car moving has anything to do with it, and yes i used sea level. because of the pressure sensor, the intake piping will ALWAYS have the same gauge pressure, so it should be relatively constant, which is why forced induction vehicles don't have nearly the losses that all motor cars do at high elevations. if you are higher, use a smaller number for ambient pressure however.

if you have a BT, increase the pressure, but also increase the temperature...

this model would be HIGHLY accurate with this data:

ambient pressure
peak boost
ambient temp (for intercooler efficiency purposes)
air temp at the turbo inlet (for ambient temp calculations)
air temp just before first intercooler (for temperature gains due to compression and heat imparted by the compressor)
air temp at the intake manifold (for intercooler efficiency)

until then.. plug away at the numbers. i think the numbers are a good ballpark and not too out to lunch.

[quickaudi07]

42.5hp?!?!?! i highly doubt that... if thats the truth i want to see some dyno's and i want to know where you got this damn intake lol

YES me too :) lol
but i have to wait untill i get my A4 fixed lol