MAX Update No. 80: Cooling Tests and Travels

Back in October of '09 (MAX Update No. 35: Nose Job for Better Aerodynamics) I mentioned I believed MAX could get away with a much smaller air inlet for the radiator—about 1/3 the size of its original area (which was one square foot). And I calculated that this smaller inlet would reduce drag by about a horsepower in cruise, which is a significant bite of MAX's modest horsepower needs. And then about a year ago (MAX Update No. 52: Cooling System Bug Report) I did some test driving with the air inlet partially blocked off, which gave me confidence in my calculations…enough confidence to make the cooling air inlet in MAX's streamlined body about half the size of the inlet in the Escape from Berkeley body.

And my static experiments with low power fuel consumption (MAX Update No. 68: Idle Speculation and MAX Update No. 70: MAX's Theoretical Max) made me daring enough to start last month's trip to Ohio with a small roll of white duct tape in my tool box, so I could experiment with closing off the inlet even further.

So here's how MAX looked when I left Cave Junction (ignore the cardboard box in the passenger's seat, it was a shipment I had to drop off at UPS on the way) with the radiator opening taped up to 60 square inches of inlet area—about 40% of its EfB size. Purists may think me snooty because I didn't use the traditional silver-grey duct tape, but with the pink bandana on my face and the red plaid Elmer Fudd hat on my head, I think I looked sufficiently proletariat that the white duct tape passed without notice. It's not like I was putting on airs.

The advantage of duct tape was I could hop out and tear it off if I had an overheating problem—remember, I'm still experimenting and still learning, and at this stage I preferred expedient to classy.

Up through Oregon (including a bumper-to-bumper traffic jam in Portland) through Washington, across Idaho, climbing into Montana and across the Great Divide and into Wyoming…no overheating problems, so I added more duct tape and narrowed the 5-1/2” tall radiator inlet to 8” wide. That's 44 square inches, less than a third of the Escape from Berkeley nose opening. And that's how I drove across South Dakota and into Minnesota, and by the way, did I mention there was a record heat wave going through the Midwest in mid-July?