MPG inconsistencies (answered!)

[dan50]

Originally Posted by felixdd

Even for a manual?

Sure think so. Fuel is turned back on at a certain rpm point for either trans so the engine doesn't stall when the clutch is depressed or you arrive at a stop. While the strategy probably varies somewhat, the basics are the same.

[doublej]

Hello "suss6052", your calculations might change if you use the right conversion factor.... 4.54 litres to a imperial gallon compared to your US gallon which is only 3.78 litres.

[suss6052]

Originally Posted by doublej

Hello "suss6052", your calculations might change if you use the right conversion factor.... 4.54 litres to a imperial gallon compared to your US gallon which is only 3.78 litres.

The calculation is correct even if I wrote down a slightly lower number for the imperial gallon, the point wasn't the specific size so much as it was the fact that the imperial gallon contains 20% more volume and therefore the published figures are 20% apart before accounting for differences in test methodologies.

Therefore subtracting the energy difference (a factor of 20%) the only remaining difference is that of the tests run to get the fuel economy figures.

[kam327]

Originally Posted by felixdd

That makes more sense then. Crazy canuck/euro testing

Does the "don't coaset in neutral" thing apply for manual cars too then?

The US EPA rating system changed in '08 and used to be more optimistic too. The '07 Focus window sticker said 27/34, but the "new" ratings (under the '08 system) on fueleconomy.gov are 23/31. That would suggest that the '12 Focus manual would be rated at 29/39 under the old system, much closer to the current Canadian rating of 30/42.

[c5karl]

Originally Posted by dan50

This has been said before, but to maximize fuel economy don't coast in neutral. While this seems counterintuitive, when coasting in gear fuel supply is generally cut-off as the mechanical connection to the wheels keeps the engine "running". If you shift to neutral, fuel has to be supplied to accomplish the same thing. This won't make a big difference, but manufacturers engineer it this way for a reason.

I've seen this mentioned on this forum several times, but are we sure the Focus has this feature? This Ford document, dated last June, does not list the Focus as one of the cars with ADFSO.

http://media.ford.com/images/10031/Ford_Tech_Fuel.pdf

[dan50]

Originally Posted by c5karl

I've seen this mentioned on this forum several times, but are we sure the Focus has this feature? This Ford document, dated last June, does not list the Focus as one of the cars with ADFSO.

http://media.ford.com/images/10031/Ford_Tech_Fuel.pdf

Maybe it doesn't. I thought this feature was almost universal but maybe not. Seems odd that Ford would go through the trouble of installing active grille shutters and not this, but maybe it's harder to implement on cars with manual gearboxes or DCTs. There are are posts here that seem to conclude the Focus has this feature, but maybe it isn't the "aggressive" fuel cut-off described in the Ford document.

[suss6052]

Originally Posted by c5karl

I've seen this mentioned on this forum several times, but are we sure the Focus has this feature? This Ford document, dated last June, does not list the Focus as one of the cars with ADFSO.

http://media.ford.com/images/10031/Ford_Tech_Fuel.pdf

Originally Posted by dan50

Maybe it doesn't. I thought this feature was almost universal but maybe not. Seems odd that Ford would go through the trouble of installing active grille shutters and not this, but maybe it's harder to implement on cars with manual gearboxes or DCTs. Learn something new every day...

That is an old and incomplete list of specific vehicles mentioned that have ADFSO, its basically already been confirmed that the 2012+ Focus does infact have ADFSO based on scangauge readings and reports from Ford engineers.

This was discussed at length here: http://www.focusfanatics.com/forum/showthread.php?t=281522

[kam327]

Originally Posted by c5karl

I've seen this mentioned on this forum several times, but are we sure the Focus has this feature? This Ford document, dated last June, does not list the Focus as one of the cars with ADFSO.

http://media.ford.com/images/10031/Ford_Tech_Fuel.pdf

Also the 2013 Source Book says we have it.

[thisisbenji]

Originally Posted by felixdd

Even for a manual?

Yup. For the first few years I drove manual (in my 95 civic 1.6l vtec) I would coast in N to stops. I averaged about 34-36 MPG, yet when I started downshifting to a stop my mileage instantly shot up to above 40 MPG every tank usually at about 42. The cool thing about that car is you could feel the exact RPM that the ECU started to give the car fuel as the RPMs fell. So if I was coasting to a stop in 3rd gear I could feel when the fuel came back on, I would downshift just before that point.

I miss that car (my younger sister has it now), I might try to steal it back. The gas mileage was so much better than the Focus.

[c5karl]

Originally Posted by thisisbenji

The gas mileage was so much better than the Focus.

According to Edmunds:

1995 Honda Civic sedan curb weight: 2313 lbs.
2013 Ford Focus sedan curb weight: 2907 lbs.

The '13 Fiesta is closer in weight and size to the '95 Civic than either the '13 Focus or the '13 Civic. Probably would get you similar fuel economy, too. Newtonian physics still rule the day.