L31MaxExpress
I'm Awesome
I know this may seem goofy, but does that section of road have moderate rolling hills? Everything I own even without lean cruise gets freakishly good fuel mileage on roads that have rolling hills as long as there is not a large total elevation change. The hyper miler guys use a technique called pulse and glide. Where they accelerate and then coast then rinse and repeat. They claim better mileage doing it. I think the rolling hills have the same effect. The engine operates more efficiently climbing because it is not fighting the parasitic loss of the vacuum throttling the engine, then when you go down hill the engine practically freewheels and there are times DFCO even activates at highway speed.The heavier the vehicle the more noticeable this effect. I noticed this even with a stock Q-Jet fed engine. In over-run conditions with minimal throttle the carb actually lean cruised to a certain extent. I have actually read alot of their experiments on EcoModder.I got to reading and saw the same thing with the MAP readings, so to get any better I'd need to log for that in and out of lean cruise on the same stretch of road to find out what makes it happiest. Looking at where it's 17:1 and leaner it's where I barely have the throttle cracked going downhill, so very low threat there. Flat roads are scarce near the house to get a feel for 70-80 mph, but I figured if I dragged it out at too high a load I'd just be shooting myself in the foot. I have a 1300mi one way/2600mi round trip road trip coming up next Saturday. If the wind isn't blowing like a sunofabitch I'll be able to get a good idea for the change in highway economy. Makes me want to try it on the Z06, but I think it'll kill cruise control if I do it. Worth a shot though as it's totally reversible. That gets 25+ mpg highway, 30 would be pretty sweet. I saw 31 on a trip to Denver and back. I don't know what it is about that stretch of interstate, everything I own gets freakishly good mpg on it.
FWIW, slightly modifying my driving style on those rolling hills also increased my mileage more. Rolling downhill, I pickup ~5 mph, then using steady throttle let the uphill section munch down the mph a little, near the top of the grade, let off a little so that the momentum is still carrying you over the grade and let the downhill slope lightly accelerate you again. Lets say I am in an area with minimal traffic and the speed limit is 75 mph. On flat land I hold the throttle steady at 70 mph, holding the throttle steady going uphill it munches down to 65 mph, then going downhill it climbs to 75.
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