View Full Version : post your average intake temp.

08-18-2004, 04:16 PM
Okay, because of popular disbelief i'm going to try and prove that my intake system actually works. I ask that you tell me what your intake temps are, what mods you have (exhaust, chip, etc) what the humidity was as well as temp. I need to know so I can get an accurate measurement of how well this thing works. I do realize that the stock box pulls enough air, I just don't think it's cold enough

08-18-2004, 04:29 PM
Uh oh. Here we go.

Where are you measuring intake temps from? What are you using to measure them? The VAG-com cannot really give you the numbers you're asking for. You'd have to do a custom setup with a temp gauge at the air intake, and them somehow log the figures.

Either way, having a bunch of people post numbers will not be relevant due to the many variables in each unique case/car.

If you're relocating your filter to the lower bumper, then I'd say you likely have a nice setup. Nice work, stick with it.

But if you're trying to say that having a cone under the hood could somehow equate to lower air temps than the stock airbox, then I'd say you're crazy.

08-18-2004, 04:32 PM
Dan, don't even try to argue, it's a losing battle. You'll never win on this site with that one. [:p]

08-18-2004, 05:08 PM
you'd be better off testing CAPs times on your car with and without the filter

08-18-2004, 09:36 PM
It's more than a filter.....lol....I have the full piping. My filter set up sits right behind the passengerside headlight by the A/C hose

08-18-2004, 09:49 PM
I am going to test my intake temps with a wireless meat thermometer. I just have to figure out where the best place to mount it is. I am thinking right on the filter would be best. Any ideas?

08-19-2004, 08:28 PM
Ok I have reall data to add to the discussion. I did measure my intake temps with a wireless meat thermometer. The pics show how I mounted the probe (with duct tape of course) in front of my filter.


OK a few ground rules:
This is meant to be a discussion about performance and benefits. If you have actuall data and you want to share it please do. I dont know if this is the best set up or not but I am trying to find out through real fact finding. Any jack off can regurgitate something he read from some one else on some forum or website so if you want to flame do it some where else. Otherwise please contribute REAL KNOWLEDGE if you have it. We want to find the best intake on the A4. Bottom line is this: if you are gonna post an opinion than back it up with real data.

Here is an explanation of the experiment. I placed the temp probe outside on my porch and let hang in the air so it could measure a no wind plane out side air temp and it stabilized at 74F. Then I taped it in place and went for a drive to get the temps up. The water temp pegged and the oil temps peaked a 195. Then I idled until the meat thermometer peaked. No surprise here, it peaked at 195 degrees and then went up and down a few degrees. Then I went driving on a highway for about 10 miles at an average of 50 peaking at 85. The lowest temp I got was 78 degrees (4 above outside air).
Then I put my heat shield on thinking it might trap some of the cool air or some of the hot air (bad). It turned out that the heat shield made things a little better. It got as low as 74 degrees (one above outside air) going 60 mph for several miles.

Now I need a way to measure the temps on an A4 with a stock air box. Im not sure how to do this but I think I can just run this probe down into the box where the maf is. Ill need to find a volunteer, and Ill post the results when I get one.



08-20-2004, 12:07 AM
This will be interesting.

08-20-2004, 06:43 AM
I'm telling you right now, you need to measure the air temps in the intake pipe before the turbo. You also need an air temp sensor that will react quickly to temp changes. A meat thermometer is designed to be reasonably accurate in the 120F - 180F range. That is the range at which most meats are cooked to. If you are measuring below that key range, it becomes extremely inaccurate and has a very slow reaction time. The only proper part of your measurement was the ability to watch it real-time inside the car.

So to confirm the rules to getting a valid reading:

#1. real air temp sensor
#2. located in intake pipe before turbo
#3. ability to watch while driving.

Quite honestly, I have no confidence in the open element filters at all. It's just illogical to think that it can ingest cooler air while the filter is located near the engine. If anyone had a true cold air intake (filter inside front bumper or lower grill area) then I'd see a reason to try it. Otherwise, intake temps will always rise above ambient temps.

Just to remind anyone who isn't clear on why intake temps matter, your temp coming in will directly affect your charge air temps.

The intercooler has a pre-determined efficiency rating when paired with the K03 at stock boost. Now most people have raised boost almost double and thus the charge air temps will be far hotter at the turbo's compressor outlet. The IC has a much harder time cooling the air back down to make peak efficiency of the charge air. Cool air = dense air, yada yada yada.

If any of you want to see what the effects of adiabatic compression (compression that turbo creates on intake air) are on intake air, try out this calculator and see for yourself:


08-20-2004, 08:13 AM
If I was still in college I would write a paper about why cone filters in the Audi 1.8T should be banned. Many experienced members here and on AW at one time or another installed these kits, tested it, and then removed it and went back to stock.

People go crazy trying to find new ways to modify their air intake without ever measuring flow or anything. For someone to think that an open element under the hood could somehow lead to lower intake temps than the stock airbox, then they would be defying the laws of physics.

The key to a CAI is to get the filter out of the engine bay and relocate it. Just putting a cone under the hood is pointless. especially since the stock setup is not restricitive to begin with.

And I won't even get into the issue of the bad MAF readings as a result from using a cone filter, ruining the MAF as a result from oil for the cotton filter, or the crappy filtration qualities caused by not oiling it enough.

08-20-2004, 09:14 AM
if you guys want to know a little bit of info about my old car here it is. i used to have an 89 s13 and i had a cold air intake that was inside my engine bay and not in the fenders, i had tons of mods on that car including headers which glows much brighter than our turbos do. in my car the headers were on the same side of the intake so haveing a hot turbo next to my intake wasnt a problem but having headers there was. anyway i had a water temp gauge that was not hooked up so what i did was tape it to the intake, i can read all the results on my gauge pod in the car. This worked nicely and was realy simple. when the car was driven for a while and was at idle my intake temps shot up high but once the car started moving the temps lowered drasticly. i had a little duct comming from the lower front of my bumper going straight to the intake which helped when the car was moving, i realy wish i had logged number but all i know is my set up worked. as soon as the car started moving my intake temps lowered as much as 20 degrees no joke......... maybe if some of you guys have some extra cash you should hook up a gauge to the cabin of the car, do two tests. one with the thermometer inside the factory airbox and one with the cold air and just log numbers on the same day around the same time. i garauntee you this kind of setup will work, i saw drastic improvements and its a fast acting brass thermometer. i think its worth the 15-40 bucks for the guage to see the results in the cabin of the car like i did, it turned out my cold air intake on the 240 worked///////// hope this helps

08-20-2004, 09:54 AM
Many other cars benefit from an open element filter. Especially NA cars.

But with the Audi the stock setup is a great design. I think we can all agree that the stock air box has been shown to provide more than enough air for pretty much everyone here (even APR Stage III uses the stock airbox).

Strike 1.

The next consideration is temps. How can you get air cooler than the outside air? You can't. So the best you can do is grab as much outside air as possible. You do this by closing off the filter off from the engine bay with a duct to the outside (which the stock setup already does perfectly). Or you can relocate the filter outside of the engine bay.

Strike 2.

Compare cost/benefit. Intake kit: about $200+. Stock air box: free. Benefits of a cone? None, and potentially harm the MAF, give bad readings from turbulent air (which causes the car to run rich).

Strike 3.

The best you could hope to accomplish with a cone is to get it to do what the stock airbox already does. So what's the point? It's counterintuitive.

08-20-2004, 11:40 AM
people realy like the sound, and i have to admit it does sound nice, also im running stock airbox but when i put my evo in it seems like the car is more responsive. i realy dont know about it so im over it, i want to put it back on now that i have my k04 on but unsure, me and some buddys will be renting a race track for ourselves and im going to have tons of runs. so im going to test 1/4mile times with stock and evo to see what gets better times. period

08-20-2004, 01:49 PM
I will point out that I have vents running from the front bumper up to the cone filter and I am not using a cotton/oil fiter (i think is actually polyuerothane). Maby I need to do an adaptation to it so that I can put the filter down by the fender but I am concerned about water getting so I ran the tubing (its a clothing dryer duct) from the fender to the intake instead.