Vehicles that get great gas mileage at 75-80 mph?
 

Just for talking sake. I know that higher speeds reduce gas mileage, but was wondering what vehicles get better gas mileage at higher speeds in general. I guess gearing is important at those speeds for starters and so is aerodynamics I'd assume.

Are there any vehicles that are champions at those speeds?

Thanks

90's model GM cars with the 3.8 V6 do well on the highway, as well as Camaros, Firebirds, and Corvettes.

I get about 35 mpg at 75 mph in my Chevrolet Malibu Eco.

Doesn't a Malibu Eco count as a mild hybrid? (I thought it came with auto stop)

The eAssist models are classified as hybrids.

Any thing with decent aerodynamics should do better than what the EPA implies. That said, 60 to 65 mph seems to be the tipping point with most models when it comes to declining fuel economy.

Thanks all...I was thinking about older cars. I know that the 3.8 gets great gas mileage on the highway. That is actually not a bad idea. I'd like to stay away from RWD when possible though and I know that at least some of the 3.8 vehicles are RWD like the Camaro for example.

You'll find a lot of 3.8L Buicks (LeSabre, Park Avenue, Regal) and Oldsmobiles (88, 98, some Intrigues), and Pontiacs (97+ Grand Prix, Bonneville) that are front wheel drive. They are cheap and plentiful. A good 2000-ish Grand Prix, for example, can be had for about $2,000 where I live.

This car does.

https://www.aerocivic.com/imgs/aerocivic-top-2.jpg

Ooooh, how could we have forgotten about the AeroCivic? That's not exactly stock though.

If by great gas mileage at high speeds, over 40 mpg at 75 mph is meant, there really aren't any cars that can do that. At high speeds, aerodynamics is the biggest factor in fuel economy, and no manufacturer has had the guts to get serious about aero. They are too afraid the public will reject such a car for being "ugly". It most certainly can be done, but no major car manufacturer has really tried. There aren't any stock gas or diesel vehicles that can do 40 mpg at 75 mph. Hybrids can't do that either. Compared to gas, hybrids are really good for city driving. Long distance high speed driving is exactly the kind of driving hybrids are worst at, as in that use case, the hybrid power train is nothing more than extra weight.

The only cars that can do 40 MPGe or better at high speeds are the pure electrics. So long as it takes hours to recharge batteries, and there aren't stations where one can do a quick battery swap, electrics will not be suitable for long distance drives.

Currently, the only way to get a gas powered car above 40 mpg at 75 to 80 mph is to modify a suitable car yourself, like was done with the Aerocivic. Otherwise, will have to settle for about 35 mpg at best, and maybe more like 30 mpg. And I'd guess a sports car with tall gearing would be best at that, rather than an econobox.

My BMW does 40mpg @ 90mph and about 50mpg @ 65mph. I believe it's because of the efficient diesel engine and the low aerodynamic drag coefficient. The undercarriage of the car is almost completely flat, except for the wheel arches and the rear end where the rear muffler comes out. The grille is blocked by something similar to window blinds that automatically opens if the engine needs to be cooled. I think the Cv overall is very low for the body for a normal looking car.

This is with an automatic transmission. There is an EDE (Efficient Dynamics Edition) with only a manual high geared transmission that does even better.

They're not sold in the US though.

We are getting the 328d, which I think is the 320d overseas. It gets 45+mpg highway on the EPA.

The new 2014 Audi TDI's are comfortable, and will crush the EPA ratings on the highway. I just spent the weekend driving one on a cross country road trip.

A 2014 Audi A6 TDI starts at $58,395 so if you got an older model Honda or even a new fuel efficient car priced in the $20K the other $40K you saved would buy a lot of gas. :lol:

Yes, that is true, but it is a vehicle that can easily do incredible numbers on the highway with the a/c on. I know that for a fact.

Naturally one would conlcude the Passat isn't bad either: Couple gets 84 mpg in Passat diesel on real roads

I had a 1991 Chevy Cavalier 2.2L 4 cylinder and 5 speed manual that would get 35 mpg at 60-65 mph, but would get 42 mpg at 80 mph. I used to know several others that got similar results as I had at similar speeds.

Come to find out, the 2.2L motor and 5 speed combo sits right at peak torque when cruising at 80 mph (2700 rpm or so).

The 3.1L V6 doesn't get as good of fuel economy at those speeds, but is still in the mid 30s which is still pretty good.

Its interesting to have that much of a difference. Even though the engine is operating at peak torque, I would have guessed that you were just giving all the extra efficiency to the wind in drag.

I just added this to my site as one of the "Testimonies" to keep in mind. I am new to this but am looking for proof that our cars are woefully inefficient and that inefficiency has been shelved by car producers and oil companies...Once I know this for a fact...maybe I can inspire others to act with the knowledge. I will be trying things on my personal vehicle but what we really need is a national uprising :mad:

Car manufacturers only make cars people are willing to buy. As long as the cost of petrol is a fraction of the total running costs of a new car nobody is going to care unless money is not an issue or the environment (ecology=long term economy) is more important on a personal level.

More like they only make cars the bean counters think people are willing to buy.


Just look at the Pontiac Aztek!! :facepalm:



It has been a slow progression, but look at a lot of high mpg cars today. Now look at the home made boat tails that some of us have done in years past. Grill blocks, lowering suspension to improve aero, ect. The auto manufactures are coming around.

This thread really turned out well. Thanks for all of the help!