I have installed a coolant temp guage a few weeks ago and removed my Radiator fan at the end of the last tank. I did not see any improvement in engine response or economy without the fan, which baffles me.
So my next thing on the list was the air dam. I have cut up a cardboard box and started sticking the pieces behind my grill in front of my radiator. Right now 95% of the grill is blocked with a small ~2"X12" opening on one side exposed(not even in front of the radiator).
I drove to work with 79 degree ambient temps and never got beyond 218 degrees (same as without block). It will be warmer out when I go home this evening, so that will be a better test.
One awesome thing I noticed is it only took 1-2 miles to get up to 200 degrees, where it usually takes 4 miles or so. Big improvement there that should increase economy by itself.
I am still not sure if I can coast any further with the cardboard in place. It is not evenly put on like the nice blocks I have seen here, as I don't want to cover up my chrome grill and make my car ugly . I might be able to paint the cardboard silver and put it closer to the grill for a more permanent install (or maybe black?).
How much should a grill block improve on a car as big as mine anyhow? Is it going to be a smaller improvement in comparison to a metro with a grill block?
No, I don't have a fan yet. I don't drive in traffic though, and turn off at stoplights. From my testing today it looks like it takes 30-60 seconds for the temp to start rising from 210 after my coast to the stoplight. (had to leave it running as I had run my battery down the night before leaving my lights on)