by side mount, do you mean top mounted?
Wherever the intercooler is located, it is getting the air it needs to keep cool.
if the intercooler is located on "top," then the car will have a Hood
scoop, allowing air to travel into it and cool it...i.e. the impreza WRX...
or, you can have no Hood
scoop and have the intercooler front mounted, where the front bumper's massive mouth allows air to hit it directly on...
either way, air is still blowing on it.