I have had my FEH for over a month now. I am at 832 miles, most of this is shorter trip around town. On Dec. 16 I am going from VA to Atlantic City NJ. I will be on interstates most of the time. Is there a perfect speed to keep at on the highway to maximize MPGs? The speed limit is 65 most of the way.

 

I've heard that ideal is 48 but I would not recommend that on the highway. I just got back from my first long trip and I'd think sticking it on 65 would do fairly well, better at 60. With a good tail wind the thing will get 40mpg even at 70 and it loves going down hills too, you'll hear a slight whine (jet engine noise) when you are getting the best mpg... anytime you can keep the RPMs under 2300 seems best.

 

I will try to stick with 60 to 65, but on I95 it feels like your are going to get run over sometimes.

 

I look for a semi truck that is going about 65mph. Then I draft off of him. We got 32.5 mpg and it has less than 2K miles and is an AWD 08. I think once broke in it will get about 35mpg.

 

I too draft a truck. Sometimes it is hard to find one that will stay pretty much in the 65-70 range, but when I do 38-40 mpg is my average just on the highway.

 

My experience is to use drafting when safe and feasible and to control ICE rpm between 1800 and 2200 (preferrably 2000 or less). Therefore, your speed will vary with up hills and down hills and turns and traffic....but this may be a better way to optimize FE.

 

I'm not sure what the weather is like in Virginia, but I recently got done taking my AWD FEH on its first long distance trip (from Chicago to Columbus, OH and back). Cold, wind, and some snow - always a pleasant mix for driving.

The thing that surprised me the most was the huge difference a little speed made. 65 is significantly more fuel efficient than 70, and 60 even more so than 65. That was tough for me, since most of Indiana is speed limit 70 miles per hour (meaning traffic is usually a few shy of 80).

The other surprise was the feeling that the car was "fighting me" when I tried to push it past 60/65. In my old V6 Explorer, even on the highways, when I was at 65 a minimum amount of gas pedal pressure was needed to stay there. In the FEH, it felt at times like I needed to put my foot down more and more just to stay at speed. Could be adjusting from being such a lightfoot around town, but regardless it was noticable.

On the highway you'll definetly want to take as much advantage of hills and gravity whenever possible. It didn't do a huge improvement for me, but every little bit helps. Out East there might be more to gain with bigger hills, I don't know. I found cruise control wasn't too bad about backing off the RPMs when we were on a flat surface, but the moment the road angled even a little bit uphill, the RPMs jumped over 3000.

Lastly, consider what kind of mileage you hope to get. I can do really well on the highways around Chicago, and can regularly increase (or regain) MPG on my way home from work every day. I have yet to have a good highway fuel economy experience. In 20 degree cold, going about 400 miles each way, my FE was around/about 24-25 MPG averaging 65-70 miles per hour. Drop that to 60-65 miles per hour if you can, and 27 MPG shouldn't be unreasonable ... and thats the vehicle's 2008 EPA estimate for HWY driving

Sorry to rant; hope this helps! Best,
-Andrew

 

This is true. There's often a "happy" speed where a vehicle feels it was made to to travel. Go faster and you can feel the reluctance. My 4WD FEH seems happiest at 50. The ICE coasts at low RPMs but not low enough to bog if it's needed. Electric assist is strong there, too. 60 MPH is still relatively effortless, but beyond that it changes and mileage drops.

I avoid interstates unless it's snowing and I'm going to the mountains. Changing that behavior was key for me in surpassing 30 MPG. It's a choice between impeding traffic, or going with traffic but getting 25 MPG. If a truck must slow because of me then burn diesel to get back up to interstate speed, how am I helping by going 60 in a 75? Not to mention safety.

Besides, slow + smug in a hybrid is a growing stereotype and I'd rather not perpetuate that. Slow helps, definitely, but only when everyone is doing it. I'm not a speed nanny or the Mileage Police.

Our 2005 Buick gets 30 MPG at 75 MPH, so we take that on trips.

 

I concur with AMB4. I have found that I can still get slightly over 30 MPG at about 67 MPH (if I'm not fighting a headwind!). But after that - even another 3 MPH up to 70 MPH will cause a drop of 2 to 3 MPG - and that's when the weather is moderate - temps in the 50s and 60s. Lower temps will cause lower fuel economy.

As others have stated - watch the tachometer and try to stay under 2,500 RPM. That seems to be the magic number for best fuel economy. Of course 2,000 RPM or lower is even better to really maximize fuel economy - but that means you have to be content to drive at lower speeds - 55 MPH and slower.

 

Most vehicles get better MPG when driving slower.

Actually, if we dropped the national speed limit to 60 interstates and 50 highway, think of our reduction in foreign oil.

Insurance companies would probably be happy with the results also.

Sounds like a good law for once?