Airspeed indicator for your car

[krousdb]

Originally Posted by rh77

A while back MetroMPG noticed an increase in FE on his ScanGauge when cars passed him on the highway, or cruising in a heavy flow of traffic (the econ dropped when exiting the highway). The theory asked whether it was better to take the 2-lane road, or the "Interstate" (or Canadian equivalent). I can't recall the thread, but there was discussion that heavy traffic provides an airflow beneficial to FE vs. a desolate road, and if a continuous pocket of air existed to cruise in. Since the oppositely passing car effected you for longer than expected, there may be some weight to the theory. Good work!

RH77

I tested this theory today. Previously my best trip to work was 60.41 MPG at 30F, Dry roads and a 9MPH tail wind. Ths was pulling out all of the stops and taking the "road less traveled" route which takes 55 minutes. The distance was 40.57 km, 1.580 L, engine on 67% of distance.

Today I took the "road that more traveled" route which includes 6 more miles of highway and three fewer miles of engine off coasting. It took ten fewer minutes that the normal route. I didn't do any drafting, just took advantage of the wake left behind by cars in front of me and cars passing in the left lane. The windspeed / speedometer difference was -10 to -20 mph as a result.

The temp was 44F, wet roads, light and variable winds. The result was 59.59 MPG, 39.60 km, 1.563 L, engine on 81% of distance. So the MPG was slightly less, but the fuel used was also less because of the shorter distance.

One other benefit of the faster drive is that when I get off of the highway, there is less traffic and I made all of the lights. Had I not done that I would have been 2-3 MPG lower.

This deserves further study. More aerodynamic mods could help further now that I might be spending more miles at higher speeds.