First Aeromod (Grille Block)
 

So yesterday I decided to cover the upper grille on the Corsica with masking tape, to see if it made any noticeable aerodynamic improvement. I figure simply taping over the grille is the easiest way to check before doing anything permanent. I also wanted to find out how hot the coolant would get.

On a 170 mile trip across the state (despite fierce crosswinds) I found that coasting times were significantly extended. There were many hills that I was able to coast down and not lose speed, some even accelerating, where I couldn't before. Level-terrain MPG might have been noticeably improved by about 2 MPG, but it was difficult to tell with the winds.

The only real noticeable difference in coolant temp was that it maintained 195 instead of 190 for the whole trip, although it was unusually warm (85 degrees), which might have influenced that as well. I don't think the temp went above 205 for the whole trip, the fan never came on.

I have to say that I am quite impressed by this mod. There was noticeable aerodynamic gain, and coolant temp didn't seem to be affected much. In fact, I could probably block off some of the lower grille as well. I even kind of like the new aesthetic value of the grill block, kind of gives the ol' girl a sportier look :D. Now I'll just have to look into a more permanent solution for this fix. I've never used any of that coroplast stuff mentioned on here, so I'll be looking into that when I find the time.

Happy hypermiling!

Nice job. Look foward to seeing something more permanent.

How did you monitor if your fan kicked in or not?

Nothing technical. I just know that it doesn't turn on when the temp gauge is below a certain level, which it was below for all of the highway portion. There really wasn't much idle time to give the coolant a chance to heat up. At idle and low speeds it is easy to hear and feel when the fan kicks in. It rarely ever comes on on that car. That was one of the problems that I had anticipated with the upper grille block. I can see how it might be a problem in stop-and-go traffic or extensive idling, but those are situations in which the engine would be running hot anyway, with or without the grille block. And I have some level of control over the amount of idling.