[apk919]

One of the things I had briefly mentioned was the need to calibrate the air flow meter... I set up a blower to force air into the roof scoop, and then took readings from the back face of the intercooler. Dividing the face into 15 segments (5 wide by 3 high), I took flow readings (in fpm) at all 15 segments, then a flow reading from the location that the meter would occupy during the rolling test. By averaging the readings, I could estimate the volumetric flow being forced through the intercooler by the blower by multiplying the average fpm by the area of the intercooler (0.6076 sqft.). Then the ratio of the average flow to the meter location flow would give me a correction factor for the logged data, i.e. if the average was 283.5 fpm, the meter read 374 fpm in its logging location, I'd have to apply (283.5 / 375) * 0.6076 to the logged fpm readings to approximate cfm through the intercooler.

Below are the calibration matrices for the pre- and post- fettle calibrations. Notice that after fettling that the average flow is higher, and better distributed across the face of the intercooler. I also tried two positions for the meter during the post-fettle calibration... the original pre-fettle position, and an alternate position that gave the same static flow as the pre-fettle position

First (left) image: Calibration matrix before fettling
Second (right) image: Calibration matrix after fettling (with alternate sensor position)