My wife drove our 2009 FEH AWD from New Mexico to Detroit, Michigan Starting February 20th, stayed there until March 20th and drove back. This was 1500 miles one way, 700 miles in Detroit area, and 1500 miles return.

She got 26.2 MPG for this trip, which was about 2-3 MPG less than I thought it would have been. She drove on the interstates the whole way, driving 70-80 MPH using the cruise control most of the time. I know this is a little fast, but it seems the MPG wouldn't have affected it that much.

We were getting 30-31 MPG in New Mexico before the trip and we're getting the same again now. We have 11,000 miles on this vehicle, use 5W-20 Mobil-1 and this vehicle runs fine in all respects.

These MPG figures are based on the INFO display. We live at 6800 feet elevation - could the FEH computer be calibrated to get the best MPG at this elevation and will get less MPG at lower elevations as we did going to Detroit?

 

Cold winter weather will significantly drop mileage. The mileage champ on this site has reported a 15 mpg drop when the temperature in his location dropped to all 35 degrees! The temperature change by itself can explain the mpg loss.

 

I agree cold weather will drop the mileage, but it was the same cold temperature here in New Mexico before/after my wife's trip, so the drop should have been the same everywhere, but instead she got a good 4 MPG less on the trip.

 

Could there have been a difference in the gas. Do you guys have E10 in your area of New Mexico yet. How about in Detroit? Could there have been an issue with "Winter Blends" as well.

I know we've heard that the 2009 FEH handles E10 better than older models but there's still the ~7% change in energy density between 100% gas and E10.

 

Driving over 70 MPH you start get some real wind resistance.
Driving at 80 MPG really drops off.
Just my two cents.

 

I think the biggest factor was the speed and the cold weather was a contributing factor as well. Last September we took a 200 mile trip all on New Mexico highways driving 65-70 mph and we got 31-32 MPG on that trip and the air temperature was 65-75 degrees.

I'm sure all the miles driven at 80 mph was where most of the fuel was consumed.

 

From what little experience I have in the hybrid arena, I see three issues, other than having an AWD: first, 80MPH. That's definitely going to be a factor, like Tiger mentioned. I seldom drive over 70, if I'm going for the mileage. Second, you didn't mention whether or not the cruise was used for the trip. Cruise, with the exception of going uphill, is a definite booster for mileage. My 06 FEH will average 33-36 at 70, with CC on. I also take it out of CC going uphill and keep egg pressure on the accelerator going up until I'm down to 55, then keep just enough on to maintain that. Third, oddly enough, is simple, a good wash and wax before a long trip. My FEH gets a good W&W every month, as did my truck before that. A dirty vehicle can cost you up to 0.5MPG. BTW, that's a hand wax (or buffer, if you desire), not a car wash spray wax.


As others have mentioned in other forums, also make sure your tires are up there, per the sidewall numbers, not the doorpost numbers. I gained almost 1.5MPG, just be boosting my tires from 30psi to 42psi. A shade harsher ride. but mileage was the more important factor. I've also gone to K&N filters throughout; better filtration.

I hope this is of use to you.


Bob
2006 FEH, 2WD

 

If your a pilot, you didn't mention a head wind. I was driving home from a cottage yesterday through some open farm land. A bit of rain but very high winds were pushing me around. My Scanguage showed a 10MPG drop at 60MPH with the wind. I drove though a series of passing storms, when it finally cleared up, my MPG returned to normal.

 

The posts above have identified most of the obvious culprits. I will add one more possible factor, the load. If you stuffed the FEH with a lot of luggage, the added weight will decrease your gas mileage.

However, the biggest factor was the decision to drive 70-80 MPH as Tigermidge said. Wind resistance roughly doubles from 55 to 70 MPH and keeps on increasing exponentially as you go faster. So there was a significant hit by choosing to drive close to 80 MPH. Another wind factor is whether or not you kept the windows and sunroof closed. While you probably did not open them traveling in cool weather, opening them adds an additional hit on MPG when traveling at highway speeds. Bottom line, hybrid car or not, slowing down increases gas mileage. In my Mustang Cobra, which is a lot more aerodynamic than the roughly square-shaped FEH, my highway MPG increases from 20 MPG to 24 MPG just by slowing down from 75-80 MPH to 70 MPH on the expressway. Of course, the only way to drive such a vehicle so slowly is to use the cruise control.

The second biggest factor was probably the temperature. In driving my 2007 FWD FEH in Michigan, the MPG drops about 1 MPG for every 10 degree drop in temperature, so making the trip in the summer would give you better gas mileage. Right now, every fill up of my FEH is showing 10-20 more miles of range as the temperatures have risen this spring.

The third biggest factor was probably the cruise control. Cruise control will work great on flat roads but the RPMs will really zoom if you are climbing hills, particularly at 70+ MPH. I agree with Bob95fxdl on the ways to keep your RPM down when climbing hills at highway speeds and the effect of boosting tire pressures to the 40 PSI range.

 

I don't think cruise control will every improve mileage. At best, on a dead-flat road, it might match what you can accomplish using your foot. As soon as you get any amount of up or down grade, it will impact mileage, due to it's dumb adherance to the set speed.

Without cruise, you will naturally fall into Driving With Load, ie: letting your speed fall off on the upgrade, recoup on the down grade.

The cruise control, OTOH, will quasi-accelerate on the up grade, consuming much more gas-per-distance in the process. You partially, but not wholly, recoup that extra consumption on the following down grade.

Either way, hilly terrain is tough on mileage, but with cruise control more so.

Maybe, for an all-day run on relatively level terrain, the mileage hit is worth it, to preserve your foot.