Range difference between RWD and AWD on highway

[wavyphotons]

Hi folks,
I'm almost ready to order mach-e premium but trying to decide between extended battery rwd (303 miles) vs extended awd (277 miles). I'll mostly be driving it in texas where rwd is fine most of the time. Only reason I'll get awd is if we go on long road trips in mountains/snow (we are talking about 10-12 hours drive, so it'll be quite rare given charging needs). I don't mind paying $2700 extra to get awd but don't want to take the range hit of 26 miles.
On most days, range hit isn't a problem, but i'm planning on doing regular road trips (let's say once / twice a month) that are ~215 miles each way and will be nice to do so without taking a break.
Will I be pushing the awd range (assuming 75mph highway driving, nothing too aggressive) ?
Then I read this interesting comment by kltye that " MME has the ability to turn off the front motor for cruising efficiency, so on the highway it near enough makes no difference between the RWD and AWD. ".
I can't find any other comments / proof of it, so not sure if it's true or not.
Any thoughts ? Should I just stick to RWD given my driving scenarios ? Is AWD actually slower even in cruise control/highway driving and we lose range ?

thanks!!

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[kltye]

Hi folks,
I'm almost ready to order mach-e premium but trying to decide between extended battery rwd (303 miles) vs extended awd (277 miles). I'll mostly be driving it in texas where rwd is fine most of the time. Only reason I'll get awd is if we go on long road trips in mountains/snow (we are talking about 10-12 hours drive, so it'll be quite rare given charging needs). I don't mind paying $2700 extra to get awd but don't want to take the range hit of 26 miles.
On most days, range hit isn't a problem, but i'm planning on doing regular road trips (let's say once / twice a month) that are ~215 miles each way and will be nice to do so without taking a break.
Will I be pushing the awd range (assuming 75mph highway driving, nothing too aggressive) ?
Then I read this interesting comment by kltye that " MME has the ability to turn off the front motor for cruising efficiency, so on the highway it near enough makes no difference between the RWD and AWD. ".
I can't find any other comments / proof of it, so not sure if it's true or not.
Any thoughts ? Should I just stick to RWD given my driving scenarios ? Is AWD actually slower even in cruise control/highway driving and we lose range ?

thanks!!

Hey, that's me right there! I don't remember where I got that info from exactly, but IIRC it's from a thread with someone charting their OBD output on their trips, and tracking things like power to the motor and/or regen power.

I can tell you, though, that 1300 mile roadtrip had me averaging between 2.1 mi per kWh (raining, elevation gain of a couple hundred feet) to 2.6 mi per kWh (dry, but still cold). All this was done with next to no heat, at temperatures between 30-40F, at a speed of between 74-80 mph with cruise control. Maybe others can chime in on their efficiency, but I don't really see much difference from what's been reported on various threads here.

If I could do it all over again, I'd get the AWD just for more power.

 

[wavyphotons]

thanks for the info and quick reply - I was about to send you a private message to bring attention to this thread

For now, I went ahead w/ AWD just as insurance and extra power - but definitely want to make sure I can still get ~225miles of actual range on highway in normal conditions.

Let's see if others have data on this!

 

[Kevin P]

I did an 85 mile mostly highway trip today in my GT. Roughly 40 degrees outside. Used 36% of battery, which would equate to 235-ish if I went from 100% to 0% at the same rate. A 225 mile trip would make me very nervous, and would leave you with a completely depleted battery. Warmer weather would give somewhat better range though, and the GT gets a bit worse than an AWD4X so you might be ok.

 

[kltye]

thanks for the info and quick reply - I was about to send you a private message to bring attention to this thread

For now, I went ahead w/ AWD just as insurance and extra power - but definitely want to make sure I can still get ~225miles of actual range on highway in normal conditions.

Let's see if others have data on this!

Personally, I would plan on ~170-180 miles of real-world range on the highway (2 miles per kWh, and 80kWh out of the 88kWh useable), since you probably don't want to pull in on "fumes", will probably use some heat, and Texans seem to drive a little bit faster than ~70mph I, too, like to drive as far and fast as possible without breaks, but sadly I think 215 miles might be pushing it a bit far.

 

[timbop]

Then I read this interesting comment by kltye that " MME has the ability to turn off the front motor for cruising efficiency, so on the highway it near enough makes no difference between the RWD and AWD. ".

I'm not sure how accurate that is as the front motor is a permanent magnet motor, but I don't know enough to confirm that. Even if it is not getting power from the battery it is likely going to induce a little extra drag. With that said, a lot depends on your speed, temperature, altitude change, wind, and precipitation. Most of the year you should be just fine making that distance without charging, but in colder weather you might need to stop for 5 to 10 minutes at a fast DC charger just to be sure.

 

[wavyphotons]

Personally, I would plan on ~170-180 miles of real-world range on the highway (2 miles per kWh, and 80kWh out of the 88kWh useable), since you probably don't want to pull in on "fumes", will probably use some heat, and Texans seem to drive a little bit faster than ~70mph I, too, like to drive as far and fast as possible without breaks, but sadly I think 215 miles might be pushing it a bit far.

got it ... I guess even with RWD, the added 26 miles will conservatively add 13 miles, so it's not that much extra range. AWD seems like the right decision here. And who knows, it won't be long before texas gets a snow storm again

thanks for your advice !!

 

[SashaLondon]

I think someone with the OBD data showed that the front motor only switches on when you trying to accelerate hard. Other than that I guess it is heavy and has a small extra amount of friction compared to not having a front motor.

 

[mkhuffman]

I would compare the EPA highway ratings of the RWD vs the AWD to determine the approximate difference. One thing to keep in mind is the EPA test is not at 75 mph, and no adverse weather is taken into account either. The EPA highway range test is slow and in ideal conditions, so your range will be lower. But at least you can get a pretty good idea what the difference should be.

https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=43605&id=43603

https://insideevs.com/news/460270/ford-mustang-mache-official-epa-numbers/

 

[RickMachE]

thanks for the info and quick reply - I was about to send you a private message to bring attention to this thread

For now, I went ahead w/ AWD just as insurance and extra power - but definitely want to make sure I can still get ~225miles of actual range on highway in normal conditions.

Let's see if others have data on this!

Lots of threads that you probably want to read.

225 miles of highway range, in warm weather, with AWD and the extended battery, is fine - from a 100% charge at your house. 225 / 91kWh = 2.47 miles per kWh. Totally doable.

HOWEVER, if you then charge at a fast charger, you'll get to 90% (used to be 80%), and only have 91 x .9 = 81.9 kWh of available battery. 225 / 81.9 = 2.75 miles per kWh. Doable? Yes, if you don't drive 80 miles an hour. But you'll arrive home with very little margin for error. I wouldn't do such a trip without a fallback charger enroute home.

I've done close to 5,000 highway miles, and getting an efficiency of 2.75 is right on the edge. Up your speed to high 70s / low 80s and you won't make it.

 

[AZBill]

I have a CR1 with RWD and have been able to get 3.1 mile/kWh at 75mph going up an elevation change of 5000 ft. That was in the summer running AC in Arizona.

 

[mkhuffman]

I have a CR1 with RWD and have been able to get 3.1 mile/kWh at 75mph going up an elevation change of 5000 ft. That was in the summer running AC in Arizona.

My AWD GT got 3.2 mi/kWh on a drive from DC to Williamsburg, VA, with an average speed of 75 mph. For most of it I had the cruise set for 77 mph. For that drive I accelerated slowly, only used 1PD, and there was some stop and go/slow traffic that increased efficiency. I didn't use any climate control or heat, and the temp outside was in the 60s. I doubt I will be able to repeat that efficiency very often. In fact, none of my other trips have been nearly that good. Probably some of it has to do with the elevation change in that direction.

 

[RickMachE]

One of the things that people don't realize is that the country isn't flat. What a person can get in one state at 75 degrees isn't what a person can get in another state at 75 degrees.

We just drove our F-150 from Michigan to Florida and back. Yes, gas blends are slightly different, but it's illustrative. MPGs by fill.

18.79
19.43
18.5
19.98
18.83

From the low of 18.5 to the high of 19.98 is an increase of 8%. Put that in EV terms - if I got 2.75 instead of 18.5, 19.98 translates to 2.97.

We saw 21 mpg at one point, which quickly cut back to 20.

I plan my trips with 17.5mpg. Same as planning an EV trip at 2.6.

 

[mkhuffman]

One of the things that people don't realize is that the country isn't flat. What a person can get in one state at 75 degrees isn't what a person can get in another state at 75 degrees.

We just drove our F-150 from Michigan to Florida and back. Yes, gas blends are slightly different, but it's illustrative. MPGs by fill.

18.79
19.43
18.5
19.98
18.83

From the low of 18.5 to the high of 19.98 is an increase of 8%. Put that in EV terms - if I got 2.75 instead of 18.5, 19.98 translates to 2.97.

We saw 21 mpg at one point, which quickly cut back to 20.

I plan my trips with 17.5mpg. Same as planning an EV trip at 2.6.

Good points. My E320 diesel can reach 44 MPG in the summer, but in the winter it rarely gets above 35 MPG. The average winter hit is 5-8 MPG.

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