OK, some of you asked for this, so I started a new thread for all of us to use. So here we go!
Great way to start out a new tank!
I was dreading the drive in this morning because it was dark and raining. Both FE killers due to wipers and lights on and increased rolling resistance from tires pushing water out of the way and spraying it all over. Temp was 45F. Last night I indexed my plugs and decided on a modified route to work that would cut out some FE killer lights (when I miss them). So I count 3 variables that have changed for this mornings trip, rain, indexed plugs and a new route.
Well right out of the box (garage) I noticed a difference in FE. By the time I get to the main road, about 0.2 km into my trip, my FE was 19 MPG where usually it was 16.5. Then I began the new segment of my route. Eventually when the new segment merged into the original route at about the 10 km mark, I noticed that I was about 6.5 MPG higher than my previous best to that point. At the 20 km point I was at 6.7 MPG higher, or 74.8 MPG! At this point I am at the low point of my commute so don't get too excited im telling myself. Now the merge onto I-79 and I duck in behind a fuel tanker and draft at 55 MPH, ASI showing 20-30 MPH. At the 30 km mark I am exiting I-79 and am at the high point of the commute, 61.9 MPG. The final 10 km leg has 10 stoplights and I made 5 of them. I cruised into the parking lot at 63.68 MPG which beats the old record of 62.75! The trip length is slightly shorter so the total fuel used was .384 gallons beating the previous record of .392.
So I'm sitting here wondering, WTF? It was raining, which in my experience is detrimental to FE and wind wasn't really a factor. On the downhill ign off segments, speeds seemed to be better than normal. Usually I take a hairpin curve, engine off and exit at about 35 MPH and coast for a mile or so to a 25 MPH speed limit sign at about 27 MPH. Today I took the curve slower, exiting at 32MPH and was still at 30MPH when I got to the 25 MPH sign. ASI showed same as the speedo so no tail wind.
I have heard some Prius and Insight drivers say that they notice an increase in FE with very light rain but could never prove it definitively. I can't prove anything at this point but what i know for sure is that starting a new tank this way is very satisfying. Mehbe the indexing helped? Mehbe the new route? We shall see on Monday which is supposed to be cooler but dry. Thunderstorms and wind for tonights drive, but 63F too. Maybe I will be surprised again?
Doh! I thought of possibly a 4th variable.... I might have gotten the summer gas formulation yesterday! That would be an increase of 1.7% in energy content per gallon. Apply 1.7% increase to the 62.75 MPG and you get 63.87. Hmmmm.
Well the storms held off and the weather was perfect. 72F, dry and a nice tailwind, 62.0 MPG on the way home, another record for me. I can't think of any better conditions for FE. I think this is the wall for the drive home, 62 MPG. Still room for improvement on the way to work, warmer temps and dry roads for one. But Not much more to squeeze out there either. From now on it's Built-in FE Mods. Wheels/tires first, then CX tranny and CX IM/TB. Im running out if things in my bag of tricks.