No problem. This exercise has helped me put together the
first WBTA article (everything has a purpose, right?
).
There's so much more to do here though.
The next part I'd like to get into, is how you're going to maintain a steady air inlet temperature.
Personally, I favor using a heater with a smart temperature controller, to set the inlet air temp slightly above room temperature, i.e. 25 deg C. Not sure how anyone else feels about that, but I don't believe that it would impact the performance test in any significant way.
The advantage is that it'll be a lot easier to maintain a steady inlet temp, asuming that you can setup the controller correctly. It would have to have a pretty quick response time though.
What you have left, is to measure the radiator inlet and outlet coolant temp, with some kind of accuracy, and that's going to be really tricky, because the temp difference is going to be awfully small.
That aside, you might consider measuring the pressure drop, of both the coolant and the air, if you're looking to fully characterize the radiator. Maybe you can share your thoughts on that too, then we can break it down?
edit: ps: it's not uncommon to find high shipping charges on eBay; it's an easy way to get around taxes...