[jime57]

I've been doing some testing on the Interstate on my Insight 1 to try to establish a FE baseline for aero modification assessment. From what I'm seeing here in somewhat hilly Richmond, and in this nice summer weather, the baseline FE looks like 99-100 MPG at 55 MPH trip average using best hypermiling techniques.

A few observations:
1. 55 MPH is not the optimum speed for FE, but it is about as slow as one dares test if the question is aero assement. I think...........
2. If there are any hills of any degree, it is virtually impossible to maintain a constant 55 MPH and lean burn, therefore it seems that the best course would be to target a roundtrip average of 54 MPH, allowing a slight deterioration for the turn-around. This method would allow the speed to drift up and down by about 4-5 MPH while maintaining the 54 MPH trip average. I have been monitoring the trip average by use of a Scangauge.
3. Lean burn must be maintained at all or nearly all time if the data is to be relevant. A large mix of lean burn and standard mixture is not going to be stable or repeatable.
4. Any traffic holdup at all will ruin a test run. Just start over if there is any stop or pertubation.
5. The RT test course must be of some significant length, 35-45 miles, to allow slight driving errors or pertubations to be submersed in the larger data set.
6. An "uncomplicated" turn-around location must be selected since the turn-around has a significant effect on the data. I found a cloverleaf without lights which allows me to have a perdictable turn.

I'd love to have comments on these points. I'm moving along on my mod package, which I intend to test as a whole, grill block, underbelly, boat tail.
Like Metro, I am trying to execute the boat tail in cardboard as a first effort.

OBTW, has anyone tried to duplicate the Cd baseline of .25 by coastdown method?

Jim E.