[thrifty118]

Air speed in Intercooler compared to road Speed

Andy, I was looking at your data on the airflow velocity in the intercooler and tried to look at it another way. I tried to calibrate the vertical axis in the same units (mph) as the vehicle speed.
With your corrections (between average IC airspeed versus sensor), I end up with the flow through the IC approximately 5% of the vehicle speed.

This is way below what a front mounted intercooler would provide. Have I got this right?

 

[thrifty118]

Hmmm... I'm not sure. If you look at the Y-axis, it's in feet/minute. Your red (5%) line intersects the 80mph line at about 450 fpm, which is (450 * 60 / 5280) = 5.11 mph. 5.11 / 80 = 6.4%... a bit above 5%.

I see what you're getting at though... yes, the flow through the intercooler is below the potential flow that an unobstructed, properly ducted front mounted intercooler would receive. Keep in mind that even a front mounted cooler would not see a flow equal to vehicle speed... it creates quite a bit of drag and would slow the airflow down just by itself... not to mention other obstructions in front or behind in the path of the cooling air. The airflow you see in my graphs is *after* the intercooler.

I was not sure if your plot had already applied the 284/374 (average/sensor location) factor that you mentioned later. I you had already corrected it, you are quite right.
I have had a couple of Evo's and suspect that the airflow would be about 50% of the incident velocity. That is still 10X better than 5! The Lotus intercooler is much deeper, I suspect to compensate for the lower velocities.