GM Volt Forum banner

1 - 20 of 82 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter #1
I picked a 2017 Volt because my 2015 Leaf was unable to meet travel requirements for my job. Having driven a Leaf for 2 and half years, I was very familiar with the whole EV experience. What I wasn't prepared for was the high speed fuel efficiency. I assumed the Volts 42 mpg EPA rating was determined by putting the car on cruise control at 65 mph over a long distance. Experience has taught me fuel efficiency drops off a cliff after 65 mph in most cars. In the first month I had the Volt, I put 3,058 miles on it, mostly 140+ mile highway trips driving at sustained speeds between 75 -78 mph. I used the cruise heavily and got 39 mpg on the hilly trips and 41 mpg on the flat ones. These numbers are after factoring out any electric miles. On top of that, if I had to pass a truck while doing 75 I would punch it at the car would accelerate quite impressively. I am sure a Prius would get better MPG at that speed, but it definitely lose more than 1-3 mpg over its EPA rate mpg, and it sure as heck wouldn't have the passing power. This got me wondering, does anybody have data on steady speed mpg for the second gen Volts in gas-hybrid mode?
 

·
Registered
Joined
·
1,013 Posts
In my opinion since no one actually travels at a steady speed for very long the numbers would be meaningless. You have seen the low end and the high in mixed driving on gas would be "up to 50 mpg. So, it all depends....
 

·
Registered
Joined
·
532 Posts
In my opinion since no one actually travels at a steady speed for very long the numbers would be meaningless. You have seen the low end and the high in mixed driving on gas would be "up to 50 mpg. So, it all depends....
My wife's CLA 250 gets around 50 MPG on a steady flat road at 65 MPH. That's really impressive considering the fat wheels, pretty strong engine, and not exactly a very lightweight car.

I don't understand how the Volt can't get well over 50 MPG in HOLD mode traveling the same speed in a steady click on a flat road.
 

·
Registered
Joined
·
902 Posts
By traveling at 75 to 78 MPH, you are increasing your likelihood of killing yourself or others by about 50%:

The NCHRP study found that higher speed limits were associated with an increased likelihood of deaths and incapacitating injuries. It found that increasing a speed limit from 55 to 65 mph on an "average" section of high speed road resulted in about a 3% increase in the total number of crashes and a 24% increase in the likelihood that a vehicle occupant would be fatally injured. This increased crash rate would yield a 28% increase in the number of fatalities following the speed limit increase.

The study also found a similar, but lesser, impact when speed limits were raised from 65 to 75 mph. In those cases, the total number of crashes increased by 0.64%, increasing the probability of a fatality by 12%, with an overall increase of 13% in total fatalities. Although the analysis did not explain why a smaller increase occurred at the higher speeds, the study suggested that people may drive more cautiously when driving faster, or that roads deemed appropriate for a 75 mph limit are safer.
https://www.cga.ct.gov/2013/rpt/2013-R-0074.htm
 

·
Registered
Joined
·
1,366 Posts
By traveling at 75 to 78 MPH, you are increasing your likelihood of killing yourself or others by about 50%:

The NCHRP study found that higher speed limits were associated with an increased likelihood of deaths and incapacitating injuries. It found that increasing a speed limit from 55 to 65 mph on an "average" section of high speed road resulted in about a 3% increase in the total number of crashes and a 24% increase in the likelihood that a vehicle occupant would be fatally injured. This increased crash rate would yield a 28% increase in the number of fatalities following the speed limit increase.

The study also found a similar, but lesser, impact when speed limits were raised from 65 to 75 mph. In those cases, the total number of crashes increased by 0.64%, increasing the probability of a fatality by 12%, with an overall increase of 13% in total fatalities. Although the analysis did not explain why a smaller increase occurred at the higher speeds, the study suggested that people may drive more cautiously when driving faster, or that roads deemed appropriate for a 75 mph limit are safer.
https://www.cga.ct.gov/2013/rpt/2013-R-0074.htm
If people that didn't belong on the higher speed roads stayed off them, higher speeds are safer. It's the clueless idiots that go 50 in a 65 that make the road unsafe and therefore don't belong. Even more so when they don't understand why blocking the left lane deserves a slap to the face, with a brick.
 

·
Registered
Joined
·
488 Posts
Travel from Michigan down to Florida, the average speeds are 76-78 on interstate. Traffic on I75 southbound past Lake City FL. Is insane. I am parked in the left lane cruise control set on 79. Traffic flying by regularly on the right weaving in and out those idiots running 80-95 mph. Eventually all lanes come to a screeching halt, appropriately right at my exit. By the way my 2011 with 91,000 on the odometer gets about 33 into the wind, 36 with a tailwind at interstate speeds.
 

·
Registered
Joined
·
488 Posts
If people that didn't belong on the higher speed roads stayed off them, higher speeds are safer. It's the clueless idiots that go 50 in a 65 that make the road unsafe and therefore don't belong. Even more so when they don't understand why blocking the left lane deserves a slap to the face, with a brick.
When I am maintaining my 9 over the limit, 79 in a 70 in the left lane I don't consider that blocking the lane. Am I wrong?
 

·
Registered
Joined
·
2,486 Posts
We have had a few trips of over 50 mpg on our 2016 Volt on just the gas engine. Our current mpg from voltstats.net is 44.08 mpg just on gas, and that is for well over 3,000 gas driven miles.

Seems like speeds on Highway 101 along the coast of Oregon with a max speed of 55 mph and many areas of 25-45 mph, driving in town and approaching towns, high 40's to low 50's mpg just on gas is easily obtainable especially in summer with temps in the 70's and dry roads.
 

·
Registered
Joined
·
9 Posts
In my opinion since no one actually travels at a steady speed for very long the numbers would be meaningless. You have seen the low end and the high in mixed driving on gas would be "up to 50 mpg. So, it all depends....
FL to NC--400 miles steady speed up I-95, then 200mi steady up I-26. I haven't had my Gen2 long enough to have made the trip yet, but I'm very curious what the gas mpg will be, so "no-one" does exist in the real world. I will be making this trip several times in the summer.
 

·
Registered
Joined
·
4,405 Posts
My wife's CLA 250 gets around 50 MPG on a steady flat road at 65 MPH. That's really impressive considering the fat wheels, pretty strong engine, and not exactly a very lightweight car.

I don't understand how the Volt can't get well over 50 MPG in HOLD mode traveling the same speed in a steady click on a flat road.
Don't ever sell that Benz. You got a very special model that must have been hand built. Just sayin'.
 

·
Registered
Joined
·
4,405 Posts
Yes. You are driving in the passing lane. Move to the right when you done passing.
Absolutely. It was taught in driver's ed, is mentioned in the Driver's Handbook, and there are tens of thousands of road signs. But people still do not understand the concept.
 

·
Registered
Joined
·
1,312 Posts
Yes. You are driving in the passing lane. Move to the right when you done passing.
That sounds nice in theory, but if there is any decent amount of traffic around you, both lanes are needed for travel... you can't fit everyone in the right lane. Of course the left lane should be for people going faster... but if you are continually passing cars in the right lane, you can continually stay in the left lane (thus "driving in the left lane" is fine). I agree that if traffic is light, you should move to the right once done passing, of course.
 

·
Registered
Joined
·
2,634 Posts
In my opinion since no one actually travels at a steady speed for very long the numbers would be meaningless. You have seen the low end and the high in mixed driving on gas would be "up to 50 mpg. So, it all depends....
Driving in a lot of west to midwest states I would disagree. It is easy to drive 75 to 80 mph with cruise for multiple hours at a time.

However, to move a car at a certain speed takes a certain amount of energy, there is no getting away from that. Generally, highway speeds are mostly dictated by car aerodynamics and maybe engine thermal efficiency. I have seen Corvettes do as well at 80 mph as efficiency cars at the same speed. It takes X HP to drive 80 mph in any car with the same aerodynamics.

With my 2012 Volt, my experience is it behaves like any other aerodynamic car. It drops off steadily at higher speeds, fairly quickly after 65 to 70 mph. I might get over 40 mpg at lower speeds and 30-35 mpg at 75 mph. Depends dramatically on wind speed and direction of course, it isn't unusual for me to drive into a headwind or tailwind most of the day. Driving into a 20 mph headwind sustained for many hours at 75 mph ground speed is brutal on fuel economy.
 

·
Registered
Joined
·
292 Posts
As the speed limits are 75, I have averaged 50 on a tank from Denver to Des Moines with my tdi. Granted it is down hill and I could not get the same going the other way, low 40's on the return trip. I am curious to see how the Volt does on the same trip. I don't like to hear that they get less than 40 at 75. That means a lot of gas stops due to the small tank.
 

·
Registered
Joined
·
105 Posts
Ummm... Kinetic energy increases with speed. If you hit something at that speed the forces your body will be subject to will be much worse than if you were traveling at lower speeds. I don't know what the speed limit is on these roads but I am guessing 79 is not on the list, unless you live out in Montana.

Not to lecture, but the difference between an impact at 65mph and one at 80mph is the difference between serious injury and fatality.

Prying the remains of people out of those types of crashes is not a fun job.
 

·
Registered
2017 Volt Premiere
Joined
·
382 Posts
A couple of comments from caronjeff's post ...

Driving in Florida is a nightmare ... congested roads, highish speeds, older drivers, and tourists ... really bad combo ... I give minivans from Iowa the same amount of buffer that I would a crazed person in a bomb vest; likewise for large Caddies and Lincolns during the early bird special hours.

I was well-trained to avoid the left lane except when passing, but there are times when congestion essentially forces you to hang out there. My rule of thumb is that is if I am driving less than my intended speed and traffic is heavy, I will hang out in the left lane. If traffic is moderate or light and even if I'm passing cars regularly, I will always get over to the right lane when safe even if I need to slow down occasionally.

In heavy traffic, I might be passed on the right due to the vagaries of traffic or someone being an overly aggressive douche.

If you are passed on the right in light to moderate traffic, God kills a kitten. I'm not really a cat person, but I don't want that on my conscious.
 
1 - 20 of 82 Posts
Top