08-10-2010, 10:44 PM
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#11 (permalink)
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Ohh snap
Join Date: Mar 2008
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I still think with cars with power to spare, hills can actually increase mileage with proper technique. I'll do 95 mph down them, and 55 mph up them in top gear (god bless the third lane) and this mileage usually bests my flat land mpg by a few%.
I'm going to have to try to see a measurable difference with extra weight, as I also feel if it has power to spare, it can essentially have a bigger 'battery' with more weight. (More kinetic energy stored in the mass of the car)
Or maybe I'm just crazy.
__________________
 Daily Driver
 Winter Beast
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08-10-2010, 10:45 PM
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#12 (permalink)
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EcoModding Apprentice
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4way stop signs at the bottom of hills should be outlawed.
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08-11-2010, 12:20 AM
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#13 (permalink)
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Left Lane Ecodriver
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You're not crazy, Brucey, you just have power to spare and a four speed tranny.
Driving a mile at 95mph, then a mile at 55mph results in 7% more aero drag than just driving 75mph. 7% is quite a lot, but evidently the Subaru gains more 7% with DWL instead of cruise control.
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08-11-2010, 09:57 AM
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#14 (permalink)
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Master EcoModder
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The Beast - '98 Grand Cherokee (ZJ) 5.9 Limited 90 day: 14.58 mpg (US)
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I don't do a ton of long highway trips, so I don't know if hills do better than flat ground in the beast, but I'm pretty sure they're not worse.
However, compared to the 4.0 I6, I get the same or better mpg on the hills, although it can beat me by 1 or 2 on the flats due to the displacement difference. It definitely helps to be able to pull at a hill at 50 in top gear turning 1500, or even 60 turning 1800, while the 4.0 would have to downshift a gear at any speed on most hills, meaning it would be turning 2100 at 50, or a bit over 2500 at 60. In these not-so-efficient old school engines, the extra RPM loses to the extra displacement.
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Call me crazy, but I actually try for mpg with this Jeep:
Typical driving: Back in Rochester for school, driving is 60 - 70% city
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08-11-2010, 09:57 AM
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#15 (permalink)
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...beats walking...
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Quote:
Originally Posted by miket
4way stop signs at the bottom of hills should be outlawed.
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...also, derisively, called "Mexican Stand-Off Signs"
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08-14-2010, 11:36 PM
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#16 (permalink)
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Northern most ecomodder
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there are a couple kinds of hills some are good some are bad.
slightly hilly roads up and down. help pulse and glide remain at a steadier speed so as to annoy other drivers less.
only round trips count for the next statements
bad hills are so steep, or have obstructions at the bottom so as to require the use of brakes. glide down engine off then waste energy with brakes. then on the drive up low MPGs
good hills are steep enough for steady speed engine off then can coast down or continue on your way. On the way back up if you can get better than half your flat ground MPG then your doing well.
I can think of quite a few of both types of hills in my area.
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Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.
One mile of road will take you one mile, one mile of runway can take you around the world.
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08-14-2010, 11:47 PM
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#17 (permalink)
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Banned
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Quote:
Originally Posted by Old Tele man
...also, derisively, called "Mexican Stand-Off Signs"
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Here in the Northeast I've heard of these referred to as being the "Sicilian stand-off".
Last edited by Thymeclock; 08-14-2010 at 11:55 PM..
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08-14-2010, 11:51 PM
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#18 (permalink)
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Banned
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Quote:
Originally Posted by brucey
I still think with cars with power to spare, hills can actually increase mileage with proper technique. I'll do 95 mph down them, and 55 mph up them in top gear (god bless the third lane) and this mileage usually bests my flat land mpg by a few%...
...Or maybe I'm just crazy.
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You are more lucky than you are "crazy".
You're lucky that the cops aren't around when you're goin' 95... 
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08-16-2010, 02:02 AM
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#19 (permalink)
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Ohh snap
Join Date: Mar 2008
Location: WV
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It's relative.
In some places 5 mph over is a big deal, but on those stretches of interstate through the mountains I've been passed by semi's while I was doing 90 mph. Not that I'm advocating speeding, it's just when the flow of traffic is doing 20 over the limit anyway, what are you going to do?
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 Daily Driver
 Winter Beast
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08-16-2010, 06:15 AM
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#20 (permalink)
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Master EcoModder
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Toss it in neutral a grab a 4 or 5 stripe draft, use 5th gear DFCO and AC if you need to slow down.
I have seen downhill grades of 7% for several miles around Blacksburg Va, probably a lot like WVa.
Ever gone downhill on a two lane at speeds that scare you with a logging truck on your arse?
Slow down and die.
Hit your brakes and become a postage stamp.
Those guys are CRAZY!
regards
Mech
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