[Matt Herring]

Home now and put a total of 80 highway miles on the buggy today while experimenting with the GPS Xguage SGII feature. Total mpg for the route was 62+. Not the best I've ever done on the highway but not bad considering it's an improvement from the 58-60 I've seen prior to using the GPS XGuage.

After having some time with the GPS feature I would say the following about driving a Prius on the highway in terms of SGII instrumentation:

1. IGN 5 produces the best mpg but acceleration is nearly non existent and it's only slightly above an ICE coast. But, on some nice downhills you can pick up more speed than in an ICE coast and max out mpg. I'd liken it most closely to neutral coast in an ICE-only vehicle (which is not recommended in a Prius in the 60+ mph range).

2. Xguage GPS 16.0 to 16.5 seems to be ideal for mpg at speeds between 50-60 mph. Alot of times I have been running 17.0 to 17.5 to get a little more accel than in the 16-16.5 range (to limit the time I need full ICE to accel the car before repeating GPS 16-17). Although it's not max mpg when running above 16.5 GPS it seems to work better in the flow of traffic (especially on 65 mph marked roads where I'm struggling to stay at/around 55 mph due to hypermiling techniques and terrain).

3. If you're running GPS 10-11 (at 50+ mph) you're better off releasing the GO pedal and dropping down to IGN 5/GPS 0.0 before reapplying the GO pedal ever so lightly to stay in IGN 5. This way you are maxing out mpg since GPS 10 accel is only slightly better than IGN 5 and GPS 10 mpg is much lower than IGN 5 mpg.