Modern cars...

[dd74]

Why aren't we getting 100 mpg? And at least 200 hp for that 100 mpg?

[Tidybuoy]

300+ hp
power windows/locks
traction control
anti-lock breaks
leather interiors
front & rear headrests
dvd players
12 speaker systems w/amp
20" wheels
seatbelts
center console
cruise control
rear wipers
air bags - front, side & center
etc..

All of these "necessities" add to the weight of the car. A 1970 Toyota Corolla probably had 80 horsepower and probably weighed about 2500 lbs. A Toyota Corolla today probably weighs 4000 lbs and has at least 180 hp. Effeciency has enabled us to have way more power and conveniences but has barely been used for economy.

Hard to believe that an early 60's VW bus got by on about 60 hp.

[porsche4life]

I'd have to go check on the sticker in the door but I would guess the Latest Corollas to be in the 3-3500 range. They aren't that big.

[KaptKaos]

And early 70s Corollas were ~2k lbs.

[pwd72s]

Originally Posted by Tidybuoy

300+ hp
power windows/locks
traction control
anti-lock breaks
leather interiors
front & rear headrests
dvd players
12 speaker systems w/amp
20" wheels
seatbelts
center console
cruise control
rear wipers
etc..

All of these "necessities" add to the weight of the car. A 1970 Toyota Corolla probably had 80 horsepower and probably weighed about 2500 lbs. A Toyota Corolla today probably weighs 4000 lbs and has at least 180 hp. Effeciency has enabled us to have way more power and conveniences but has barely been used for economy.

Hard to believe that an early 60's VW bus got by on about 60 hp.

I'd say that about covers it. When much younger, I went on a long road trip with a buddy in his 1960 Bugeye Sprite. Sacramento, California to Alturas, California on a single tank (7gallon capacity) of gas...I calculated 48 mpg!
Now, imagine what a 1400 pound car running a 948cc engine could do using todays injected and computer controlled methods...

Ahhh, but other than a limited number of odd folks, nobody would want such a car these days. No air...a one speaker transistor radio shoved in the dash for tunes. That car had none of the weight adding features taken for granted today.

[GH85Carrera]

There are limits of physics. We all heard of the magic carburetor that would get 50 MPG on a 1970 Cadillac. It was as real as flying dragons that breath fire.

To get 100 MPG in a car of any real mass in a real world environment just ain't gonna happen above 5 MPH on level ground. Hold your hand out the window at 60 MPH. That is aerodynamic drag. I don't have the equations but to get something moving and keep it moving at highway speeds takes a lot of energy.

[pwd72s]

Originally Posted by GH85Carrera

There are limits of physics. We all heard of the magic carburetor that would get 50 MPG on a 1970 Cadillac. It was as real as flying dragons that breath fire.

To get 100 MPG in a car of any real mass in a real world environment just ain't gonna happen above 5 MPH on level ground. Hold your hand out the window at 60 MPH. That is aerodynamic drag. I don't have the equations but to get something moving and keep it moving at highway speeds takes a lot of energy.

A point made there...once we figured out that a gas station was far from us on that run, we backed wayyy down on engine speed in that Sprite...the final 100miles or so were done at 45 miles per hour. Keeping revs low was our main concern, but I'm sure thedrag was less as well. Seeing the open Shell station in Alturas was like finding an oasis in a desert...

[KaptKaos]

What's better for society? A car that can get 70-80 MPG or a car with 8 airbags? I think I feel a poll coming on =D

[Heel n Toe]

200 MPG ----> http://www.hotguygadgets.com/blog_9.shtml

70 MPG ---> http://portland.craigslist.org/clc/mcy/1305541082.html

[RWebb]

Originally Posted by GH85Carrera

There are limits of physics. We all heard of the magic carburetor that would get 50 MPG on a 1970 Cadillac. It was as real as flying dragons that breath fire.

To get 100 MPG in a car of any real mass in a real world environment just ain't gonna happen above 5 MPH on level ground. Hold your hand out the window at 60 MPH. That is aerodynamic drag. I don't have the equations but to get something moving and keep it moving at highway speeds takes a lot of energy.

I agree with the general notion expressed here, but not the specifics.

You could get 100 mpg if your drivetrain was 2x as efficient as it is currently. The IC motor is very inefficient (note: I did not say it wasn't fun)...

Think about how much heat is generated... that is all wasted energy.

And think about this too:
The idea is to rotate the wheels, right? To do that, you would ideally want a circular force field right at the wheels (a la Lohner). But no. We take a rotating shaft and connect that to the wheels at right angles. Most cars make the shaft really long (= heavy).

It's worse - we don't create a rotational force to run that shaft. Except in the Wankel, we take a linear force and "force" it to make curves, then transmit that.

And to make the linear force? We set off a fire - almost an explosion.

Now, we have gotten real good at setting off these slow explosions in the last 100+ years. But the original concept is kinda Rube Goldberg.

[dd74]

Originally Posted by RWebb

But the original concept is kinda Rube Goldberg.

I've always thought that too. Or is it over-engineering? Who knows?

But in the vein of lost energy, would FWD cars, or mid-engined cars be regarded as more efficient than front engine-RWD drive cars?

And how about gearing. The new very high-performance Lexus IS model has an 8-speed transmission. Not that it's the case with the Lexus, but couldn't more gears make a car more efficient as well as faster?

[RWebb]

yes

in fact, P KG used to state that in their ads

more gears has to help, sure

[jyl]

The best hypermilers are getting 120-150 mpg from stock Honda Insights. And 100 mpg from stock Toyota Priuses. And nearly 70 mpg from VW Jetta TDi's.

These are real world circuits of anywhere from 60 to 2000 miles. Admittedly they aren't climbing any mountains or keeping up with the SUVs that blow by at 80 mph or stop-go-stopping in traffic for hours. Think flat or rolling hills, country roads, small rural towns, etc.

The Prius is a 3,000 lb gas-electric hybrid that seats four to five with airbags, A/C, sat nav, all mod cons as they say. The Insight is a 1,900 lb two-seater gas-electric hybrid with fewer conveniences. The Jetta is a 3,300 lb four to five seat turbodiesel with all the conveniences.

So, kind of guess-triangulate what a 1,900 lb two-seater turbodiesel-electric hybrid might be capable for a hypermiling type of driver - maybe 170 mpg?

Now, the average driver in a Toyota Prius - not a leadfoot like my wife, nor an obsessed hypermiler, but someone like, well, me - can easily get 50 mpg driving a rolling hills country road sort of route. 50/100 = 50%. 50% of 170 mpg = 85 mpg.

That's my guess of the top fuel economy attainable by normal drivers using the best technology in production road-legal cars "today".

Not terribly far from 100 mpg, but unfortunately not with 200 hp. Need some new technology.

[dd74]

Maybe that might be the next wave: more closer ratio gears. Particularly those that can exploit a smaller turbo or turbo diesel engine's power.

The new Taurus's Ecoboost engine is quite interesting - twin turbo V6 that puts out more hp than a Mustang GT.

[DARISC]

Originally Posted by dd74

Maybe that might be the next wave: more closer ratio gears.

Doesn't the CVT adress that?

[RWebb]

yes, but they have not been implemented for higher hp cars

[slodave]

A Toyota Corolla weighs 2822 (curb weight).

[pwd72s]

Enjoy your golf carts....I'd rather have a V-8! BTW, it gets better mileage than my old 911S did...

[HardDrive]

Geez...I was going to make a joke about the turbo 911's gas consumption, but it actually isn't THAT bad considering it has 480hp, and will dash to 60 in 3.4 seconds.

16 city/23 hwy.

I'm guessing those numbers might go down a bit if your doing 3.4 second runs to 60......

[chapo]

Awesome, the 911 mileage isnt far off of my 4x4 diesel crewcab that can carry more than two people and a suitcase, lol.