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Old 12-26-2008, 06:47 PM   #3 (permalink)
X-Frenchy: very
groar's Avatar
Join Date: Jun 2008
Location: Toulouse, France
Posts: 595

scenic - '01 renault scenic
90 day: 43.09 mpg (US)

megane - '97 renault megane classic
90 day: 72.53 mpg (US)

dennisius - '06 Toyota Prius
Team Toyota
90 day: 69.27 mpg (US)
Thanks: 9
Thanked 34 Times in 23 Posts
Lessons learned

I didn't pass the finish line yet, but already learned a few lessons. Some are only confirmations for me, but others are brand new.

Confirmations :
  • Inflate your tires at max sidewall and the car will coast forever... I love the feeling to coast in neutral in city
  • Limiting its max speed will save fuel.
  • Safety & courtesy (per ex keeping a higher speed than what DWL permits you) do impact FE, but they are non maskable rules. They are worse in mountain roads when your DWL max speed limit becomes the lower speed limit and make you a dumb cruise control...
  • I have to improve my drivings in mountain roads, even when I have no safety or courtesy constraint.
New lessons :
  • 5w oil do save gas. This is visible when coasting in neutral. Before oil change the consumption was at 1.4L/100 (168mpg) when coasting in neutral at 60km/h. Since oil change it's at 1.2L/100 (196mpg) ie at least a 8% saving, at least when idling...
  • Following situations do hit FE :
    • Freezing or near freezing temperatures (3°C = 37°F)
    • High humidity (raining or fog)
    • Head and side wind
    In all cases, FE is lower and DWL is more difficult. Trying to optimize the FE generates an higher deceleration which will need an stronger acceleration that will eat more than what was saved.

The rules I'm following are :
  1. safety and courtesy are unmaskable rules
  2. do not pay for more than 80 km/h (50mph) except if offered by gravity
  3. pulse 'n coast in neutral in cities (45-55 km/h 28-34mph)
  4. DWL out of cities (>60 km/h 37mph) : max FE of 4.0L/100 (58mpg)

With all these descriptions, 3 people and tens of Xmas gifts, you guess correctly that I will not achieve my goal of 66.66mpg, but I'm currently at my best tank with 4.45l/100 (52.82mpg) and my Xmas challenge is currently at 4.37L/100 (53.82mpg) which is my best trip result.


PS thanks for table support, I will use it to publish my results.
Save money & CO2 at home :
Created and managed by the creators of
Earth and health are priceless, so are kilotank and AT-PZEV
Best Mégane tank: 1268.9mi @ 77.847 MPG(US)
2008/06-2011/10 saving:
  • 5725.5 kg CO2 (5342.6+382.9)
  • Diesel / Money: 42.17% = 2446.25€ = 3357.26$

megane : thread - kill switch.
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