Real World Highway MPG @ 75-85 MPH speeds?

That's true, but if cost is the main factor, you're not going to recoup the hybrid premium (compared to a cheap compact car) over the car's lifetime if you mainly drive on the highway at 70+ mph.

 

I went 60 mph on an 80 mile trip from Morganton NC to Charlotte NC and the car got 60 mpg according to the computer, so probably 58 mpg in reality. On the way there I did 70 mph and computer said only 47 mpg so probably 45 mpg. It is hilly all the way to and from but no real climb, just rolling hills

 

seems like the Prius C looses about 1 mpg for every mph over 60 mpg to 70 mpg, is that about right? And then another maybe 0.5 mpg between 70 and 80 mph. So it gets 58 mpg at 60 mph, 46 mpg at 70 mph and 42 mpg at 80 mph?

 

MPG is affected by roads as much as speed. Flat roads and down hill roads can increase the MPG up to 77 MPG at 55 to 66 MPH.

 

I rarely go over the speed limit. That's just my nature. But here are my results from a recent long trip.

The first photo is the trip to my destination, the second is my overall once I got home. I did some driving around town during the week I was there.

 

pretty impressive

 

on a 470 mile trip to Florida on the interstate going between 70 and 80 mph depending on what the traffic flow would allow, I got about 45.5-46 mpg. On the way back I took the state highways in the country for 2/3 until I hoped on the interstate for the last 2 hours. This cut off about 70 miles but the State roads are only 55 mph. There was zero traffic so it was great. I got 58 mpg according to the computer (so probably 56) until the interstate. I started doing about 80 until my average dropped below 55 so I slowed to 68 mph for the remainder of the trip, costing only a little time but it never dropped below 54.5 mpg trip computer all the way home. Travel time was about the same as the interstate but mpgs were much better. I think the key to this car is going 68 mph or less.

 

Why is this such a popular opinion? I hear stuff like this all the time, and it's so weird.

Just because someone drives 70-80 MPH, doesn't mean they think they're Tom Cruise in Days of Thunder. The highways I drive on have a speed limit of 70 MPH. You have to drive 75 MPH just to keep with the flow of traffic.

Some people just need to drive that fast in their daily commute.

 

States will need to lower the speed limits in the future to help increase MPG for us and others driving small high MPG cars, don't you agree?

 

It's now weird at all. You went on to change the discussion around.
Whether or not you NEED to go 80 MPH is NOT what is being discussed.

The simple fact IS that the smaller the engine, the more it's efficiency will suffer when you start going really fast. The C has a small engine; it was designed to be most efficient at slow and medium speeds.
You may not like that but you can't change it.

If you "think" you "need" to drive 80-85 MPH a lot (nobody really NEEDS to do that) then the Prius C probably was a bad choice for you. It's a pretty simple concept. Trying to argue about it won't change the facts.

 

Maybe but not any time soon.
Most of Europe has lower speed limits.
Most of Europe taxes the CRAP out of petrol.
Both of those things tend to reduce consumption.

On the OTHER hand, the State of Florida is wanting to INCREASE their interstate speed limit to 75.
I have yet to figure out who this will really benefit........except those who think they are in a hurry.
Fuel usage will go up.
Highway deaths and injuries will go up (speed really does KILL).
Politicians are a weird group.
Sometimes it is not all that obvious as to whose rear end they are kissing today.

 

I wasn't talking about anything other than the opinion that those who drive 70-80 on a highway should buy a high performance sports car. It's ridiculous. And I'm not sure where you came up with 80-85, since I was talking about driving 75 in a 70. I definitely do not need to drive 80-85...which is why I don't.

 

85 was in the title of the original thread.

And **I** never said anything about a "sports car".

There IS some speed where the efficiency of a tiny engine suffers so much that a more powerful engine will actually get better gas mileage. I don't know for sure exactly what that speed for the C is, because it would depend on what you are comparing it to, but at 80 you HAVE to be getting close. And at that speed, it buzzes and the road and wind noise is bad and it feels a tad unstable. You can NOT argue that it was built to do that a lot.

 

He didn't say you said anything about a "sports car." That's why he specifically "quoted" the post about the person who mentioned the "sports car."

 

I average 50 mpg @ 68-69mph and 43 mpg @ 80-85mph which is still better than the 33 mpg I was getting in a 2003 civic or 16 mpg in a tahoe

 

I got 52 mpg on a 7 hour drive from CLT to MD Thursday and about 51 mpg on the way back as well. Sunny and warm, used AC, no rain. NO CC used. Very hilly through VA, WV and MD. I let speed vary but tried to average 70 mpg. I would go as fast as 85 mph downhill and as slow as 60 mph uphill, generally tried to keep the PWR bar out of the red.

 

I have driven my Prius C around a race track averaging 75 mph and during that 12 miles I got only 28 mpg. Mind you that the best mpg by a factor of 3 over my more potent cars averaging 83 mph.
I believe your mpg at 33 mpg is probably correct and still far better that other vehicles.
If you communted the same with other vehicles what mpg did you get with them. There are smasll cars with very high gear ratios that can get better mpg.
If you have to cruise at 80 mph may I suggest a Mazda 3or Honda Civic hybrid, coupe. Perhaps even a regular Prius that isn't so close to hp needed at rpm required. It takes about 10 hp for a Geo Metro xFi at 60 mph and 33 hp at 80 mph. The more hp required and the closer it is to the power the engine can generate the less efficient and the more mpg consumed.
At 60 mph the XFigot 60 mpg and at 80 only 40 mpg. Its much lighter than a Prius C and I believe a slihghtly smally Cd so your mpg appears good to me.

 

why? my Prissy does just fine cruising at 70-75 mph getting 48 mpg.
I have a high performance sports car but almost all my trips are in the Prissy.

 

Not necessarily. The purpose of a vehicle is set by the owner. It has a particular set of strengths and weaknesses that the owner must figure in to their usage profile, but the C overall is an MPG car. There may be a better Prius product for his commute speeds, but it's getting a lot better MPGs at speed than many get going 55.