So I've always been told the most efficient speed is about 50-55mph. I've been trying to calibrate my new MPG guage (amazingly it finally arrived only 40 days late, an no attempt from the company to contact us, but that's another story). The guage says the Smart has "MAF" (or was it MAP?) and my guage reads really low, so far I've got it set to +65%, +70% was reading too high. @ 0 it reads that I'm getting 12mpg. The instructions say to drive at 50-55mph (the most efficient speed) and adjsut until the guage reads the advertised Highway MPG, 41MPG, which seems to be about 65%.
So while doing my calibration, I've noticed that I seem to get the most efficient reading at 75mph? That doesn't seem right? If my guage is correct @55mph (41MPG) than driving @75mph yields around 48MPG, these are rough estimates for now. Again, I have no way of knowing if my guage is right or not, at least not until I can do a single trip filling up at the beginning and again at the end to calculate gas in/miles out and more tests, its only been 3 days. Every time the car shuts off the thing starts a "new trip," so I don't know what it is reading overall for the tank of gas. Wish it could realize when the tank is filled and track it that way also, it does read the fuel level after all.
Anyone tested it? 55mph or 75mph? Which is more efficient MPG wise?