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Old 10-26-2009, 06:28 PM   #4 (permalink)
Gen II Prianista
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Join Date: Jul 2009
Location: Ballamer, Merlin
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Time for a preliminary assessment of this proposed cold weather
thermal retention enhancement.

I've been doing my regular ~28 mi. round trip commute and weekend
errands runs with the radiant barrier in place on my Gen II for 13 days
now. Temps have been between 43 and 63 degF. I'm also running a
full upper grill block, and all but the lowest slot on the lower grill

The radiant barrier seems to be having a positive FE/MPG effect.

On my commutes, I'm seeing an apparent 2-3 MPG gain. On the stop,
park, and go weekend errand runs, the gain may be as much as 5
MPG. In addition, I am seeing an apparent 5-10 degF higher coolant
temps across the board.

I am being intentionally fuzzy about the possible gains. What with
driving safely and using hyper-mileing tactics, I haven't been able to
record hard coolant temp data despite having a ScanGauge to read
coolant temps and get trip and daily MPG numbers. I have made
numerous runs over very familiar routes, and I am seeing both MPG
numbers and coolant temps that are higher than I would have
expected to see without the barrier.

And that is about as good as I can do.

I'd like to encourage others, not just Prius drivers, who have the more
sophisticated monitoring gear and data recording capabilities -- or maybe
it's just more patience than I have -- to give the barrier a try and get some
good, hard numbers so it can be determned whether this is worth adding to
the established list of cold weather thermal retention enhancements.
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