Coast Down Testing - 2000 Honda Insight

[jime57]

Originally Posted by 3-Wheeler

Hi Jim,

OK, finally got around to looking at pictures taken of the car with the tail on and off and have updated the fuel mileage logs to reflect this....

Tail was taken off car at 06-05-11 and found water logged

Tail was put back on car at 09-25-11 after painting with primer.

Happy number crunching Jim.

Jim.

I looked at the logs, but was unable to reach any conclusions from the tank fills. One of the best tanks occured when the tail was off the car, but your comments indicated a lot of FAS coasting on that tank. That could make a big difference in itself. Some of your later lower FE tanks were done with the tail on. I guess you are experimenting with a lot of stuff at once. I know you were concentrating mainly on trying to develop Crr by coastdown, so would not have expected much direct FE measurement. The overall tanks are very impressive, I just can't draw any FE conclusions from the data. Thanks for the good record

[3-Wheeler]

Originally Posted by jimepting

I looked at the logs, but was unable to reach any conclusions from the tank fills. One of the best tanks occured when the tail was off the car, but your comments indicated a lot of FAS coasting on that tank.

Actually Jim, I started doing key-off-FAS's before this time in the mileage logs. If you look back further, you should be able to see a comment about this. I have been driving and using this same technique with the FAS board installed, so you can consider this something that is *normal* to the data.

Originally Posted by jimepting

That could make a big difference in itself. Some of your later lower FE tanks were done with the tail on. I guess you are experimenting with a lot of stuff at once.

Actually my driving technique is very consistent, even though the gas log does not reflect this. The dip in mileage is due mostly to the colder weather!!

Originally Posted by jimepting

I know you were concentrating mainly on trying to develop Crr by coastdown, so would not have expected much direct FE measurement. The overall tanks are very impressive, I just can't draw any FE conclusions from the data. Thanks for the good record

Remember also that my speeds are at or lower than 40 mph most of the time, so any gain of the tail aero wise, is minimized at this slow speed, and as you mentioned, makes it harder to determine it's affect.

If you recall however, I did post an A-B test with the tail on/off about two years ago, at a speed of 56 mph. If I recall correctly, it showed an aero gain of about 18% at this speed.

Jim.