Hey All,
I decided to test out the Cone Air filter install today, and more importantly, compare some data points to try and separate myth from fact. The first thing I wanted to validate was whether or not IAT (Intake Air Temperatures) change much, since a cone style filter does not draw air from outside, but from inside the engine compartment. Secondly, I wanted to compare the flow rates at the MAF and see if it made any changes to MAP. For my data logging, I used an Actron CP9185 Auto Scanner. This is a nice tool, and allows for all sorts of fun when you don't have access to tuning software.
First up was to take a look at the stock setup, and see what it does. I did runs in both 3rd and 4th gear, but the results were pretty much the same. From here on out, all my testing is done in 3rd gear.
What I found was the following with the stock box. Air flow at a 100% ECU load flows around 34lb/m (average) for full out runs, with MAP peaking at 73.8in /Hg (full boost) and settling to around 66in/Hg towards redline. The IAT stayed equal to the exterior temps, which is a good thing. Means we weren't sucking in any air that was warmer then the outside air.
Next up was the standard cone filter you can buy at any auto parts store. I went with a K&N air cone filter to ensure it had high flow rates. This is what I found with the cone filter.
First things first, the IAT was not noticeably effected by the filter. I left the snorkel on, so this may be providing enough cool air to ensure that the engine is still able to draw in cooler then engine bay air. This is a good thing. Air flow at 100% ECU load also went up by an average of 2lb/m across the board. However, this did not equate to more manifold pressure. For whatever reason, MAP was down 2in/Hg across the board. I find this interesting because this was reporting exactly what I was seeing in the car. I was having a harder time building boost. My boost gauge showed some eradicate behavior that I did not get with the stock box. To verify that the cone filter was causing this, I put the stock components back on, and the issue went away. Not sure why this is happening, since I am using a MBC, its not an ECU thing. Something to play with more in the future.
On a good note, I noticed that timing was advancing a lot faster with the Cone then with the stock air box. This may have something to do with the load cells being different, since with the stock box I was getting an ABS load of around 222 peak, but with the cone I was only getting into the 215 range. The car also felt slower to me, and a lot less linear. This may change over time, so I am going to put the cone filter back in and see if it changes over the next few days. But, right now, I am losing power with this thing, not gaining. This may be fixable though with some boost adjustments.