I had to try a Renault Twingo during one day [1] :
- diesel 1.461L 65hp
- manual 5sp
- 3 doors
- rated 45.2 (city) 61.9 (highway) 54.7 (combined)
- CO2 113 g/km.
I plugged my SG2, which is incompatible with my 2 older Renault, and it was nearly fully compatible. It was missing TPS so the SG2 didn't had the open/closed loop information...
As I didn't know the cubic capacity when I plugged the SG2, I configured 1.6L, so the following figures are what I remember multiplied by 1.461/1.6.
I didn't had time this day so I have only been able to test the information I do not have in my scenic : the instantaneous consumption at speeds under 35km/h (21mph).
When the engine was started, the consumption at idle was at 1.65L/h (0.43gph). Ten seconds after it was down to 0.9L/h (0.24gph). After 1/4h of stop&go traffic, the consumption at idle stabilized at 0.73L/h (0.19gph).
Another thing I wanted to know is how much consumption the car has when you drive in 1st/2nd gear with the engine at idle (ie you doesn't touch any pedal). The results were :
| gear | L/100 | km/h | mpg | mph |
| 1st | 18 | 8 | 12.9 | 5 |
| 2nd | 9 | 15 | 25.8 | 9 |
At these speeds, coasting in neutral would consume at 0.73L/h (0.19gph) :
| km/h | L/100 | mph | mpg |
| 8 | 9 | 5 | 26 |
| 15 | 5 | 9 | 48 |
The conclusion is that at low speeds it's certainly better to pulse 'n coast in neutral than keeping the engine in gear at idle rpm.
[1] the megane had a leak near the water pump, the thermostat melted in part and the temperature gauge was shifted down. As I didn't drive this car since months I though the low temperature shown by the gauge was because of near freezing temperatures and short commutes (20 miles). I worried when i saw the gauge going up & down... I had then not enough water in the cooling system. Happily it wasn't the water pump, but the water tank and a pipe.
Even without front grill (removed because this problem) and heating system at full load (in the hope to remove as much heat from under the hood) I achieved 43mpg, only 10% under my summer tanks
Denis.