Quote:
Originally Posted by MetroMPG
I suspect that my car may have had more to gain, percent-wise, than your Insight:
The main difference being the cross sectional area at the rear where each of our OEM shapes end and where the tails begin (or began in the case of my prototype tail, which has long since gone out with the recycling). I suspect the area at the rear of my car is bigger - thus more room for improvement.
I'd be willing to calculate/estimate that rear area of my car if you're interested in comparing. I bet this has probably come up already.
Darin
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Hi Darin,
I think you will prove to be most correct in your assessment!
Besides the ongoing coast down tests, I have two tanks of gas that say the increase in efficiency due to the tail is small for the Insight. Of course we can always take this with a grain of salt, as the ambient conditions are not the same now as they were last spring, when I stopped driving the car, but check the figures during the same months last year, and there is a slight increase, but not 10%.
About the only way I can think of to really get an idea, is to stay late some night after work where we have a small garage that the tail can be bolted/unbolted and checked on a 55 mph stretch of road that is normally busy during the day, but may quiet down enough at night and very close to work.
There is only the Interstate that is really flat near my house, but is always very busy, so this option is out.
There is one other 55 mph country road that I normally drive, but it is old and very bumpy, plus being 20 miles from the house, makes it hard to drive home to swap the tail on/off.
I think a definitive A-B-A test is in order when time permits; maybe in a couple of weeks on a Friday night.
Jim.